Calcium is essential for plant and animal health. It is not often deficient on New Zealand farms as the natural calcium content of our soils is quite high, and our practice of liming helps to maintain these levels. Using RPR-based products such as Cloverking and Enviromag will also boost soil calcium levels, as will lime-based products such as BioLime.
Gypsum is a naturally occurring calcium sulphate mineral. Our BioGro-approved gypsum contains 23% calcium.
Although it adds calcium and sulphur to the soil, gypsum is most often used as a soil amendment, especially to improve soil structure, which it does by flocculating clay particles. Better soil structure can leader to improved water infiltration, and so reduce losses from run-off.
Our dolomite is a naturally occurring mineral that is mined in the South Island. It is found in sedimentary rocks and is a calcium magnesium carbonate, containing 24% calcium. Dolomite also has a liming effect.