Decreases pH of sodic soils: The sodic soils are characterised by the high soil pH (>8.5). Gypsum lowers the high pH of sodic soils or near sodic soils to 7.5 to 7.8. These values are in the range of acceptability for growth of most crop plants. Increased calcium uptake by roots when gypsum is applied can decrease the pH of the rhizosphere.
Creates favorable soil EC: The more EC value of the soil is undesired for the crop growth. The high EC of soil are due to fertilizer application as well as by the weathering of soil minerals. Gypsum, being readily soluble, results in proper buffered solute concentration (EC) in soil to maintain soil in a flocculated state.
Makes excess Magnesium non-toxic: Calcium is essential to the biochemical mechanisms by which most plants nutrients are absorbed by roots. Without adequate calcium, uptake mechanisms would fail. In soils having unfavorable calcium magnesium ratios, such as serpentine soils, gypsum can create a more favorable ratio. Thus render Magnesium non-toxic.
Decreases heavy-metal toxicity: Calcium plays a role of regulator for balance of micro-nutrients, such as iron, zinc, manganese and copper, in plants. Calcium prevents excess uptake of many of them; and once they are in the plant, calcium keeps them from having adverse effects when their levels get high. Calcium in liberal quantities helps to maintain a healthy balance of nutrients and non-nutrients within plants. Gypsum also removes excess of Boron from sodic soil. It also regulates non-essential trace elements.
Improves soil structure: Gypsum provides calcium, which, flocculate clays in acid and alkaline soil. A flocculated clays form friable soil with improved soil structure and tilth. It also allows for deeper, healthier root development and water penetration.
Prevents crusting of soil: Gypsum application can decrease and prevent the crust formation on soil surfaces which result from rain drops or from sprinkler irrigation on unstable soil. It can prevent crusting that result when acid soils are limed and the gypsum is coapplied with the lime. Improves compacted soil: Gypsum can break up compacted soil and decrease penetrometer resistance. Combination with organic amendments also helps, especially in preventing return of the compaction. The soils applied with gypsum have low bulk density.