How does gypsum help sodic soils?

Applying gypsum helps reclaim sodic soils where sodium that’s attached to the cation exchange complex becomes too high. The most economical way is to add gypsum which supplies calcium. The calcium supplied by gypsum displaces the sodium held on the clay-binding sites.

How does gypsum reclaim sodic soil?

Sprinkling is usually the preferred reclamation method under these conditions. Sodic and saline-sodic soils are reclaimed by replacing the exchangeable sodium with calcium. This is commonly accomplished by adding gypsum, since it is relatively soluble and inexpensive.

How much gypsum do I add to sodic soil?

After broadcasting the calcium source on the soil surface, mix it, and make sure adequate moisture is present to dissolve it. Recovering a foot depth of sodic soil on one acre requires approximately 1.7 tons of pure gypsum (CaSO4-2h2O) for each milliequivalent of exchangeable sodium present per 100 grams of soil.

What is the best treatment for sodic soils?

Sodic soils can be directly treated through the application of gypsum (particularly on the surface), which serves to replace the excess sodium in sodic soils with calcium. In southern Victoria, typical application rates of gypsum are around 2.5 t/ha and applied on a 3 to 5 year basis.

Does gypsum increase salinity?

Gypsum slightly increases the salinity of the soil solution, and hence reduces swelling. The same effect can be seen when using saline bore water, but this often contains high levels of sodium and chlorine that are toxic to plants. Gypsum will slightly increase salinity without any detrimental effect on plants.

Does gypsum make soil more acidic?

Gypsum can be spread with lime and litter spreaders. Gypsum is not acid soluble and will not change the soil pH. It helps to shift the Ca and Mg levels in soil and offers a readily available form of sulfate sulfur, a valuable secondary nutrient that benefits the soil and crop.

Why is gypsum used to overcome Sodicity?

Calcium from the gypsum will swap with the sodium that is held on the clay surfaces. This reduces the sodicity of the soil and is called cation exchange. Gypsum can have its most beneficial effect at sowing time.

How do I know if I need gypsum?

Put some soil in clean water and shake it until it goes milky. Then stand it for about five or 10 minutes. If it doesn’t clear in the water, chances are it is going to respond to gypsum. “Do the test adding some gypsum.

What is the rate to apply gypsum?

To use gypsum as a soil amendment, spread it over soil at a rate of about 10 to 15 pounds per 100 square feet of soil surface using a garden spreader or by gloved hand, then till it into the top 6 to 8 inches of soil. Handle gypsum carefully and apply according to manufacturer recommendations.

What happens when we add gypsum to soil?

Adding gypsum to the soil reduces erosion by increasing the ability of soil to soak up water after precipitation, thus reducing runoff. Gypsum application also improves soil aeration and water percolation through the soil profile.

Is gypsum good for alkaline soil?

Gypsum has been used for centuries to reclaim sodium affected soils (alkali soils). It is effective since it has good solubility regardless of soil pH. In fact, its solubility is enhanced in sodic soils.