Haifa DownUnder Edition 25

DownUnder SPECIAL BULLETIN FROM HAIFA AUSTRALIA EDITION 25 DECEMBER 2023 CMYK Haifa Australia (03) 9583 4691 australia@haifa-group.com www.haifa-group.com THE terrorist events in Israel on October 7 have deeply shocked the country’s people and will heighten the nation’s concerns for some time to come. We would like to express our gratitude for the support and encouraging messages we have received and the continued trust in Haifa Group. Fortunately, with the war confined to the Western border of Israel, the rest of the country remains robust and the business and manufacturing sectors continue to function normally. At Haifa, we are also continuing our operations, producing and exporting the company’s renowned, high quality fertiliser products to our partners and growers around the world. Earlier, we did take the opportunity to close our production facility for a few days to address maintenance requirements and increase inventory levels, and we have since been back at full capacity to meet demand. As with many things in Israel, we are experienced in adversity and our team is dedicated to bringing the best products to market to help feed the world. Our team is strongly focused on our customers and partners, working to fulfil all orders without any delays. Expanding capacity despite adversity By Motti Levin CEO, Haifa Group We cannot rule-out logistical disruptions in the future, however with 130 warehouses around the world and two months of inventory on the high seas, our global partners and customers can have confidence in the supply of Haifa products. Currently, there are no supply chain disruptions affecting product delivery. Haifa management monitors the situation closely and adapts operations to ensure the continued supply of products around the world. In Australia, we look forward to continuing our strong commitment that has now spanned more than 40 years. We are proud to be the only global potassium nitrate manufacturer with a subsidiary in Australia, which has been operating for 15 years with a great local team led by Trevor Dennis. Despite the current difficult time, we remain dedicated to promoting investment in expanding our production capacity, developing new products and technologies as planned and to secure a stable and promising future for the agricultural sector and all its partners. During the shutdown of our facility, our staff also had the ability to spend important time with their families. Our people, like for many businesses and crop production enterprises, are the most important asset at Haifa. Our thoughts and prayers go out to all those who have been impacted by these events and for the safe return of all hostages – children, women, the elderly, Israelis and international guests. A part of us is still missing! Chris Warr, Regional Manager for Victoria and South Australia with Lindsay Rural, and Sheri Robinson, Southern Agronomist with Haifa Australia, pictured with new supplies of Haifa magnesium nitrate and magnesium sulfate that have arrived into Lindsay Rural’s Mildura store.

3 2 THE conflict in Israel has reinforced to us in Australia that strong leadership and teams are vital in business. The decision by our CEO Motti Levin to take the opportunity to close our factory in Israel for maintenance and upgrades, so we can accommodate higher inventories, also sent a strong message to all Haifa employees and their families at this difficult time – that they are valued above revenue and family comes first. This message is not lost on our team in Australia. Actions speak louder than words and our CEO has shown that the staff are the most important asset of the company. We have a strong local team in Australia and we are proud that the Haifa brand has been growing over its 40 years here, and particularly since the company strengthened its commitment with the establishment of an Australian subsidiary 15 years ago. While the factory was closed for a few days, it is now back in full operation and the team at Haifa is working together to ensure our products are on every shelf for growers across the globe. The drive and enthusiasm of the Haifa management team in Israel has ensured a return to full swing quickly and to work diligently through the adversity. Here in Australia, we are sitting safely, with fertiliser products arriving weekly and there is strong demand for our leading fertilisers. The introduction of the Haifa micronutrient fertiliser range also has further strengthened our product offering. Many growing enterprises already are using our class-leading iron EDDHA chelate, which features the highest orthoortho component in the Australian market. In the near future, we will be launching a range of biostimulant products, which are adding a new approach to growing and already have been well adopted in Europe. For further information about Haifa and our fertiliser products, please feel free to contact myself or our Australian team. Business as usual, with new products coming By Trevor Dennis Managing Director, Haifa Australia Never miss an edition of DownUnder SUBSCRIBE Email australia@haifa-group.com with the subject line Subscribe to DownUnder Sheri Robinson, Haifa Australia Southern Agronomist, with stocks of the company’s Multi-K potassium nitrate Quality rises at Coffs harbour conference HAIFA Australia highly values its long-term partnerships with key rural retailers throughout the country and was pleased to support Lindsay Rural’s recent major company conference held at Coffs Harbour in New South Wales. The value of Haifa to the Lindsay Rural business and through to its customers also was clear, with the team declaring “quality’’ to be the number one reference attached to the Haifa name in the industry. It was acknowledged that some Haifa product had remained in bags for three years in a customer’s shed and had not gone hard, which can occur with other fertilisers, while the company also was known for supplying the lowest sodium and chloride fertiliser options in the industry. Haifa Australia Managing Director Trevor Dennis said the company worked hard to tailor its fertiliser offer to retailer businesses and it was the only potassium nitrate supplier providing local support. Trevor said the importance of quality in all goods was once again coming to the fore amid the changing global market conditions of recent times and had remained a primary purpose for Haifa and its Australian team. Haifa can supply certificates of analysis Fertilizer Australia said customers should source products from its members, which have to comply with a code of conduct, or ensure they requested product labels, which assist traceability. To help guide industry best practice, Fertilizer Australia has developed the ‘National Code of Practice for Fertiliser Description and Labelling’ and this is available on its website. for its products to ensure growers know they are getting what they pay for, and full control over manufacturing ensures its fertilisers are free of any impurities. This quest for quality in the industry is being strongly supported by Fertilizer Australia, which is undertaking a product labelling and stewardship awareness program. The aim is to ensure growers are buying products that can be traced for food safety and which comply with Australian industry regulations. Fertilizer Australia has claimed product via new suppliers in recent times has not always met Australian standards and it has urged users to insist upon labelled fertiliser products. Some products also have arrived without certificates of analysis or safety data sheets. Lindsay Rural National Sales Manager George Piccirillo and Haifa Australia Managing Director Trevor Dennis sample raspberries on a field trip during Lindsay Rural’s recent company conference at Coffs Harbour. Haifa Australia Southern Agronomist Sheri Robinson (third from left), with some of the latest members to join the Lindsay Rural team, including (rear) Paul Truong, James Dunn and Warick Bellert and (front) Tan Nguyen, Marija Tromp and Pardeep Kumar, with Michael Singh.

5 4 NutriNet advances praised for latest fertigation programs FURTHER refinement of Haifa’s NutriNet online tool, used to help design customised fertilisation programs for growers and advisers, impressed the Lindsay Rural team at its recent company conference at Coffs Harbour in New South Wales. Haifa Australia Northern Agronomist Peter Anderson took the team through the latest developments before generating an example fertiliser program for blueberries grown in the local area. The powerful NutriNet program incorporates plant nutrition knowledge accumulated by the company over decades of field and research and development activities worldwide. It integrates data regarding crops, soil type, water analysis, irrigation system setup and other grower preferences. Together with comprehensive plant nutrition databases covering 80 common crops, the data is then compiled in order to generate precise fertilisation programs that meet the specific need of the particular crop under actual growth conditions. To obtain the correct application rates within their nutrition programs, all growers have to do is plug-in their irrigation and fertiliser data. Lindsay Rural team members praised the significant jump in sophistication of the latest Haifa NutriNet system and, consequently, its fertiliser application accuracy within wider irrigation and fertigation programs. Unique tools to help grow better crops FoliMatch NutriNet YOUR PERSONAL ASSISTANT FOR FOLIAR SPRAYING PLANT NUTRITION EXPERT SYSTEM. TM • Enjoy a rich and updated database about the crops you grow • Incorporates local climate data, soil analysis, irrigation water quality and more • Design customised Nutrigation™ programs • Work with the most accurate plant nutrition program • Manage your fertilisation programs online In three easy steps, FoliMatch™ generates accurate fertiliser recommendations based on local conditions and specific crop growth stages .... and you can share it! CMYK Click for further info NutriNet

7 6 DON’T miss out on micronutrients! That was the clear message from Haifa Australia Southern Agronomist Sheri Robinson to the Lindsay Rural company conference at Coffs Harbour in New South Wales to ensure growers maximised crop production and returns. It also came with some living proof examples following some deficiencies of some micronutrients in select crops during the most recent season, plus some investigations being carried out with Lindsay Rural team members for the benefit of their grower customers. “NPK nutrients are the big wheels, but micronutrients play a key role and we don’t want to miss them,” Sheri told the conference. “There also can be a lot of synergism and antagonism, so we need to monitor and test for them.” She said some soil, plant tissue, water and soil solution testing had been conducted in South Australia as a case study where a lot of NPK had been previously applied to crops, but there had not been such a strong focus on micro element nutrition. “Looking at a full range of data, we are then able to go back and show what is happening, including the relevant antagonisms and synergisms, and find the necessary balance of nutrition and pH adjustments for optimum availability.” Sheri said micro elements were largely cations (boron an exception) that competed particularly with calcium, potassium, magnesium and each other. “Ammonium to nitrate balance also influences plant cation/anion uptake. Fast growth caused by high ratio of ammonium to nitrate and high nitrogen blends can dilute the micro elements at a plant level due to competition of uptake and micro element supply not meeting the growth demand by the plant.” “Most micronutrients are poorly available in soils above 7.5 pH or below 5 pH. Molybdenum, as an exception, is available at high pH but not low pH.” She said irrigated water was immediately available to plants, so growers should consider balanced feeding, including micronutrients, as well as the water’s pH and EC whilst fertigating. These can be easily checked at the dripper with a hand-held pH and EC meter during fertigation. “If your soil or water has high pH and you want your nutrient solution to be in the more acidic range, consider using Haifa’s Multi-K pHast product. Typical Multi-K potassium nitrate has a pH of 9, while the pHast product has a pH of 4. You can choose between these two products in your fertigation recipe to help adjust to the ideal water pH for nutrient uptake.” “Check pH and EC at output to the crop to ensure fertiliser is delivered at ideal levels – for example, pH 6 if alkaline soil and pH 7.5 if acidic soil. This will induce buffering that can help availability in soil solution. “Don’t forget our micronutrient products as part of your balanced feeding recipes. Or try our Poly-Feed fertilisers that are recipe-mixed for establishment, vegetative growth or productive stages. These also come in pHast low pH blends to address your soil needs.” Sheri said achieving a balance of ions, a full range of nutrition including micro elements and correct pH was the key to high production and plant performance. “Plant analysis gives a guide to performance and uptake of nutrients, and notes on plant growth and vigour, as well as photos of leaf health, should also be considered when reading these results.” Micronutrients key to maximum returns “Another reason to do plant analysis is micro elements like boron and manganese don’t show symptoms in crops until it has become more drastic, and by then it has already had a big impact.” She said the southern almond industry experienced cooler conditions last season and there were noticeable leaf health differences between trees. “Micronutrient availability for uptake is affected by soil temperature and soil moisture levels. Root activity also determines uptake and, thus, more focus on micronutrient applications is essential for uptake in these conditions.” “Microelements don’t relocate in the plant, so consistent supply to the plant is essential. “If trees are not taking up enough micronutrients from soils, then foliar applications need to be applied. Foliar applications are a good backup when root activity is slow, or when overcast and hot conditions slow transpiration. “To increase root uptake in cool, wet springs, higher phosphorus blends can be used and seaweed added to maximise root growth. Micro element soil applications combined with foliar are best in cool, wet seasons.” Haifa’s popular Poly-Feed fertiliser supplies micronutrients and the company also is now separately supplying a suite of chelated micronutrients to the local market, including a range of iron chelates. Haifa’s EDDHA iron chelate offers the highest ortho-ortho level in the market at 5.2 per cent, ensuring more efficient use of the nutrient and improved production and quality especially in high pH soils. “For foliar applications of iron, ensure pH is correct in the water and use EDTA chelates in the evening due to light degradation and optimum uptake at dew point,” Sheri said. TM Haifa quality now available in micronutrients Haifa, renowned for supplying the highest quality water soluble fertilisers, is now offering the highest quality chelated micronutrients. This includes chelates with the highest stability, such as EDDHA iron with the strongest holding ability. Haifa also can supply specific micronutrient blends compatible with a wide range of fertilisers. Introducing the highest quality iron chelate with 5.2% ortho-ortho Haifa Micro Fe-EDDHA (6% Fe) Don’t waste time and money Choose the correct iron chelate for your soil pH and carefully check its analysis Strong new option for soluble chelates Chau Hoang, who supports South Australian growers for Lindsay Rural, and Haifa Australia Southern Agronomist Sheri Robinson pictured inspecting cucumbers during a field trip held in conjunction with Lindsay Rural’s company conference at Coffs Harbour. Click for further info Multi-K pHast Poly-Feed Micronutrients

9 8 Adding value in the supply chain THE Haifa Australia team joined Lindsay Rural on a one-day field trip during the company’s weeklong conference at Coffs Harbour in New South Wales recently and it reinforced the important role both play in the horticultural supply chain. The event commenced at one of Lindsay Rural’s most successful retail stores at Woolgoolga, which supplies mainly blueberry, raspberry, blackberry and cucumber growers in the surrounding areas, before viewing one of the region’s leading blueberry, raspberry and cucumber growing operations, as well as Oz Group’s hi-tech blueberry packing facility. There has been a greater focus on raspberry and cucumber growing in the region in more recent times and banana crops also have returned, while blueberry production has eased slightly. The local growing operation on a 28-hectare property featured soil-grown blueberries, substrate-grown raspberries and cucumbers produced under the Chouhan Produce brand. The property highlighted the benefits of strong investment, including in the Priva greenhouse control system from Powerplants Australia for irrigation and fertigation control, which also has allowed labour efficiencies, as well as in high quality fertilisers such as Haifa’s Multi-K GG and MKP. With similar yields produced whether in soil or substrate, the property is leaning toward substrate-grown crops due to their easier measurement and management, including via simple drip and drain testing. In pots, trace element fertilisers also can continue to be added without concern over them building up, as occurs in soils, while new crop genetics also are increasingly being released for substrate situations. The latest technologies continued at Oz Group’s state-of-the-art blueberry packing facility at Coffs Harbour, which processes about 6 million trays a year sold to produce markets and direct to supermarkets. About 140 local growers deliver fruit to the store via their trucks and utes, with their relevant blueberry variety and tray numbers all recorded and the growers later receiving fruit quality reports from Oz Group’s marketing partner, Driscoll’s. The highly sophisticated fruit grading, packing and handling equipment at the facility was an eye-opener for Haifa Australia and Lindsay Rural staff based around the country. An automatic sorting and packing machine at the facility collects eight photos per second of every berry and is the only machine of its kind that packs berries automatically. It requires only one person to operate compared with five under previous systems. Oz Group also has shown its own innovation with the development of a tray featuring a ventilation system, which already has saved the business $10 million over five years. In partnership with gas and welding specialist, BOC, Oz Group also earlier entered the growing frozen berry market through the use of controllable vibration technology at the facility that quick-freezes each individual berry. During peak operation times, up to 84 staff are employed at the site and the facility operates 14 to 16-hour shifts daily, before machines are thoroughly cleaned at the end of every day. Haifa Australia and Lindsay Rural team members enjoyed a guided tour of Oz Group’s state-of-the-art blueberry packing facility at Coffs Harbour as part of Lindsay Rural’s recent company conference. The Lindsay Rural and Haifa Australia teams visited a leading raspberry and blueberry grower as part of Lindsay Rural’s company conference at Coffs Harbour recently. Click for further info Multi-K GG Haifa MKP

11 10 Sources of potassium and nitrogen By Peter Anderson Northern Sales Agronomist, Haifa Australia HARVESTING and shipping fruit and vegetables results in mineral removal from the field. Potassium and nitrogen are exported with the crop and ideally should be replaced. Potassium nitrate supplies two x plant nutrients – the cation, potassium, as K+ and the anion, nitrogen, as NO3- (nitrate). Nitrogen Plants require nitrogen for synthesising amino acids and proteins, and N is a part of the chlorophyl molecule. Nitrogen is assimilated by plants in leaves and in roots. N can exist in different forms. The most common nitrogen fertilisers are Urea and salts of ammonia (NH4+) and nitrate (NO3-). Plants can absorb N as either NH4+ (ammonium) or NO3- (nitrate). While plants can absorb Urea directly, most N uptake derived from Urea is after it has been converted by soil bacteria into the NH4+ or NO3- form. Urea absorbed directly is not available for nutrition within the plant until it has been converted by urease into ammonium. While NH4+ is toxic to cells, it is quickly converted into amino acids and so neutralised in the roots and leaves by combination with sugars that have come from leaves as products of photosynthesis. Ammonium absorbed by roots is quickly metabolised to amino acids within the roots, using sugars that have been transported from leaves via phloem flow. These same sugars are required not only for ammonium metabolism, but also as fuel for respiration within the root cells. Nitrogen in leaves has been transported from roots in xylem flow as nitrates and it is converted to ammonium. This ammonium is quickly de-toxified by combination with nearby sugars to produce amino acids. These sugars are photosynthetic products abundant in leaf cells. Soil Urea in soil needs to be converted to NH4+ (ammonification) by an enzyme in the soil (urease) to be useful for plants. At this stage, N can be lost through volatilisation of ammonia (NH3) gas if there is no clay to bind it. Fertilising with urea and ammonium fertilisers, ie, sulphate of ammonia (SOA), is usually more efficient when soils contain high organic matter and clay, because these soil particles bind the NH4+, and some stays in the soil solution. In light soils, some N applied as Urea Potassium is very easily taken up by plant roots, but more slowly cycled between the sinks and the rate of mobilisation of K cannot match the rate of K uptake by plants, requiring application of K fertilisers. WHILE fertiliser prices have retreated significantly, global supply issues continue to pressure the market for horticulture customers. Haifa Australia Managing Director Trevor Dennis told the Lindsay Rural team at its recent Coffs Harbour conference in New South Wales that shipping costs were around half of what they were during their peak in 2021-22, while the cost of raw materials also had reduced. However, he said supply was the biggest immediate concern, with difficulty in shipping from Europe, while potassium could not be shipped in fertiliser products by Chinese exporters. “There is less than 20 per cent on the water of what there would be every other year,”Trevor said. LINDSAY Rural is on a strong growth curve and at its recent company conference it also recognised the role of its strategic supplier partners as part of the journey. A member of the Lindsay Australia group, the business has had a growth spurt of about 70 per cent since 2019 and recently added the WB Hunter chain of merchandise stores through Victoria and New South Wales to its stable. “We have been a strong services provider to the horticulture market and that will remain our core focus, and ensuring we resource the business accordingly with the suitable skillsets,” said General Manager Chris Kerton, who joined Lindsay Rural late last year. “We are a true independent with the firepower of a multi-national because of our wider business scale, and we want to keep that independence and provide great value to growers. “The breadth of our business means we can provide different areas with the right product offerings.’’ Chris said Lindsay Rural had consolidated and become more aligned with many of its strategic partners and it was looking to grow with more partners that placed a strong focus around innovation and sustainability. He said Haifa had been one of the company’s standout long-term partners. “This year Lindsay is celebrating 70 years for transport and 40 years for rural and Haifa has been a special part of that. It’s a big testament to the success of our longterm relationship together.’’ “Haifa provides high quality and fantastic support to our business, including with marketing and events. I have met the Haifa Australia team only recently in my short time with the business and I have been blown away by their support. Lindsay Rural General Manager Chris Kerton during a visit to a leading blueberry and raspberry growing operation near Coffs Harbour in New South Wales as part of its recent company conference. Haifa recognised in Lindsay Rural growth “There has also been very strong collaboration with Haifa in key product development and associated support for our customers. “We don’t have a transactional relationship with Haifa and that has been a very big aspect for us,’’ Chris said. Fertiliser prices dive, but supply concerns remain

13 12 application is much greater in higher salinity treatments. Sodium (Na+) is also antagonistic to Ca++ and at higher salinities, less Ca++ enters the fruit. Both factors are likely to cause increased BER in susceptible species. Some high-tech greenhouses growing tomatoes try to eliminate NH4+ altogether during the fruiting stage. So, for solanaceous crops when the plant is in the generative stage of flowering and fruiting, and particularly if water is saline, NO3- is the preferred N source, and application of NH4+ should be reduced or avoided in saline situations. Potassium (K+) Potassium is found in the soil in three locations – absorbed to clay and organic material (exchangeable), part of the clay structure (fixed) and dissolved in the soil water (available). K+ moves between these “sinks”. It is very easily taken up by plant roots, but more slowly cycled between the sinks and the rate of mobilisation of K cannot match the rate of K uptake by plants, requiring application of K fertilisers. Unlike N, K as a plant nutrient is found only in the cation (K+) form, but available as fertiliser in different molecules. K has many functions in plants, including transport of water, nutrients and carbohydrates, as well as for enzymes, which affect protein and energy production. The common K fertilisers: Potassium chloride KCl (muriate of potash, MOP) Potassium sulphate K2SO4 (sulphate of potash, SOP) Monopotassium phosphate KH2PO4 (MKP) Potassium nitrate KNO3 (nitrate of potash, NOP) The difference is in the anions. MOP is the cheapest acceptable form of K fertiliser, yet chloride (Cl-) is least required of all the K+ anions and it competes with NO3-. So, in saline conditions, where the impact of Cl- supplied in MOP fertiliser could further reduce crop outcomes, alternative K sources are more appropriate. SOP is roughly 44.9% K+ and 18.4% SO4--. Sulphur concentration in plants is about 6% of N concentration, and so much lower than the K concentration. Using SOP as a soluble K source in fertigation will result in much of the SO4-- being left in the soil or media near the root surface, as the roots will can be lost as ammonia gas (NH3). N is also lost through denitrification – where, under anaerobic conditions (waterlogging), soil microbes use NO3- that has been applied, or has come from the conversion of Urea or NH4+, as their oxygen source, leaving the N behind. This results in losses of N as gasses like N2O (nitrous oxide) and NO (nitric oxide) or molecular nitrogen (N2). Waterlogging is more likely to occur in heavy soils. Fertigation with trickle helps mitigate losses if Urea is applied “little and often”. The high solubility of Urea means it is pushed well under the soil surface in sandy soils, but can rise to the surface where it becomes vulnerable if soil is allowed to dry out. Use of Urea and NH4+ as N sources can also acidify the soil due to plant root chemical reactions needed to absorb NH4+. Sulphur in sulphate of ammonia (SOA) NH4+ fertilisers in time will be converted to sulphuric acid in soil, as well as by microbes, and add to soil acidity. Soilless media With intensive crops grown in media, unlike soil-grown crops, the N uptake is largely decided by which form of N is supplied. If Urea is the N source, the soilless plants requirement for nitrogen is usually higher than the rate at which Urea can be transformed by bacterial activity to NH4-, so N is normally supplied as ammonium and/or nitrate. NH4+ application to the media of soilless plants has a more pronounced effect on media pH than for soil-grown plants because of the limited media volume. So, for light soils with low organic matter and low clay content, and plants grown in soilless media, it is recommended to use the nitrate form of N. Plants Some plants are not sensitive to the N source, like grasses and beans. Some others are sensitive to the N source, like solanaceous crops, (tomato), brassicas and cucurbits. Such crops prefer nitrate and are sensitive to high ammonium concentrations. Sensitivity is moderated by temperature. As temperatures go up, respiration goes up and consumption of sugars (from photosynthesis) by all parts of plant goes up. If sugars are in high demand for root respiration during warm weather, there is less available for amino acid production, and so less absorbed NH4+ can be neutralised, resulting in free NH4+ within the roots, causing cellular damage. This same temperature effect is more pronounced in soilless crops because of the limited media volume. So, under hot conditions and particularly with NH4- sensitive crops, NO3- is the preferred N source. Physiological crop stage While there is an interaction between the cations, calcium (Ca++), magnesium (Mg++) and ammonium (NH4+), it is less important in the vegetative stage. However, it becomes more of an issue in the generative (fruiting) stage when particularly Ca++ needs to get to the developing flowers and early fruit set. While there is direct antagonism between the cations NH4+ and Ca++, there is another effect. Ca++ is transported to the flowers and fruit carried in water pulled up the xylem (transpiration) or pushed up (root pressure). NH4+ reduces root pressure, so plants like tomato and capsicum that rely on root pressure to deliver Ca++ can have the disorder “blossom end rot” (BER) regardless of the Ca++ supply. This is known as “ammonium induced calcium deficiency”. Experiments with tomato at the same total N application have shown the incidence of BER increases with higher ammonium N levels in the applied fertiliser, and that the incidence of BER at the same ammonium N take up more K+ than SO4--. In hard water (high Ca) sulphate, SO4- -, can combine with Ca++ to form gypsum, a common mineral with low solubility. SOP is an acceptable K source in situations where irrigation water supply has low Ca++ content. MKP – normally MKP is considered as a phosphorus source, as the concentration of P in plants is a lot lower than the concentration of K. NOP – N-nitrate has already been discussed above. So, when fertigating valuable crops, particularly in light soils, KNO3 can supply all the K nutrition and some of the N nutrition. For salty or sodic soils, it is well documented that KNO3 and Ca(NO3)2 are the fertilisers of choice to compete with sodium (Na+) and chloride (Cl-), as both Ca++ and K+ replace Na+, and NO3- replaces Cl-. Trickle irrigation wets a small part of the total soil area and roots are confined to the wetted zone. This means there is less available soil volume for roots to extract K, so with trickle or micro sprinklers, it is important to add K. Click for further info Haifa MKP

15 14 WE have emphasised in previous DownUnder editions that plants do not eat, they drink, hence all the mineral nutrition supplied to plants, whether in soil or soilless cropping, must be dissolved in water. Atoms and molecules dissolved in solution are electrically charged and called “ions”. Such ions are either positively charged (“cations”), eg, potassium calcium, ammonium, magnesium, iron, manganese, zinc and copper, or negatively charged (“anions”), eg, nitrate, phosphate, sulphate, molybdenum and boron. The charge of each ion is known as its valency. So, for example, calcium has valency +2, written as Ca2+, and nitrate has valency -1, written as NO3-. Because ions of opposite valency attract, bonds are constantly being formed between positive and negative ions, sometimes in the nutrient solutions and sometimes in the irrigation system and media. Once these bonds are formed, the combined molecules are no longer soluble and, hence, are no longer suitable for plant nutrition. Some of these combined molecules are very stable, will not supply nutrients to the target plants and can be difficult to remove from irrigation equipment. Chelates The minerals iron, manganese, zinc and copper can be supplied in hydroponics as sulphates, but, depending on pH, these minerals can precipitate with phosphates, carbonates or hydroxides in the nutrient solution or media and become unavailable to plants. Chelating these minerals protects them from precipitation, allowing them to be available to plants. The term “chelate” comes from the Greek word “chela”, meaning claw of an animal like a crab or scorpion. It is an apt description of the chelating agent, which is the organic molecule used to “envelop” or “bind” a target metal ion, protecting it from reaction with negatively charged ions in the nutrient solution and/or media. Chelates are usually organic molecules with long names like “diethylenetriaminepentaacetic acid” (DTPA) and so are normally known by their acronyms. Some chelates, such as EDDHA and HBED, exist as complex molecules with different configurations, or bonds, between the component atoms, giving them different spatial shapes. In the case of iron FeEDDHA, there are two configurations, known as “isomers” (Figure 1). Each isomer has different bonding strength with the iron it contains. The most effective chelating agent for alkaline soils is the ortho-ortho configuration. It is the most stable. For hydroponic use, where pH in the nutrient solution and media is managed, the ortho-para configuration works. For Fe-EDDHA chelate products, the higher the proportion of the ortho-ortho isomer in the product, the higher the stability of the metal-chelate. Once the metal-chelate bond is broken, the unprotected metal ion is liable to precipitate after reaction with anions in the nutrient solution or media. Chelating agents exist in nature. Certain plants, bacteria and fungi can produce natural chelating agents, called “siderophores”, in bacteria and fungi and “phytosiderophores” in plants. Organisms produce these compounds to absorb iron from their substrates. Soilless nutrition In soilless nutrient fertigation, the main cations, such as calcium, and anions, such as phosphate, are separated in twin tank hydroponic systems to minimise reactions that would potentially render the minerals in the nutrient solution unavailable. It is common practice to use chelated iron products in hydroponic nutrient solutions. The stability of iron in such solutions is largely dependent on pH, but in soiless cropping Chelates By Peter Anderson Northern Sales Agronomist, Haifa Australia also on the presence of other cations, notably unchelated calcium, magnesium, manganese, zinc and copper. While pH of the soilless nutrient solution is managed in hydroponics, it is true that many plants prefer pH of 6 to 6.5. At this pH, the stability of Fe-EDTA in the nutrient solution and the root zone is reduced (Figure 2). Non-iron EDTA chelated microelements are not a problem at a wide pH range (Figure 3). For Fe in hydroponic nutrient solutions, Fe-DTPA or Fe-EDDHA are a better choice than EDTA for Fe chelates, particularly if the pH of the nutrient solution and/or the root zone is above 6.5. EDTA is a suitable for Mn, Zn and Cu. Figure 4 shows that the Iron in the Fe-DTPA chelate is replaced by the unchelated copper, zinc and manganese in that order. This Fe is subsequently lost to precipitation. There is no Fe replacement in the Fe-EDDHA. If the non-Fe minerals were already chelated, they would not replace the Fe in the Fe-DTPA (or Fe-EDTA). If a proportion of the total-Fe is in the form of EDDHA, then this helps compensate for the loss of Fe from the Fe-DTPA (or Fe-EDTA), even if using unchelated Mn, Zn and Cu. Fig 2: pH Stability of iron (Fe3+) chelates in practical conditions Fig 3: Stabilities of non-iron EDTA chelates in practical conditions Fe-EDDHA and Fe-HBED have a practical lower stability limit of around pH 3.5. These are normally dissolved in the A-tank, so the pH of the A-tank needs to be above pH 3.5. Experiments in Europe with greenhouse tomato demonstrated that in a nutrient solution using Fe-DTPA, chelating the microelements Mn, Zn and Cu with EDHA delivered retention of more Fe in the solution and more again in the media (rockwool in this case) than using Mn, Zn and Cu sulphates. Plots combining Fe-DTPA with chelated Mn, Zn and Cu had leaves with significantly higher chlorophyl content when compared to plots with Fe-DTPA and unchelated Mn, Zn and Cu. Plots with greater retention of Fe had significantly higher yield, mainly through larger fruit. In conclusion, chelating Fe in hydroponic nutrient solutions ensures that iron is available for the crop. Not all Fe chelates are stable at slightly acid-neutral pH, and the presence of non-chelated Mn, Zn and Cu can replace Fe in some Fe-chelates, resulting in loss of this Fe. Chelates acidity akalinity Fe-HBED Fe-EDDHA Fe-DTPA Fe-HEDTA Fe-EDTA pH 1234567891011 Chelates acidity akalinity Mn-EDTA Zn-EDTA Cu-EDTA Ca-EDTA Mg-EDTA pH 1234567891011 Ortho-Ortho Soil and Hydroponic application Ortho-Para Hydroponic application Para-Para No application Source: Nouryon 4 5 6 7 8 100 80 60 40 20 0 Fe-DTPA Fe-EDDHA Cu-DTPA Zn-DTPA Mn-DTPA Relative to [metal] (%) pH Fig 4: Fe-DTPA (85% of total Fe), Fe-EDDHA (15% of total Fe) and unchelated Cu, Mn and Zn Source: Nouryon Source: Nouryon Fig 1: Isomers of EDDHA Click for further info Micronutrients

16 In uncertain times, there’s a quality and team you can trust… Haifa Australia (03) 9583 4691 australia@haifa-group.com www.haifa-group.com YOUR HAIFA AUSTRALIA TEAM Trevor Dennis trevor.dennis@haifa-group.com 0400 119 852 Managing Director Sheri Robinson sheri.robinson@haifa-group.com 0428 686 264 Southern Sales Agronomist Peter Anderson peter.anderson@haifa-group.com 0459 488 850 Northern Sales Agronomist Jason Teng jason.teng@haifa-group.com 0488 036 528 Customer Service/Logistics CMYK Haifa has pioneered the use of potassium nitrate since the 1960s and steadfastly remains the leading source of the highest quality today. Entirely used by crops, with no residual remaining in soils or groundwater, Haifa’s potassium nitrate fertilisers provide application efficiencies and reduce the effects of chloride and sodium whilst enhancing crop quality and yields. As the world’s largest and only potassium nitrate supplier with an Australian office, growers can have confidence in their Haifa fertiliser applications and the support of a local team – that is for certain!