Sulphur (S) is one of the secondary macro nutrients that has often been forgotten or neglected in planning a fertilizer program. The general “rule of thumb” was that crops required the same amount of S as they do phosphorus. Prior to the advent of high grade phosphates which form the back bone of todays NPK bulk blends the S requirement of crop was supplied through NPK compound containing AMS, single super phosphate, enriched super phosphate and ammoniated super phosphates such as AMP(16), and atmospheric S from industrial SO2 emissions. Alternative sources of S are found in Potassium Sulphate, ASN and Ammonium Sulphate. The cheapest source of S is from gypsum. Disclaimer: The figures published are not a guarantee of analysis, they are sourced from published Product Data Sheets and provided to serve as an indicator of typical analysis which may vary due to production processes, impurities and changes in minerology of natural sources. Please note: Consult a qualified person (Act 36 of 1947) for specific applications / recommendations.
All figures quoted should be considered as a typical product analysis and may vary due to manufacturing process and raw materials. PHYSICAL PROPERTIES A granular crystal or fine white crystalline powder. Critical Relative Humidity: 96.3. Solubility @ 20°C: 11.1 g/100ml of water. CHEMICAL PROPERTIES Chemical formula: K2SO4. 42% Potassium (K). 17% Sulphur (S). Salt index: 46 (relative to Sodium Nitrate @ 100). AGRONOMIC BENEFITS Suitable for crops that are sensitive to chloride. Technical grade product should preferentially be used for foliar feeding and drip irrigation. Compatible for blending with Mono Ammonium Phosphate, LAN, Urea, Ammonium Sulphate, Potassium Chloride. Please note: Consult a qualified person (Act 36 of 1947) for specific applications / recommendations.
All figures quoted should be considered as a typical product analysis and may vary due to manufacturing process and raw materials. PHYSICAL PROPERTIES A fine white crystalline product. Crystal colour may vary from white – yellow to blue – green and brown due to impurities. Granular forms may be produced by compaction, chipping or crystal growth. Particle size distribution of granular product typically ranges from 2.0 – 5.5mm. Critical Relative Humidity @ 30°C: 79.2. Solubility at 20°C: 75.4g / 100ml of water. CHEMICAL PROPERTIES Chemical formula: NH4SO4. 21% Nitrogen (N). N in the Ammonium (NH4+)form. 24 % Sulphur (S). S is in Sulphate (SO4–) form. Acidification index: 7.14 kg pure lime/kg N or 1.5kg pure lime per kg ammonium sulphate applied. Salt index: 69 (relative to Sodium Nitrate @ 100) AGRONOMIC BENEFITS & CAUTIONS N immediately available for plant uptake. N losses due to volatilization are very low. Ammonium – N doesn’t leach due to its positive charge. S is immediately available for plant uptake. Highly soluble and may be put through irrigation systems. The most acidifying N source and should be used with caution on acidic soils. May be used beneficially to drop the pH in alkaline soils and improve availability of micro nutrients. Compatible for blending with MAP, LAN, Urea, Potassium Chloride. Please note: Consult a qualified person (Act 36 of 1947) for specific applications / recommendations.
Sulphur (S) nutrition of crops has received a lot of attention since the advent of high grade phosphates and higher grade NPK fertilizer mixtures which typically contain very low levels of S. When considering your source of Sulphur (S) containing fertilizer, take time to assess the availability of the S sources that are available. Plants take up S in the Sulphate – SO42- form which is water soluble and immediately available for plant uptake while elemental S is not water soluble and must first be oxidized to the SO42- form by microbial action before becoming available for plant uptake. The oxidation rate of elemental S into the plant available SO42- form is also dependent on the particle size of the elemental S; the finer the particle size the quicker the conversion to the SO42- form. Granular elemental sources of S have been used in blends to “supply” the crops requirement, these granules don’t supply the crop’s immediate S requirement and can often be found encased in the soil or lying on the soil surface several years after application.