Soil health: Know how to improve and manage saline soil
Salinity and alkalinity are very serious problems for 67.3 lakh hectares of land in the country.
Soil health is a major concern for India. Healthy soil is the backbone of productive and sustainable agriculture. We bring to you some very useful analysis. 47 percent of the country’s land (159.7 million hectares) is cultivated. While 67.3 lakh hectares of land is such for which salinity and alkalinity have become a very serious problem. This reduces soil fertility and yields fall. The problem of salinity and alkalinity is usually seen in such arid and semi-arid areas where there is no arrangement for the salts present in the saline soil to run off in the rain or where there is not enough rain. There is 38 lakh hectares of barren land in the country, efforts are being made to improve it and make it cultivable.
The problem of saline soil in the country is particularly visible on a large scale in Gujarat, Uttar Pradesh, Maharashtra, West Bengal and Rajasthan. Three-fourth of the country’s total saline and alkaline soil area is present in these big states. Its area is about 67.3 lakh hectares. Saline soils contain high amount of sodium, calcium, magnesium or their chlorides and sulfates. All these elements are soluble in water. White crust of these soluble saline elements is formed on the upper surface of the soil in the field.
Saline soil outbreaks are often seen on land that is prone to water logging. That is why it is also called waterlogged saline soil or sand land. Due to water logging, the soluble salts present in the soil float to the upper surface of the soil and remain frozen on the soil surface after evaporation of water due to lack of proper drainage system. That’s why if proper drainage is done in saline soil, its physical condition generally improves because most of the soluble salts deposited in the field by forming a white crust get washed away with water.
According to experts from ICAR-Indian Institute of Soil Science, Bhopal and Department of Soil Science and Agricultural Chemistry, Jawaharlal Nehru Agricultural University, Jabalpur, white crust of alkaline and saline soils is classified on the basis of electrical conductivity, exchangeable sodium content and pH value is classified.Â
![saline soil](https://eng.kisanofindia.com/wp-content/uploads/2022/12/Copy-of-Untitled-54-750x430.jpg)
Soil ClassificationÂ
Soil Nature | Electrical Conductivity (Deci Siemens/m) | Exchangeable Sodium (%) | pH value |
Saline | >4.0 | <15 | <8.5 |
Alkaline and Usar | <4.0 | >15 | >8.5 |
Saline-alkaline | >4.0 | <15 | <8.5 |
Crop selection to improve saline soilÂ
Crop selection is also very important for reclamation of saline soil. Salt tolerant crops and varieties should be adopted on such land, so that maximum yield can be obtained. Oilseed crops which require less water can easily tolerate saline water whereas pulse crops are very sensitive to it. The salt tolerance of crops and the selection of improved varieties also depend on the nature of the soil of the field. That’s why varieties of different crops developed to give more yield by tolerating the salinity or alkalinity of irrigation water should be adopted.Â
Salt Tolerant Varieties of CropsÂ
Crop | Salt Tolerant Varieties | Alkali Tolerant Varieties |
Paddy | CSR 30, CSR 36, Sumati and Bhoothnath | CSR 10, CSR 13, CSR 23, Sumati and Bhoothnath, CSR 30 |
Wheat | WH 157, Raj 2560, Raj 3077, Raj 2325 | KLR 1-4, KLR 19, KLR 210, KLR 213, Raj 3077 |
Mustard | CS 52, CS 54, CS 56, CS 330-1 | CS 52, CS 54, CS 56 DIRA Pusa Bold, RH 30 336 |
Chana | Karnal Chana-1 | Karnal Chana-1 |
Bajra | HSB 60, HM 269 HM 331, HM 427 | HSB 392, HM 269, HM 280 |
Source: ICAR-Central Soil Salinity Research Institute, KarnalÂ
How to improve saline and alkaline soil?Â
Use of Gypsum: Gypsum is a very effective reclamation agent for improving alkaline soil. It is easily available in the market at a cheap price. Being cheap and extremely useful, it is widely used. But before using gypsum, it should be ensured that its purity is not less than 75%. If the pH value of the soil is high then gypsum should be applied directly in the fields. Generally, 10 to 15 tonnes of gypsum per hectare is required to improve alkaline soil. But to know how much quantity of gypsum would be suitable for a particular field, farmers should treat the soil only after getting it tested.
Water drainage method: Since saline soil starts growing in the field where there is no good drainage system, therefore it is very important to strengthen the drainage system by making more and more drains etc. in the fields affected by salinity. This method is very useful where the layers in the ground are hard or the ground level is high. Correct management of irrigation on such land is also very important, because the amount of irrigation, the interval between them and the crops to be planted, all have a direct relation with the groundwater level. The yield also decreases with more or less irrigation and improper spacing.
Leaching method: In this method, first of all, the field affected by salinity is divided into small pieces and embanked. After this the field is filled with water up to a height of 10-15 cm. Due to this, the soluble salts present in the soil get dissolved in the water and go below the level where the roots of the crop plants reach and get nutrition for themselves. Leaching method should be adopted in those areas where the ground water level is very low. Otherwise, there will be a risk that the soluble salts of the soil will pollute the ground water itself. The summer season is considered best for leaching method. The leaching method should not be adopted in areas where the lower layers of the soil are hard layers.
Area of saline soil in Indian statesÂ
State | Saline soil (thousand ha)Â | Alkaline soil (thousand ha)Â | Total saline soil (thousand ha) |
Andhra Pradesh | 77.6 | 196.6 | 274.2 |
Gujarat | 1680.6 | 541.4 | 2222.0 |
Uttar Pradesh | 22.0 | 1347.0 | 1369.0 |
Maharashtra | 184.1 | 422.7 | 606.8 |
West Bengal | 441.3 | 0 | 441.3 |
Rajasthan | 195.6 | 179.4 | 375.0 |
Haryana | 49.2 | 183.4 | 232.6 |
Bihar | 47.3 | 105.9 | 153.2 |
Punjab | 0 | 151.7 | 151.7 |
Madhya Pradesh | 0 | 139.7 | 139.7 |
Tamil Nadu | 13.2 | 354.8 | 368.0 |
Karnataka | 1.9 | 148.1 | 150.0 |
Odisha | 0 | 147.1 | 147.1 |
Kerala | 20.0 | 0 | 20.0 |
Andaman and Nicobar | 77. 0 | 0 | 77.0 |
Jammu and Kashmir | 0 | 17.5 | 17.5 |
Total Area | 2809.8 | 3953.3 | 6745.1 |
Total saline and alkaline soils: 67.5 lakh hectaresÂ
Source: ICAR-National Bureau of Soil Survey and Land Planning, Nagpur
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