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