Following are the statements with respect to economization of irrigation water in rice
A. Rice should be cultivated on heavy soils with percolation above 5 mm per day
B. Subsoil loosening to enhance water flux to soil.
C. Rice should be grown in small isolated blocks to reduce seepage
D. Application of tank silt to light soils
E. Puddling to reduce soil permeability
Choose the correct answer from the options given below
Show Hint
To conserve water in rice fields, the goal is to reduce soil permeability.
This is achieved mechanically by Puddling (E) and physically by applying clay-rich Tank Silt (D) to light soils.
Step 1: Understanding the Concept:
Rice is traditionally grown under flooded (submerged) conditions, which requires large volumes of water.
Much of this water is lost through deep percolation and seepage. Economizing water in rice cultivation focuses on reducing these soil permeability losses. Step 2: Detailed Explanation:
Let us evaluate each of the statements:
- Statement A: "Rice should be cultivated on heavy soils with percolation above 5 mm per day."
This is incorrect.
To conserve water, rice should be grown on heavy clay soils with low percolation rates (ideally less than 2-3 mm per day). High percolation rates lead to excessive water loss.
- Statement B: "Subsoil loosening to enhance water flux to soil."
This is incorrect.
Loosening the subsoil increases infiltration and deep percolation, which increases water consumption. Instead, we want to create a compacted, impermeable subsoil layer.
- Statement C: "Rice should be grown in small isolated blocks to reduce seepage."
This is incorrect.
Isolated blocks have a larger perimeter-to-area ratio, which increases lateral seepage losses. Growing rice in large, contiguous blocks reduces total seepage.
- Statement D: "Application of tank silt to light soils."
This is correct.
Applying clay-rich tank silt to light, sandy soils fills the macropores, reducing their permeability and deep percolation losses.
- Statement E: "Puddling to reduce soil permeability."
This is correct.
Puddling (plowing wet soil) destroys soil aggregates and aligns clay particles, creating a compacted, nearly impermeable "plow-sole" layer that drastically reduces percolation losses.
Therefore, only statements D and E are correct agronomic practices for economizing water in rice. Step 3: Final Answer:
The correct option is (D).
