Gypsum Benefits Plants

Cornfield

Calcium Sulfate as a crop nutrient

Calcium sulfate is good for plants but generally no one thinks of it as a source of important source of plant nutrients. Generally everyone thinks of calcium sulfate, or gypsum, as a soil amendment and it is. But it much more than that – it is also a fertilizer that has nutrient value.

Gypsum is best known for improving soil structure, increasing aeration and infiltration, and it reduces nutrient runoff and soil erosion. The benefits to the soil are long and detailed. And naturally when you improve the soil, you also improve the growing conditions for plants.  In addition, it is also a natural source of calcium and sulfur for plant nutrition, both of which are secondary macronutrients. Plants need as many as 15 nutrients in addition to water, carbon dioxide and oxygen. These are broken into three groups including primary macronutrients that include nitrogen, phosphorus and potassium; the secondary macronutrients calcium, magnesium and sulfur; and finally the micronutrients boron, chloride, copper, iron, manganese, molybdenum, nickel and zinc.

Calcium is an essential nutrient and plays an important role in nutrient uptake.  Without adequate calcium, nutrient uptake and root development slows. And calcium is also essential for many plant functions including cell division, soil wall development, nitrate uptake and metabolism, enzyme activity and starch metabolism.

Calcium is important to fruit and tuber quality and often is deficient. Good fruit and tuber quality requires adequate supplies of calcium. Calcium moves slowly within the plant so it must be constantly available to the roots. Calcium in gypsum can help prevent blossom-end root of watermelon and tomatoes and bitter pit in apples.

Soils have a lot of calcium but it is either tied up in the soil structure, attached to the cation exchange complex or tied up with carbonate form calcium carbonate – an insoluble mineral. The most available calcium is the water soluble form that is in the soil solution and directly available to the plant. Replenishing the soluble supply regularly keeps calcium readily available to plant roots.

Soil though doesn’t have a lot of sulfur. Sulfur in the soil primarily exists in the organic matter phase or as a sulfate ion (SO42-) in the cation exchange complex. There is also some sulfur in the soil mineral but this is not a readily available source as it is only released when soil minerals weather. Additionally, plants are showing more sulfur deficiencies because of reduced levels of sulfur available in the atmosphere.  Gypsum is an excellent source of sulfur for plant nutrition.

Next time you head out to book some fertilizer for your garden, lawn or farm fields, consider adding some gypsum to the mix. It will provide your plants with much needed calcium and sulfur.