Sodium Adsorption Ratio and its Effects on the Soil Characteristics

the presentation is about the soil characters according to sodium adsorption ratio as how much amount of sodium is suitable for soils.

1. PRESENTED BY: SARAH MALRYAM MALIK ROLL NO. 112-BH-BOT-14 SOIL SALINITY AND WATER LOGGING BOTANY DEPARTMENT GOVT. COLLEGE UNIVERSITY LAHORE SAR AND ITS EFFECTS ON THE SOIL CHARACTERISTICS SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS 1

2. Sodium is an essential element for plants but can be used in small quantities, similar to micronutrients, to aid in metabolism and synthesis of chlorophyll . In some plants, it can be used as a partial replacement for potassium and aids in the opening and closing of stomata's, which helps regulate internal water balance.  SODIUM : SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS 2

3. Soil provides sodium in plants . There is a natural accumulation of sodium in soil from fertilizers, pesticides, run off from shallow salt-laden waters and the breakdown of minerals which release salt. Excess sodium in soil gets taken up by plant roots and can cause serious vitality problems in your garden. Let’s learn more about sodium in plants . EXCESSIVE SODIUM ACCOMULATION: SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS 3

4. Sodium toxicity appears as necrosis or scorching of the leaf tips and margins, similar to micronutrient toxicities. The majority of sodium pockets in soil are from concentrated runoff of pesticides, fertilizers and other soil amendments. Fossil salt runoff is another cause of high salt content in soils. The sodium tolerance of plants is also tested in coastal areas with naturally salty ambient moisture and leaching from shorelines. EXCESSIVE SODIUM ACCUMULATION: SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS 4

5. Sodium adsorption ratio is a measure of the amount of sodium (Na) relative to calcium (Ca) and magnesium (Mg) in the water extract from saturated soil paste. It is the ratio of the Na concentration divided by the square root of one-half of the Ca + Mg concentration. Sodium-adsorption ratio (SAR)  Describes the tendency for sodium cations to be adsorbed at cation-exchange sites in soil at the expense of other cations, calculated as the ratio of sodium to calcium and magnesium in the soil. Sodium adsorption ratio: SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS 5

6. The sodium hazard of soil usually is expressed as the sodium adsorption ration (SAR). This is the proportion of water soluble Na to Ca plus Mg in the soil. Ions in the equation are expressed in millequivalents per liter ( meq /L) and are obtained from a saturated paste soil extract. 6 SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS

7. A low sodium content gives a low SAR value . In practice, allowance must be made for other reactions within the soil that do not involve sodium but that affect concentrations of calcium and magnesium. The SAR value is most likely to be changed by irrigation water 7 SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS

8. SAR allows to assess the state of flocculation or of dispersion of clay aggregates in a soil. Sodium and potassium ions facilitate the dispersion of clay particles while calcium and magnesium promote their flocculation. The behaviour of clay aggregates influences the soil structure and affects the permeability of the soil whose directly depends the water infiltration rate. The SAR parameter is also used to determine the stability of colloids in suspension in water. 8 SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS

9. If irrigation water with a high SAR is applied to a soil for years, the sodium in the water can displace by the calcium and magnesium in the soil. This will cause a decrease in the ability of the soil to form stable aggregates and a loss of soil structure and tilth. This will also lead to a decrease in  infiltration and permeability of the soil to water, leading to problems with crop production. Sandy soils will have less problems, but fine-textured soils will have severe problems if SAR is greater than 9. When SAR is less than 4, there will not be a problem 9 SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS High concentration of SAR:

10. The problem with excess salt in soil is the effects of sodium on plants. Too much salt can cause toxicity but more importantly it reacts on plant tissues just as it does on ours. It produces an effect called osmotion , which causes important water in plant tissues to be diverted. Just as in our bodies, the effect causes tissues to dry out. In plants it can impair their ability to even uptake adequate moisture . Buildup of sodium in plants causes toxic levels that cause stunted growth and arrested cell development.  Effects of sodium concentration in plants SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS 10

11. Sodium in soil that is not at toxic levels can easily be leached out flushing the soil with fresh water. This requires applying more water than the plant needs so the excess water leaches away the salt from the root zone. Another method is called artificial drainage and is combined with leaching . This gives the excess salt laden water a drainage area where water can collect and be disposed of . Improving Sodium Tolerance of Plants SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS 11

12. In commercial crops, farmers also use a method called managed accumulation . They create pits and drainage areas that funnel salty waters away from tender plant roots. The use of salt tolerant plants is also helpful in managing salty soils. They will gradually uptake sodium and absorb it . SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS 12

13. The physical and mechanical properties of soils are mainly dependent on the quantity, size and strength of soil aggregates and their stability in water. Soil characteristics SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS 13

14. 14 SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS

15. Soils that have SAR values of 13 or more may be characterized by an increased dispersion of organic matter and clay particles, reduced saturated hydraulic conductivity and aeration, and a general degradation of soil structure. Aggregate stability Bulk density Available water capacity Infilteration Slaking Soil crusts Indicators of change in soil characteristics: SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS 15

16. The concept of SAR addresses only the effects of sodium on the stability of soil aggregates . However, high K and Mg concentrations have also negative effects on soil permeability. The effect of potassium can be similarly treated by means of the potassium adsorption ratio (PAR ). 16 SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS

17. THANKYOU 17 SAR AND ITS AFFECTS ON SOIL CHARACTERISTICS