Classification of salt affected soils
What are all the classification of salt-affected soils?
Based on pH of the saturated paste, electrolytic conductivity of the saturated paste extract (ECe), and exchangeable sodium percentage (ESP), these soils have been classified as saline, alkali, and saline-alkali per the criteria of the U. S. Salinity Laboratory.
What are the characteristics of salt-affected soils?
Salt-affected soils are characterized by a strongly alkaline soil reaction (Schaetzl and Anderson, 2009). The soils containing sodic salts have an enhanced content of exchangeable Na+ and pH > 8.5. The soil profile S shows a pH between 9.5 and 10.0 in the upper soil horizons (Fig. 5.8.
How many types of soil salinity are there?
The term “salinity” refers to the concentrations of salts in water or soils. Salinity can take three forms, classified by their causes: primary salinity (also called natural salinity); secondary salinity (also called dryland salinity), and tertiary salinity (also called irrigation salinity).
How salt-affected soils are formed?
The possible causes for salt-affected soils could be poor drainage, saline or sodic subsoil exposure due to erosion, parent soil material, use of high salt irrigation water, long-term use of some fertilizers, low rainfall or oil field activity.
What is reclamation of salt affected soil?
The reclamation of salt-affected soils follows the exact reverse of the process by which they are formed. The first step is to improve the drainage so that upward movement of ground water to the soil surface ceases and water applied to the surface can move down through the soil profile.
What is ESP soil science?
Exchangeable sodium percentage (ESP) is, accordingly, the amount of adsorbed sodium on the soil exchange complex expressed in percent of the cation exchange capacity in milliequivalents per 100 g of soil.
What are the main effects of salt affected soil on plant growth?
Salinity affects production in crops, pastures and trees by interfering with nitrogen uptake, reducing growth and stopping plant reproduction. Some ions (particularly chloride) are toxic to plants and as the concentration of these ions increases, the plant is poisoned and dies.
Which is the most harmful salt in salt affected soil?
Excess sodium (Na) can lead to the destruction of soil structure through its ability to disperse clays. This leads to decreased aeration and consequently, restricts root growth. 2. Excess salts in soil solution affect the osmotic potential of soil water.
How does salt affect soil pH?
High salt content increases the osmotic potential of the soil solution and prevents crop uptake of water. Crops are generally most sensitive to salinity during germination and emergence. Some plants are more sensitive to salinity than others, depending on growth habit, root system, etc.
What are 3 consequences of high salt levels in soils?
Salinity not only decreases the agricultural production of most crops, but also, effects soil physicochemical properties, and ecological balance of the area. The impacts of salinity include—low agricultural productivity, low economic returns and soil erosions, (Hu and Schmidhalter, 2002).
What level of salinity affects plants?
Most plants will typically suffer injury if sodium exceeds 70 milligrams per liter in water, or 5 percent in plant tissue, or 230 milligrams per liter in soil, in the extract from a saturated soil paste.
What are the causes of soil salinity?
Salinity occurs when the water table rises, bringing natural salts to the surface; in sufficient quantity, these salts become toxic to most plants.
How do you reduce salt in soil?
Gypsum (calcium sulfate) or lime can be used to help leach salt from the soil. The calcium in these products replaces the sodium salt from the soil exchange sites and helps bring the salt into solution. Large concentrations of salt may be leached from a soil in this way.
What is high salinity in soil?
If this water contains less than 3 grams of salt per litre, the soil is said to be non saline (see Table below). If the salt concentration of the saturation extract contains more than 12 g/l, the soil is said to be highly saline. Salt concentration of the soil water (saturation extract) Salinity.
How do you test for salt in soil?
Soil salt content can be measured in a laboratory by measuring the total dissolved solids in a sample. In the field, salt concentration can also be estimated using electromagnetic induction-based soil sensors.
How does salt affect plant growth experiment?
The experiment shows that salt is damaging to plants. The damage increases as the salinity increases. In pure freshwater, cut vegetables should remain largely unchanged for several days without showing much sign of wilting. The higher the salt concentration in the water, the worse the plants will fair.
How does salt affect plant cells?
If a higher concentration of salt is placed outside of the cell membrane, the water will leave the cell to bond with it. The loss of water from this movement causes plant cells to shrink and wilt. This is why salt can kill plants; it leaches the water from the cells.
Does salt prevent plant growth?
A team of researchers, led by the Carnegie Institution’s José Dinneny and Lina Duan, found that not all types of roots are equally inhibited. They discovered that an inner layer of tissue in the branching roots that anchor the plant is sensitive to salt and activates a stress hormone, which stops root growth.
How does salt affect plant germination?
In general, high soil salinity inhibits seed germination due to the low osmotic potential created around the seed, which prevents water uptake (Welbaum et al., 1990). In addition, high concentrations of sodium and chloride ions in the soil may be toxic to seeds (Khajeh-Hosseini et al., 2003).
How do you remove salt from soil?
Gypsum (calcium sulfate) or lime can be used to help leach salt from the soil. The calcium in these products replaces the sodium salt from the soil exchange sites and helps bring the salt into solution. Large concentrations of salt may be leached from a soil in this way.
How does salt affect root growth?
The results indicated that salinity caused a reduction in root growth (volume, area, diameter, total and main length and root dry weight), and shoot biomass accumulation. Both root and leaf sodium (Na) content and leaf proline content increased with increasing salinity.
What plants are sensitive to salt?
Relative tolerances of shrubs to salinity — Two sources of data
| Botanical name | Common name | Tolerance to salt spray |
|---|---|---|
| Ixora coccinea L. | ixora | sensitive |
| Jasminum polyanthum Franch. | jasmine | moderate |
| Jatropha multifida L. | coral plant | sensitive |
| Juniperus chinensis | blue point juniper | — |
How do you test the salt content of soil?
Soil salt content can be measured in a laboratory by measuring the total dissolved solids in a sample. In the field, salt concentration can also be estimated using electromagnetic induction-based soil sensors.