THE DESERT SOUTHWEST

How To Manage Desert Southwest Water Efficiently

In the arid regions of the desert Southwest, water is by far the most limiting resource for crop production systems. As such, it is an extremely valuable resource to producers and an incentive to conserve and use with utmost efficiency.

Irrigation and crop production systems in the desert Southwest have evolved to include techniques that conserve water resources and improve irrigation efficiencies.

Some of the adaptations include higher efficiency delivery systems, such as notched ditches, sprinkler, micro-sprinkler, and surface and subsurface drip irrigation systems. They have increased efficiencies with respect to irrigation water delivery to the field.

Additionally, production practices, such as minimum tillage and no-till systems and cover crops, have changed to increase soil water-holding capacity and retention. Genetic advances have created more waterefficient crops and varieties.

The introduction of higher efficiency irrigation systems has allowed growers to more precisely manage crop water status by more closely supplying the amount of water the crop requires and when it is needed.

Reference Evapotranspiration Data

Crop water use can be estimated on a daily basis by using reference evapotranspiration (ET o ) data that can be obtained from weather monitoring systems maintained by universities or government agencies. Arizona desert ET o ranges from a low of 0.075 inches daily to just under 0.40 inches.

Knowing reference ET is important, but it does not tell how the crop will use water based upon growth stage. The other component to estimating crop water use is a well validated crop coefficient curve. A crop BY RANDY NORTON UNIVERSITY OF ARIZONA

coefficient (K c ) is a factor used to adjust the ET o value to account for crop water use at different growth stages. Crop coefficients depend on growth stage and are typically presented as a function of time.

The K c developed for Arizona cotton was developed as a function of heat units (HU – thermal time), which is well correlated to various stages of crop development.

Using both ET o and K c for a given day or other time period, one can effectively determine the crop water use. This calculation can be used to monitor crop water status and schedule subsequent irrigation.

Once the amount of crop water use is determined, it is important to consider other factors that influence the amount of water needed to achieve that replacement. Take a look at irrigation system efficiencies when determining total amount of water to be applied to meet crop demand.

If a high-efficiency subsurface drip irrigation system is used, irrigation efficiency may be close to 90% or better, meaning an additional 10% of applied water is needed to meet crop demand.

Less efficient systems may be Notched ditches let trash pass through and support better water control.

around 75% where an additional 25% is needed to meet crop demand.

Leaching Requirement

In the arid Southwest, salinity management is another critical factor due to the potential of salt buildup in the soil that will negatively impact crop growth and development.

A leaching requirement should always be employed. This is simply a percentage increase in applied irrigation water to effectively manage salts in the soil profile. The leaching requirement is based on the salinity of the irrigation water being applied and the salinity of the soil at which less than 100% yield potential may be realized for a given crop.

Managing the incredibly precious water resource in the desert is critical to sustaining farming operations in the western United States. Advances in irrigation technologies and strategies in crop production go a long way in helping to effectively oversee this resource.

As producers implement these technology advances, they are becoming more effective in producing environmentally and economically sustainable crops.

Gary Adams

COVID-19 Crisis Management II

The National Cotton Council has continued to aggressively seek COVID-19-related assistance for its members.

The NCC urged additional CARES Act funding be authorized for the Small Business Administration’s Paycheck Protection Program. the Paycheck Protection Program Flexibility

What recent steps has the NCC taken?

n One of the more important actions in the past two months was NCC’s coordination with Congressional allies to include important agricultural, small business and tax relief measures in the “Coronavirus Aid, Relief, and Economic Security Act” (CARES). Chairman Kent Fountain expressed the industry’s gratitude to Sens. John Boozman and Mark Warner who led a bipartisan letter from 21 Senators to Agriculture Secretary Sonny Perdue that highlighted industrywide losses and urged support of our industry’s relief recommendations conveyed to USDA.

The NCC joined 164 other national groups on a letter to House/Senate leadership requesting authorization of additional CARES Act funding for the Small Business Administration’s Paycheck Protection Program (PPP). Soon after, President Trump signed Congressionally approved legislation containing a $484 billion coronavirus package to replenish relief/assistance programs created in the CARES Act. That legislation, which included $321 billion for the PPP, also allowed farms to be eligible for the Economic Injury Disaster Loan program. Among other COVID-19-related actions, the

The NCC then joined 37 other agriculture groups and businesses on a letter to congressional leaders 1) requesting changes to PPP as the agricultural, forestry, fishing and hunting sectors received only 1.3% of the original $349 billion in approved funding and 2) noting that the PPP implementation made it challenging for farmers and ranchers to participate. The NCC facturing and business organizations on a letter to Congressional and Administration leaders requesting emergency legislative and administrative action that led to the President signing Act. That legislation made numerous technical but substantive changes to previously issued and future PPP loans. For current PPP borrowers, the legislation allows 24 weeks to use the funds instead of eight weeks and for up to 40% (not 25%) of loan funds for non-payroll costs and still have the loan forgiven. For prospective borrowers, it extends the time to use the funds to Dec. 31. Regarding taxes, the NCC joined 151 other agricultural and business associations on a letter to the chairmen of the Senate Finance Committee and the House Ways and Means Committee conveying concerns over PPP’s tax implications, specifically an IRS ruling that would significantly increase loan recipients’ tax liability.

Any other significant actions?

n Following USDA’s release of Coronavirus Food Assistance Program (CFAP) details, the NCC 1) prepared a CFAP summary that included an example calculation for upland cotton and 2) advised USDA that some producers across the Cotton Belt were having CFAP signup trouble. The NCC also submitted comments to USDA urging ELS cotton’s eligibility for CFAP. The NCC also urged Congress to provide USDA with the necessary funding/policy direction for critical support to the textile manufacturing and merchandising segments as well as 2020 crop year support for producers.

also joined numerous other agricultural, manuNCC joined more than 200 organizations on a letter urging Congress to provide temporary and targeted liability protections for businesses struggling to reopen and operate safely during the crisis. It also worked with USDA and other federal agencies to provide relief on H-2A visa processing to ensure guest workers can get to their agricultural employers in a timely manner.

The letters mentioned above and other COVIDrelated information are on the NCC’s COVID-19 resources page at www.cotton.org/issues/mem bers/covid19/index.cfm.

40 th

ANNIVERSARY

CCOY

The Cotton Consultant of the Year (CCOY) Award celebrates its 40th anniversary this year. The award recognizes a consultant who has made great contributions to the cotton industry through outstanding customer relations, leadership and innovation. It is given to the consultant who not only meets these requirements but also exceeds them.

Syngenta and Cotton Farming magazine — CCOY sponsors — are soliciting your help in selecting the 2020 recipient, who will be named at a special celebration Friday, Feb. 26, 2021, at the Peabody Hotel in Memphis, Tennessee.

The winning consultant and the person who nominates the winner receive a two-night hotel stay and airfare to Memphis. The 2020 CCOY recipient also will be featured in a four-page salute in the February 2021 issue of Cotton Farming.

Submit nominations by July 31, 2020.

Mail: Carroll Smith 7201 Eastern Ave. Germantown, TN 38138 Scan/Email: csmith@onegrower.com

You can print out an electronic version of the form located on the Cotton Farming Web site at www.cottonfarming.com.

Nominate online: cottonfarming.com/ccoy

Cotton Consultant of the Year 2020

NOMINATION FORM

If you would like to nominate a consultant deserving of this outstanding recognition, please take a moment to fill out the following form.

Please use a separate page for biographical/professional information. Additional recommendations via letters or emails from other farmers, consultants and industry members are also encouraged to provide support for the nominee.

Consultant’s Name: Company Name: Mailing Address: City: Phone: State: Email: Zip:

In your own words, please tell us why you are nominating the consultant above for the “Cotton Consultant of the Year” Award. Additional pages may be attached, emailed or attached to the online nomination form.

Background:

Biographical/Industry Involvement Background. This information as well as support letters may be attached to this form, emailed or attached to the online nomination form.

Your Name: Mailing Address: City: Phone: State: Email: Zip:

Adult whiteflies

Good Guys, Bad Guys

Consider The Use Of ‘Natural Enemies’ To Help Control Western Cotton Pests

In the Arizona cotton insect arena, the most notorious villains are Lygus bugs and sweetpotato or silverleaf whiteflies. Lygus damage squares with their piercing-sucking mouthparts, which can adversely affect potential yield. Whiteflies are also piercing, sucking pests. But they primarily cause cotton quality loss by depositing a sticky, sugary secretion called “honeydew” on the cotton leaves that ultimately drips onto the fiber in open bolls.

According to the University of Arizona Cooperative Extension, “Effective control of whiteflies is absolutely essential to produce high qual

BY CARROLL SMITH EDITOR

ity cotton.” The first step is to sample the number of whiteflies present in a field, and then compare it to established action thresholds to determine if a spray is warranted.

Over the years, the trend has shifted from using broad-spectrum insecticides to ones that are more selective against target pests and safer for beneficials (predators) or “natural enemies.”

Integrated pest management experts around the world have consistently repeated the mantra, “Preserve your beneficials.” Until now, farmers and pest control advisers did not have any guidelines to follow about “which ones” and “how many is a good number to be considered a threshold.”

Predator Thresholds Developed

Dr. Peter Ellsworth, director, Arizona Pest Management Center at the University of Arizona, says it’s important to be able to identify the six key players in the ecosystem service of biocontrol and enlist their help in reining in the “bad guys” that attack cotton fields.

The natural enemy roster for whitefly control includes lacewing larvae, minute pirate bugs, big-eyed bugs, Collops beetles, crab spiders and Drapetis flies or “dance flies.”

Collops beetle

Big-eyed bug eating whitefly nymphs

He describes the predator thresholds that have been developed to help control whiteflies as a “careerlong culmination of research that I and my close collaborator, Steven Naranjo from the U.S. Department of Agriculture, started 25 years ago. Our goal isn’t just to remove sprays but make them in a timely manner according to what we understand the economic need to be, which is to preserve the quality of the crop.

“Anytime you can defer a spray in our system is another opportunity for biocontrol to resolve the problem or for a monsoon storm to come through and remove a lot of whiteflies from your field. We think considering predator thresholds does two things: spray for at least a week because biocontrol is working quite well.  “About one-third of the time, tells you to advance a spray ahead of the regular whitefly threshold because, for whatever reason or reasons, your field does not have enough biological control potential to function on its own.”

The Arizona entomologist says he believes incorporating the biological

Crab spider with Lygus nymph Lacewing larva control with the use of insecticides safe (or selective) to natural enemies is the path to sustainability.

“It’s not just about the pests anymore,” Ellsworth says.

A Field Man’s Perspective

Arizona pest control adviser Gordon Goodwin with FertizonaYuma says cotton is one of the most interesting crops to watch, and there are a lot of variables to consider. Some of these include varieties, plant growth regulators, nutritional requirements and disease and insect control.

He samples cotton fields for insect pest counts to determine if they have reached action threshold levels.

“We have established whitefly and lygus thresholds,” he says. “Several years ago, Peter Ellsworth asked us to also consider watching our beneficials, which made a lot of sense. Crab spiders and Collops beetle really help keep the whitefly down.

“With that being said, in the past seven or eight years, it’s been important to only use selective insecticides or insect growth regulators on cotton to preserve our predators and reduce

Drapetis fly eating

 “Tells you when you can defer a

whitefly adult Minute pirate bug eating whitefly nymphs

the number of applications we need to make to complete a successful cotton crop. If you introduce an organophosphate or a pyrethroid into the crop after bloom, beneficials are destroyed, which makes it tougher to control whiteflies.

“When we started paying attention to the natural enemies, we actually postponed a whitefly treatment by about two to three weeks. We eventually did have to treat the field for whitefly, but we cut down by one application.

“This system may not save money every season but using established thresholds and selective chemistries and keeping an eye on beneficials, especially for whitefly control, are the big things.

‘Think A Little Harder’

“If farmers can control whiteflies, they get better cotton quality in the end because the honeydew secretions are not there. I always try to do the best job I can for my growers.”

When asked if incorporating the new natural enemy threshold system into his pest control program creates more work for him as a PCA,

FIgure 1. Decision flow for taking appropriate action to control whiteflies in Arizona cotton using predator-based thresholds to inform pest-centric thresholds (modified from Vandervoet et al. 2019). For more resources, visit https://acis.cals.arizona.edu/agricultural-ipm/field-crop.

Goodwin says it just makes him think a little harder.

“I inspect cotton fields twice a week, and I have to keep my mind in the game,” he says. “As a field man, I maintain an accurate count of the pests and have also started paying attention to the predators in my net. I may not document an exact count of their numbers, but I know in general they are present or that their numbers have gone up.”

Goodwin recalls an instance several years ago involving the crab spider’s relationship to the sweetpotato whitefly. After observing whitefly numbers going way up, he noticed it took about three or four days for the crab spider numbers to increase and whitefly numbers to go down.

“It was interesting to watch,” he says, “but you have to be patient.”

Natural Enemy Thresholds Evolve

In central Arizona, Karl Button grows several different crops on his 4,000-acre operation, including 800- plus acres of cotton this year. Over time, he has been a farmer cooperator with Ellsworth and other researchers on various projects.

He says when Bt cottons were introduced, producers finally had a selective approach to control lepidopteran pests. But broad spectrum insecticides were still in use for other pests, making sweetpotato whiteflies and “sticky cotton” still an issue.

“Peter spent a lot of time developing guidelines for when to spray, when the whitefly populations could be tolerated and when it was necessary to spray to avoid population increase,” Button says.

At this time, beneficials still were

Predator to Count (per 100 sweeps) Minimum Number of Predators Needed to Provide Biocontrol

When Whitefly Adults are at Threshold

When Whitefly Large Nymphs are at Threshold

Drapetis Fly Crab Spider Collops Beetle Big-Eyed Bug Lacewing Larva Minute Pirate Bug

26-41

4-6

NA

NA

2-3

5-8 44

4

2

1

NA

NA

Table 1. Minimum number of predators per 100 sweeps needed at the normal whitefly threshold (40%-57% adults, 40% large nymphs) to continue deferring sprays. Whitefly infestation percentages based on sampling 30 leaves (with 3 or more adults) and 30 leaf discs (with 1 or more live, large nymphs). Each of these predators can be counted and considered independently. NA, not applicable.

not being taken into account because farmers were using organophosphates, which also took out the predator populations.

As selective insecticides that only worked on sucking, piercing insects came on the scene, the predators began to return to the field, but no one knew what they were actually accomplishing out there.

Ellsworth, Naranjo, and their students began to turn their attention to identifying and counting the natural enemies in cotton fields to determine at what thresholds they might be a legitimate criterion to include in the decision-making process of whether to spray or defer a spray.

A Subjective Decision

Button says he attends a lot of the UA Extension meetings, is familiar with the predator threshold system and has agreed to test it on one of his commercial cotton fields for usability if he is needed for the project.

“We have occasionally deferred sprays for a couple weeks because of a privately held suspicion that the pest numbers weren’t high enough, and something seemed to be going on in the field that we didn’t want to mess with right now,” he says.

“When the numbers started increasing after a long plateau, we felt that whatever was in there holding the equilibrium had shifted.

“At that point, it becomes an economic determination of risk, which is always a subjective decision on the part of the grower. How much risk will I tolerate and how much damage will I tolerate? It’s the individual farmer’s call.

“But Peter’s predator thresholds do give us another component to consider when making that subjective decision.”

Research Benefits Southern Plains Cotton

Despite the COVID-19 pandemic, Cotton Incorporated leaders and scientists continue to advance the crucial agricultural and environmental research for which they are responsible.

Cotton Incorporated’s Agricultural and Environmental Research Department has taken a steadfast approach to managing ongoing research projects and priorities through these challenging times. Along with university and U.S. Department of Agriculture research partners, the AERD team at Cotton Incorporated is committed to research that helps cotton growers’ bottom line.

Weed Control

Dr. Gaylon Morgan, director of agriculture and environmental research, joined the Cotton Incorporated staff one year ago and has inspired a renewed emphasis on weed management research. He currently oversees 14 weed management projects, both in season and end of season, across the U.S. Cotton Belt. Projects crucial to producers in the Southern Plains region include:  Weed management in Texas and Oklahoma — A statewide collaboration of applied research and outreach to address regional weed issues, including the evaluation of new herbicide tolerant traits, herbicide combinations and slowing herbicide resistance.  Precision tillage — An integration of precision technologies to remove weeds in the crop row and between various tillage attachments.  Balancing inputs — An evaluation of high and low herbicide input BY SHELLEY HEINRICH SLATON, TEXAS

systems to quantify the importance of late-season weeds on weed seed bank accumulation or depletion.  Cover crops and impacts on weeds and soil health — Focus on cover crops and how they fit into an integrated weed management system, while simultaneously improving soil health.  Palmer amaranth metabolic resistance and mitigation — Identification of potential herbicide resistance by Palmer amaranth to dicamba and S-metolachlor.

“Weed management, traits, herbicides and application costs remain one of the biggest expenses that our growers face in West Texas and across the Cotton Belt,” Morgan says. “More herbicide resistance is occurring each year with many weeds resistant to multiple different herbicides. Increased occurrence of herbicide-resistant weeds leads to fewer and more expensive weed management options.

“We have to continue to identify alternative methods that complement our herbicides and slow the spread of herbicide-resistant weeds. Similar weeds affect all crops in West Texas, and we are working to develop a multi-commodity approach to combating herbicide resistance.”

Seed Quality

Cotton Incorporated’s AERD team also is investing in research addressing seed quality. Dr. Murilo Maeda, a Texas A&M AgriLife Extension research collaborator, is working on project that includes seed quality surveys from 15 locations across the Cotton Belt. This Cotton Incorporated-funded research project will comprise field and laboratory analysis.

While this research is vital to all cotton producers, it is especially relevant to those in the Southern Plains, where extreme weather often affects soil temperatures, cotton seed emergence and plant survival rate. For example, a cold snap can affect root development, stand uniformity and ultimately potential yield and profitability.

“Seed quality is complex,” Maeda says. “From the time a field destined for seed production gets planted, many external biotic and abiotic factors will play a role in determining the final product quality. After harvest, the seed goes through many steps, from ginning and delinting to treating and bagging, before it ends up in a grower’s field. That being said, the seed is where it all starts.

“Given challenging weather conditions many have to deal with during planting, seed quality must be adequate for growers to succeed. Thanks to the support from Cotton Incorporated, research and Extension personnel from universities across the southern United States will have the opportunity to learn more about physical and chemical seed characteristics that will help improve our overall understanding of seed quality. At the end of the day, our collective objective is to survey cotton seed quality and generate information that will keep our industry moving in the right direction.”

U.S. cotton producers are strong, resilient, careful and ready to produce a crop. The Cotton Research and Promotion program will continue to work and fund research during these challenging times to ensure the cotton industry can also remain strong and resilient.

Shelley Heinrich is the Cotton Board Southern Plains regional communication manager. Email her at sheinrich@ cottonboard.org.