Low sodium diet is best for turf Calcium, in the form of gypsum, will lower soil sodium content. Spreading calcium will lower soil salt content. The movement of water and air through soil is dependent on good porosity, which is contingent on the individual components, clay minerals and organic matter remaining clumped together in aggregates. Sodium destroys this soil structure and hinders water and air transport by causing the individual soil particles to repel each other similarly to the repulsion between like poles of a magnet. Excess soil sodium arises from the use of high-sodium irrigation water, and symptoms include puddling of water at the soil surface and thinning turf.
Calcium promotes soil aggregation and is the antidote to sodium.
It displaces sodium from the soil particles, allowing it to be leached from the rootzone with rainfall and irrigation. Unfortunately, many soils and irrigation sources are low in calcium, and it must be added to the soil either directly or through the irrigation system in order to correct the problem. Confirmation of excess sodium is obtained by soil sampling and determination of the exchangeable sodium percentage. If sodium occupies more than about 10 to 15 percent of the soil cation exchange capacity, then it may be degrading soil structure. Calcium will typically occupy 50 to 70 percent of the cation exchange capacity.