Undercover
farming
ucf
I
january/february 2020 Volume 17 No 1
I I R40.00
growing medium
CROP PRODUCTION
CANNABIS
FOOD SECURITY
Company expands growing medium plant Page 4
GLOBALG.A.P. Certification Page 10
Cannabis growers’ licensing Page 16
Insurance for undercover farmers Page 18
Undercover Farming expo & Conference 2020 Pretoria Program pages 12-13
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MAIN ARTICLE
PROPRIETOR I ADVERTISING SUZANNE OOSTHUIZEN 012-543 0880 I 082 832 1604 suzanne@axxess.co.za EDITORIAL CONTENT & COMPILATION Johan Swiegers 082 882 7023 editors@axxess.co.za ADDRESS PO Box 759, Montana Park 0159 E-MAIL magazine@axxess.co.za FAX 086 518 3430 ADDRESS PO Box 759, Montana Park 0159 DESIGN Fréda Prinsloo PRINTING Business Print Centre DISCLAIMER Undercover Farming accepts no responsibility for claims made in advertisements or for opinions and recommendations expressed by individuals or any other body or organisation in articles published in Undercover Farming. COPYRIGHT Copyright is reserved and the content may only be reproduced with the consent of the Editor. Subscription Online subs: Email to suzanne@axxess.co.za If you subscribe on-line, e-mail your deposit and address details to: magazine@axxess.co.za. More information from Suzannne Oosthuizen: 012-543 0880. Subscription form available on inside back page. visit us at I besoek ons by
From the Scriptures
Haggai 2:19 “ ‘Is the seed still in the barn? Even including the vine, the fig tree, the pomegranate and the olive tree, it has not borne fruit. Yet from this day on I will bless you.’ “
Contents 4
Moving ahead with the times – Bark ’n Fibre Enterprises
6 Female greenhouse producer excells 8 Avocados reap increase in supply and price 10 A brief look at GlobalG.a.p. and how to get certified 12 Undercover Farming expo & Conference
FRONT PAGE: Lelanie Trollip, director of Bark ’n Fibre in a greenhouse that makes use of her growing media and growbags. See page 4.
INSIDE ...
2020 Pretoria Program pages 12-13
14 Haifa Chemicals is pioneering the future of calcium
16
nitrate Nutrigation™
16 Cultivating Medical Cannabis in South Africa 18 Insurance and the greenhouse or shade net farmer 19 Why sanitation is important to undercover farmers 20 Ammonia management in aquaculture 21 About Soil-less plant production – Nutrient Solution
20
Management 1
23 The importance of daily inspection of grow slabs 23 Subscription form
14 21
T
he undercover farming industry started with a new year; surely with high expectations of having a steady market, healthy crops with least or better still, no onslaughts of diseases or pests. We would have loved to mention a continuous flow of electricity, but already in many areas load shedding is in full swing. Unfortunately the smaller operators that cannot yet afford a proper generator are hardest hit. This once more brings the question of entrenchment against all kinds of adverse events to the fore. Insurance of your business and protection of the financial assets, crop and infrastructure are facts of life. In this edition we touch on that subject to enlighten the fresh producer, et al on the basics of agriinsurance. Latest news has it that all farmers who are not members of an irrigation board have to install water meters according to a notice in the Government Gazette dated 17 January 2020. This is to ensure water security for the country. They have 30 days to install these. Cannabis for pharmaceutical or medicinal purposes is surely the crop that took the world by storm. This can be seen by the increased number of delegates at the Undercover Farming Conferences of late. In the next edition an editorial on one such major new facility will be published to give you as a reader insight into what it takes to plan and construct a cannabis production facility. The obtaining of a license to produce cannabis is also discussed under separate title. To be fully GLOBALG.A.P. certified is another aspect of producing for markets beyond our borders. What does it entail? Read in this edition what are the basic requirements to become certified in order to market superb quality produce to an enormous market off-shore. The Undercover Conference offers yet another opportunity of rubbing shoulders with major input suppliers and men and women in the industry that are enthusiastic about tomorrow. Enjoy and we also look forward to meet up with the producers of the Western Cape in October this year. As always, we at Undercover Farming welcome calls from producers with questions and new entrants to the industry in order to match these up with authorities on every subject. Happy undercover farming!
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Moving ahead with the times -
Bark ’n Fibre Enterprises Tunnel growers require the best sustainable and repeatable quality substrate, in which to raise crops. Whether used for seedlings, greenhouse plants or for nurseries, specific ingredients or recipes for different plant types may be required. Lelanie Trollip of Bark ‘n Fibre Enterprises, has an excellent understanding of the requirements for these industries.
A
temperatures are reached (40-70 C) fter years of development, and at that stage cellulose is reduced, Lelanie and her team have whilst windrows are turned. embarked on a program to upgrade their facilities into a full 3) A stabilization period, during which the blending and packing plant in Brits, Northrate of decomposition decreases and West Province. temperatures decline “We have decided to follow the trends After composting has been fully of the industry that we support,” Lelanie completed, the product is screened into explains. “We can now blend different different sizes. products required by customers for their By maintaining a careful monitoring specific requirements and then file the program of the composting conditions, formulae of each mix for their future use. we are able to produce composted bark Traceability is of utmost importance and of a consistent quality. As traceability is the filed formulae will always be available of utmost importance, records are kept to be repeated. Some ingredients of our of the full composting cycle per windrow blends are imported and our pine bark and per batch. products are processed by ourselves. We A growing medium testing facility is being place significant emphasis on producing, constructed and installed. The facility will consistent, pure, disease free, quality be equipped with top quality equipment products. We are committed to offer such as photometers. These amongst products marketed under our brand name other equipment will be used to assess – MultiPro Blends - that is N, P, K, Calcium, By maintaining a careful currently known to be a Magnesium, PH, EC, leader in our industry.” monitoring program TDS and Sodium. Bark ‘n Fibre’s raw of the composting This information will product comes from their be available to clients conditions, we are able facility at Amsterdam as each batch will be to produce composted Mpumalanga, where the accompanied by a bark of a consistent pine bark is composted certificate displaying this quality. As traceability by a thermophilic information. process. This is done in is of utmost importance, In addition to the three stages, records are kept of the industries mentioned 1) Preparation Phase, at full composting cycle per previously, Bark ‘n Fibre which time raw bark supplies a growing windrow and per batch. is milled to reduce range of products to particle size, and thereafter set in greenhouse producers, shade net growers windrows (pic) and mixed with organic and large commercial tree growers in urea and water. South Africa. 2) A thermophilic phase, (lasting The company’s base products for blends several months) during which high are, pine bark, cococoir and sphagnum
Composting windrows at our Mpumulanga site.
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peat that is imported from Latvia. The additives used for blends amongst others are, vermiculite, perlite, gypsum, lime, fertilizers, and thereafter anything a customer requests. There are three ways products are delivered, 1) In bulk. 2) In bulk bags of 100 litres. 3) Or in MaxiBags. Maxibags are a new addition that contains 2.2m3 of pressed product that allows the
I Volume 17 No 1
Bulk Loads
MaxiBags
company to load a Superlink with 110 m3 at a time. This makes the load economical allowing delivery to the Northern Cape and other
distant areas. In part of the production facility, Lelanie has constructed a buffering station specifically for cocopeat. The cocopeat is expanded and soaked with a calcium nitrate solution and then rinsed with RO water. The RO machine that is used was imported from Malaysia and enables the cocopeat blend to be rinsed down to EC 0.2 ms/cm wash. “The bulk of product offered by the company is pine bark and because it is lignitic and a hard product, it keeps its structure. However pine bark needs to be blended with coir peat to increase the water holding that it lacks, thereby improving the product for the grower. We are experts in blending the growing media products to specific standards and recipes for our clientele. The properties of each particular product are tested and proven, long before being offered to our clients. Any new product is thoroughly tested. Information of the precise content used to blend the product is kept and available for the exact specifications to be passed onto a greenhouse producer,” Lelanie explained. 5
greenhouses I shade net I hydroponics I aquaponics Bark n’ Fibre Enterprises
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Currently the company have 36 different menus in its database that can offer product to clients in different production systems. As discussed previously, should a customer prefer a specific blend, the company will happily formulate a new blend and place on file that blend for the customer for any future requirement. This allows the company to quickly respond to a specific prescription blend order. Bark ‘n Fibre has included hardy plastic pots for blueberries, raspberries and cannabis in its range. This range has been trademarked as the TuffPot range. To prove how tough these pots were, they were sent to Philadelphia USA for UV testing where the solar company simulates desert conditions to determine how long the pots will last in intense sun. The test simulated 8 years of sunlight degrading and has determined that the TuffPots exhibited very little deterioration after a simulated 8 year period in California desert conditions. The TuffPot range consists of round pots, square pots, bag stands and water collection plates. The volumes range from 27 litres down to 4.5 litres and the bag stands also vary in size. Bark ‘n Fibre are agents for Agaris Belgium – the sphagnum peat mined in Latvia. Agaris produces substrates with chemical and biological characteristics
Disc for Blueberry Pots
that are ideal for seeding, The Cocomill 100 is very popular in South Africa as an effective rooting, cuttings and for all way to expand cocopeat blocks without damaging the structure long term based cultures. of the product. This product will be marketed extensively by The pharmaceutical cannabis industry has Bark ‘n Fibre in 2020. grown exponentially and therefore Bark Bark ‘n Fibre have expanded their ‘n Fibre have started to produce blends to cocopeat products to include growbags, grow these medicinal plants. The blends pop-up bags and have developed a are registered and trademarked under the coco-disc for blueberries. These can be CannaBanna logo. Once again this industry dropped into a blueberry pot, watered demands high standards of operation and and left to expand to the volume of the consistency of product; therefore Bark Tuffpot. This saves time, effort and labour. ‘n Fibre will be ISO9001:2015 and TUV registered by June 2020. Bark ‘n Fibre are proud agents of Logitech Machines from Holland. The Cocomill 100 is very popular in South Africa as an effective way to expand cocopeat blocks GrowBags without damaging the structure of the product. They have sold 12 machines countrywide and aim to offer many more units. Lelanie Trollip is a hands-on director of her company and will always be proactive in her business. The company has loyal, experienced staff in the office and in the manufacturing plant in both company locations, which allows Lelanie to personally visit clients. A quick tour of the upgraded and Pop-Up Bags additional facilities is inspiring. Lelanie has confidence in the growth of the industry, The pharmaceutical cannabis industry has grown exponentially and both locally and outside S.A. borders. therefore Bark ’n Fibre have started to produce blends to grow these She would like to maintain being an medicinal plants. The blends are registered and trademarked under the industry leader with supplying growing CannaBanna logo. media, and expanding the range of associated products.
Lelanie Trollip, director of Bark ’n Fibre appears on the right with her Brits plant staff; (front) Tindo, Daniel, Fred, Eddie and Ermindo and behind them; Erlindo, Frank, Innocent, Alonso and Thodoza.
The administration staff at Bark ‘n Fibre at the Brits plant are, from left; Janet, Lelanie Trollip (director), Ruaan, Annemarie and Betty.
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In 2018, Amanda Mpabanga became part of Mabogo Dinku Agricultural Cooperative, an urban farm where she Amanda Mpabanga of Mabogo grows vegetables such as Dinku Agricultural Co-operative, Brits, North West. spinach, beetroot, spring onions, and green beans. Amanda’s farm is 37.2 hectares, but 26.9 hectares of that is arable land.
Female greenhouse producer excells
M
abogo Dinku Agricultural Cooperative currently has six tunnels with a size of 250 square meters each. “We supply spinach and spring onion to FoodLovers in Greenstone and only spring onion to Pick n Pay in Brits.” Amanda believes in Sustainable Development. “I have always been a vegetable gardener, but in a very limited space. I then decided to become a farmer to supply my family and others with fresh vegetables and make a living out of it as well.” Amanda currently employs seven people and hopes to employ more as the business grows. “I love the process of growing food from seed to a consumable product. The science of seed sprouting, germinating and becoming a product to be consumed is what excites me about urban farming.” “People believe that I am rich, which is one of the stereotypes about being a farmer. This is not the case, as the business has expenses to be paid on a regular basis.” Also, people think that being a farmer means wearing overalls and gumboots. “I often get people asking me “You - a farmer?” when I introduce myself because I appear different to what they think farmers are supposed to look like.”
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Amanda is part of an Urban Agriculture Programme, where she hopes to learn how to be consistent in supplying good quality produce and to build a strong rapport with her customers. Now in its second year, the Urban Agriculture programme invests in high potential farming businesses, by integrating technology solutions that will grow the businesses and create lasting employment. The 15-month business development programme provides participants with technical and operational training, hydroponic infrastructure investment, industry-based mentorship, as well as market access. About her entrepreneurial journey, Amanda said;” I never imagined myself a farmer or leaving my 08h00to 16h00 job to be a farmer. I don’t even have a mom and dad who own a farm. I personally wanted to be an engineer or pilot growing up and ended up doing a BCom, because I was told I will be rich quick, and be able to support my family back home. I have, though, always loved and believed in Sustainable Development and gardening and my partner asked me why I don’t consider farming. He introduced me to this journey that I love and am passionate about. “My drive is to understand the bigger picture. I am motivated by knowing that I will always be relevant even in 20 years
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from now in this industry. I am motivated by the process of learning and helping others in that process. I’ve met farmers who have been farming for over 10 years, but they need my assistance even though I have less than two years’ experience. “I have a couple of mentors: My partner at home, Dave who helps me when I feel drained and lost and reminds me of where we have been and what the ultimate goal is. Mme MaChauke – who is a founder of our organisation, this lady is a gem and believes in me and is a hardworking woman. Also, Nthabiseng Kgobokoe and Eric Mauwane are two young farmers with much experience. They share information all the time and they even share their failures. In this industry you feel better when you know you are not alone. Amanda advises young agricultural entrepreneurs; “Be open-minded and do not think life is a straight line. The exciting news about agriculture is that you can start your career now, with the limited resources at your disposal such as a veggie garden in your backyard. Even if you decide this is not your passion, you would have supplied your family with fresh vegetables. Be open to learning better ways of doing what you do, effectively, productively and at very minimal cost.” Source:SAB.
Undercover growing solutions to help your business flourish
Turnkey Solutions
Greenhouse Structures
Irrigation
Cape Town
Climate Control
Crop Management Technology
Growing Products
Johannesburg
Telephone
021 987 6980
Telephone
011 974 5254
Address
Vegtech, 25 Kiaat Road, Kraaifontein
Address
Vegtech, 23 Brewery Street, Isando,
Industria, Cape Town, 7570. Email
info@vegtech.co.za
Johannesburg, 1600. Email
www.vegtech.co.za
info@vegtech.co.za
greenhouses I shade net I hydroponics I aquaponics
Few commodities can boast over simultaneous increases in supply and price. But with an ever increasing demand for avocados, this industry has much to celebrate.
Avocados
reap increase in supply and price
T
he success story of avocados continued at the Subtrop Marketing Symposium held in November in White River, Mpumalanga. Furthermore, the litchi and mango industries have recently gained access to new markets, and entry of avocados to Japan and some other major markets is on the cards. During the Symposium it was made clear that there is a strong focus on expanding market access and increasing consumption. This is especially important for the avocado industry which is experiencing strong growth globally and necessitates strong advocacy to ensure the industry enjoys continuous prosperity.
Horticulture production growth Dr Tracy Davids, manager of the commodity markets division at the Bureau for Food and Agricultural Policy, noted that, over the coming decade, growth in the value of field crop production is not expected to outpace inflation, whereas the value of horticultural production is expected to grow faster than inflation. This is due to longer term crops established in recent years reaching full production potential, as well as a recovery from the lasting effects of the recent drought conditions. Paired with the increase in production is an increase in consumption, both in a growing export market and domestically
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as improved income levels in the longer term allow greater dietary diversification. This entails a shift from a staple based diet (predominantly maize) to include higher value goods like meat and fruit. This bodes well for the subtropical fruit industry in terms of domestic market growth, but prospects for exports are also strong and will remain the primary driver of growth.
come to grips with the complexities of the middle class population as they invest in marketing campaigns. “Middle class as a concept is complicated and there is no clear cut and dry definition, although it is usually perceived as the segment of people who have disposable income. But there is still healthy growth taking place in a number of places and while Sub-Saharan Africa only has 10% of the world’s working aged Didiza assists with new markets population currently, by the end of the access century it will grow to just under 40%. Derek Donkin, CEO of Subtrop, Populations in Africa are urbanising and noted the market access success of this often brings more prosperity and countries Peru and Columbia where household buying power. Some 13 African the government has aligned itself with cities will have a combined income of the interests of the $13 trillion by 2030, industry. He said that Providing a successful model “Lappeman said. since agricultural
for training a new generation
minister Thoko Training of farmers, Louise de Klerk, Didiza has been in Providing a successful CEO of Timbali Technology office there has been model for training Incubator, related that an improvement in a new generation gaining traction for competitiveness, productivity of farmers, Louise access to new markets and inclusive growth were the de Klerk, CEO of for subtropical fruit, key driving factors for success. Timbali Technology as both industry and Incubator, related government are actively pursuing export that competitiveness, productivity and growth which will benefit the economy inclusive growth were the key driving and people of South Africa. factors for success. “We designed an environment where there is order and Dr James Lappeman, head of projects control and farmers follow a system at the UCT Liberty Institute of Strategic that can give them a predictable, quality Marketing, gave a snapshot of the African product.” market and encouraged marketers to
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AVOCADO’S UNDER SHADE NET? Solar radiation in South Africa is excessive for optimal avocado tree growth and development, resulting in heat and light stress for the trees and sunburn to fruit, according to researchers on the subject. Wind, hail and frost are other environmental risks affecting avocado production. A shade net structure over an avocado orchard can provide a degree of protection from these factors and reduce tree and fruit damage. While netting is widely used on deciduous crops, avocados have crop-specific challenges that need to be addressed. These include: Tall trees with large inter-row spacing, synchronous dichogamy flowering pattern, protracted flowering period of up to 6 weeks and vigorous vegetative growth. This requires a much higher, stronger structure which is considerably more expensive than a structure required for deciduous fruit – if built to the same quality specifications. If built to a lower specification to save capital expenditure, there is a higher risk that the structure will collapse in a storm. The following questions need to be answered before large scale use of shade nets over avocados should be considered: 1. What is the return on investment? 2. What is the best structure design, and how long does it last? 3. How is cultural management affected? 4. How are flower development, pollinators and pollination affected by the nets? 5. How is yield, fruit quality and fruit maturity affected?
Aims 1. Determine the long-term effect of shade net over avocado orchards on yield, pollination, cultural management, fruit quality, fruit maturity, and tree pheno-physiology. 2. Examine different construction methods and nets. Estimate the economic benefit of installing these shade net structures.
Technical and cost information can be supplied from a number of shade net manufacturers in South Africa. SAAGA
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GLOBALG.A.P.’s roots began in 1997 as EUREPGAP, an initiative by retailers belonging to the Euro-Retailer Produce Working Group. British retailers working together with supermarkets in continental Europe became aware of consumers’ growing concerns regarding product safety, GLOBALG.A,P, environmental impact and the health, safety and certificate recipients. welfare of workers and animals.
A brief look at
GlobalG.a.p.
and how to get certified
T
he solution entails to harmonize own standards and procedures and develop an independent certification system for Good Agricultural Practice (G.A.P.). The EUREPGAP standards helped producers comply with Europe-wide accepted criteria for food safety, sustainable production methods, worker and animal welfare, and responsible use of water, compound feed and plant propagation materials. Harmonized certification also meant savings for producers, as they would no longer need to undergo several audits against different criteria every year. To reflect both its global reach and its goal of becoming the leading international G.A.P. standard, EUREPGAP changed its name to GLOBALG.A.P. in 2007. Currently, Dr Kristian Moeller is CEO of GLOBALG.A.P. with its head office in Köln, Germany. GLOBALG.A.P. today is the world’s leading farm assurance program, translating consumer requirements into Good Agricultural Practice in a rapidly growing list of countries – currently more than 135. The majority of retailers in today’s markets require certain standards that
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ensure safe and sustainable agriculture, and GLOBALG.A.P. certification is highly regarded as a reliable standard for demonstrating on-farm food safety and sustainability. By complying with GLOBALG.A.P., control points and compliance criteria (CPCC), producers are able to sell their products both locally and globally. GLOBALG.A.P. certification thus offers producers a ticket to the global market. The GLOBALG.A.P. Standard is available for 3 scopes of production: crops, livestock, and aquaculture.
GLOBALG.A.P. today is the world’s leading farm assurance program, translating consumer requirements into Good Agricultural Practice in a rapidly growing list of countries.
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FIVE Advantages of GLOBALG.A.P. Certification 1. Add value to products by complying with a globally recognized standard. 2. Gain access to new local and global customers, markets, suppliers, and retailers. 3. Reduce exposure to food safety and product safety reputational risks. 4. Improve the efficiency of farm processes and management. 5. Get a GLOBALG.A.P. Number (GGN) for easy identification and traceability on a B2B level. Cost of certification The costs for GLOBALG.A.P. certification consist of the following: • Costs for implementing the standard: Each farm is unique, so depending on their specific situation, some farms may need to implement new policies, processes, and installations to comply with the standard.
GLOBALG.A.P. certicate held by shade net farmers.
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bodies in the country, register Farm Assurance Standard certificate with the one you choose, and for the relevant version and scope • GLOBALG.A.P. registration fee: get your GLOBALG.A.P. Number which is valid for one year. Charged by the GLOBALG.A.P. (GGN). Find a full Environmental Sustainability Secretariat via the list of GLOBALG.A.P. on the farm certification bodies. The majority of retailers in approved The GLOBALG.A.P. Integrated Farm To view the fee today’s markets require certain certification bodies Assurance Standard for crops and table, visit https:// at www.globalgap. standards that ensure safe and aquaculture production addresses www.globalgap.org/. org/approvedcbs. sustainable agriculture, and environmental sustainability elements, content/.galleries/ • Carry out a selfwhich are assessed by a technical auditor documents/170411_ GLOBALG.A.P. certification assessment using the who also assesses the food safety General-GG-Feeis highly regarded as a reliable checklist and correct elements. These elements include the Table_2017_V4_ standard for demonstrating all the points you development of a waste and pollution en.pdf. do not comply with. on-farm food safety and action plan, evaluating the impact of the For producers A GLOBALG.A.P. sustainability. farming activities on the environment, farming crops, the licensed Farm responsible use of water, and generally GLOBALG.A.P. Assurer (approved being mindful of unproductive sites and producer registration fee is charged consultant), who is a trained and using energy efficiently. per area (hectares) under production. approved consultant, can Currently, there are more GLOBALG.A.P. distinguishes between provide you with than 209 000 certified covered (plastic tunnels or shade net valuable assistance producers in over 135 structures) and non-covered production. during your audit GLOBALG.A.P. countries (19,4% Service fees to the certification body: preparations. certificate of these are in Costs for the audits (time, travel costs) Visit: https:// recipient Africa). There and services provided by the independent www. are more than certification body are negotiated globalgap. 600 products directly between the producer and org/uk_en/ that producers the certification body and depend on what-weof these can individual price policies, duration of do/thecertify under the audit, travel costs, time needed for gg-system/ GLOBALG.A.P . preparation, and follow-up. gg-farmFresh produce assurers/FarmTo find a list of all certification bodies, are the main types Assurer-List go to www.globalgap.org/approvedcbs. of produce being • Arrange an Please note: Certificates are issued per certified for. There are appointment with the product and are valid for 1 year. more than 2 000 inspectors GLOBALG.A.P. approved Steps to Get Certified from about 160 accredited certification body. An inspector certification bodies (CB’s) which are • Download the relevant will then conduct the first on-site approved to inspect the GLOBAL G.A.P. GLOBALG.A.P. Standard documents inspection. standards. and checklists for free by visiting • Once you successfully comply with the website: www.GLOBALG.A.P. Readers of Undercover Farming who the standard’s requirements, you will documents wish to know more about GLOBALG.A.P. receive a GLOBALG.A.P. Integrated • Compare offers from the certification should visit www.globalgap.org. globalg.a.p.
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Undercover Farming CTICC International Convention Centre, Pretoria
Monday 24 February 2020 07:00 - 09:55
Registration: ALL DELGATES & EXHIBITORS – Network on Expo Floor
09:55
Welcome: Suzanne Oosthuizen, MD: Undercover Farming Expo
10:00 – 10:45
“Greenhouse Leasing Concept” Presented by Vaughan Coetzee - Model Capital
10:45 – 11:30
“Clearing and Forwarding in 2020” Presented by Laura Dewar - GAC Laser
11:30 – 12:15
“The role of regulation in agriculture” Presented by Zodwa Cibane & Francois Knowles - APAC
12:15 – 14:00
LUNCH BUFFET - (Registered Delegates & Exhibitors Only)
14:00 – 14:45
“Characteristics of an efficient irrigation system” Presented by Isobel van der Stoep - Cherry Irrigation
14:45 – 15:30
“Integrating bio-solutions with conventional chemistry” Presented by Jaco Marais - SABO
15:30 – 17:00
Networking on Expo Floor
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Expo & Conference ’20 Tuesday 25 February 2020 008:00 – 09:00
Registration / Networking session with Exhibitors (Tea & Refreshments will be served)
09:00 - 09:45
“Soil health” Presented by Koos Coetzee - Shiman
09:45 – 10:30
“Current world trend: Control of pest and diseases without chemical residue” Presented by Nico Uys - AgroOrganics
10:30 – 11:15
“New innovation in Calcium nutrition” Presented by Gerrit Burger - Haifa
11:15 – 12:00
Tea
12:00 – 12:45
“Organic waste management, Growing media amendments and Plant & pest disease control” Presented by Roger Jaques - UkuZwana Project Management Solutions
12:45 – 13:30
“Herb Health & Essential oil - Growing Commercially” Presented by Dr Gail Pedra - The Herbal Counter
13:30 - 15:00
LUNCH BUFFET - (Registered Delegates & Exhibitors Only)
15:00 - 17:00
Expo Floor open to visitors
17:00
Breakdown of expo stands
CTICC International Convention Centre, Pretoria
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Ideal for soilless grown crops and hydroponics
Recommended for Izones of I hydroponics ExtraI convenience greenhouses shade net aquaponics high sun irradiation in handling
Haifa Chemicals
Haifa South Africa
P.O.Box 1409, Brackenfell, 7561, South Africa Gerrit Burger | 082 8008766 | gerrit.burger@haifa-group.com Michael Koch | 083 2314516 | michael.koch@haifa-group.com www.haifa-group.com
is pioneering the future of
Calcium Nitrate Nutrigation™
All greenhouse growers will know that calcium (Ca2+) is an element that is required in large volumes by most plants. These include tomato, pepper, lettuce and cut flowers etc.
H
owever, calcium can be a very delicate nutrient to manage, not only in the nutrient solution, but also in the plant itself. Calcium is specifically known to cause chemical interactions with other nutrients when present in high concentrations, e.g. phosphates and/ or sulphates, within the same nutrient solution stock tank. Furthermore, certain growing systems and environments tends to create abiotic conditions that predispose a potential calcium deficiency within the plant or fruit. Selecting the correct fertilizer product for your unique farming system will ensure that your plants have the best possible fertilizer which promote nutrient uptake and results in optimal yield and quality. Haifa Cal™ Prime is the new improved and concentrated calcium nitrate fertilizer from Haifa South Africa. Haifa Cal™ Prime is 100% water soluble and is setting new standards with its near zero ammonium (N-NH4+) level. Standard calcium nitrate typically contains between from 1.1 – 1.5% ammonium nitrogen. Haifa Cal™ Prime contains 0.3% N-NH4. This unique property becomes very important when growing soilless crops, especially in NFT or soilless systems which have low buffering properties. Research by Kafkafi (1990) has clearly shown that elevated N-NH4+ levels and subsequent plant uptake becomes dangerous and detrimental within the plant at high temperatures and radiation levels. These challenging growing conditions, coupled with a dry/ low
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N-NH4+ to reduce the potential toxic effect thereof within the plant. Haifa Cal™ Prime is highly concentrated and offers a 10% increase in nitrate (N-NO3-) contents and 24% increase in calcium compared to other calcium nitrate products. The higher level of nitrate nitrogen (N-NO3-) further promotes the uptake of other important cations, including Ca2+, Mg2+ and K+. The superior solubility compared to other calcium nitrate products, makes Haifa Cal™ Prime extra Haifa Cal™ Prime is convenient to apply by Nutrigation™ or the new improved and foliar spray. Further concentrated calcium improvements nitrate fertilizer from with regards to Haifa South Africa. hygroscopicity also Haifa Cal™ Prime is ensures that Haifa 100% water soluble Cal™ Prime remains dryer for longer and is setting new when exposed standards with its to air. These near zero ammonium characteristics make (N-NH4+) level. Haifa Cal™ Prime the ideal option when needing to supply you crop with humidity climate, are typical to most the best source of water-soluble calcium of South Africa’s production areas. nitrate on the market. With elevated plant transpiration and subsequent water uptake, it is even more important to ensure a nutrient solution with near zero levels of
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Contact your closest Haifa distributor for details about this unique product offering.
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NEW
Haifa Cal™ Prime Concentrated Calcium Nitrate + More calcium + More nitrogen + Near zero ammonium Haifa's new prime grade of calcium nitrate offers multiple benefits for growers who seek the most precise results in challenging growth conditions. With high concertation and near zero ammonium level this new product sets new standards of calcium nitrate.
Ideal for soilless grown crops and hydroponics
Recommended for zones of high sun irradiation
Extra convenience in handling
Haifa South Africa
P.O.Box 1409, Brackenfell, 7561, South Africa Gerrit Burger | 082 8008766 | gerrit.burger@haifa-group.com Michael Koch | 083 2314516 | michael.koch@haifa-group.com www.haifa-group.com Undercover farming I
January/February 2020
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Cultivating Medical Cannabis in South Africa The South African Cannabis industry is on the move. This editorial takes a look at growing medicinal cannabis in South African regions, including the medicinal cannabis industry’s impact on the South African economy.
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he past year has been a tough one for local farmers, who face a more uncertain future than ever before. Debates over land reform and battered by the weak currency, the local Rand has seen a downward trend over recent years that has culminated in record high fuel prices and higher unemployment. Farmers might be turning the corner however, given a recent decision made by the Constitutional Court, the highest court in South Africa.
New industry growth Some light has been shone on the beleaguered farming community, with many thinking now is the time to take advantage of a burgeoning new global industry – legalised medicinal cannabis cultivation and CBD exportation. The Constitutional Court’s decision has paved the way for medical cannabis cultivation in South Africa, with licenses now being given out to farmers meeting stringent criteria. The question is often posed; “What makes South Africa a great place to grow medicinal cannabis for exportation?” SA ideal for cannabis cultivation
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The experts in medicinal cannabis cultivation believe South Africa is an ideal country to cultivate and manufacture medical marijuana (medical cannabis including CBD products). Here’s why South Africa production license applications, GMP extraction methods, related engineering designs, safety and security measures are growing in demand. Climate conditions, temperatures and rainfall averages affecting medicinal cannabis crops and yield • The climatic conditions in South Africa generally range from Mediterraneanweather conditions in the southwestern corner of South Africa to temperate conditions in the interior plateau; with subtropical conditions prominent in the northeast regions. Most of the country has warm, sunny days and cool nights. • Temperatures are influenced by variations in elevation, terrain, and ocean currents more than latitude. • Rainfall in South Africa generally occurs during summer months (e.g., November through March in the southern hemisphere). • In the southwest around Cape Town,
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however, rainfall generally occurs in winter (e.g., June to August).
Solar radiation averages The southern African region mostly has sunshine all year round. According to the South African Energy Department (the Department of Energy in the Republic of South Africa), the annual 24-hour global solar radiation average is about 220 W/ m2 for South Africa, compared with about 150 W/m2 for parts of the USA, and about 100 W/m2 for Europe and the United Kingdom. • This makes South Africa’s local solar resource one of the highest in the world. • Thus, making use of solar energy can be highly beneficial and is a readily accessible resource in South Africa for cultivating medicinal crops for herbal medicines, such as hemp and CBD products. Most areas in South Africa average more than 2,500 hours of sunshine per year • The average solar-radiation levels range between 4.5 and 6.5kWh/m2 in one day. • These solar radiation levels make it
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highly suitable to cultivate medical cannabis in specially-designed greenhouses for growing medicinal cannabis in the region. • This will dramatically reduce the cost of production when compared to indoor facilities, making it a highly competitive product.
South Africa industry expansion Licencing application requirements and licence approval timeframes in South Africa Cannabis cultivation, exportation, extraction and GMP requirements All cultivation of medicinal cannabis is subject to strict regulations and good manufacturing practices (GMP). Policies and regulations will examine a variety of additional licencing factors. These are likely to include crop yield and cannabinoid consistency, CBD product quality, security, safety and sustainability including land and water resource management. In historically disadvantaged countries, security, stock monitoring and exportation logistics are also likely to require close supervision with dedicated, tamperproof software systems. Other strict cultivation, CBD extraction and exportation standards are likely to apply; e.g., many industry experts expect to see frequent Government Regulation Agency audits of plantations, production and CBD extraction processes, and logistics and quality testing of exported products designed to meet global demand. Licensing The number of South African licences issued for medicinal cannabis cultivation and exporting is not precisely clear, but at least four (4) licences appear to have been granted according to industry reports. • Timeframe for getting a medicinal cannabis licence approved for cultivation in South Africa: Estimated 6 months, with some variance • Estimated cost of licencing including facility design: Up to R 6,000,000 • Medicine Control Council of SA (MCC) controls and regulates the exportation licencing
Medical Cannabis License To obtain a medical cannabis license in South Africa is not simple to come by. There are rumours of only a handful existing licenses. The process evidently only caters for rare cases that can rely on the one dimensional aspect of isolate and synthetic cannabis pharmaceuticals. Many genuine medical users therefore have neither the time nor the motivation to deal with the bureaucracy. This is before even considering the significant personal and financial costs involved. Those who would like to grow “medical cannabis” need to ask themselves one question - Do I have the means and five or more years to invest in producing legal pharmaceutical drugs? Because, that is what it will take to begin production of medicinal or pharmaceutical cannabis. This is well before you are even able to produce something that can compete with existing, over the counter pharmaceuticals. Interested parties should contact the South African Health Products Regulatory Authority to find out more. Industry and Investor update: The response since foreign cannabis production consultancies entered South Africa has been truly phenomenal. It is understandable why organisations view the medical cannabis industry as an appealing new sector opportunity, with unprecedented growth expected in consumer demand worldwide. However, this is a heavily regulated industry with strict production requirements to protect patient safety and employee security in view of producing and exporting this recently legalised drug.
Latest news: Small farmers A report published at the time of going to press, indicated that government decided to open the cannabis growing licensing to small farmers as well. Which means the small entrepreneur will now also be able to obtain a license for medicinal cannabis production and be able to compete in the market of SA growers. South Africa’s suitability for growing cannabis and for medicinal cannabis startups (industry consensus) • In a fledgling industry expected to be worth from $20 billion to potentially $650 billion by 2025, many people believe this is an optimal time to invest in large scale medicinal cannabis cultivation in South Africa. • Given the unique combination of weather and climate, labour costs and some of the best infrastructure in Africa, the country’s prospects for economic growth, including increases to South Africa’s GDP and GNP, appear
significant in the global cannabis sector.
SA Cannabis Sector Growth expected 2019-2025 • South Africa has an ideal climate for cultivating cannabis, with the world health organization estimating that South Africa is the 3rd largest producer of cannabis in the world. • Employed in both the formal and informal market, the Cannabis industry is keeping the bread on the table for an estimated million South African workers in a critically scarce job environment. • The key to going forward will be using these informal skills and industrializing it, with the rigours of meeting the current market requirements and GMP to compete at a global level. Progressive legislation in Europe and the Americas represents a unique opportunity for the cultivation and exporting of medicinal cannabis and CBD. Given the value of the rand, South African cannabis could be highly competitive in the global market. A recent report by Prohibition Partners suggests that South Africa’s domestic market for cannabis and related products would be worth R27 billion by 2023. This means a welcome financial injection to a country that is seeking alternative ways to stimulate growth and reduce unemployment levels. With legal licenses being judiciously approved in South Africa, many are seeking to ‘get their piece of the pie’. There is a massive new opportunity in South Africa. While the market is still establishing itself, things are moving forward very quickly. Many believe that now is the time to get involved. This could be the modern day South African gold rush…the green rush if you will. Source: PharmOut
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close to an airport; objects which may fall from the aircraft), Electronics (all electronic gear; greenhouse management system, office computers, portable phone instruments, printers etc), Specified items like pumps and important loose items which can be stolen or burn out), Transport (all vehicles, business and private covered under separate cover) and lastly; Once-off insurance when bulk loads of produce are transported to a harbour, shipped between ports and transported to the merchant overseas – up to that point the farmer still owns the product, therefor needs to be covered. Claims are made for business interruption when produce are either lost in a storm, stolen or other events in which case you have to be insured and your general monthly expenses covered against loss of income. Crop insurance is generally offered in To entrench your business or private property against damage, the form of a hail (cold or fire included) theft or natural disasters, is simply taking responsibility of what or a multi-risks policy. As some of the you own and those you employ, market to and, last but not major agri-insurance companies in South Africa re-insure with mostly European least, your family. companies, they are limited by these according to the major commodity crops. third; External factors that is not under ife has changed much and the Thus, only so much is paid out in the case the producer’s control. Entrench your greenhouse farmer is not void of of a hail storm for instance to so many business against calculated risks; the one or another disaster or loss claimants for their loss off their apple ‘What if?’ type of happening. Look at key which could affect any or all of the crop (for example). elements in the production and logistical aforementioned people. Unfortunately, Excess payments are not always well spheres of your business to avoid major some has had poor experiences with understood. However, you are able to losses. personal insurance or short term discuss this with the broker if seek a insurance and would give the ‘terms At this point and time, the reader’s mind lower premium. There and conditions’ on the back page the is milling around the cost Be careful not to is a difference between discredit. With this editorial the intent of premiums etc. under insure – this infrastructure insurance is to enlighten the producer of how to Ask yourself the alland crop insurance – these insure in order to sleep pretty well at may negatively affect important question; “What must be defined and night. your claim in the keeps me awake at night?” separately insured. The major insurance companies that event of a loss. Now, switch on the bed Your broker and you have look after the agricultural industry have lamp, and start making to list all the possibilities brokers who are well-versed and have notes in order of importance. The second as described above and those you knowledge on agricultural matters. step is to decide what is the worst case are personally caring about. Together Whether it be open land farming, cattle scenario that would halt your business if you may then work out premiums on or dairy, fresh produce or nuts, the basics you are not there or, not there anymore? different options which is open to a are the same. It is wise to make use of a Not all of us think about the Consumer certain amount of barter and obtain by reputable broker who will visit your farm Protection Act – the producer have to this means peace of mind for you, your or greenhouse premises to understand entrench his business against claims that business, staff and family. exactly what you are producing, who could be made by a third and even fourth and where to the produce are shipped Be careful not to under insure – this party; as traceability of fresh produce, and your infrastructure related to the may negatively affect your claim in the or for that matter, all edible goods is at business. event of a loss. Most insurers enclose the order of the day. In certain countries, this clause to cover themselves. Lastly, people thrive on finding something wrong One must understand from the insurance when the policy document is handed to with a product, trace it back to the company’s point of view how they you for signature, read every entry as, producer and have him fined for millions. operate in order to take cognizance once signed you are legally bound to the of the different risks involved and When deciding to insure, take the time contract and confirmed all details are what the order of importance is of the and effort to make a list of all possible correct. infrastructure under ownership. risks. List them in compartments of
Insurance and the
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Three types of risk are to be taken into account; Natural disasters (commonly known as an ‘Act of God’), Losses incurred under management and the
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infrastructure (life expectancy of plastic covering, shade cloth, actual support system), Fire and Peril insurance items (wind, hail, water, malicious damage, if
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This editorial was compiled with the kind assistance of Andries Wiese of Hollard and Martin Malan of MM Makelaars.
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Why sanitation is important
to undercover farmers
The term sanitation is seldom used in everyday life, but should be practised by all members of society on an on-going basis throughout our lives through personal hygiene. We are fortunate that sanitation is also forced upon us by legislation, for example, most of the water we drink has been sanitised. The main purpose of sanitation in our daily lives is to prevent us from getting diseases.
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s our population increase, the pressure to keep basic sanitary standards high also increases. The same basic sanitary requirements are also applicable to plants. The higher the population of a plant species in a greenhouse, the more important sanitation becomes as a method of controlling plant diseases and pests. Sanitation is an integral part of disease and pest control in any greenhouse situation and furthermore, sanitation must be part of the initial planning. Three basic components must be present for a plant disease or disease epidemic to occur namely; a susceptible host, a pathogen and a favourable environment. If any one of these components can be eliminated, the onset of the disease or pest can be prevented.
Knowledge is power The first step is to get to know as much as possible about the pests and diseases that can affect the crop you are growing. In the case of a disease, for instance, learn about the primary sources of inoculum, methods of secondary spread of the disease, environmental conditions conducive for disease development and possible methods of eliminating the disease. Not all pests and diseases can be effectively controlled with the use of chemicals. Planning The term “crops under protection� can include a very wide range of production methods from crops grown directly in the soil under shade netting to highly sophisticated closed hydroponics systems where the environmental (temperature and humidity) are automatically controlled. The following are important regarding standards of sanitation and should be taken into account in the planning of the greenhouse: The layout must favour natural ventilation in all parts of the greenhouse.
The greenhouse must preferably have a solid concrete floor with an effective drainage system. Plant containers (open bag system) must not be placed directly on the floor/ground, but on plastic sheeting. Drainage water from pots must not be allowed to accumulate or to flow from one container to the next. Sufficient space between rows must be allowed for workers to move freely between benches without touching the plants.
A wash basin must be available for workers. Growth medium must be stored in a closed environment with a solid floor. Precautions must be taken to avoid contaminating the medium with soil. A site, well away from the greenhouses must be allocated where plant debris and old plants are destroyed. A reliable water source must be available. Borehole or municipal water is preferable, but if other sources are used, water must be sanitised. All water must be stored in closed tanks, not in open dams. Access to the greenhouse must be restricted, and a foot dip, containing a disinfectant, must be installed at the entrances.
Greenhouse assistants One mistake by one person can cause a disease epidemic. The selection and training of the assistants that work in the greenhouse is the key to success in the operation. The assistants are the people that must practice dayto-day sanitation measures. The disinfection of equipment is critical, but the assistants must also be equipped with disinfectants/detergents and wash facilities to minimize the spread of disease. The most successful operations are neat and have well trained personnel. A set of written sanitation guidelines is the most efficient way to get every assistant familiar with sanitation
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Ammonia Management in Aquaculture Several times per day we feed our fish a high quality diet so that they will grow quickly and retain optimal health. They digest this feed, reduce the proteins in the diet to amino acids, and then reassemble these amino acids into their own form of protein for growth. During this process a nitrogen-rich by-product called ammonia is produced, but this ammonia is toxic to the fish.
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mmonia is transported by the blood from the cells to the gills where it is released into the water by osmosis, preventing its accumulation within the body which would result in the poisoning of the fish. Different species of fish tolerate ammonia differently; at 0.5mg/ℓ trout are already showing signs of discomfort, whereas tilapia and catfish tolerate a concentration of even 5mg/ℓ without problems. Fry are significantly more sensitive than adults of the same species with a hatchery ammonia level of 0.5mg/ℓ being highly undesirable, even for tough species such as catfish. The concentration of ammonia in fish water is measured by means of an ammonia test kit or a spectrophotometer, the latter rarely being used as it is expensive, slow and the highly accurate reading is seldom justifiable. Test kits are inexpensive, quick and easy to use, and provide an answer that is accurate enough to serve as an early warning system should the Why sanitation is important
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measures. The greenhouse manager must be familiar with these guidelines too and must set a good example to the staff. The practise of sanitation must become a habit. Signs can be used to remind employees about the sanitation programme. Assistants should be prohibited to grow the same crop in their gardens, as it can be a source of
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water borne ammonia concentration approach an undesirable level. In truth, what we measure is not ammonia but the less toxic form ammonium. The ratio of ammonia: ammonium in water is a function of temperature and pH, with an increase in either resulting in a swing towards the more toxic ammonia. As such, it is important not to farm fish at temperatures or pH levels than are higher than is optimal for the species being cultured. In cages the ammonia released by the fish washes out of the cage with water movement, and thus never accumulates to problematic levels. Earth ponds contain low numbers of fish and are fertilised weekly to stimulate the growth of the feed chain within the ponds, and as such ammonia in a correctly stocked pond is not a problem. Under recirculating conditions the fish are stocked at high densities and the water continuously re-circulated through filters and back to the fish, allowing for rapid accumulation of ammonia to toxic levels. To avoid ammonia build up in a Recirculating Aquaculture System (RAS) we make use of a bio-filter which is colonised by desirable bacteria that convert the ammonia via nitrite (also toxic) to nitrate which is benign, allowing for the water to be re-circulated many
times before toxic levels are reached. The bio-filter bacteria require certain specific conditions in order to be able to perform optimally, including 27°C, saturated oxygen, pH of 7.5 and darkness. Under these conditions their performance is rapid and predictable, but away from these conditions they slow down. Trout farmers who produce their fish at 15°C therefore require a larger bio-filter because the bacteria operate slower at 15°C than at 27°C. All systems require saturated oxygen to function at their best, and this is part of the reason why the global aquaculture industry moved to using fluidised biofilters in the early 2000’s as they provide conditions of saturated oxygen. Ammonia is tested daily in most RASs to stay abreast of the trend and avoid toxic levels. If the readings are found to approach the threshold, ensure the bio-filter is clean, ensure the bio-filter is aerating evenly, check that the pH is correct and if necessary add Bio-Pond to mop up the ammonia in the water. Feeding is one of the most important activities on a fish farm but remember; that over-feeding can quickly result in undesirable ammonia accumulation. As you feed your fish, be sure to give them enough for good growth, but not more, to limit the risk of ammonia toxicity. Leslie Ter Morshuizen, AquaAfrica
contamination. In the greenhouse The primary inoculum source depends on the disease. Some diseases are airborne while others are water and/or soil borne, and some are transmitted by insects. Many diseases are disseminated through seed or other propagation material. The seed source must be very reliable. In the case of bacterial diseases
of vegetables, warm water treatment of seed is strongly recommended. This treatment should be done by a reliable laboratory. The other sources are eliminated or kept at a minimum by measures already mentioned. All steps must therefore be taken to prevent possible introduction of the pathogen into the greenhouse. Source: ARC – OVP Roodeplaat
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About Soil-less plant production – Nutrient Solution Management 1 Greenhouse crop production can be optimized by improving conditions favouring photosynthesis. Carbohydrates are produced in green leaves of plants, using light energy, carbon dioxide (CO2) and nutrient-rich water. Plants need thirteen essential nutrients, an aspect that must be well managed in soil-less (hydroponic) production systems. Therefore, nutrient management will receive special attention in this and future similar editorials by Dr NJJ (Nic) Combrink of the Horticultural Faculty, University of Stellenbosch.
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s a guide for fertiliser needs of field crops, soil samples are taken and nutrients are extracted from the soil, using salt- or acid solutions. With these extraction methods, almost all the adsorbed nutrients are removed from the sample. These relatively high levels of extracted nutrients are used as norms to determine fertilizer needs for field crops. Compared to these high levels of extracted nutrients, nutrient levels that are found in soil water are much lower. These relatively low nutrient concentrations can be compared with concentrations used in nutrient solutions. Arnon and Hoagland (1940) developed one of the first nutrient solutions for soil-less crop production. Several other nutrient solutions followed (Cooper, 1979; Steiner, 1984). Modern nutrient solutions do not differ much from those published by Arnon and Hoagland (1940) and Cooper (1979), apart from the introduction of chelated 22
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iron (Deckers, 2006). In this publication, guidelines from Naaldwijk in the Netherlands (De Kreij et al., 1999) were used as basis to propose nutrient solutions for different greenhouse crops. Since lower concentrations of nutrients are needed under warm conditions with high light intensities (Chiloane, 2013), these Naaldwijk levels were slightly lowered to be used under South African conditions. Techniques to correct the total alkalinity of feeding water for different crops and substrates, as well as local procedures to top-up existing nutrient levels in feeding water, received attention and results were reported as progress was made. In Europe, nutrient solutions are managed by specialist companies, serving growers in densely populated production areas in the Netherlands and in Belgium. In South Africa, production areas are thousands of kilometres apart. Since South African growers rely on help from local advisors, the proposed guidelines in this editorial series should be tested and improved to serve the local hydroponics industry.
is logarithmic, meaning that a solution at pH 5 is hundred times more acidic than at pH 7, and a solution at pH 6 is ten times more acidic than at pH 7. At pH 8, a solution is ten times more basic than at pH 7. Therefore, the pH value of water will not decrease linearly when acids are added. Total alkalinity is the aggregate concentration of bases such as carbonate (CO32-), bicarbonate (HCO3-) and hydroxide (OH-). The total alkalinity of a solution is determined by measuring the volume of a known acid to lower its pH to a fixed value. Total alkalinity may be expressed as HCO3-, but some laboratories prefer to express it as CaCO3 or as CO3. By manipulating the total alkalinity of a solution, the pH can be controlled. Before fertilizers are added to feeding water to prepare a nutrient solution, the water’s total alkalinity should be set at a level, suitable for the crop and production system. This is needed to prevent precipitation of insoluble salts (at high alkalinity levels) and to ensure that optimum pH-levels are reached in nutrient solutions.
Electrical conductivity (EC) Electrical conductivity is a well-known term amongst soil-less growers and is used as an indication of the salt content of water and nutrient solutions. Higher concentrations of charged particles (ions) in water increase its EC. When salts are added to water, the crystals dissolve or ionise, causing an increase in EC. Using table salt (sodium chloride; NaCl) as an example, one sodium cation (Na+) and one chloride anion (Cl-) will be released per dissolved NaCl unit. These charged particles in the water enable the flow of an electrical current. The higher the concentration of ions per unit volume of water, the higher its EC will be. High EC solutions are better buffered against pH change than pure water. This means that small applications of H+ or OH- may drastically Managing the EC and pH of the solution irrigated to your plants, lower or increase the ensures a healthy crop.
Acidity and alkalinity The pH is a value taken to represent the acidity or alkalinity of an aqueous solution with values ranging from 1 to 14. The pH is neutral at a reading of 7, where equal concentrations of hydrogen ions (H+) and hydroxide ions (OH-) occur. Values lower than 7 indicate acidity whereas pH values higher than 7 are alkaline. The pH scale
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pH of pure water compared to more H+ or OH- needed to change the pH of a well buffered or high EC solution. The use of different EC units may confuse growers. Siemens (S) is the SI unit for conductivity. Since the conductivity of standard nutrient solutions are relatively small, the 1000 x smaller unit; milli Siemens (mS) is used. The unit ‘mho’ is equivalent to S and mmho to mS. Certain laboratories use the electrical resistance of soil as indication of its salt content. Due to an inverse relationship between conductivity and resistance, higher resistance values (measured in ohm) are indicative of low salt contents. A lower resistance implies that more salts are in solution and the conductivity will thus be high. The direct relationship between conductivity and salt content is easy to understand and an extremely important managerial tool for soil-less growers. The distance between the two electrodes, used to measure the conductivity of a solution, also affects the reading. The reading in mS m-1 will be 100 times bigger than a reading in mS cm-1. Most growers use mS cm-1 as unit. Depending on the crop and the season, these values may vary between 0.7 mS cm-1 and 3.0 mS cm-1. The EC of good quality feeding water may be very low, explaining why most laboratories prefer to express the conductivity of irrigation water in mS m-1. Since temperature affects EC readings, EC meters are calibrated at 25oC. The electrical conductivity of a solution increases with an increase in temperature. For example, EC readings can be expected when a standard 2 mS cm-1 solution is measured at different temperatures. Further information on this important aspect of undercover farming will follow in future editions of Undercover Farming. Readers who wish to obtain this very valuable updated manual on Nutrient Solution Management by Dr NJJ Combrink, you may contact him at njjc@sun.co.za.
Dr NJJ (Nic) Combrink, author of Nutrient Solution Management.
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The importance of daily inspection of grow slabs Daily measurements of the grow slab by hand meter offer essential information on what is going on in the slabs. It is important to confirm the readings of any fixed sensors and to show the standard deviates across the greenhouse.
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every plant. More and his data will give more potential control over the crop more growers are using fixed sensors to increase yield and quality as and weigh scales to well as more efficient use of monitor the changes water and fertilisers. Greenhouse crop in the root zone to production uses a fair amount of water. In the future this has to change as water control plant balance. This is an important is becoming increasingly scarce in some tool for controlling countries and more expensive. More the irrigation strategy efficiency in the use of fertilisers and a so it is vital to be reduction in emissions is also becoming sure that these legislation. measurements which To reduce water and fertilizer use to come from a small sample of slabs are the substrate needs good management giving a representative reading for the to avoid problems and stresses. There whole of the greenhouse. should be target levels for water content, EC and Greenhouse crop production Hand held meters for measuring water drain percentage uses a fair amount of water. content, EC and for the crop, but it In the future this has to temperature have is also important to change as water is becoming been used in the monitor the standard industry for many deviation in these increasingly scarce in years but not in a figures around the some countries and more constructive way to greenhouse. Hand expensive. measure, store and held metering and use the data produced. The measurement data are important. It is important that protocols are a procedure for measuring growers know exactly what is going on in and storing the data to be used by the the root zone. When using substrate, it is grower to help him make accurate becoming more and more important for decisions on his watering strategy. controlling the balance of the plant. By standardising the way of measuring, Standard deviations around the greenhouse are also important to monitor it no longer matters who carries it out: measuring is always performed in to maximise the production potential of
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the same way. The data, which should preferably be processed in an Excel sheet, can be used to determine the crop strategy. The data collected also gives a good insight into the developments during growing and can be viewed again in the future. The grower can use the conclusions and insight to optimise the growing strategy and water in a more targeted way, in order to achieve the target moisture and nutrient levels. A grower who knows what is going on in his substrate can be more efficient and therefore save water and fertiliser. The grower can also control and manage the crop better and keep the root zone under better control. This results in better quality and yield. Small corrections can be made more frequently. Prevention is better than cure in horticulture too! Source: Hortibiz
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