Speciality fertilizers in agriculture: An overview Dr. Hugo Opperman Head chemist MBFi FERTASA Congress 19 APRIL 2018
Biggest problem the world is facing today is food security Reasons for the crisis? Decreasing agricultural land and increasing world population Erosion Desertification Poor soil management Poor water quality Pollution FAO study reports 2 billion hectares lost since 1950’s By 2050 there will be 9 billion mouths to feed (FAO, 2010)
Only 12 % of the surface area of South Africa has South African context the potential for efficient crop production. Most of the crop production areas are marginal, with only 3 % being classified as high potential cultivatable land. SA population expected to grow 2 % annually and reach 82 million by 2035.
Decrease in cultivatable land per capita (ha/person) 0,8 0,6 Ha per capita 0,4 0,2 0 1961 1970 1980 1990 2000 2007 2017 2027 Year Constant land Decreasing land
SA Maize production 15000 13000 11000 9000 7000 5000 3000 1000 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 YEAR Crop production (1000 Ton) Area planted (1000 Ha) Consumption (1000 Ton)
Holistic approach Traditional Nutrition Increasingly Plant physiology Soil biology Structural Nutrition
Definition: ‘Fertilizer’ can be defined as any substance, natural or chemical, that is added to the soil or directly to plants to improve fertility or enhance plant growth and health . Better soil and plant fertility practices = Smarter speciality fertilizer
Speciality fertilizers provide tools in your toolbox to improve/manipulate various plant growth factors Can be overwhelming and feel more like a black box
Specialty fertilizers are applied to soil, seed and plants to improve the crop’s physiological processes – its growth, blooming and maturity period. Speciality fertilizer is a fast growing market, with an estimated growth rate of 8.5 % per annum globally. The market is estimated to reach 24 billion USD by 2022.
Speciality fertilizers to improve productivity Speciality fertilizers 3 main classes Nutrients Biostimulants Biologicals
Nutrient speciality fertilizers
Nutrient speciality fertilizers Nutrient speciality subclasses High purity macro- and secondary nutrient salts • Micronutrients • Modified fertilizers - Inhibitors and slow/controlled • release fertilizers Very versatile can either be applied via seed treatment, pre-plant, with planting fertilizer or as foliar fertilizer
Speciality micronutrients Micronutrients are often overlooked and can limit crop production significantly 88 % of soils in Sub-Saharan 73 % of soils in South Africa Africa is deficient in zinc is deficient in boron
Various application methods Applied to soil: Pre-plant With planting fertilizer Seed treatments Foliarly applied
Special considerations Must be in water soluble (ionic) form for plant uptake Most micronutrients with the exception of boron Foliarly applied and molybdenum are in a cationic form – divalent transition metals M 2+ Highly reactive to anions such as phosphates and sensitive to changes in pH Can also react with other compounds such as herbicides in tank mixture
Problems can be overcome by process of chelation Many types of chelation molecules have been developed Synthetic chelates – EDTA, DTPA, EDDHA etc. Organic chelates – Organic acids such as amino acids, fulvic acid, citrates, carbohydrates Binds to metal (M) ion and protects it from reacting
The foliar uptake of nutrients is one important part, but the aspect which is even more critical is the ability of the nutrients to be translocated to other plants cells and organs once taken up. Chelates bulky molecules - decrease absorption and translocation of the nutrient Excellent chelating agents - high absorption and translocation characteristics Should be comparable with inorganic salt nutrients
Micronutrient seed treatments Supply young seedling with micronutrients for its early growth period - roots are still developing. Micronutrients are immobile in most soils - early season deficiencies. A polymer in often added - adhesion onto the seed Colorant for identification of treated seeds. This has been shown to result in stronger seedlings which can translate into higher yields.
Micronutrient application with fertilizer Most bulk blenders in South Africa add micronutrients to a blend in the form of micronutrient Granules. Coated micronutrients Blended micronutrients Micronutrients immobile soil Even spatial distribution Leads to uneven spatial distribution
Blended vs coated zinc trials 40 Zinc leaf analysis of maize at 4 different trial locations LEAF ZINC CONCENTRATION (2016/2017 season). Treatments differed only in zinc type. No 30 zinc, granular zinc sulphate and coated zinc. The same zinc equivalent was used for the zinc sulphate and coated zinc 20 (PPM) treatments per hectare. 10 10000 MAIZE YIELD IN KIOGRAM PER 0 8000 Bothaville Delmas Lichtenburg Bethlehem Trial location 6000 No zinc Granular zinc sulphate Coated zinc HECTARE 4000 2000 0 Average maize yields of the four trial locations for the Bothaville Delmas Lichtenburg Bethlehem different zinc treatments (2016/2017 season). Five TRIAL LOCATION statistical plots were planted for each treatment at each location. No zinc Granular zinc sulphate Coated zinc
Modified fertilizers - Inhibitors and controlled release fertilizers Main goal of modified fertilizers are to enhance the nutrient use efficiency of the fertilizer Nitrogen cycle Urea Urease Ammonia Ammonium (volatile gas) Nitrosomonas - ) Nitrites (NO 2 Leaching Nitrobacter - ) Nitrates (NO 3
Inhibitors - chemical action Urease inhibitors inhibit urea to ammonium Nitrification inhibitors inhibit ammonium to nitrites and nitrates. Inhibition lasts between 14 and 28 days. Controlled/slow release fertilizer - physical barrier Usually polymer coating. Release nutrients under very specific conditions – temperature, humidity, soil water level etc. Provides a sustained nutrient release.
Biostimulants
Biostimulants Definition: Biostimulants are defined as any substance or microorganism applied to seeds, plants or the soil with the aim to enhance nutrition efficiency, abiotic stress tolerance and/or crop quality traits, regardless of its nutrients content. Global market value of almost 2 billion USD in 2018.
Seaweed extracts Synthetic plant hormones Biostimulant classes Organic compounds Inorganic compounds
Seaweed extracts Contains complex carbohydrates, plant hormones (cytokinins and auxins), macro- and micronutrients, betaines and sterols. Can be applied on soils, in hydroponic solutions as seed or foliar treatments. Growth stimulating effect High amounts of antioxidants which is effective in plant stress relief. The effect of seaweed treatment (left) and untreated (right) on root development.
Synthetic plant hormones The use of synthetic plant hormones (also produced naturally in the plant) has also been shown to be very effective in stimulating plant growth and crop quality traits. There are 5 major classes of plant hormones and each of them are involved in controlling specific metabolic processes. Auxins – IAA, NAA, IBA Cytokine – Kinetin, Zeatin, 6-BAP Gibberellins – GA3, GA7 Abscisic acid - ABA Ethylene – Ethylene releasing compounds
Hormones levels fluctuate with phenological stages. Each hormone type causes specific metabolic response. Hormones work in synergy with plant specific plant nutrients at the specific growth stages. Adapted from Stoller USA.
Soya trials Bethal Soya trials Delmas X-press Fuctional at sprayed V6 X-Press MoB sprayed V4 and R1 SOYA YIELD IN KIOGRAM PER HECTARE SOYA YIELD IN KIOGRAM PER HECTARE 3285 3600 3546 3150 3136 3310 3190 3130 3080 2834 2761 2690 2014/2015 2015/2016 2016/2017 2014/2015 2015/2016 2016/2017 Trial year Trial year Control X-press functional Control X-press MoB The effect of two different hormone products containing complimentary nutrients on the average soya crop yield over 3 trial years. The control treatments only contained nutrients without the hormone compounds. Five replicates were done per treatment.
Organic compounds Humic acid Fulvic acid Amino acid
Organic compounds Vast amount of organic compound have been identified and are being used for their biostimulant properties. Only the most commonly used examples will be discussed in this presentation. Humic and fulvic acid compounds – Improve soil structure, improve nutrient uptake, protects against stress conditions Amino acids – improves nutrient uptake, increase stress tolerance, increases plant energy Salicylates – increases plant stress tolerance
Riversdal trials Aminex at 2L/Ha - 2016/2017 YIELD IN KIOGRAM PER HECTARE 5500 5000 5153 4500 4475 4000 3500 3000 2500 2585 2000 2232 1500 1000 Wheat Canola CROP TYPE Untreated control Aminex The effect of an amino acid spray treatment on the yield response of wheat and canola in the Riversdal area. Application of the product was 2L/Ha. Wheat was sprayed at flag leaf stage, whilst canola was sprayed at the end of flowering.
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