Potash is a general term used to describe a variety of K-containing fertilizers used in agriculture. Potassium Sulphate, also called sulphate of potash (SOP), is an inorganic compound with formula K2SO4. It is a white water-soluble solid. It is commonly used in fertilizers, providing both potassium and sulfur.
SOP is doubly essential not just because of the potassium, but also because it provides plants with sulphur – the first micro-nutrient. Every plant needs sulphur. If you add SOP to soils, the plant gets both sulphur and potassium. With MOP, you still face the additional cost of adding sulphur.
SOP doesn’t contain chloride and therefore can be put on all crops and plants. SOP has a nil salinity index which means even though it’s a salt, it doesn’t build up the soil’s salinity. Where soils are saline or sodic and where irrigation water may have high chloride levels SOP is the preferred form of potassium to use.
SOP can be sown with the seed or near the seedling, ensuring maximum root access to potassium.
Plants deficient in potassium can appear scorched on the leaves, be stunted in growth, and have less water circulation resulting in heat and drought susceptibility. They will also have poor resistance to pests and weak roots.