Soil Salinity Research Institute, Pindi Bhattian

The soil in which plant growth is affected due to excessive amounts of soluble salts / excessive amount of sodium on exchange complex are called salt affected soils. These are of following three types.

• Saline soils
• Sodic soils
• Saline-sodic soil

Saline soils

Saline soils can be reclaimed by applying good quality water so that soluble salts can leach down below the root zone. The EC of water should be less than EC of the soil

Sodic soil

Soils which contain excessive amount of exchangeable sodium to affect the crop growth adversely are called sodic soils.Sodic soils can be reclaimed by the application of amendments like gypsum or sulphuirc acid on soil test basis. Soils samples should be collected from the affected field and get analyzed from the laboratory. Gypsum application should be done on soil GR basis. If soil is sandy, gypsum application should be done on 50% soil GR basis. If soil is loam, gypsum application should be done on 75% soil GR basis. If soil is clayey, gypsum application should be done on 100% soil GR basis. If soil is done sodic, 75% gypsum and 25% sulphuric acid should be applied on soil GR basis. After gypsum application, water should be applied@ one acre foot per ton of applied gypsum.

Saline sodic soils

Soils which have both excessive soluble salts and exchangeable sodium to affect crop growth adversely are called saline sodic soils. Saline sodic soils can be reclaimed by the application of amendments like gypsum or sulphuric acid based on soil test. Sols samples should be collected from the affected field and get analyzed from the laboratory. Gypsum application should be done on soil GR basis. If soil is sandy, gypsum application should be done on 50% soil GR basis. Of soil is loam, gypsum application should be done on 75% soil GR basis. If soil is clayey, gypsum application should be done on 100% soil GR basis. After gypsum application, water should be applied @ one acre foot per ton of applied gypsum. If soil is dense sodic, 75% gypsum and 25% sulphuric acid should be applied on soil GR basis

Ultra salt affected soils are not suitable for the cultivation of conventional crops and grasses but they can be managed for growing of fruits and forest plants. Following points should be kept in mind before plantation in saline/sodic soils

• Field should be prepared twice with chisel plough and leveled.
• Soil should be analyzed to know the extent of salinity.
• Furrow should be made at the recommended distance.
• Pits should be dugged having width 2 ft x depth 3ft.
• Pits should be filled with mixture of silt and gypsum in 20:1.
• Plantation should be done on the shoulders of the furrows.
• Plants should be transplanted form 25th February to 25th March and irrigated immediately after transplantation.
• Plastic bags should be removed before transplantation.
• During the March-April, irrigation should be done at the interval of 15 days, May to July weekly and in August and September according to need of the plants, in November to February one in a month.
• Urea @ 15 kg acre-1 should be applied 3-4 month after the plantation of saplings.

Following plants can be grown in salt affected soil.
Fruit plants -Falsa, Dates, Guava, Jamin and Ber etc.
Forest plants - Eucalyptus, iple, Kikar and Jand etc.

In areas where canal water supply is in limited quantity and brackish water of medium quality {(EC 2 dSm-1, SAR 18 (mmol L-1)1/2 and RSC 3 meL )} is available, it can successfully be used through seasonal cyclic strategy i.e. brackish water for rice, canal water for wheat or brackish water for wheat and canal water for subsequent summer fodders.
If there is an acute shortage of canal water, then three irrigation of tube well water followed by tow of canal water can be practiced without significant losses in yield.
Sodic water can be used by placing gypsum stones in water courses or by application of gypsum (calculated on the basis of quality of tube well water) in to the soil after harvesting of wheat crop.
Saline water can be used by application of 10-25% more water than the crop requirement. Interval between irrigations should be greater than fit water.
Organic matter application or green manuring should commonly be practiced to use poor quality water.

Following points should be kept in mind while sampling salt affected soils for analysis.
Before soil sampling, field should be observed carefully. If salinity in the field is uniform then 6-8 subsamples from 0-15 cm and 15-30 cm depths each should be taken in two separate buckets and mixed thoroughly. Then a composite sample of one kg should be collected from each bucket in a leveled plastic bag having following information.

1. Name of farmer            
2. Address of Farmer        
3. Square Number            
4. Field / Kill No.
5. Depth of sampling
6. Date of sampling
7. Signature of sampling person

If the salinity in the field is not uniform then field should be divided into sub plots and from each subplot separate composite soil sample should be collected as mentioned above.