Which strategy is the best for remediation of the saline soils?
Use of organic materials?
Washing the soil?
Using the plants?
other methods?
Dear Hewa,
There are many effective ways for improving salt-affected land, such as water leaching, chemical remediation and phytoremediation. The remediation of salt-affected soil using chemical agents, including gypsum (CaSO4.2H2O), calcite (CaCO3), calcium chloride (CaCl2.2H2 O), and organic matter (farmyard manure, green manure, organic amendment and municipal solid waste), is a successful approach that has been implemented worldwide, being effective, low cost, and simple The physical, chemical and biological properties of soil in salt-affected areas are improved by the application of OM, leading to enhanced plant growth and development. Therefore, the application of OM for soil remediation is important for sustainable land use and crop productivity.
Crop management practices for the safe use of salt-affected soils and saline water primarily consists of growing suitable salt-tolerant crops, managing seedbeds, and grading fields to minimize local accumulation of salts, soil management, improving irrigation efficiency and soil, water, and salinity monitoring for assessing leaching and drainage requirements. Important crop management consideration includes:
Appropriate crop genotypes for satisfactory yield under existing and predicted saline conditions (Toderich et al., 2008).
Appropriate planting procedures to minimize salinity near the vicinity of seed (Bernstein and Francois, 1973).
Maintaining soil water at relatively high levels for plant growth (Payero et al., 2009).
Appropriate soil management such as tillage, ploughing, sanding, and chemical amendments, mineral fertilizers, organic manures, and mulching to improve soil organic matter and increased soil percolation (Ben-Gal et al., 2009).
An efficient water distribution system and irrigation scheduling (Kruse et al., 1990).
With my best regards
Prof. Bachir ACHOUR
Do you mean remediation of saline soils for engineering applications ?
The practical methods are:
1. Washing the soil.
2. Compaction of the soil.
Dear Hewa,
There are many effective ways for improving salt-affected land, such as water leaching, chemical remediation and phytoremediation. The remediation of salt-affected soil using chemical agents, including gypsum (CaSO4.2H2O), calcite (CaCO3), calcium chloride (CaCl2.2H2 O), and organic matter (farmyard manure, green manure, organic amendment and municipal solid waste), is a successful approach that has been implemented worldwide, being effective, low cost, and simple The physical, chemical and biological properties of soil in salt-affected areas are improved by the application of OM, leading to enhanced plant growth and development. Therefore, the application of OM for soil remediation is important for sustainable land use and crop productivity.
Crop management practices for the safe use of salt-affected soils and saline water primarily consists of growing suitable salt-tolerant crops, managing seedbeds, and grading fields to minimize local accumulation of salts, soil management, improving irrigation efficiency and soil, water, and salinity monitoring for assessing leaching and drainage requirements. Important crop management consideration includes:
Appropriate crop genotypes for satisfactory yield under existing and predicted saline conditions (Toderich et al., 2008).
Appropriate planting procedures to minimize salinity near the vicinity of seed (Bernstein and Francois, 1973).
Maintaining soil water at relatively high levels for plant growth (Payero et al., 2009).
Appropriate soil management such as tillage, ploughing, sanding, and chemical amendments, mineral fertilizers, organic manures, and mulching to improve soil organic matter and increased soil percolation (Ben-Gal et al., 2009).
An efficient water distribution system and irrigation scheduling (Kruse et al., 1990).
With my best regards
Prof. Bachir ACHOUR
Please have a look a look at this useful link and PDF attachment.
http://www.fao.org/docrep/x5871e/x5871e04.htm
Please check this useful ResearchGate link also.
https://www.researchgate.net/post/What_are_the_possible_amendments_organic_and_or_inorganic_for_saline_soil
Good explanation by Prof. Bachir ACHOUR. The links provided by Dr.Arvind Singh are useful. Thanks and regards
If your aim is related to improving saline soils for agricultural production:
Saline soils can be improved by addition of chemical amendments and leaching by quality irrigation water. Addition of chemicals like gypsum and washing is a temporary solution as salts continually produced in some environments, Therefore, selection of salt tolerant crop variety is a permanent solution to management salt affected soils.
"....selection of salt tolerant crop variety is a permanent solution to management salt affected soils" (Comment of Dr. Birhanu). This is an important point. Thanks and regards
Accumulation of excess salts in the root zone resulting in a partial or complete loss of soil productivity is a worldwide problem. Soil salinity has caused heavy loss of national wealth in India. Out of 329 million hectares of land in the country, about 175 million ha (53 %) is suffering from degradation.
The extent of this problem area as given by different sources varies from 8.56 M ha to 10.9 M ha. According to Central Soil Salinity Research Institute (CSSRI), Karnal, 1.7 M ha of land is affected by salinity among the 6.7 M ha of salt affected land. World as a whole is losing at least three hectare of arable land every minute by soil salinization. The problems of soil salinity are most widespread in the arid and semi-arid regions. Soil salinity is also a serious problem in areas where groundwater of high salt content is used for irrigation. The most serious salinity problems are being faced in the irrigated arid and semi-arid regions of the world and in these regions that irrigation is essential to increase agricultural production to satisfy food requirements.
Development of saline soil
There are several reasons for development of salinity in the soils such as,
- Excessive and uncontrolled irrigation
- Accumulation of salts in the top layer due to evapo-transpiration in arid conditions
- Water logging conditions in perennial river basins/ irrigation sources due to seepage
- Excessive use of chemical fertilizers containing chlorides, sulfates etc.
- Poor drainage conditions.
Characteristics of saline soils:
Salinesoils are rich in soluble salts such as sodium, potassium, calcium, magnesium, chloride, sulphate, carbonate, bicorbanate etc. that leads to alkaline pH of soil i.e. 7 to 8.5. Since, these soils are rich in soluble salts electrical conductivity (EC) of these soil is higher i.e.EC > 4 dSm-1. Also these soils are having considerable quantity of sodium but not as sodic soil that leads to low exchangeable sodium percentage (ESP) and sodium adsorption ratio (SAR) i.e. ESP < 15 and SAR < 13.
Effect of salinity on crop growth and development
Increasedosmotic pressure of soil solution due to excessive salts retards moisture and nutrient absorption by crops. High concentration of soluble salts produces toxic effect directly to the crops. Microbial activity also be checked and the soil becomes barren. But these soils are potentially productive soils and their potential can be improved by proper ameliorating techniques.
Ameliorating techniques for saline soils
The main objective of amelioration is reducing the quantity of soluble salts from saline soil.The following technologies can be followed to reclaim the saline soil.
1. Scraping
It is removal of the salts that have accumulated on the soil surface mechanically. It has limited success and may temporarily improve crop growth.
2. Leaching
This is the most effective management technique for removing salts from the root zone of soils. Stagnation of fresh water can dissolve the salts in the field. Now this water with dissolved salts can be drained out from the field. This way salts can be leached from the salt affected field. Leaching should preferably be done when the soil moisture content is low and the groundwater table is deep. Leaching during the summer months is less effective because large quantities of water are lost by evaporation. If adequate fresh water is not available, lesssalinewater (EC 0.25 dS/m) also can be used.
3. Drainage
Poor drainage condition leads to accumulation of rain water in low lying areas during rainy season. If it is not drained out properly the groundwater table is raised to less than 2 m within 5-10 years and result accumulation of salts due to evaporation from the surface. In general, the critical depth of water table ranges between 1.5 to 3.0 m to check the salinization. So drainage is necessary to prevent salinization.
4. Irrigation frequency
More frequent irrigations prevent the salt accumulation by keeping the soil at higher soil moisture content. So crops grow in saline soils must be irrigated more frequently.
5. Irrigation method
Sprinkler or drip irrigation is ideal method for irrigating frequently and with small quantity of water at a time. Leaching of soluble salts is also accomplished more efficiently when the water application rates are lower than the infiltration capacity of the soil and such a condition cannot be achieved by flood irrigation methods.
6. Proper use of irrigation water
Salt free or less saline (if salt free water is not available) water only to be used.Moistureshould be kept at optimum field capacity to check the salt accumulation.
7. Management of soil fertility throughproper fertilizer application
Generally saline soils are low in fertility status. Response of nitrogen is better when it is applied with green manures and green leaf manures such as dhaincha. However, excessive fertilization on a highly saline soil is of no value. Uses of acid forming fertilizer such as ammonical and amide form help to drop the pH level of soil.
8. Mulching
Soil salinization is particularly high when the water table is shallow and the salinity of groundwater is high. Mulching can reduce evaporation from the soil surface and encourage downward flow of soil water there by check the accumulation of salts on soil surface.
9. Placement of seed or seedling
Salts tend to accumulate at the raised portion of soil. So planting or seeding at sides or shoulder of ridges help them to emerge in saline soil.
10.Growing salt tolerant crops
Gypsum – can be an amendment for saline soil?
The application of an amendment such as gypsum may not be essential for desalinization but can hasten the process by maintaining a higher infiltration rate by continuously supplying soluble calcium to the leaching water. Thus, requirement of gypsum application depends on soil infiltration rate, the electrolytes and calcium level of the irrigation water and soil. So, light textured soils do not require gypsum application whereas heavy soils require gypsum. Gypsum application can reduce the salinity of deeper soil but do not show any effect in surface soils.
summary:
Saline soils are barren but potentially productive soils. All the problematic soil are need to be rectified and made to be productive to ensure the food security of ever growing population. Soluble salts concentration of saline soil can be minimized by the above technique and made into productive. Tolerance of crops to be improved through salt resistant root stocks, genetic and molecular approach those further helps to get higher yield in saline soils.
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