| India ranks second on the basis of population in | | | | drops or from sprinkler irrigation on unstable soil. It |
| the world. Agricultural land utilised by the | | | | can prevent crusting that result when acid soils |
| burgeoning population, the cultivable land resource | | | | are limed and the gypsum is coapplied with the |
| is shrinking day by day. To meet the food, fibre, | | | | lime. |
| fuel, fodder, and other needs of the growing | | | | Improves compacted soil: Gypsum can break up |
| population, the productivity of agricultural land has | | | | compacted soil and decrease penetrometer |
| to be increased rationally. This requires the use of | | | | resistance. Combination with organic amendments |
| all resources judiciously. In India, the mineral | | | | also helps, especially in preventing return of the |
| gypsum is mostly used in the manufacture of | | | | compaction. The soils applied with gypsum have |
| cement, fertiliser, plaster of Paris, ceramics and | | | | low bulk density.Makes slightly wet soils easier to |
| distemper. Smaller quantity is used as soil | | | | till: Soils that have been treated with gypsum |
| conditioner, for carving and statuary purposes. | | | | have a wider range of soil moisture levels where |
| India has huge resources of natural gypsum of | | | | it is safe to till without danger of compaction or |
| the order of 1120 million tonnes, of which | | | | deflocculation. Even a liberal application of gypsum |
| recoverable reserves are estimated at 237 million | | | | is a good procedure for starting a piece of land |
| tonnes. Over 95 per cent of the natural gypsum | | | | into no-till soil management or pasture. Gypsum |
| come from Rajasthan.Gypsum is chemically | | | | also improves the ability of soil to drain and not |
| calcium sulfate dihydrate (CaSO4.2H2O). When | | | | become waterlogged due to a combination of high |
| dissolved in water, it yields calcium ions (Ca2+) | | | | sodium, swelling clay, and excess water.Stops |
| and sulfate-sulfur ions (SO42-). Both of these ions | | | | water runoff and erosion: Gypsum improves |
| are essential major nutrients for growing plants. In | | | | water infiltration rates into soils and also the |
| addition to this, calcium also plays a vital role in | | | | hydraulic conductivity of the soil. The use of |
| establishing and maintaining good chemical balance | | | | gypsum can decrease wind and water erosion of |
| in soil, water and plants. Gypsum is one of those | | | | soil.Improves swelling clays: Gypsum can decrease |
| rare materials that perform in all three categories | | | | the swelling and cracking associated with high |
| of soil treatment: an amendment, conditioner, and | | | | levels of exchangeable sodium on the |
| fertilizer. The usage of gypsum in agriculture can | | | | montmorillonite-type clays. As sodium is replaced |
| be grouped into following heads:Reclaims soil | | | | by calcium on these clays, they swell less and |
| sodicity: The sodic soils have exchangeable sodium | | | | therefore do not easily clog the pore spaces |
| percentage (ESP) more than 15, it must be | | | | through which air, water and roots |
| lowered for soil improvement as well as better | | | | move.Increases water retention in soil: Gypsum |
| crop growth. The calcium supplied by gypsum | | | | when applied to sodic soil reduced the levels of |
| replaces the sodium held at the clay-exchange | | | | exchangeable sodium resulted in increase in water |
| sites. The replaced sodium can be leached from | | | | retention. The improved soil structure help in the |
| the soil as sodium sulfate to an appropriate | | | | more retention of water. |
| sink.Decreases the toxic effect of NaCl salinity: | | | | Increases the stability of soil organic matter: |
| Calcium from gypsum has a physiological role in | | | | Gypsum is a source of calcium responsible for the |
| inhibiting the uptake of sodium by plants. Thus | | | | binding of soil organic matter to clay and gives |
| plant are mitigate the sodium toxicity, which is | | | | stability to soil aggregates.Improves low-solute |
| more pronounced in the salt affected | | | | irrigation water: Gypsum is used to increase the |
| soils.Decreases pH of sodic soils: The sodic soils | | | | solute concentration of low-solute water used for |
| are characterised by the high soil pH (>8.5). | | | | irrigation. Irrigation water from rivers that no |
| Gypsum lowers the high pH of sodic soils or near | | | | longer have sources of leachable salts either |
| sodic soils to 7.5 to 7.8. These values are in the | | | | penetrates poorly into soil or causes soil particles |
| range of acceptability for growth of most crop | | | | to degrade which results in low-water penetration. |
| plants. Increased calcium uptake by roots when | | | | The problem can be corrected with |
| gypsum is applied can decrease the pH of the | | | | surface-applied gypsum or application to the |
| rhizosphere.Creates favorable soil EC: The more | | | | irrigation water.Improves water-use efficiency: |
| EC value of the soil is undesired for the crop | | | | Gypsum application increases water-use efficiency |
| growth. The high EC of soil are due to fertilizer | | | | of crops. Improved water infiltration rates, |
| application as well as by the weathering of soil | | | | improved hydraulic conductivity of soil, better |
| minerals. Gypsum, being readily soluble, results in | | | | water storage in the soil all lead to deeper rooting |
| proper buffered solute concentration (EC) in soil to | | | | and better water-use efficiency.Efficiently use low |
| maintain soil in a flocculated state.Makes excess | | | | quality irrigation water: Use of reclaimed municipal |
| Magnesium non-toxic: Calcium is essential to the | | | | wastewater is important for conservation of |
| biochemical mechanisms by which most plants | | | | natural resources. Reclaimed water can be |
| nutrients are absorbed by roots. Without | | | | satisfactorily used if amended with gypsum and |
| adequate calcium, uptake mechanisms would fail. | | | | water-soluble polymers.Improves fruit quality and |
| In soils having unfavorable calcium magnesium | | | | prevents some plant diseases: The quality of fruit |
| ratios, such as serpentine soils, gypsum can | | | | depends on the amount of calcium. Calcium is |
| create a more favorable ratio. Thus render | | | | nearly always only marginally sufficient and often |
| Magnesium non-toxic.Decreases heavy-metal | | | | deficient in developing fruits. Calcium moves very |
| toxicity: Calcium plays a role of regulator for | | | | slowly, if at all, from one plant part to another |
| balance of micro-nutrients, such as iron, zinc, | | | | and fruits at the end of the transport system get |
| manganese and copper, in plants. Calcium | | | | too little. Calcium must be constantly available to |
| prevents excess uptake of many of them; and | | | | the roots. In very high pH soils, calcium is not |
| once they are in the plant, calcium keeps them | | | | available enough; therefore, gypsum helps. |
| from having adverse effects when their levels | | | | Gypsum is used for peanuts, which develop below |
| get high. Calcium in liberal quantities helps to | | | | ground, to keep them disease free. Gypsum helps |
| maintain a healthy balance of nutrients and | | | | prevent blossom-end rot of watermelon and |
| non-nutrients within plants. Gypsum also removes | | | | tomatoes and bitter pit in apples. Gypsum is |
| excess of Boron from sodic soil. It also regulates | | | | preferred over lime for potatoes grown in acid |
| non-essential trace elements.Improves soil | | | | soils so that scab may be controlled.Decreases |
| structure: Gypsum provides calcium, which, | | | | loss of fertilizer nitrogen to the air: Calcium from |
| flocculate clays in acid and alkaline soil. A | | | | gypsum can help decrease volatilization loss of |
| flocculated clays form friable soil with improved | | | | ammonium nitrogen from applications of ammonia, |
| soil structure and tilth. It also allows for deeper, | | | | ammonium nitrate, urea, ammonium sulfate, or |
| healthier root development and water | | | | any of the ammonium phosphates.Keeps clay off |
| penetration.Prevents crusting of soil: Gypsum | | | | tuber and root crops: Gypsum can help keep clay |
| application can decrease and prevent the crust | | | | particles from adhering to roots, bulbs and tubers |
| formation on soil surfaces which result from rain | | | | of crops like potato, carrots, garlic and beets. |