Irrigation water having SAR value of 20, is called
high sodium water
Irrigation Water Classification Based on SAR
The Sodium Adsorption Ratio (SAR) is a crucial indicator used to evaluate the suitability of irrigation water. It helps predict the potential for sodium to accumulate in the soil, which can negatively affect soil structure, permeability, and plant growth. A higher SAR value indicates a greater risk of sodicity.
The classification of irrigation water based on SAR is generally standardized, helping farmers and water managers make informed decisions. The SAR value is calculated using the concentrations of sodium, calcium, and magnesium ions in the water.
The specific classification for a SAR value of 20 is as follows:
| SAR Range | Classification | Sodium Hazard |
|---|---|---|
| 0 - 10 | Low Sodium Water | Low |
| 10 - 18 | Medium Sodium Water | Medium |
| 18 - 26 | High Sodium Water | High |
| > 26 | Very High Sodium Water | Very High |
Based on this classification, an irrigation water sample with an SAR value of 20 falls into the High Sodium Water category. This classification implies a significant risk of sodium affecting the soil structure if this water is used for irrigation without proper management practices.
Important Questions from Water Requirement of Crops
- A tubewell operating $10\text{ hours}$ per day discharges water at a rate of $25\text{ m}^3\text{.h}^{-1}$. The average irrigation depth is $80\text{ mm}$, and irrigation interval is $20\text{ days}$. If intensity of irrigation is $80\%$, the culturable command area (in hectares) is ________. (Rounded off to two decimal places)
The ratio between the areas of a crop irrigated and the quantity of water required during its entire period of growth is known as
Alkaline soils are reclaimed by
For crops like potato and sugar-beets, the commonly adopted method of surface irrigation is
12 m 3/sec of water is diverted to a 30 hectare field for 5 hours. Soil probing after irrigation showed that 0.4 m of water had been stored in the root zone. Water application efficiency in this case would be
