Edition - May 2024

TOPICAL NEWS

EDITORIAL

Service crops: the means... on trending?

HIGHLIGHTED ARTICLES

CROP MANAGEMENT

Everything you wanted to know about service crops but never dare to ask

CROP MANAGEMENT

Let us discuss Camelina, the crop that intensifies rotations and takes care of the soil

LIVESTOCK FARMING

Cover crops grazing: the best of both worlds?

Reduction of carbon footprint in agriculture: a challenge with scientific-based solutions

INSTITUTIONAL

Transformative encounters: Chronicles of EAR 2024

CROP MANAGEMENT

Malting barley in Argentina: 40 years of genetic progress promote yield and quality

Aapresid's Red de Cultivos de Servicios: synergies for sustainable agriculture

When to introduce service crops in a sequence with late corn?

ALTERNATIVE PRODUCTION

Carinata on the runway: sustainable aviation with 2G biofuels

TRENDS AND GLOBAL CHALLENGES

Argentine agricultural trade: strategic responses before new geopolitical risks

BIOTECHNOLOGY

A unique biotechnological laboratory in Argentina to improve competitiveness within the seed industry

Everything you wanted to know about service crops but never dare to ask

Let us discuss Camelina, the crop that intensifies rotations and takes care of the soil

NOTEWORTHY ASSOCIATE

An Argentinian in Africa: the story of the farmer that took no-till farming directly into the African continent

Cover crops grazing: the best of both worlds?

Service crops for more meat and less methane

EDITORIAL Service crops: the means... on trending?

In a world where environmental concerns have become an undeniable priority, the search for sustainable agricultural practices that not only feed the global population, but also protect and regenerate natural resources are a pressing matter more than ever. From their beginnings, the Argentine No-Till Farmers Association (Aapresid) has been at the forefront, seeking alternatives to improve the agricultural production system, always by the prime approach of soil and environmental caring.

Producing food, fibers and biofuels by maintaining a balance between economic, ethic, environmental and energetic variables in our society is a massive challenge. Aapresid has built its agriculture on four essential pillars: no tillage, always green agriculture, diversity and balanced nutrition. These pillars represent a philosophy that seeks to integrate agricultural production and environmental conservation.

A paramount means to strengthen these pillars is service crops, which provides a wide range of ecosystemic services. One of the most distinguished services is the increase of carbon and nitrogen in the soil, essential for its long-term fertility and health. It is worth noting that the idea of service crops is not new. For more than a century, visionaries like George Washington Carver in 1920, addressed the importance of service crops to protect the soil against erosion, to improve their structure and fertility, and to reduce chemical fertilizers dependency. "A farmer's best friend is a vegetation cover on the soil." In some scientific works, McCully Russell, Oregon 1909, and Pieters, Australia 1938, have explored and proved the benefits of these crops to modify and enhance the physical and chemical conditions of the soil.

However, despite its proven efficiency and the scientific advances supporting its usage, service crops are not yet adopted at a large scale. Nevertheless, fallow lands are still a regulation, often misunderstood as a means that consumes water instead of acknowledging their potential to increase water usage efficiency. Moreover, service crops are criticized for immobilizing nitrogen, without considering their capability for fixing and recycling nitrogen more effectively than conventional fallows, avoiding losses within the system.

There is talk about the cost of production of these elements, not taking into account their value as an investment. On many occasions, we destined 100% of their cost to the previous crop instead of distributing it proportionally in the rotation cycle. We fear they turn into weeds, but we overlook their potential as a valuable means to reduce the pressure when selecting resistant weeds. We are also concerned about the possible presence of pests, such as grasshoppers, ignoring that these elements provide refuge and food for beneficial insects.

It is crucial to overcome those fears and prejudices surrounding service crops. Instead of seeing them as a threat, we should acknowledge them as a long-term investment regarding the health of our soils and agricultural ecosystems. It is time to leave aside the ever-changing labels and names, and to embrace service crop practices in modern agriculture in an integral manner.

As a conclusion, service crops represent an unmatched opportunity to enhance agriculture's sustainability and resilience. The responsibility lies in the conjoint work of farmers, researchers, governmental institutions and society as a whole, so as to promote and assimilate the use of these crops as an integral part of a holistic approach toward a sustainable agriculture. It is time to look forward to the future and to make the most of the available means and tools, in order to protect and regenerate our natural resources for next generations.

Marcelo Arriola Executive Committee of Aapresid

Partner Companies

STAFF

RESPONSIBLE EDITOR

President of Aapresid

Marcelo Torres

DEPUTY DIRECTOR OF PROSPECTIVA

Paola Díaz

EXECUTIVE EDITOR

Rodrigo Rosso

WRITING AND EDITING

Antonella Fiore

CONTENT MANAGEMENT

María Eugenia Magnelli

PROOFREADING AND EDITING

Lucía Cuffia

TRANSLATION

Laura Cudugnello

LAYOUT AND DESIGN

Daiana Fiorenza

Chiara Scola

COORDINATING MANAGER

Tomás Coyos

PROSPECTIVE PROGRAM

Rodrigo Rosso

Antonella Fiore

Lucía Morasso

Delfina Petrocelli

RESOURCES GENERATION

Matías Troiano

Alejandro Fresneda

ASSISTANT DEPUTY DIRECTOR

Carolina Meiller

INTERNATIONAL PROGRAM

Carla Biasutti

Elisabeth Pereyra

COMMUNICATION

Matilde Gobbo

Florencia Cappiello

Elina Ribot

Magalí Asencio

Agustina Vacchina

Delfina Sanchez

MARKETING

Lucía Ceccarelli

CHACRAS SYSTEM

Andrés Madias

Suyai Almirón

Magalí Gutierrez

Lina Bosaz

Ramiro Garfagnoli

Solene Mirá

PEST MANAGEMENT NETWORK

Eugenia Niccia

Juan Cruz Tibaldi

AAPRESID REGIONALS

Matías D’Ortona

Virginia Cerantola

Bruno De Marco

Joel Oene

Mailén Saluzzio

Federico Ulrich

AAPRESID CERTIFICATIONS

Juan Pablo Costa

Rocío Belda

Eugenia Moreno

Myrna Masiá Rajkin

ADMINISTRATION AND FINANCE

Cristian Verna

Vanesa Távara

Dana Camelis

María Laura Torrisi

Mariana López

Daniela Moscatello

Samanta Salleras

Julieta Voltattorni

PERSONNEL MANAGEMENT

Macarena Vallejos

INSTITUTIONAL RELATIONS

Lucía Muñoz

STRATEGIC PROJECTS

María Florencia Accame

María Florencia Moresco

SECRETARY

Karen Crumenauers

Reduction of carbon footprint in agriculture: a challenge with scientificbased solutions

Science is offering some crucial means for carbon footprint reduction in agriculture. Healthy soils, rhizosphere exudates and predictive models are some examples thoroughly addressed in this article.

By Hugo Permingeat

Aapresid’s Technology

Prospective Committee

The term carbon footprint has been the topic of discussions ever since the planet has been a witness of the effects of climate change. It is interpreted as the quantity of gas emissions relevant for climate change and linked to production activities or human consumption. Therefore, carbon footprint is greenhouse gas (GHG) emissions from all sources and processes associated with a particular product, individual or system, from its creation to its disposal.

Originally, only CO2 was considered when estimating carbon footprint. However, nowadays CO2, CH4 and N2O are considered the main GHG emissions in terms of CO2 equivalent (CO2-eq).

Carbon footprint–which measures all GHGs–is a component within life cycle assessment (LCA), which analyzes the whole environmental impact related to a product. Global-warming potential (GWP) on every level increases carbon footprint.

In a recent review, Ozlu et al., (2022) proved the effect of environmental factors, land usage and agricultural practices on carbon footprint processes. The study emphasizes that, to reduce carbon footprint, healthy soils have a crucial role by promoting stability, resilience and erosion resistance. In addition, they provide a good habitat for microorganisms, and encourage the development of fertile soils with good structure and C capture.

Tillage damages soil structure as it oxidizes C and causes GHG emissions. Because of this, no tillage practices are suggested, as well as maintaining optimal humidity. Cash crops that are good for soil structure can help C sequestration. Those systems with crop diversity are better for the soil than monocropping. Minimize operations with machinery can help to prevent soil compaction.

Searching for organic carbon in the most stable manner is the most efficient practice for a sustainable agricultural production.

Another novel aspect, besides carbon sequestration, is proposed by Lu et al., (2024). These authors discuss the search for a reduction in nitrogen loss and a decrease in carbon footprint through exudates of the plant’s rhizosphere.

These exudates are small molecules present in the rhizosphere that regulate those key compounds in microbial processes of the N cycle, and can contribute significantly to sustainable practices during production.

The authors debate about rhizosphere exudates specifically of plants and microorganisms, as well as those mechanisms by which these exudates reduce N losses and the subsequent N contamination on terrestrial environments. Among these mechanisms are biological nitrification inhibition (BNI), biological denitrification inhibition (BDI) and biological denitrification promoters (BDP).

It is encouraging that plants' BNI/BDI/BDP activity can be enhanced by altering the synthesis and secretion of rhizosphere exudates. This opens the possibility to develop more plants respectful toward the environment, with a finer BNI-BDI-BDP capacity through genetic improvement or genetic engineering. The progress on this field of study

could be improved by identifying candidate genes and mechanisms involved in the synthesis and release of BNI/BDI/BDP authorized by PANOMICS technology, like genome-wide association studies (GWAS), metatranscriptomics and metabolomics.

Nevertheless, it should also be considered the effects and ideal concentrations of BNI/BDI/ BDP, as the excessive application of exudates may also inhibit plants' root growth, threaten microorganism diversity beneficial for the soil, and increase plants' carbon emissions. For instance, an LCA suggests positive impacts of BNI in wheat, with a nitrification inhibition of 40% to 2050. Wheat-BNI cultivation could enable a reduction

of 15% in the application of nitrogenous fertilizers, a decrease of 15.9% of GHG emissions during the life cycle, and an increase of 16.7% in nitrogen usage efficiency within the state. Therefore, an optimum objective could be reachable, with low supplies and environmental burden, maintaining at the same time soil health through genetic engineering of BNI/BDI/BDP capacity.

Chemical signaling of those organisms associated with the rhizosphere also involves bilateral interactions between roots and microorganisms, crossing borders between species and kingdoms.

intense network of mycorrhizae and fungi. In addition to the direct impact on N-recycling microbes, the later effects of rhizosphere exudates involved in the composition and functioning of the whole microbial community justify a more exhaustive investigation.

It is important to have a better understanding of the nature of feedback loops in which rhizosphere exudates participate. This understanding will set

Although a series of rhizosphere exudates have been identified as crucial synergistic for the development of fertilizers and "green" agents, up until today, the assessment of their environmental impact has been based on types of soil or limited plant species. There is a lack of solid evidence about rhizosphere exudates efficiency, and their capability to predict the reduction of N emissions on a variety of temporal and spatial conditions, especially in the field. These studies are necessary to obtain a more accurate picture of where and how these rhizosphere exudates influence N emissions in terrestrial ecosystems. Moreover, it is necessary to consider rhizosphere exudates’ cost and stability for them to compete on the market in the future. It is expected for green biosynthesis

technologies of rhizosphere exudates to reduce production and application costs.

In addition to reducing N2O emissions, root exudates may also contribute to the elimination of carbon dioxide and methane in the atmosphere through carbon sequestration in the soil. Therefore, it is expected for rhizosphere exudates to contribute to carbon neutrality in several manners, while preserving crop’s yield and quality as well.

Overall, a more thorough understanding of the underlying mechanisms by which rhizosphere exudates reduce N emissions and contamination, along with regional adequacy and application measures, will be beneficial for crops' future

productivity. In addition to the development of low-carbon strategies that ensure nature-based environmental sustainability (Lu et al., 2024).

It is important to develop models to estimate carbon footprint in the farming sector. Some of these models use physico-chemical properties of the soil, data obtained from crops and farming supplies so as to provide information about the dynamics of organic carbon and GHG emissions. However, these models not only should be used to estimate carbon footprint, but also as a means to foresee the positive effects of management practices (Jaiswal y Agrawal, 2020).

In summary, carbon footprint reduction in the farming sector is essential to address climate change issues and to ensure long-term environmental and economic sustainability. The employment of more sustainable farming practices–like regenerative agriculture, crop diversification and a more efficient usage of technologies–allows us to mitigate greenhouse gas emissions and to promote soil health, biodiversity and food security.

Moreover, by reducing our dependence on fossil fuels and improving agricultural supply chain efficiency, we can significantly contribute to the fight against climate change and build a more resilient and fair future for generations to come.

REFERENCES

Check the references by entering www.aapresid.org.ar/blog/revista-aapresid-n-219

Argentine agricultural trade: strategic responses before new geopolitical risks

Global geopolitical changes threaten the evolution of Argentine farming exports, which tend to be concentrated in a few products and markets. The latest report of the Group of Producing Countries from the Southern Cone (GPPS) analyzes the possible impact of systemic risks within the agrifood trade, and proposes a diversification strategy to mitigate them

By Martin Piñeiro, Nelson Illescas and Jimena Vicentin Masaro

Argentine farming exports are of paramount macroeconomic importance, representing more than 65% of the country's exports of goods. However, said exports are based on a small number of products and tend to be concentrated within a few markets, which exposes vulnerability before fluctuations in the demand of those importing countries. This dependency is aggravated by global geopolitical changes,

highlighting the need to analyze several current systemic risks and their possible impact on the agrifood trade. The purpose is to define an international insertion strategy for the country that seeks to ensure its stability and promote its growth by diversifying products and target markets.

Global context, increasing economic fragmentation and systemic risks affecting agrifood trade

All main geopolitical changes in the last decade are connected with growing conflicts, fragmenting of trade and increasing implementation of trade policies.

This fragmentation of the global economy has affected, only marginally, those trade flows of agricultural raw material and food. Nevertheless, it has progressively become evident that global agrifood trade and, therefore, global food security, is threatened by these new geopolitical conditions. It is also necessary to consider the growing difficulties that have emerged when building a more open international trade within a framework of multilateral trade regulations. In addition to considering the increasing imposition of environmental standards that limit and condition agrifood trade.

These aspects can be synthesized within the following five systemic risks that will affect agrifood trade in the near future:

a) Regional conflicts

The Black Sea campaign originated a first disruption in logistic chains, proving the sensitivity of agricultural markets to armed conflicts and their effect on food supply chains. Moreover, it emphasized the difficulties in building alternative logistic routes and their high costs.

b) Direct and indirect potential impacts of nearshoring and friendshoring policies

Nearshoring and friendshoring policies seek to reduce supply risks that can emerge from

the new geopolitics. Nearshoring prioritizes environmental and supply security; whereas friendshoring is based on the trust and closeness of both culture and politics with "politically friendly" countries.

Even though these policies have not been broadly applied to agriculture as the agroindustry production is associated with natural agricultural resources–imposing important restrictions regarding the geographic location of production–increasing conflicts may alter this situation.

c) Weaponizing - Utilization of food trade as an instrument of political pressure or containment

Despite that up until now food trade has not had any restriction of political nature, an increasing global unsettling situation could cause the imposition of explicit trade restrictions to those "unfriendly" countries. This would give a particularly special international positioning to those net exporter countries of food.

d) Multilateralism crisis and rise of protectionism

Multilateral trade negotiations within the World Trade Organization (WTO) have been stalled for the past twenty years, particularly as regards the agrifood sector. This originates growing risks that affect the possibility to build a multilateral system to

make the agrifood trade flexible, by establishing a hierarchy of importance of plurilateral and bilateral agreements in the international insertion strategy.

e) Environmental standards and food trade restrictions

Raising concerns about global warming, and other environmental matters, have led to the implementation of environmental standards that regulate production and agrifood trade. Therefore, environmental standards promoted by the European Union–mainly through the Green Deal–and their efforts to internationalize said standards, affect the agrifood trade both within the bloc as well as at a global extent.

These systemic risks will be expressed differently in the main agrifood markets in which Argentina participates. The possible intensification of these risks in the following years, emphasizes the importance in defining an export strategy that explicitly considers these five systemic risks connected to each one of the import markets, as well as the potential expansion of these markets.

Current flows of agroindustrial exports in Argentina: primary destinations and products

As it was previously mentioned, agroindustrial exports represent a large part of the country's total exports, characterized by a noticeable concentration of a small number of products and relatively limited destinations.

When analyzing this scene as regards the various product categories, it can be observed that:

a) In relation to animal-derived products, the three primary destinations represent 65% of total exports, and there are ten countries receiving 100% of Argentine exports in this area.

b) Plant-derived products show a minor concentration as the first six import countries represent 50% of exports.

c) In the case of food products, the main five recipient countries cover 50% of exports.

These concentration levels entail a risk for Argentina, and reflect the degree of vulnerability before possible export difficulties to any of these destinations. Whether it be an economic/political decision of the country's government, global geopolitics evolution, or temporal disruptions of logistic chains, any situation of this type would have a negative impact on Argentina's economy in its entirety.

Diversification strategies of markets and products as a response to new geopolitical risks

Within this context, given the current geopolitical situation and the increasing importance of systemic risks, it is crucial to make progress in defining a trade and productive policy that address four basic aspects:

1 The development of a productive development strategy, that enhances production and productivity of a wide range of exportable agroindustrial-based products, and that considers the full progress of bioeconomy.

2 An effort of commercial intelligence to assess the most promising agroindustrial product

markets, both currently and for the future. In addition to an analysis of population evolution, incomes, and systemic risks in each market.

3 A sustained, long-term effort to develop and expand trade relations with a larger number of countries.

4 The design of a flexible and informed international insertion strategy, that considers the potential demand of the largest number of countries possible, as well as the new geopolitical conditions and the increasing systemic risks taking place in the current world.

Report published by the Group of Producing Countries from the Southern Cone (GPPS) on 02/28/2024. GPPS is a group of experts and institutions committed to contribute to the creation of a South American hub capable of responding to new food demands in a sustainable manner, besides generating wealth, employment and social capital in the region.

The complete report is available in the portal www.grupogpps.org.

Transformative encounters: Chronicles of EAR 2024

Aapresid's annual meeting of branch offices (EAR in Spanish) gathered hundreds of members from all across the country in Chapadmalal city to enjoy a series of trainings and recreational activities

Two whole days of sheer content and exchange of experiences. Hundreds of Aapresid's regional members came together in Chapadmalal city, Buenos Aires Province, on May 2nd and 3rd, 2024. Attending offices were from 25 de Mayo, Bahía Blanca, Bolívar, Coronel Suárez, Cuenca del Salado, Del Campillo, Guaminí-Carhué, Henderson Daireaux, Justiniano Posse, La Pampa, Laboulaye, Las Encadenadas, Lincoln, Los Surgentes, Mar del Plata, Montecristo, Necochea, Paraná, Rosario, Tandilia, Trenque Lauquen, Tres

Arroyos and Vicuña Mackenna. Attendees had the chance to participate in several lectures and recreational activities.

With more than 32 years of history in the farming sector, Albor–main sponsor of this EAR edition–is distinguished as the leading company on management systems for the countryside, with more than 4,000 users in Argentina and Latin America.

At the opening ceremony, Martín Marino, Deputy Director of Aapresid's Regional Program, accompanied by Daniel Cotorás, Assistant Director, mentioned that EAR is the space where the notion of network, conjoint work and team dynamic reach full potential.

The president of the institution, Marcelo Torres, was excited to welcome in his "home", the Nodo Sur–southern group of regional offices–all regional members of the country: "I want to thank

all of you for traveling several kilometers to share together these couple of days. We know that EAR is the space to deepen our commitment within the institution. We face the challenge of carrying our mission to those places in need of sustainability progress and leading-edge technology and scientific productive systems. We have so much to say about it, and I am glad to be surrounded with people like you to keep on disseminating producers' voices in every one of our areas and regions of influence, as well as the world."

Later, members of the programs Aapresid Joven and Aula Aapresid, presented the fieldwork they have conducted in classrooms with children and teenagers of the country. This presentation was intended to motivate producers to expand the project in their respective areas.

Forthcoming perspectives on the farming sector

As regards the exhibited technical content, Dr Fernando Andrade, ex-researcher at INTA and current researcher at CONICET, and Florencia Accame, Agr. Engr. and coordinator of Instituto Aaprender, opened the day by speaking about sustainability and how to be prepared for future challenges.

Andrade mentioned that agriculture is facing the challenge of disconnecting production and environmental impact, so as to respond sustainably to the increasing demand and maintain producers' profitability as well. "To achieve this, it is necessary to increase

production per unit of area and time. It is key to promote innovative interaction models, where researchers, extension agents, institutions, companies and producers share visions and disciplines righteously, and cooperate to innovate and create learning societies."

Accame emphasized the role of regional branches in the process of adapting production systems to every environment, another great challenge in the sustainability path.

Instituciones que nos acompañan Institutions that accompany us

Aapresid conecta

Another revealed novelty during the encounter was "Aapresid Conecta": an integral platform available for producers where they can find useful, easy-to-assess information based on a sustainable approach. The speakers highlighted During dinner, the president of Aapresid, Marcelo Torres, the deputy director, Paola Díaz, and the leader of Aapresid's Prospective Program, Rodrigo Rosso, gave a preview of the XXXII Aapresid Congress: "Everything is connected".

A new Congress is coming

"This year, we will host more than 300 national and international speakers. There will be 9 rooms working simultaneously, with high-level technical lectures and a needed prospective view so as not to lose focus as farmers, and to be part of the key mechanism for a global climate change mitigation," Díaz said.

Torres mentioned that the Aapresid Congress is the space par excellence to show the world what Aapresid members do best as producers in matters of experience, network innovation leadership and sustainability.

that it is not enough to communicate what is being done, but that it is also important to be capable of proving it with reliable and solid data: "Aapresid Conecta is a tool to show the world who we are and what we are doing," they claimed.

As regards the alliance with Exponenciar, Torres added that they conjointly assumed the challenge to take the XXXII Aapresid Congress to the Predio Rural in Palermo, Autonomous City of Buenos Aires. "Our alliance with Exponenciar extends the boundaries and visibility of an innovation-leading event within the farming sector."

To conclude, Rosso underlined that, since 2023, they have been working in a co-creation of content, in order to define the approach of each sustainabilityrelated axis: productive-environmental, economic, social and technological.

A tour through day 2

Near the end of the EAR 2024, the economist and businessman, Gustavo Lazzari, conducted a diagnosis on Argentina’s economy and its connection with the farming sector at the panel: "Perspectives emerging from economic reform and downturns. Scenarios for what is coming."

Lazzari started his presentation by advising that appropriate institutions are the path to overcome impracticability, as it happened between 1880 and 1910 when Argentina quadrupled per capita GDP.

To give some context, in Argentina's current situation the government is proposing reforms and downturns with the objective to achieve a free economy–being the signing of the "Pacto de Mayo" one key point. According to Lazzari, this could be translated as a scenario of growth, prices and wages that recover their values in dollars–among other positive indicators–only if there is a successful implementation of the measures considered in it.

Moreover, the economist said that it is necessary for the farming sector to assume an active role by investing in the surroundings, thinking long-term, and "denaturing" a context of overregulation and excess of barriers.

To conclude the encounter, Rebeca Borrell–lawyer, facilitator and ontological coach–held a participatory workshop alongside the regionals. This workshop was to identify tools and strategies that confront the most frequent challenges within groups functioning. Afterward, the first training for regional technical consultants was conducted, under the title: "Leadership and communication. The challenge in building committed teams".

The EAR 2024 was joined by the companies Albor, Atanor, LDC, NK Semillas, Agro 24, Alltec Bio, Spraytec, Volkswagen, Ceres Tolvas, Gleba and Orbia.

A unique biotechnological laboratory in Argentina to improve competitiveness within the seed industry

The laboratory of genomics and molecular markers at FAUBA is a high-performance, genotyping platform that assists SMEs with their improvement programs to increase the performance of their commercial materials.

By Juan Manuel Repetto (FAUBA)

The laboratory of genomics and molecular markers (LGMM in Spanish), from the School of Agriculture of the University of Buenos Aires (FAUBA in Spanish), works as a consultant agent for more than 20 Argentinian seed SMEs and public institutions. LGMM assists their crop improvement programs through a cutting-edge, biotechnological platform. In addition, they provide farmers with major yield potential seeds resistant to prime biological (diseases) and environmental adversities.

This technological platform, set up by the Biochemical Department at FAUBA, enables genotyping analysis rapidly and at a large scale. The objective is to identify, through molecular markers, genes that enhance both yields and quality of agricultural crops.

The project started in 2015, with the participation of the Argentine Seed Producers’ Association (ASA in Spanish) and under UBATEC management. UBATEC is a company from the University of Buenos Aires (UBA) devoted to the development of science, innovation and technology, which enabled them to get funding from the Argentine Technology Fund (FONTAR in Spanish).

Hence, a committee was created, made of six seed centers that presented their development projects. These seed centers were supported by laboratories from the biochemical departments of the Faculty of Agricultural Sciences at the National University of Rosario–who proposed transgenesis and gene edition strategies–and UBA, whose proposals were oriented to molecular markerassisted improvement.

"A project of such magnitude could also be an opportunity to accomplish an original initiative for Argentina. It consists in creating a biotechnology laboratory for those SMEs without the capacity for development, so they can access this type of tools at reasonable costs," explained Eduardo Pagano, Director at LGMM. He also reminded that the department was already working on a project with the seed breeding company Don Mario, focused on the development of molecular markers for extensive crops. "This company helped us to know the productive system beyond papers in order to get to the field with solid solutions," he added.

With FONTAR fundings, the biochemical department built a technological platform that was inaugurated in 2022, and that consists of a model laboratory of 100 meters square with a genotyping line named SNP lineTM. This genotyping line was provided by LGC company from the United Kingdom, and it allows the detection of up to 200,000 SNP–single nucleotide polymorphism–markers per day. It is the only laboratory in the country with said capacity.

A push for domestic companies

LGMM was the first laboratory authorized by the National Institute of Seeds (INASE in Spanish) to study molecular markers to perform a trade control. Today, this service is provided to INASE and URUPOV, the Uruguayan chamber that assembles seed nurseries of the entire country in order to protect seeds copyrights. "Moreover, we carry out an important task to help seed SMEs to create their own programs of molecular

marker-assisted improvement. It is an essential technological advance for companies to become competitive at an international level," said Pagano.

"In our laboratory we can assist breeders on a wide range of needs, involving thorough genomic assessments and regular detection of molecular markers," the researcher emphasized. He also mentioned that the main objective of the project is to generate benefits for farmers, who will have better materials at their disposal every year. "Currently, molecular improvement enables the access to the market with competitive products, with significant savings on supplies and infrastructure resources, and in half the time," he added.

"In our laboratory we can assist breeders on a wide range of needs, involving thorough genomic assessments and regular detection of molecular markers."

Andrés Zambelli, Project Manager of the laboratory, claimed that: "We use molecular genetics tools to contribute to increasing crops' genetic advantages, meaning to increase yields faster. All molecular tools we use are applied to genetic improvement for the development of marketable varieties."

"Furthermore, through the usage of molecular genetic tools we can characterize the germplasm of a company, know what genetic diversity they have, how heterotic groups are formed, family relationships–for those companies producing hybrids–and, if other licensed material from other companies is included, how is it genetically related with base materials," said Zambelli. He also added: "All of this information is essential for improvers, as it enables them to know which types of improvement populations they have to work on, aiming at generating better materials and making the most of the genetic diversity available."

Pagano mentioned that the laboratory does not conduct transgenesis or gene editing, but that their contribution is to facilitate the assimilation of agricultural features or characteristics to other

materials. For instance, it is possible to incorporate a feature from a genotype edited for disease or herbicide resistance, to an elite line in a domestic nursery, both at an accessible price and in a short time. "Today, starting to engage in a program of molecular improvement entails a reasonable price that an SME can afford," he claimed.

This working methodology created good experiences with those seed centers that were part of the initial phase of the laboratory. Moreover, that group has currently reached approximately 20 companies, that include several conventional crops like soybean, sunflower, corn, sorghum, wheat, and rice. In addition to emerging crops like camelina, and forage crops like fescue and ryegrass. Ultimately, molecular improvement can be applied to every species, whether their genome is known or not.

"We use molecular genetics tools to contribute to increasing crops' genetic advantages, meaning to increase yields faster."

Highly-capable resources

Currently, LGMM laboratory is made of 18, highlytrained technicians. Therefore, it is emphasized that, by being a part of the university, professionals of excellence are trained. Professionals that work on the platform, progress on their studies and academic research, and even some of them developed their activities while attending their postgraduate courses and writing their thesis.

"One of the values the laboratory possesses is to act as a unity generator of human resources with high training levels. Actually, nine ex-members of the department are currently working at some companies of the sector," Pagano highlighted. "Professionals trained here are highly demanded because they enrich their basic studies–such as agricultural engineering, environmental sciences and agrifood management taught at the university–placing them as high-value candidates for companies and society as a whole."

"Similarly, the department provides the possibility to work on actual issues from a scientific point of view, which also allows professionals to continue their research career in the public area, in the university and at the CONICET (National Scientific and Technical Research Council)," he concluded.

"One of the values the laboratory possesses is to act as a unity generator of human resources with high training levels."

Malting barley in Argentina: 40 years of genetic progress promoting yield and quality

Argentina experienced an important advance on malting barley production. Genetic improvement enabled to increase yield and develop key features, such as weight and number of grains, malt extract and friability.

Authors: Giménez V.¹, Ciancio N.¹, Gerde J.², Ibañez C.¹, Comacchio J.¹, Abeledo L. G.¹,³, and Miralles D. J.¹,³. (miralles@agro.uba.ar)

¹Cereal Farming subject at School of Agriculture UBA, ²Faculty of Agricultural Sciences, National University of Rosario, ³IFEVA-CONICET

The importance of producing and exporting malting barley in Argentina

Globally, barley production is mainly intended for animal food, but to a lesser extent, for the malting industry. In Argentina, nearly 1,4 million hectares of barley are produced, mostly intended for the malting industry. The country is a net exporter of barley for malting, with 669,506 tons exported during 2022/23, representing more than U$S 387 million (Source: argentina.gob.ar).

Currently, Argentina is the world’s fifth malt exporter, with 8% of the export market, after France (11%), Belgium (10%), Australia (9%) and Germany (9%) (Source: Observatory of Economic Complexity). Moreover, Brazil is the primary malt import country (15%), followed by Mexico (8%) and the United States (6%). The main destinations of Argentinian malt are Brazil (80%), Chile (10%) and Bolivia (2%) (Source: cebadacervecera.com.ar).

Buenos Aires Province is the main production area of barley intended for malt, where it is concentrated around 90% of production, followed by La Pampa, Córdoba and Santa Fe Provinces.

How much have malting barley's production and yield progressed in Argentina?

Barley crop production in Argentina can be divided into three stages:

On the first stage–from 1960 to 1985–there was a halt in production, with even a slight drop of little more than 20 tons per year.

Later–from 1986 to 2000–a production growth rate of 29 tons per year was registered.

Whereas major increase in barley production was observed between 2000 and 2020, with a production growth rate of 256 tons per year (https:// datosestimaciones.magyp.gob.ar/) (Figure 1)

Figure 1. Malting barley production in Argentina since 1960. Vertical lines define three time periods with their respective production rates. Source: FAO (2024).

When observing yield per unit of area at a domestic level, there has been an increasing rise since 1960, although with different progress rates (Figure 2). Progress yield rate per unit of area between 1960 and 1980 was 13 kg/ha.year, growing significantly from that year onward and reaching yield progress rate of 64 kg/ha.year (Figure 2).

since 1960. The vertical line defines two time periods with their respective production rates.

Figure 2. Malting barley yields in Argentina

Source: FAO (2024).

Up until 1990, in Argentina predominated varieties developed by the company Cervecería y Maltería Quilmes, mainly focused on health and size matters, the latter as a key aspect for the malting industry. However, as it is observed in Figure 2, since early/middle 1980, yield has increased.

Toward the late 1990s, materials from Europe–mainly Germany–that showed significant yield potential, started entering the country, and gradually replaced domestic-origin ones. The first European material widely employed was Scarlett variety, from the seed breeding company Breum in Germany, registered in Argentina in 1996. Scarlett got to cover nearly 80% of the cultivation area due to its adaptability to a wide productive region in Argentina, its high yield potential and its appropriate quality for the industry requirements.

Since the insertion of Scarlett material, different European-origin materials have been incorporated and gradually replaced this variety–Shakira, Andreia, Montoya, Charles, etc.

It is important to emphasize that in Argentina there is a network of comparative yield tests of malting barley materials, in which companies of the private sector and public entities participate. This network is coordinated by INTA Bordenave (https://repositorio.inta.gob.ar/xmlui/ handle/20.500.12123/17359).

Genetic progress on released cultivars in the past 40 years in Argentina

To determine what is the genetic progress of barley materials employed and released in Argentina, it is important to characterize them in equal environmental and management conditions (Giménez et al., 2024a). This is because although it is possible to estimate cultivars' genetic progress with statistics at a domestic level, said analysis involves not only genetic aspects, but also environmental and of management.

A more recent study on genetic progress of barley yield in Argentina (Giménez, 2017) assessed the released materials up until 2007. To update this information, our work team carried out a series of tests so as to assess the progress on malt’s yield and quality in released cultivars in Argentina between 1982 and 2019 (see Giménez et al., 2024a).

Therefore, tests under unlimited water and nutrition supplies were performed at the experimental field of the School of Agriculture of the University of Buenos Aires (FAUBA in Spanish). A completely randomized design was used, where eleven commercially released cultivars of malting barley were studied during the above-mentioned period in two sowing dates–July 16th, 2020 and June 10th, 2021. Cultivars were Quilmes Alfa, Quilmes Paine, Scarlett, Shakira, Carisma, Andreia, Traveler, Charles, Montoya, Alhué and Yanara.

As response variables, yield, numerical and physiological components were measured, as well as malting quality variables through the

analysis of micromalting (2020 testing), that were kindly conducted by the company Boortmalt (Luis Ramírez, BA). A general view of the conducted tests can be observed on Figure 3, that shows experimental lots sowed with malting barley, indicating the years of their respective release on the Argentine market.

Figure 3. View of the test conducted at FAUBA field with different malting barley cultivars. The numbers in each lot indicate cultivars’ year of release.

The results of the study showed that the improvement process modified the length of the phase between emergence and anthesis of the crop, measured as the appearance of awns on the flag leaf. It was observed an increasing tendency on the length period between emergence and anthesis, both on days and thermal units, as cultivars’ release years advance. However, materials did not modify the length cycle between blooming and physiological maturity (period of grain filling) (Figure 4)

Figure 4. Length period of pre-anthesis (a, c) and post-anthesis stages (b, d) according to cultivars’ different years of release into the Argentine market, on tests conducted in 2020 (E1) and 2021 (E2). Length period was measured in days (a, b) and thermal units (c, d). Filled lines correspond to the regression analysis.

The feature plant height showed a slight reduction as release years advanced, on grounds of 0.22 cm/year, while stem diameter was increased between 1980 and 2000. Nevertheless, new released varieties after the year 2000 did not show an increase in stem diameter (Figure 5).

Figure 5. Plant height (a) and stem diameter (b) according to cultivars’ different years of release into the Argentine market, on tests conducted in 2020 (E1) and 2021 (E2). Filled lines correspond to the regression analysis.

As release years advanced, yield rate increased to 69 kg/ha.year, which represented a genetic gain, in relative terms, of 0.9%/year. These values are promising, as they represent a 10% yield gain in 10 years due to genetic progress. These improvements, combined with an advance in crop management, could double said values (Figure 6).

Figure 6. Yield per unit of area (expressed in g/m2, a) and relative yield (based on the mean in each environment) according to cultivars’ different years of release into the Argentine market, on tests conducted in 2020 (E1) and 2021 (E2). Filled lines correspond to the regression analysis.

Considering yield's two numerical components–grain number per unit of area and grain weight–genetic improvement produced an increase in both components when contrasted with the released year. Thus, it is not a surprise that the improvement process has raised the number of grains per unit of area, as this component is positively associated with yield (Miralles et al., 2020; Giménez et al., 2024b). However, what is really auspicious is that improvement had

also raised grain weight, in accordance with an increment in the number of grains. Size is an extremely relevant component as regards malt quality, so, despite yield growth through the number of grains, this progress through grain weight is also highly relevant (Figure 7).

Figure 7. Number of grains per unit of area (a) and grain weight according to cultivars’ different years of release into the Argentine market, on tests conducted in 2020 (E1) and 2021 (E2). Filled lines correspond to the regression analysis.

As regards quality, a slight reduction in grain protein content was observed when contrasted with the released year, probably as a consequence of yield growth that caused a dilution effect (Figure 8)

In relation to hordeins profile that composed barley proteins, greater proportions were β + γ, with a minor positive tendency to increase this type of hordeins with improvement, although not statistically significant. Moreover, the proportion of hordeins of type C and D was not affected by improvement, being both types of hordeins the ones with minor proportions (Figure 8)

Figure 8. Percentage of protein in grains (a) and proportion of different types of hordeins (b) according to cultivars’ different years of release into the Argentine market, on tests conducted in 2020 (E1) and 2021 (E2). Filled lines correspond to the regression analysis.

Finally, genetic improvement increased malt extract (Figure 9). This feature represents the percentage of malt soluble substances (in % s/s) obtained through macerating for a certain time and temperature. Moreover, friability, which measures grain capability to be grinded/broken, and it is an indicator of endosperm modification intensity, was also increased with the advance of release years (Figure 9).

Figure 9. Malt extract (a) and friability (b) according to cultivars’ different years of release into the Argentine market, on tests conducted in 2020 (E1). Filled lines correspond to the regression analysis.

Conclusions

Genetic improvement in Argentina increased yields in the past 40 years on the grounds of approximately 70 kg/ha.year, which represents a yield progress rate of almost 1% annually.

During the improvement process, plant height was reduced; whereas stem diameter was increased up to the year 2000 due to the introduction of European varieties. Yields growth caused by improvement were related with a raise in both number of grains per unit of area and grain weight. Thus, there was no observed compensation between both components, which

suggests the possibility to keep on increasing both yield sub-components in the future.

In terms of commercial and industrial quality, improvement processes reduced protein content without significantly modifying the protein profile, and enhanced malt extract and friability.

Consequently, the genetic improvement process in Argentina during the past 40 years has maintained yield growth with advances on malting quality.

14º Simposio Internacional de Genética de Cebada

Sesiones: 28, 29 y 30 de octubre Salida a campo: 31 de octubre Rosario - Santa FeArgentina

More information in https://t.co/9zTcbe970F

REFERENCES

Check the references by entering www.aapresid.org.ar/blog/revista-aapresid-n-219

Aapresid's Red de Cultivos de Servicios: synergies for sustainable agriculture

For four years now, Aapresid's Red de Cultivos de Servicios has been proving their transformational impact: reducing costs, increasing yields and diminishing environmental impact. This is a summary of their achievements and next challenges.

Contemplating and addressing agriculture's sustainability is crucial for the harmonious development of our country. Within this context, Aapresid's Red de Cultivos de Servicios (RCS), with the great support of BASF, CONICET, the University of Buenos Aires and a long list of domestic companies, has been devoted to the employment and assessment of a varied list of service crops and agricultural management

By:

practices since 2018. The purpose is to enhance agricultural systems' sustainability and efficiency through innovative practices. As a result of the multiple tests conducted in several Argentinian regions, the RCS had generated a large amount of information, expanding our knowledge and bringing service crops closer to farmers all across the country.

Gervasio Piñeiro¹, Andrés Madias², Lina Bozas², Tomás Della Chiesa¹, Priscila Pinto¹, Paula Berenstecher¹, Viviana Bondaruk¹, and Suyai Almiron² ¹ FAUBA, ² AAPRESID, Chacras System.

Service crops have proven to be capable of producing large quantities of biomass, depending on the year and the region (Figure 1). For instance, grasses and legumes have shown great capability of biomass production during those periods that once were fallow lands, with an average of around 6,000 kg/ha and 4,000 kg/ ha respectively, but reaching maxima of 18,000 and 10,000 kg/ha respectively. Service crops' high production levels are not just essential to improve soil health through the addition of organic matter, but they also offer an efficient solution for weeds control, nitrogen fixation from the air, erosion control, among other benefits.

Biomass production and soil enhance

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Figure 1. Biomass production variability from several pure and mixed service crops cultivated in various regions in Argentina. The horizontal line represents the mean, boxes represent 50% of observations and whiskers the 90%.

Natural weeds control

Weeds control has always been another distinguished benefit of service crops. In many cases, service crops have accomplished to completely suppress weeds (Figure 2). They provide a control level that can be similar to that of conventional methods, but without the non-wanted effects related to chemical treatments. This effective control is essential to maintain agricultural productivity and to reduce economic losses.

Throughout all these test years, service crops' biomass' dense coverage has demonstrated that high levels of coverage–attained with service crops of nearly 4,000 kg of biomass–hinder weeds growth significantly, thus reducing herbicides dependency and management costs. Furthermore, it has also been observed that, for many years, service crops' low coverage–less than 2,000 kg/ha–has equally achieved good weed control, possibly due to an indirect competence (allelopathic effects, etc.).

Figure 2. Percentage of weed control and its relation with biomass production from several service crops (C=cruciferae, G=grasses and L=legumes).

Impact on Nitrogen fixation and conservation

Leguminous service crops also showed a significant impact in atmospheric nitrogen fixation, as well as in nitrogen capture in the soil (Figure 3), increasing nitrogen availability for plants notably. Taking into account all studied years and sites, we estimate that legumes would supply between 20 and 30 kg of atmospheric N per ton of produced aerial biomass, meaning new nitrogen incorporated into the ecosystem. Therefore, legume crops with an aerial biomass production of 4,000 kg/ha may fixate at least 100 kg/ha of nitrogen–equivalent to 200 kg of Urea approximately.

These results are particularly relevant, because they suggest that service crops can play an essential role in reducing synthetic nitrogenous fertilizers usage, by providing both economic and environmental benefits. Similarly, we observed that the proper inoculation and nodulation of the various species of legumes are currently a great challenge, key for nitrogen supplies of these species.

On the contrary, service crops of grasses and brassicas do not fixate atmospheric nitrogen. However, they have proven to be efficient species for nitrogen capture and retention, as well as other nutrients (P, K, Ca, Mg, etc.), into the agroecosystems, avoiding atmospheric and waterways losses and contamination. Furthermore, there have been registered high carbon/nitrogen ratio (C/N close to 40) in grass service crops, which indicates a slow availability–high retention–of nutrients. Whereas cruciferae showed intermediate values, and legumes

showed very low C/N ratio (C/N close to 15) during their entire cycle, offering a fast nitrogen availability for subsequent crops (Figure 4)

Lastly, grass service crops' C/N ratio can be modified at the moment of their termination–by cycle-length management, drying or fertilization dates–as it increases significantly throughout the crop's cycle (Figure 4). Contrarily, legumes maintained a low C/N ratio through their entire cycle, while brassicas showed intermediate values with relatively less variables than grasses.

Figure 3. Nitrogen supplied by biological nitrogen fixation (NFB in Spanish) or taken from the soil (Nsuelo) from several leguminous service crops.

VICIAS

MEZCLAS

CENTENOS

Figure 4. Carbon/Nitrogen ratio from various service crops according to the length period of their growing cycle.

Efficient water management

A key point for the employment of service crops is water management. Obtained results suggest that, on average, long winter fallows consume around 190 mm of water, while service crops around 240 mm (Figure 5). This represents a service crop's water cost average of nearly 50 mm. However, despite a decrease of soil humidity at the time of the service crop’s drying, on many occasions, water availability for subsequent summer crops was not compromised. The key for this to happen, is a proper length period of the fallow land–period between service crop’s drying and summer crop’s sowing. This is particularly important in areas where water conservation is essential for long-term agricultural sustainability.

Our results also suggest that service crops improve water infiltration and retention on fallows during many years and in many areas. Hence, it was observed a relation between service crops' water cost and yield changes of subsequent soybean and corn crops (Figures 6 and 7). In many cases, there was no water cost but an increase in service crops’ water retention, which caused a raise in summer crops' yields.

Our results also suggest that service crops improve water infiltration and retention on fallows during many years and in many areas.

Figure 5. Water consumption from various plots with long fallows or service crops on different years and areas of Argentina. Each dot represents a plot, the red dot the means, the horizontal line shows the medium, and the box represents 50% of observations.

Figure 6. Relation between relative corn yield and water cost of predecessor service crops at the time of summer crop cultivation.

Figure 7. Relation between soybean absolute yield and water cost of predecessor service crops at the time of summer crops cultivation. Light-colored circles correspond to data provided by Diego Hugo Perez, dark-colored ones to data from the Red de Cultivos de Servicios.

Synergies in service crop mixtures

Finally, observed synergies in service crops mixtures have proven to be more productive–nearly 20%–than species in monocropping (Figure 8). These mixtures make the most of the beneficial interactions between different species, maximizing resource usage efficiency.

This approach not only enhances biodiversity and soil health, but also increases subsequent crops' yields, exhibiting how diversity can lead to major resilience and productivity within agricultural systems.

Figure 8. Biomass production derived from pure and mixed service crops. The dotted line represents expected production according to pure crops production. The cross represents mean production, the horizontal line the average, boxes represent 50% of observations, and whiskers 90% of observations.

The future

Aapresid's RCS's advances and results within the last years emphasize service crops' potential to revolutionize our agriculture and make it sustainable. These findings aim toward a future where agricultural practices are not only sustainable, but also more productive and harmonious with the environment. As these methods keep on perfecting and expanding, they could meaningfully transform conventional agriculture by offering a more sustainable model for the future.

During all these years, we have learned much about service crops, changing our research queries constantly. Our results suggest that service crops could be reducing production costs (private

costs), and also potentially increasing subsequent cash crops' yields (Figure 9). Moreover, service crops could also be contributing to the reduction of public costs, collateral impacts or production externalities (Figure9).

In the years to come, the RCS will focus on answering the particular questions of each region, as well as improving broadcast sowing, or the inclusion of new species–sometimes subtropical–among other challenges. To accomplish a groundbreaking change on our farming system, we believe that it is crucial to join public and private efforts on research and production, in order to promote sustainable development, with the RCS as a clear example.

9. Diagram of service crops' main impacts.

Figure

When to introduce service crops in a sequence with late corn?

A group of Argentinian researchers developed a model that can predict the impact of service crops in late corn yields in the Pampas region.

By Claudio Jesús Razquin¹,2, Horacio Videla-Mensegue³,

Andrés Madias⁴ and Lina Bozas⁴

¹RTD Chacra Justiniano Posse, ²Universidad Nacional de Villa María, ³INTA Laboulaye, ⁴AAPRESID Chacras System.

Within a context of increasing food demand, crop intensification can be an alternative to increase efficiency in resource usage–for example solar radiation, water and nutrients–and to mitigate negative externalities in different regions of the world. Intensification with double cropping or service crops, in comparison with sequences of low intensification, can be a proper means to improve efficiency in the use of radiation and water in regions with long-growing seasons.

Argentina's Pampas region is one of the main areas of commodities production like soybean, corn and wheat. Production systems are characterized by low intensification, with soybean as an annual crop. These low intensification sequences showed low productivity in the use of water, solar radiation and nutrients, as well as an increase in soil and water degradation, and hydric imbalance.

As a result, increasing intensification of production systems, through the employment of service crops, can be a feasible alternative to improve resource usage efficiency and to mitigate negative impacts caused by agricultural production. However, in regions like Argentine Pampas, characterized by high precipitation variability, the increase in crop intensification due to changes in sowing sequences requires a thorough assessment in order to avoid crop's yield losses.

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Service crops, also known as cover crops, are plants sowed with a different purpose or service than harvesting. Multiple studies recorded the benefits of service crops, that include the reduction of chemical, physical and biological degradation of the soil, and the increase in activity and biodiversity of microorganisms. They also help in reducing erosion, favoring nutrients recycling and increasing water capture.

Despite all of these benefits, the adoption of service crops as an intensification practice is much limited in many regions of the world. Some of the reasons for farmers' not to employ service crops are the potential risks for cash crops–like yield loss–and the rise of production costs.

The assessment of intensified crop systems through changes in the setup of crop sequencing requires a long period of time and a large number of field tests. The closest approach is the use of crop simulation models that enable to recreate numerous environmental and agricultural management scenarios. Some mechanistic crop simulation models, such as DSSAT, APSIM, Aquacrop and SWB, have been employed for modeling intensified crop sequences with positive results. However, these simulation models require large field data loggings, along with a meticulous adjusting and validating work previous to their utilization. Another alternative are statistical crop simulation models developed as of machine learning techniques, like Random Forest (RF)

algorithms. Machine learning techniques are based on algorithm training to find patterns and correlations within an extensive database, and their adjustment leads to better estimations of the assessed variables.

Consequently, the adoption of more intensified service crop sequences in agricultural regions like the Argentine Pampas, requires expanding the knowledge on service crop's impact in cash crop yields. Moreover, it is needed the development of simple modeling tools that facilitates producers' decision-making on erratic climate scenarios.

The targets of our research were: a) to identify environmental and agricultural management variables that affect corn yield as a predecessor of a service crop; b) to develop a machine learning model capable of predicting corn yields based on environmental and agricultural management variables in a service crop-corn sequence; c) to assess simulation scenarios that integrate climate variability and agricultural management in a service crop-corn sequence, according to the Argentine Pampas' environmental conditions. Our work was carried out by using a service crop field tests database in numerous cities in the Pampas region, generated by the Red de Cultivos de Servicios of the Argentine No-Till Farmers Association (Aapresid).

Methodology

LThe database used in the analysis is made up of 16 tests performed in a large plain region of the Argentine's Pampas (Figure 1). The broad geographical dispersion of these tests enabled the coverage of a great variety of climatic and edaphic conditions, as well as service crop and cash crop managements–hydrothermal conditions, sowing dates, service crop interruption, length period between crops, presence or not of groundwater. The database covers three agricultural cycles, from 2018 to 2021. The tests, arranged in a strip-like design, were conducted on a control crop (fallow land) and several service crops, both pure and mixed (grass + legumes).

Figure 1. Area of study and experimentation of Aapresid’s Red de Cultivos de Servicios.

Using the database on service crops, a machine learning methodology was applied for the development of an algorithm capable of estimating corn yields. Said algorithm was based on service crop's sowing dates and drying periods, as well as precipitation probabilities during the period between service crop’s drying and cash crop’s sowing. The development of the algorithm included the following variables (Table 1): type of service crop (vicia, vicia+rye), service crop’s sowing and drying dates (days), cash crop’s sowing date (days), length period between service crop's drying and cash crop's sowing (days), influence of groundwater (presence or absence), accumulated rainwater during the service crop's period (mm), accumulated rainwater during the period between service crop's drying and cash crop's sowing (mm), and water useful at service crop’s sowing and drying periods (%).

Once the model was calibrated and validated, an analysis of scenarios was carried out so as to assess the effect of changes in environmental and agricultural management variables on corn yields. Simulated scenarios represent common situations that farmers and technicians face when deciding agricultural management practices in intensified crop sequences with service crops in the Pampas region.

Simulated scenarios involved 216 situations in which environmental and agricultural management variables were combined. There were considered three situations of intensification: a) fallow land; b) vicia service crop; and c) service crop mixture of vicia + rye. Moreover, three service crop’s drying periods were simulated: August 1st, September 20th and October 10th. Simulated environmental variables

Variable Definition

Type of service crop

FS_CS

Fsec

FS_CE

Length period of fallow

Napa_Influ

pp_cicloCS

pp_barbechito

AU_inicial_prop

AU_Fin_prop

Assessed service crops were Vicia, Vicia/Rye and fallow land

Sowing date of service crop

Drying date of service crop

Sowing date of cash crop

Length period of fallow

Influence of groundwater, if present, at depths up to 2 m.

Precipitation during service crop's cycle

Precipitation during length period of fallow

Percentage of useful water at the time of sowing the service crop

Percentage of useful water at the time of termination of the service crop

Table 1. Variables used for the random forest algorithm adjustment to estimate service crop’s sowing date and drying time, and corn yield.

were the following: climatic conditions during the service crop's cycle, four different conditions of accumulated water in the soil profile at the sowing time of the service crop, and the presence or absence of groundwater.

Effect of the service crop over late corn yield

Figure 2 shows the frequency distribution results of relative corn yield–cash crop yield over service crop treatment–for different types of service crops. Relative yield exhibited a regular distribution, with variations in the degree of asymmetry.

The impact of service crops in corn grain yields is high, with maximum values of yield loss of 80%. Also, it was notable the generation of a benefit of the service crop on corn yield, with a maximum yield gain of 65%.

Figure 2. Histogram of relative corn yield frequency cultivated over pure or associated service crops. The dotted line is placed over relative yield = 1, indicating that yield on service crop is equal to yield on fallow land strip. Each graphic shows the amount of analyzed cases for every situation of the Red de Cultivos de Servicio Aapresid, and the percentage of cases with relative yield of >1 and <1.

Furthermore, pure ray or in a mixture of vicia+grass and vicia+grass+cruciferae generated a greater percentage of cases (nearly 66 to 74%) with relative yield <1. Whereas for pure vicia or in a mixture of Vicia villosa+Persian clover+ray, the percentage of cases with service crop impact over cash crop did not exceed 43% (Figure 2)

Relation between corn relative yield and water consumption

The relation between relative yield and water cost–difference between accumulated water in the soil during service crop's treatment minus fallow land–at the time of sowing each cash crop (FIgure 3) shows a major proportion of cases with a negative water cost. This explains the relative loss of grain yield over service crops (quadrant 2). This phenomenon is more noticeable in rye or in mixtures including this crop in comparison to vicia, even in environments with groundwater presence. Meaning pure or associated vicia generates less cases with negative water cost.

On the contrary, associated or pure vicia enables a higher percentage increase in the amount of cases with relative yield > 1 in situations with negative water cost (quadrant 1). Quadrant 3 represents experiments with relative yield of > 1 and positive water cost. It is limited to those cases with on-time service crop interruption and an appropriate period length between service crop’s

drying and cash crop’s sowing. These cases did not show great differences among service crops.

Lastly, quadrant 3 describes a positive water content but losses in relative yield, represented mainly by those cases in which pure rye was employed.

Variables that explain corn yields in a sequence with service crop

The RF analysis showed that eight environmental and agricultural management variables are of high relative importance for corn yield estimation (Figure 4). These variables are: service crop’s drying date, initial useful water at the time of sowing the service crop, rain during the service crop cycle, length and precipitation between the period of service crop’s drying and cash crop’s sowing, cash crop’s sowing date, service crop’s drying date, and useful water at the time of drying the service crop (Figure 4).

Figure 3. Relationship between relative yield and water cost in the service crop at the time of sowing the summer crop.

Importance of variables to predict yields

Figure 4. Relative importance of agricultural and environmental variables to predict corn yields with and without a service crop.

Based on variables with major relative importance, a model to estimate late corn yields was developed. It should be clarified that all variables selected as input of the model are easy to measure and to obtain from common data sources.

The calibration of the model showed very satisfactory results (RMSE=972 kg ha-1 and RRMSE= 13%, Figure 5A), covering a wide range of yields (approximately from 2,000 to 14,000 kg ha-1) and environmental conditions.

The validation of the model also showed a very satisfactory adjustment, with a RMSE=1,298 kg ha-1 and an RRMSE= 16% (Figure 5B). Based on the calibration and validation results, we can confirm that the model is a proper means to simulate corn yields as of environmental and agricultural management variables in a service crop-corn sequence.

Figure 5. Capability of the algorithm to predict corn yield at calibration (A) and validation (B) phase.

When is it possible to include service crops in the crop sequence?

We applied the model to analyze possible environmental and agricultural scenarios in the Argentine Pampas, where producers and technicians can employ this modeling tool to facilitate decision-making (Figure 6)

Figure 6. Corn yield according to different types of service crops, service crop’s sowing date, groundwater influence, weather conditions, and replenishment of the profile at the time of sowing the service crop. Circles= fallow lands, triangle= service crop.

The analysis of scenarios shows that corn yields were affected by changes in environmental and agricultural management variables (Figure 6). In every scenario, corn yield diminishes as service crop's drying date is delayed, especially in climate situations with no influence of groundwater. Groundwater presence and accumulated water condition at the beginning of the service crop have a notable influence on corn yield, especially on medium-to-high replenishment conditions.

Generally, both positive and negative corn yield differences between fallow land state and service crop are observed in specific situations. Positive yield differences are observed during humid years and with September as the service crop's

drying date, independently of the replenishment level of the soil profile at the time of sowing. Contrarily, corn yield negative differences occur mainly during dry years and late drying dates.

As a summary, service crops are a very effective method to intensify crop sequences and improve ecosystemic services. However, it is necessary to analyze environmental conditions and agricultural management for its employment, in order to not cause damage to the cash crop. Our work contributed to the development of decisionmaking criteria for the inclusion of service crops in a sequence with late corn. Moreover, we identified the main environmental and agricultural management variables that explain late corn yield variations in the Pampas region. This discovery enabled us to develop a predictive model to assess possible scenarios in the studied region, and to quantify their impact on corn yields, establishing a valuable tool to facilitate producers and technicians' decision-making.

Everything you wanted to know about service crops but never dare to ask

More species, benefits and uses are added to the service crops' portfolio. To ensure you do not miss the "Always Green" train, two model members from Aapresid share their vision and experiences with intensified rotation systems and provide answers to many questions

By Agr. Engr. María

Eugenia Magnelli

To Prospective Aapresid

Raise your hand those who think of themselves as Agricultural Producers

To be an agricultural producer is not only about putting a seed in germination conditions, waiting until the crop grows and develops, and later harvesting. It is also not only about feeding the livestock until reaching slaughter weight, obtaining a calf, producing milk, etc. Being an agricultural producer entails, or should entails, much more than that. Producing food, fibers and bioenergy represents a responsibility with our agroecosystems.

Thus, we need to design an agriculture based on a succession of processes that enable agricultural ecosystems to be sufficiently productive, sustainable and stable in time, where photosynthesis is the vital starting point on energy transformation and system productivity. The design of that agriculture must be based on the application of certain basic ecological principles that support the sustaining of productive capacity, by making a rational and efficient usage of natural resources and supplies.

Within this context, service crops are a method that enable the producer to intensify and diversify the system. These crops are not necessarily intended for harvesting, but instead they are incorporated in rotations so as to provide a wide variety of benefits, mainly the soil's conservation and protection. They were originally used as cover for the soil and as green compost. Eventually, it was discovered that they offered other much useful ecosystemic services–hence the name–to sustain the productive system, such as improving integrated weed and other pest management, providing nutrients, and even regulating groundwaters. Moreover, they contribute to the quality of the air, in addition to other aesthetic and recreational purposes.

Basic ecological principles to sustain service crops' productive capacity

Increasing biomass production and maintaining biological activity in the soil

Providing enough carbon into the soil to achieve a proper organic matter balance in relation to the environment

Promoting a stable soil structure

Optimizing nutrient's availability and recycling

Maintaining a living mulch as long as possible so that water's main exit route out of the field is through transpiration

Promoting biological interactions and synergies between the components of the system

Diversifying the agroecosystem in time and space

To have a better understanding of this structure and to put these concepts into practice, we talked to Navier Picco and José "Peco" Alonso, two model members of Aapresid from the north-center of Santa Fe Province. From their experiences and vision, they provide answers to the multiple questions about management, usage potential and benefits of service crops subjected within "Always Green" agriculture.

Can any species used as a service crop be adapted to every system?

A catchphrase in agriculture may be "it depends" and in this case is perfect. According to Navier Picco, regional technical assistant at Aapresid's Videla offices, choosing the species depends mostly on the intended purpose of the service crop–weeds control, infiltration improvement, erosion prevention, nitrogen (N) resource increase in the soil, etc.

As an example, Picco said: "If we are looking for weed control, firstly, we need to identify which is our driver weed." He added into the subject: "According to an analysis of the season by Aapresid's Videla office, there are three main weeds: Johnsongrass, Yuyo Colorado and Flaxleaf Fleabane. In case our problematic species is rhizome Johnsongrass–the one causing problems, as seed Johnsongrass is relatively easy to control–we aim at delaying their emergence. To accomplish this, at the very moment it starts to emerge–in this area by late August, early September–we should be sure that the soil is 100% covered with at least 4,000 kg aerial DM/ha."

Picco claimed that this can be easily attained with vicia, or a vicia-based mixture, by sowing them as early as possible–for the center of Santa Fe Province, service crop's sowing date should be between late February, March and April. "Achieved biomass will prevent the rhizome from emerging and it can only be able to do it when coverage is dry or sowed again. This enables

us to avoid early applications of graminicides and/or imidazolinone herbicides, thus reducing selection pressure, costs, and improving EIQ (Environmental Impact Quotient).

This same method would be effective for Yuyo Colorado and Flaxleaf Fleabane, as we know that more than 4,000 kg aerial DM/ha can significantly reduce the emergence of these small-seeded species. Besides weed control, with this method we would be incorporating a great variety of roots that will improve infiltration, increase life in the soil, raise organic matter (OM) levels at medium-term, and protect the soil from the direct impact of rain drops by aerial coverage. Thus, it will reduce erosion, aggregate breakdown and, consequently, soil crusting, as well as protect the soil from direct sun rays.

"Besides the purpose of service crops, another important decision is the subsequent crop and the general rotation of the plot, as it also influences the selection of species or mixtures to be used and, essentially, the drying moment," Navier added.

What is better, pure or associated species?

"We have seen that associated species, the ones called mixtures, are better from every point of view. They provide larger quantities of both aerial and root dry matter, and enable us to combine different types of roots, so that numerous services can be obtained at the same time," the Aapresid member emphasized.

In practice, he explained that a turnip provides a thick and deep root, allowing it to break the hard layers of the soil and improve water infiltration. Vicia, on its part, adds more roots in the first centimeters of the profile and fixates nitrogen (N). Moreover, the combination of both species improves C/N balance, adds several root exudates and provides mutual support.

Despite the multiple advantages of associated species, Picco suggested that mixtures can have some problems. "If we mix oat with vicia, the former has a shorter cycle than the latter. Therefore, when it is time to dry the service crop, grass will already be seeded, which can cause problems in plots intended for wheat, as it may become weed. We know that controlling grass in wheat is difficult and expensive," he said. In this case, he suggested sowing vicia with turnips, instead of oat. "Although cruciferae produce seeds as well, controlling them is easier, at least in the region of Videla, where we still do not have resistant cruciferae," he mentioned.

What is the ideal humidity for service crops cultivation?

Navier explained that the minimum necessary humidity to sow a service crop is the same as any other crop. The seedbed should provide optimal water conditions so that the crop can emerge and establish.

Which are those predecessor crops that enhance service crops' services?

According to Navier's experience, most recommended predecessor crops for service crops are grasses, such as corn or sorghum "We notice that vicia-based service crops establish, grow and produce better biomass than planted over soybean. Moreover, we are sowing something that will supply N (vicia) over something that leaves much C (corn or sorghum), therefore improving C/N ratio, favoring microorganisms’ activity, enhancing C conversion into OM, and diminishing C quantities leaving as CO2."

Another plus point for grasses in comparison with soybean as predecessor of service crops is that aerial seeding is more successful. "We use service crops scattered by plane or drone over late corn and sorghum, mainly after sowing soybean. Thus, we diversify, intensify and maintain a living mulch in the soil throughout the year, meaning "Always Green", he affirmed.

Vicia roots with a good number of nodules, essential to enhance atmospheric N capture.

Which is service crops’ ideal sowing date?

"Suggested sowing date for vicia, or mixtures including it, is as early as possible," Picco stated. At the center of Santa Fe Province, it is ideal to sow in late February/March/April. During these dates, the soil presents optimal temperature and humidity conditions so that the crop establishes and grows faster, entering winter with good coverage.

May crops had good results, but temperatures started to decrease. In June, the results are dissimilar and depend on winter weather conditions. "If winter is wet and not-so-cold (with few frosts), the results are usually good; but if it is dry and very cold, it may be plant loses (patches) and consequent weed in those areas. We also depend on how August progresses, as vicia starts its exponential growth. If August is wet and with no-frosts, the progress of service crops is fast," he explained.

Ground or aerial seeding: which is better?

Before choosing one seeding method or the other, it is important to understand that the selection of the seeding system depends on our objective. "With seeder machines, service crops will establish faster and with better planting results, therefore, we will require a lower number of seeds/ha. In case of employing aerial seeding, planting results are not that good, having to

raise density to a minimum of 50%, causing establishment to be slower. However, success is practically assured. It has been many years since we mixed vicia and turnips over late corn or sorghum and, both during wet and dry years, the result is always positive. It is ideal to scatter seeds before rain," he claimed.

Aerial seeding of Carinata over corn and seedling emergence.

An important point the engineer mentioned is that aerial seeding enables us to have other logistics, because by using a plane we can sow in one day ten times more than what a seeder would. Another advantage is that, at the same time we are harvesting soybean crops, we can be cultivating service crops, something that we could not do with seeders due to the lack of personnel. On the opposite side are costs: more seeds/ha are needed and plane service costs need to be considered.

What is the production of dry matter and N fixation that can be achieved?

Dry matter (DM) production of service crops varies according to the years and the composition of mixtures. Sharing results, Navier said: "We obtained vicias of up to 8,000 kg aerial DM/ha, and mixtures of vicia+turnips+oat of 14,000 kg aerial DM/ha. These numbers are really high, but they can be reached in proper conditions and correct management."

As regards vicia's N supply, the Aapresid member pointed out that this is always guaranteed, because the soil is better supplied of N after the legume. "N kg that vicia leaves in the soil varied and there are many papers on the subject. In practice, we have observed that all subsequent crops respond favorably; it does not necessarily have to be grass, soybean following vicia is excellent, and on predecessor wheat of that soybean, we keep on seeing residual response of vicia," he emphasized.

Whether we sow by plane, drone or pneumatic machine, to calibrate the equipment is crucial Bad adjustments regarding sowing density or the seeding width of a machine can originate nonsowed areas that will next be occupied by weeds, complicating subsequent management.

Which factors influence when defining the optimum drying time?

The objective of drying is to eliminate the service crop. Defining the appropriate time is crucial and depends primarily on precipitation and/or water replenishment of the profile, as well as the sowing date of the subsequent crop. "In the case of sowing soybean crops in mid/late November, in a year with typical precipitation rates, we should dry between late September and early October. If we are sowing late corn–late December–we can

delay drying a little more," he explained. Moreover, he highlighted the importance of studying the profile's humidity and to work with forecasting. "If they announce Niño, we can risk leaving the crop a few days more; but if it is Niña–as next season appears to be–it is essential to move on with the drying process, otherwise we risk losing the subsequent crop's yield," he assured.

It is that simple to sow over a service crop, this is the case of soybean over vicia.

Can I harvest a service crop without giving up services?

To clarify this doubt, José "Peco" Alonso, Aapresid Videla regional offices, shared his experience with cruciferae in the San Justo department at the center of Santa Fe Province.

For Peco, the path toward rotation intensification and "Always Green" agriculture started in 2008, when every plot had permanent double-cropping. Non-selling of wheat due to export restrictions in 2011, led him to consider other alternative species, like garbanzo, pea and rapeseed. The fact is that they chose rapeseed, and from there they started to increase the surface area intended for cruciferae–rapeseed, carinata and even camelina for the past three years. "We have switched the idea of conventional service crops for crops that generate income. Thus, we cover the entire winter and summer with rapeseed, camelina, carinata, sunflower and fist-crop corn; and

during summer with soybean over cruciferae, second-crop corn over wheat, third-crop corn over sunflower, and service mung bean crop over first-crop corn," he explained.

As rapeseed, camelina and carinata are all specialties, Alonso made clear that they are establishing exclusive agreements with companies that commercialize them. Unlike commodities like wheat, it is needed to outline the plot, make an agreement with the seed company, sow, and be subject to a regular monitoring on the part of the company. He advised that there are restrictions in phytosanitary usage, and it is necessary to meet the requirements in order to achieve the quality goal of the final product.

The great advantage of sowing soybean after cruciferae is that the legume obtains between 500 and 600 kg/ha more yield compared with a predecessor wheat.

For further details, he mentioned that the sowing of canola and carinata is extended from April 20th to May 15th, depending on the cycle of the materials. The seeder machine is adjusted to plant 6.2 kg of seeds/ha so as to reach 75 plants per m2. In case of camelina, sowing is conducted around June 20th, aiming at 30 kg of seeds/ha and 250 plants/m2.

Now, what happens if the species providing these services are harvested? "Obviously, behind every species is a service. What is interesting about cruciferae is that they improve the structure of the soil due to their important taproots. They are natural subsoilers that loosen the horizon, enabling better rainwater infiltration in comparison with other

crops. Moreover, they vacant the plot early–between the last week in October and the first days of November–as opposed to wheat that vacant the plot in late November. This time gain allows us to sow second-crop soybean, but with similar yields to that of first-crop soybean. The great advantage of sowing soybean after Cruciferae is that legumes obtain between 500 and 600 kg/ ha more yields than with predecessor wheat," Peco claimed.

Cruciferae taproot favors microporous formation, improving soils’ rainwater infiltration and aeration.

The table below presents agricultural comparisons and services of rapeseed, carinata, camelina and wheat observed in Videla region. It is interesting to see the advantages and ecological niches of every crop so as to set them in winter.

Coverage after threshing

Vacancy of the plot

Competence with weeds Very good/ rare post-emergence

Johnsongrass control

good/ rare post-emergence

post-emergence 35%

Clopyralid Metsulfuron, hormonal

Presence of caterpillars Always Plutella No Rare

Fungicide

Harvesting

Direct without drying/ Diquat Diquat Direct without drying

Sowing date for second-crop soybean Early, as first-crops soybean Early, as first-crops soybean Second-crop dates

Post crop/yields

Soybean VI 15/11

Yield= than first-crop soybean

Soybean VI 15/11 Yield= than first-crop soybean Second-crop soybean Yield -25%, 5 QQ base

COMMERCIAL COMPARISONS

As it was previously mentioned, cruciferae are an economic and commercial backbone, given the sales assurance rate of harvested grains. Moreover, they offer the following advantages in rotation:

Advantages of camelina, rapeseed and carinata in rotation:

Results are equal to wheat, diversifying and lowering risks.

Better use of machinery during sowing and harvesting.

Increase in number of species and rotation of active ingredients of phytosanitary.

Improve deep roots exploration and water infiltration.

Vacant the plots earlier than wheat, favoring the profile's replenishment.

Subsequent soybean yields are like firstcrop soybean.

Immediate sowing possibility after soybean harvest, in line with the "Always Green" goal.

"My forte is the intensification of the system," Peco Alonso assures.

Can service crops be used as forage?

This subject has generated great interest in agricultural matters. In this regard, Navier Picco said: "I believe it is a very good option. We have performed some grazing tests with very good outcomes. However, we would have to analyze if we still obtain all the benefits provided by nongrazed service crops, as the animal would be consuming the coverage. Here starts the debate on

whether service crops are still service crops or end up as another forage source." He added that vicia works very well both for grazing and silo, and when associated with oat, is even better as it provides fiber. "We have conducted an analysis on silo quality of vicia and the results have been really good. There is still much to assess and study," he stated.

To obtain more information on this subject, we recommend you move forward a couple of pages and read the article "Cover crops grazing: the best of both worlds?", written by our columnist expert in livestock production, Dr José M. Jáuregui.

Once and a thousand times YES to service crops and no-till farming systems.

From Aapresid we observed with much concern the advance of tillage methods. Weeds control, compaction reversion, the introduction of new tools to disturb the soil, the influence between producers and technicians and, basically, ignorance, are some of the driving reasons for the employment of this non-sustainable practice.

Because of this, Navier Picco emphasized: "In the north-center of Santa Fe Province, around 40% of the surface presents some undiagnosed type of tillage, which is a serious matter." Reinforcing his viewpoint, he encouraged deep thinking and added: "We invite everyone to join us in the employment of service crops. If they are properly managed, they are an essential means for the sustainability of the system, as well as for yields’ increase and stability. Within plots with several years of usage and under proper management–intensified and diversified rotations, with balanced fertilization and no-till farming–we have it measured that organic matter percentage increases, and yields become stable in time and gradually rise, independently of the season."

Putting the cards on the table. Now is your turn to design your best move to guarantee the sustaining of productive capacity, using natural resources and available supplies rationally and efficiently.

"The secret lies in intensifying and diversifying, always on the basis of no-till farming," Navier Picco claims.

Acknowledgements:

We most especially appreciate Navier Picco and "Peco" Alonso for their valuable contributions to this article.

Let us discuss Camelina, the crop that intensifies rotations and takes care of the soil

Camelina Sativa is positioned as an alternative to intensify rotations and replace fallow lands. Tests conducted in 2023 showed Camelina’s response before herbicidal residues, fertilization impact on yields and soil benefits.

By Engr. Ana Paula Canu¹, in cooperation with Martín Beaudeant² ¹ Breeder and Manager of R&D at Chacraservicios SRL; ² Production manager at Chacraservicios SRL.

Camelina Sativa is presented as an option to replace our fallow lands by increasing intensification of crop rotations. It is a crop that Chacraservicios company has been researching and developing in Argentina since 2013. However, it was in the past few years when Camelina experienced a significant growth in different regions of the country due to the high demand of its oil to be used as advanced biofuels. As a company, this forces us to keep on researching and adapting this crop to different environments and necessities. This entails not only the development of new varieties that provide major yield and stability to the crop, but also the generation of accessible information so that agricultural management is suitable for different circumstances, enabling Camelina to reach maximum potential.

Detailed below are the results of some of the tests conducted during season 2023.

Camelina's response to the presence of residual herbicides in the soil

In a field test in Acevedo city (Buenos Aires) with an argiudoll soil characteristic of the area, plots were sowed with Camelina with previous application of low doses of herbicides to simulate residue: Sulfentrazone (1 and 10% of the used dose), Diclosulam (1 and 10% of the used dose), and Imazapyr + Imazapic (5% of the used dose).

Charts 1 to 4. Percentage (%) of plants with symptoms at 44 days post-plantation (DDS in Spanish), 51 DDS, Pre-bloom (Phase 3) and 50% Full Bloom (Phase 6). Different letters denote significant differences.

As it is exhibited on charts 1 to 4, as the crop is developing, visible phytotoxicity symptoms (chlorosis and necrosis) are less evident There is an exception for the Diclosulam 10% treatment, which maintained a significantly higher percentage of affected plants up to full bloom than the control crop. In the case of treatments with Sulfentrazone, although there was a percentage of plants with symptoms, it was never much different from the control crop.

Applied treatments did not cause the death of plants because stands did not differ. However, all treatments significantly reduced the plant's average height compared to the control crop, with Diclosulam's two treatments the ones showing major reduction (Chart 5).

Chart 5. Plants' average height to maturity. Different letters denote significant differences.

When measuring yields of the different treatments, it was observed that both the Sulfentrazone 1% and IMI 5% did not differ from the control crop notably. Nevertheless, the rest of the treatments exhibited a yield decrease, being Diclosulam 10% treatment the one that presented the greatest difference in comparison with the control crop (Chart 6). This proves that, even though phytotoxicity can be reverted, it can damage yields.

6. Yields of treatments in kg/ha. Different letters denote significant differences.

Chart

Camelina's response to fertilization

Collected from INTA's technical report “Intensificación tecnológica en un nuevo cultivo invernal. Respuesta a la fertilización en camelina sativa” (Ferraris, Gustavo).

Different letters denote significant differences.

Chart 7. Camelina sativa's yield according to source and applied dose of fertilizer: Urea (N) and Sol Mix (N &amp; S).

In a Typic Argiudoll soil in Pergamino, northern region of Buenos Aires, was conducted a study whose purpose was to assess Camelina sativa's response to fertilization with nitrogen (N), sulfur (S) and phosphorus (P). On the one hand, the response to N and S was analyzed through four doses, two sampling sites and one control crop, a total of nine treatments. The response to P was studied through a contrast between the control crop and those fertilized plots.

Yields showed significant differences (p<0,05) for N (Chart 7) and P (Chart 8). There was a considerable response to P, both in productivity (Chart 8) and biomass. As regards N, sources showed a dissimilar behavior. Urea showed a

slight increase until the N60 dose, but decreased from then on with no clear explanation. On the contrary, SolMix showed a constant increase in the entire range of doses assessed (Chart 7). A joint adjustment of both sources placed maximum yield in N80, but with values closer to N60, which would indicate the economic ideal for highyield crops. It is important to emphasize that this behavior was observed in an area with moderateto-high levels of N in the soil, as a result of poor harvests in the previous season.

Chart 8. Camelina sativa's yield with and without phosphate fertilizer. Different letters denote significant differences.

Study of

Camelina’s

impact on soil’s physical properties (School of Agriculture – UBA)

A test was conducted in Coronel Pringles (Buenos Aires), in which a weedy fallow was compared with an irrigated Camelina crop under no-till farming. After the crop was terminated, the soil’s physical properties were studied for both treatments.

On Camelina crop, a notable positive effect was observed on superficial edaphic physical properties (0-5 cm), such as: a) diminishing of large-sized aggregates (Chart 9); b) increasing of infiltration (Chart 10); c) decreasing of bulk density (Chart 11) and declining of mechanical resistance (Chart 12)

Gráfico 9: % agregados de suelo

Chart 11: Effect on bulk density

Gráfico 10: Efecto sobre infiltración

Chart 12: Effect on mechanical resistance

Carinata on the runway: sustainable aviation with 2G biofuels

Second-generation biofuels found carinata as an ally for sustainable aviation. Argentina leads the production of this strategic crop, which also enables to diversify production systems and provides profitability to producers.

By: Agr. Engr. Antonella Fiore Prospectiva - Aapresid

Second-generation (2G) biofuels derived from vegetable dry matter could represent an encouraging solution for the future of energy and the environment. Within this context, there is a crucifer destined to fly and protect the environment. It is Brassica carinata, or simply Carinata, presented as a promising alternative.

This winter crucifer enables to diversify production systems, offers profitability and is used for the production of second-generation biofuels, increasingly chosen by air transport operators.

The aviation industry is responsible for 3% of CO2–carbon dioxide–emissions globally. The greatest exponents of the industry are committed to reduce 50% of their emissions for 2030, and to reach carbon neutral for 2050.

This aviation ally, which plays a strategic role in reducing carbon footprint, is the protagonist of this month's column.

Brassica carinata: benefits and strategies

Brassica carinata, also known as Ethiopian rape or Ethiopian mustard–besides carinata–is a species from the Brassicaceae family. Including them in rotations can be very beneficial, as their taproots contribute to improve soil structure and supply carbon to the edaphic system.

Moreover, their fast development makes them a good competitor against weeds, which reduces the need for applications and promotes a more sustainable production.

Another strategic advantage of this crop involves the early vacancy of the plot. Carinata is sowed between April and May and is harvested in November, allowing an early cultivation of summer crops.

As regards the number of seeds needed for sowing, during an interview that Agr. Engr. Gerardo Andreo did for Aapresid, he said it is around 5 kg/ ha of seeds. Moreover, he said that at this stage technical demands are similar to those for alfalfa, so it is necessary a very shallow sowing with high humidity levels due to the seeds' small size.

This step should be conducted efficiently in order to achieve a crop density of approximately 80 plants/m2. Once carinata enters the rosette stage, it reaches a good development of the leaves covering the soil, leaving clean and weed-free plots.

One key factor for success is to be very cautious with greenflies and cabbage worms, that is why monitoring is paramount so as to prevent their appearance and, if needed, to use insecticides.

Carrying on with the cycle of the crop, Andreo mentioned that blooming happens around September 20th. The grain is studied so as to define the drying period, when it changes from a green color to ochre in the middle third of the plant.

The grain–the harvestable product–contains a high-quality non-edible oil, turning them into an ideal alternative for the production of secondgeneration biofuels.

Moreover, carinata is used as flour for animal feed due to high protein content and low fiber content, which makes it easily degradable by rumen bacteria. For this reason, carinata is a strategic ally on animal dietary habits within agricultural-livestock systems.

The distinctive feature of this alternative crop makes price formation to be different–higher–to that of conventional cash crops. This, together with a low phytosanitary usage, makes profitability to be considerably higher.

In relation to agricultural sequences, Andreo mentioned that carinata's sowing date enabled it to be included either in a rotation with early corncarinata-late corn, or as a soybean predecessor crop. In addition, he suggested that "aerial seeding of carinata over an existing predecessor crop is a very good and possible idea".

The boom in carinata

Argentine production of Carinata is experiencing significant expansion, and it is expected to reach 80,000 hectares in 2024 to satisfy growing demands in the aviation industry.

Argentina leads the production of this crop, followed by Uruguay. In France, Saipol company, European leader in the processing of oleaginous seeds, is currently the main buyer of carinata, with Nuseed as their primary Argentine supplier.

REFERENCES

Argentine production of Carinata is experiencing significant expansion, and it is expected to reach 80,000 hectares in 2024 to satisfy growing demands in the aviation industry.

Check the references by entering www.aapresid.org.ar/blog/revista-aapresid-n-219

Carinata: a strategical crop for sustainable aviation

Reduction of carbon footprint: the use of carinata-based biofuels lowers CO2 emissions in comparison with conventional fuels.

Argentina is the main producer of carinata in the world. It is expected to reach 80,000 cultivated hectares by 2024.

Provision of new options for crops rotation, enhancing soil health and agricultural profitability.

Fast growth which makes it an excellent competitor against weeds, reducing the need to use herbicides.

Use for animal feed: carinata flour is used in animal dietary because of their high protein content and low in fiber.

Superior profitability: this alternative crop's unique feature creates a higher price formation and a minor use of phytosanitary, resulting in major profits.

An Argentinian in Africa: the story of the farmer that took no-till farming directly into the African continent

Jorge López Menéndez lived in Africa for 8 years, where he drove improvements in production systems and founded a company from scratch. He connected with Aapresid because of a tweet and established the first regional office in the continent. Despite some tough experiences–one of his children was hospitalized with malaria and his older brother was kidnapped–he claims: "There is no amount of money that could pay for devoting years of your life to help this reality."

By Lucía Cuffia

Profile

Name: Jorge López Menéndez

Profession: Agricultural Engineering

Place of birth: Bahía Blanca (Buenos Aires Province)

Family: Married to Candelaria; dad to Felipe, Silvestre and Clemente.

Hobbies: Rugby, outside activities, and horses–he trains them to play polo.

Favorite food: "I was never one to eat rice, but when I moved to Sierra Leone–where every resident eats nearly 120 kg of rice a year–I became a fan; they prepared it with different sauces and my favorite was one with Cassava leaves. In Argentina, any meal with meat in it makes me happy."

Jorge always felt a deep interest in Africa. Despite not having any previous personal or working connections, he devoured books and documentaries, without knowing what experiences were awaiting. In 2015, he was presented with the opportunity of traveling to the African continent and did not doubt getting in the plane. He pictured many situations, some of them did not result as he expected, but many did. Africa's harshness, as he describes it, did exist.

Jorge lived there for 8 years, specifically in Sierra Leone and Ghana, although he also worked in Ivory Coast, Liberia, Guinea and Kenya. At the first consultancy he made, he thought "how easy this can be reversed". Conditions seemed

optimal: fertile soils, precipitation and favorable temperatures. He thought that replicating the Argentine model would be simple. African reality took care of proving to him that it will be everything but easy.

"You start to value Argentina's ecosystem, where it is simpler to start agricultural activities, even with the issues it involves. We have contractors, raw material suppliers and a whole supporting network. In Africa you have none of that, and it is the first slap in the face you get; nothing should be underestimated, because entire seasons can be lost due to some trivial matter you forgot.”

To say that you are an agricultural producer in Africa is a synonym of poverty, Jorge claims. "If you are a farmer in Africa, it is because you resign yourself to living to eat and support your family." That is why he insists on always remembering this reality. "You can fund a farmer so they produce more rice, but if they had faced starvation, even though they harvested 10 times more rice, they would still not sell it to you. So, how do you fund someone who is not willing to sell you their production?

When a season wastes away it is tough, because it is necessary to wait until the next year to try again, and the lesson proves expensive. But when it goes well, "it surely is great", he said excitedly. "To be able to help these families so they can think beyond just eating because there is a surplus of food, and that they even start thinking beyond subsistence and move toward the market is highly rewarding," he emphasizes. "Once a new sowing date or density that offers better results is discovered, it is hard to go back to previous practices. There is no amount of money that could pay for devoting years of your life to help this reality," he added.

The challenge of starting a company from scratch

Jorge does not hide his pride when saying he founded a company in Africa. Warc is a social company that provides technology to subsistence farming in Africa. Its purpose is to transform rural livelihood, promote a constant economic growth and contribute to the development of African farmers.

"We built it with my partner from square one," he says. This experience showed him the importance of networking. "There is no use in going for a week, do some counseling and come back. It is necessary to be 100% involved and generate networks like those in Argentina," he states.

"That the company has survived makes me feel super proud. Today, I would do it 10 times better and in less than 8 years with the benefit of hindsight. If anyone is going to do the same, I would like to help them so they have it easier than I did," he says.

Jorge is married to Candelaria and they have three children: Felipe, Silvestre and 9-monthsold Clemente. Although the three were born in Argentina–"we came a few months before and stayed until after labor"–Felipe and Silvestre were raised in Africa. "A very enriching experience as a family, but also quite hard," he claims. They went through some tough situations. "One of my children was hospitalized with malaria, in a life-threatening situation, and my brother was kidnapped. These are things you will never forget." Despite everything, the assessment is always positive. "My children keep talking about Africa, they have friends there and ask me to go visit," he expressed.

A Twitter message brought him closer to Aapresid

In his search for solutions to improve Africa's reality, Jorge sent a message via Twitter to "Pilu" Giraudo, who was then the president of Aapresid. "I was in Argentina and I told her: 'Pilu, let me tell you what I am doing'. Not two minutes had passed and she answered asking me where I was and telling me to 'Let us meet now'," he recalls.

"I always liked Aapresid's vision, it is an organization with a huge potential to be out in the world," he assures. After that meeting with Pilu, Jorge became a member of Aapresid and the first visits to Africa began. "Pilu, Pedro Vigneau, Nicolás Bronzovich and other members came and we started discussing what could be done," he says.

No-till farming is a system with the potential to transform Africa. That is why Aapresid's role is so important in that territory and goes beyond productivity: "To produce in different soils, in different realities, makes you think and be creative."

Due to this impulse, the first Aapresid's African regional office was established, of which Jorge is now the president. Besides sharing tests and results, they also share problems and seek solutions collectively. "Currently, if someone wants to produce in Africa, as a regional office we can contribute vastly.”

Although today this regional office consists only of Argentinian members, they proposed to include African farmers as well. "The key is having a local perspective. As a regional group, that is why we would like to be the bridge connecting partnerships between those companies that may want to operate there and African members," he mentioned.

Jorge is convinced of the potential Argentina has, particularly Aapresid, to go out into the world. "Aapresid's history is powerful, we have much to offer and we should be proud of everything we achieved as Argentinian farmers. We are in good condition to professionally seek funding, in addition to the international programs to help our constant growth.”

He also added: "The voice of the farmer has to be at those places involved in decision-making. We need to reach beyond the fences, communicate what is happening, and be generators of friendly policies toward the sector and society as a whole."

From playing rugby to train polo horses

Jorge's CV includes a special section: rugby. During his many years in Buenos Aires, he played for the San Isidro Club and extended his career up to his 40 years-old. He even played when he was in Ghana. "I love rugby's team spirit and sense of belonging. And that it involves everyone, because you need the one weighing 100 kg, the fast one, the one who can kick the ball, and the strong one. Every player is important."

What you learn in sports is often reflected in other areas. "Like in rugby, in a work team it is important to identify the skills of each individual and make

the most of them. There is one person that would rather be on the field, another who would like to be in front of a computer, and that is the challenge in the sector," he states.

Jorge believes that the farming sector should find new ways to attract the attention of young professionals. New technologies, regenerative agriculture possibilities and the opportunity of contributing to a more sustainable future are some of the aspects that, according to him, may seem appealing for new generations.

Besides rugby, he engaged in polo activities some time ago, something that allows him to merge two passions: sport and horses. The part he enjoys the most is the preparation of the horses. "I like to train them for the game, but I also like the possibility of sharing the experience with my children."

Jorge and his family have lived in Argentina since 2022. "There are days I miss everything in Africa, and days I miss nothing at all. Argentina is a terrific country. Also, I am quite a family guy and have many friends, and I absolutely missed that. If I had a two-hour flight and could spend every weekend here in my house, I would do it all my life," he assures.

Currently, he combines his work as an agricultural producer in the north of Argentina with the development of a new project, "Numen.Bio". The purpose is to create a company appealing to new generations, with an approach in regenerative agriculture and livestock farming going beyond food production. "Numen.Bio seeks to provide solutions to new challenges and to generate cooperation networks with numerous sectors," he says.

All of this from a vision that integrates social, economic and environmental sustainability. Thus, his experience in Africa, where it is clear that farming activities are important in the development of communities, is also present in this project that excites him.

Cover crops grazing: the best of both worlds?

Cover crops grazing arose as a profitable and ecological strategy to integrate agricultural and livestock production in a sustainable manner. Although it is not a universal solution, an appropriate management can maximize benefits and minimize risks.

By: Dr Agr. Engr. José Martín Jáuregui Adjunct ProfessorForages Lecture (FCAUNL)

Among Argentine farming systems, service crops–or cover crops–have acquired increasing relevance as a means to enhance sustainability Originally conceived as a low-cost means to incorporate nutrients into agricultural systems–mainly nitrogen from annual legumes–its usage was diversified so as to address numerous specific needs in plots.

Nowadays, there are "decompactor" crops like some cruciferae, soil "builder" crops, primarily grass, and nitrogen fixing crops–mostly annual legumes among which vicia predominates. There are also some commercial crop blends combining characteristics of several of these crops (Image 1).

Despite the multiple ecological benefits for the farming system, essentially founded on improving physical and chemical properties of the soil that are transferred to the next crop (usually corn

Cover crops grazing

One method that has been gaining attention to approach this issue is cover crops grazing. This practice allows an efficient usage of crops' aerial biomass as a source of forage for livestock, reducing food costs and generating an extra income for the farmer. At the same time, most of the service crops’ ecological benefits to the soil are maintained.

or soybean), some farmers have questioned the high opportunity costs of maintaining an "unproductive" area of the field for six months.

Actually, a recent article in the Agronomy Journal (Blanco-Canqui et al., 2023) revealed that cover crops grazing can be a viable option with no meaningful adverse effects in the soil's properties or subsequent crops' yield, as long as a proper management is conducted. Consequently, it is key to avoid overgrazing and perform grazing when the soil is in appropriate conditions so as to minimize compaction. Indeed,

Image 1. Steers grazing polyculture service crops in tests conducted at the agricultural experimental station (EEA in Spanish) in Pergamino (courtesy of Agr. Engr. Ezequiel Pacente).

according to data collected by Planisich et al. (2021) in the experimental field J. Villarino of the Faculty of Agricultural Sciences at the National University of Rosario, the best results as regards animal profit and environmental services are

Economic benefits

There are several ways to quantify possible economic benefits of cover crops grazing. The more complex ones are those associated with physical parameters of the soil, that will have an enormous impact on porosity, absorption and water retention, and on subsequent crop’s yield. However, and to simplify these variables, here is an analysis that will only consider productive aspects–kg of N and meat supplied to the system.

obtained with moderate grazing (12-18 cm remnant height). This differs from the common suggestion of grazing forages leaving "1 fist-high" remnants (5-7 cm).

Thus, it will be assessed the advantages of using Vicia to supply N to the system, or else, using Vicia with Oat for forage. The assumptions employed to build Chart 1 are the following:

Price of Urea: U$S 650/t

Application cost of Urea: U$S 25/ha

Cultivation cost of Vicia or Vicia and Oat: U$S 291/ha (including a 5 QQ

Soybean/ha rental considering 6 months occupancy of the plot)

N supplied by pure Vicia: 3% of total biomass

N supplied by associated Vicia: 1.5% of post-grazing remnant (50% of the total produced)

Rolling/drying cost of Vicia: U$S 40/ha

Grass-meat conversion index: 10:1

Harvesting efficiency of grazed crop: 50%

Meat price: U$S 2/kg

Animal-related expenses (personnel, animal health, etc.): 40% of meat income

Chart 1. Simulated net income (U$S/ha) according to biomass production (kg DM/ha) of a pure Vicia cultivation and a Vicia-Oat crop under grazing.

According to this chart, to obtain a positive net result employing pure Vicia, yields should be above 7 tons of DM/ha; whereas associated Vicia with grazing activities achieve positive net results at 5 tons.

Environmental benefits

Besides the economic benefit of using service crops as forage, grazing activities can provide other benefits to the production system. Livestock wastes can improve nutrients' cycling and provide organic matter to the soil. Similarly, grazing activities can help in weeds and pest

control, reducing the use of herbicides and pesticides. Moreover, evidence indicates that cover crops grazing can increase total biomass production by more than 50%, raising possible carbon input to the soil–and generating kilograms of meat in the process.

Cover crops grazing can increase total biomass production by more than 50%, raising possible carbon input to the soil–and generating kilograms of meat in the process.

Consideration to keep in mind

One of the primary concerns of cover crops grazing is the possible compaction of the soil because of livestock's stamping. However, several literature reviews have proven that a proper management of cover crops grazing does not increase soil compaction significantly

in comparison to non-grazed ones. Factors like animal load, grazing length period and soil conditions–humidity, texture, etc.–are certainly the cornerstones to consider for avoiding excessive compaction.

Image 2. Steers grazing cover crops consisting of Chicory and Rescuegrass in Nogoyá city, Entre Ríos Province.

Furthermore, it is also true that to be able to perform cover crops grazing is necessary to have animals and proper facilities–wire fences, water sources, personnel, etc. This makes decision-making to be often a little more complex than this article can address. In some cases, farmers devoted solely to agriculture, and who do not have animals nearby–or lack facilities or personnel to take care of them–can resort to the manufacturing of rolls or bundles to generate additional income for the farming sector. There is also the possibility of signing fattening agreements with close farmers in order to generate additional income without involving purchase expenses and animal selling.

Thus, it is important to take into account that cover crops grazing is not a universal solution, and that its employment will depend on specific conditions of each establishment. Factors such as type of soil, weather, type of employed service crop species and management practices should

be carefully assessed. During dry years, for instance, service crops can raise water deficit and compromise subsequent crop’s yield. In contrast, proper management of grazing activities will be essential to maximize benefits and minimize risks. This entails determining the appropriate animal load, grazing length period and optimal time to employ this practice, while considering soil conditions and service crops state.

Cover crops grazing is not a universal solution, and its employment will depend on specific conditions of each establishment.

Conclusion

In summary, cover crops grazing can be a valuable strategy to integrate crop and livestock production sustainably. By making the most of service crops' biomass as forage, there can be economic and ecological benefits, only if a proper management is employed, so as to avoid negative impacts in the soil and subsequent crops' yields.

This practice represents an opportunity to optimize resource usage and enhance resilience of Argentine farming systems.

REFERENCES

Check the references by entering www.aapresid.org.ar/blog/revista-aapresid-n-219

Service crops for more meat and less methane

A study on how cover crops grazing affects forage and meat production and methane emissions in agricultural systems. The results suggest that this practice could improve productivity and reduce emissions.

Work team:

INTA Pergamino: Dr Juan Mattera, Dr Silvina Restovich, Agr. Engr. MSc Ezequiel Pacente, Agr. Engr. MSc Omar Scheneiter, Agr. Engr. MSc Isabel Cattoni. Engr. MSc Jonatan Camarasa. INTA Castelar: Dr María Cerón-Cucchi, Dr Abimael Ortiz-Chura, Engr. Ricardo Bualó. UTN: Dr José Ignacio Gere; Gentos: Agr. Engr. Lucas Garro.

Employing service crops in agricultural sequences helps carbon capture, improves nutrient circulation in the soil–among other ecosystemic services–and impacts on agroecosystems productivity. Grasses are notable for supplying carbon to the soil, legumes for incorporating nitrogen through biological fixation, and cruciferae for decompacting the soil.

Moreover, service crops' aerial biomass consumption by animals may offer another additional service to agricultural producers. The use of service crops for grazing can buffer their costs through incomes derived from meat production, and thus contributing to a major dissemination of this technology in the region.

As regards greenhouse gas emissions, bovinederived one is the most significant source of enteric methane within farming systems. It is produced during food fermentation, mainly in bovine rumen, and it is released into the atmosphere through belching.

The purpose of this work was to quantify forage production, daily weight gain, meat production and enteric methane emission on a service crop grazing within an animal husbandry system. This four-yearlong study was conducted at INTA Pergamino, using a mixture of service crops included in a soybean-corn sequence under no-till farming, and comparing systems with and without grazing.

Details of the experiment

The study was developed during 2018, 2019, 2020 and 2021, on an experiment area located at INTA Pergamino, where two treatments were assessed: soybean-corn sequence with and without cover crop grazing. The design was arranged in random full blocks with three repetitions.

The soil in Pergamino is a typical Argiudoll–according to USDA's soils taxonomy–with a coarse-loamy A horizon with no erosion phase (<0.3% slope), and a strong argillic B horizon. The test area has a temperate wet climate with no dry

seasons. Average annual temperature is 16.5°C (Soriano et al., 1991; Hall et al., 1992) and average annual precipitation is 975 mm–according to data from INTA's red Agroclimatológica.

At the beginning of the experiment, values in the soil at 0-20 cm depth were the following: 3.3% organic matter, P: 16 ppm and 5.9 pH. The service crop consisted of a mixture of tetraploid annual raygrass, Vicia villosa, persian clover and forage turnip. Table 1 details precipitation during each growing season.

(April - October)

1. Accumulated rain (mm) during service crops' growing period on every year of the study.

Table

Precipitation

Animals management

Targeted grazing efficiency was of 60%, representing moderate efficiency, a value below the normal usage of winter forages. The purpose was to accumulate remnant biomass at the time of drying the service crop, thus maintaining the benefits provided by this type of resource.

During each assessed year, prior to the beginning of the first grazing cycle, steer was accustomed to this diet for 7-8 days in another plot with the same service crop. Grazing consisted of three strip-like sections (0.5 ha) per block (1.5 ha) that were successively grazed on every grazing cycle (rotational grazing). Every year, two grazing cycles were performed, with variable length-grazing periods for every strip depending on the growing

conditions of each year. There was a grazing period (between 7 and 14 days) and a rest period (between 14 and 28 days) (Table 2)

Animal load was adjusted based on available forage in each strip, with an assigned forage portion of 3% of live weight. British steer was used (200 to 300 kg of live weight). Average animal load varied among grazing cycles, depending on forage availability, with an average of 7 animals ha-1 from a range of 4 to 12 animals ha-1.

Table 2. Grazing dates of service crop included in a soybean-corn sequence.

Measurements

To measure available forage in each strip, forage production was measured before beginning grazing by using three frames of 1 m2. Also, samplings were taken to quantify dry matter percentage and botanical composition of the service crop. Sampling’s height was 5 cm above ground.

Animals were weighed at the beginning of the study, before starting the second grazing cycle and at the end of it. Daily liveweight gain (DLWG) was estimated as the quotient between weight increase in each cycle and number of days. Meat production was estimated as the product between both daily weight gain and the average animal load in every grazing cycle, and the length of each grazing cycle.

In 2021, enteric methane emission was determined during the first grazing cycle of the service crop. This measuring was performed by placing headstalls on the animals during 5 whole consecutive days with a tracer gas (sulfur hexafluoride). Moreover, each animal's food consumption amount was determined so as to be able to associate it with enteric methane emissions. To estimate individual consumption, titanium dioxide was used as tracer and administered to each animal, and afterwards, its dilution in feces was quantified.

Lastly, before drying the service crop in order to proceed with the planting of the following cash crop, remnant aerial biomass was measured in situations with and without cover crop grazing.

Obtained results

Forage production was different between years and between grazing cycles (p<0.05), with no relation between the two. During 2021 and 2019, it was observed a major forage production, a medium production in 2018, and a lower production in 2020 (Figure 1), probably related to climate conditions.

Figure 1. Forage production (kg DM ha-1) of a service crop mixture per grazing cycle (1° and 2° cycle) on every year of the study.

Average DLWG was 1.20 kg (Figure 2). In 2020, it was higher than the other years (p<0.1) and also higher during the 1° grazing cycle in comparison with the 2° (data not shown). In the case of the 1° grazing cycle, higher gain may be related to the vegetative state the service crop's component species were in. Whereas at the end of the 2° grazing cycle, species changed to the reproductive stage, with consequent forage quality declining. Regardless, on every grazing cycle, weight gains reached ≥1 kg animal-1 day-1, which indicates forage of high nutritional value.

Figure 2. Steer DLWG (kg animal-1 day-1) in an animal husbandry system grazing a mixture of service crops on every year of the study.

Meat production showed a connection between the grazing year and cycle. 2019's 1° cycle was greatly noticeable because of a high forage production, an intermediate animal load and high weight gain (Figure 3). Yearly meat production originated from the sum of both grazing cycles, and varied between 314 and 493 kg of meat per year.

Enteric methane emissions due to cover crop consumption by animals was 119 grams animal-1 day-1. This value was relatively low if it is expressed as factor Ym (enteric methane according to consumed gross energy) (Ym= 0.04) in comparison with the reference value used for estimating domestic inventory (Ym= 0.065).

In relation to post-grazing remnant biomass, at the time of drying the service crop it was observed a connection between the grazing year and cycle (Table 3). Generally, remnant biomass was lower in grazed cover crop, except in 2021 where there was no meaningful difference with non-grazed service crop.

Although remnant biomass in the grazed cover crop was lower than in non-grazed one, there were no changes regarding organic C and N concentrations in the soil (Restovich et al., 2022).

However, in grazed cover crops, there was an increase of total P in the surface associated with an increase of inorganic P (Giannini et al., 2022). These results may be related with P supplies through excretion, which contain between 55% and 75% of P on inorganic forms (Fontanetto et al., 2011).

Figure 3. Steer meat production (kg meat ha-1 year-1) from an animal husbandry system grazing a mixture of service crops on two grazing cycles for every year of the study.

Inorganic P is a source of soluble fractions of phosphorus, which are involved in crops' nutrition. Even though the using and recycling of livestock excretions are a valuable source of nutrients, organic matter and microorganisms that enhance soil fertility, their impact on C and N stocks could be more noticeable in the long term.

Aerial biomass at the time of drying (kg/ha)

Table 3. Remnant aerial biomass at the time of drying the service crop included in a soybean-corn sequence.

Different letters indicate differences p<0,05

Conclusions

Using a mixture of service crops as forage generated high production of meat due to great daily weight gains and animal loads. The usage period of service crops by animals became a determining variable in meat production, as it enabled a longer or shorter length of the grazing period. Said period could be limited by the need to use the plot for sowing the next cash crop.

Livestock farming integration in agricultural systems through the employment of service crops means an opportunity to design productive and sustainable production systems, in a short and medium-term.

The funding of this research was granted by the National Agricultural Technology Institute (INTA in Spanish) through the project 2019-PEE1-I011-001, and the INTA-GENTOS agreement. The authors express their appreciation to Juan Ceballos, Sandro Pansecchi, Pablo Barletta, Sergio Gallo, Diego Colombini and Fabio Villalba for their assistance on the field. Seeds from different forage species were provided by the company Gentos SA.