Read the following statements:
A). Water holding capacity of sandy soil is high as larger pores can hold more water.
B). Silty soils have medium to high water retentive capacity.
C). Clay soils have small size pores, thus have low water holding capacity.
D). Clay soil have poor aeration and poor drainage.
E). Water holding capacity of soil depends largely on its texture and organic matter present in it.
Choose the correct answer from the options given below:
Show Hint
- Sandy soils: Large pores \(\rightarrow\) Low water holding capacity, high aeration.
- Clay soils: Small pores \(\rightarrow\) High water holding capacity, poor aeration.
This basic physical relationship rules out statements A and C immediately.
Step 1: Understanding the Concept:
Soil water holding capacity (WHC) is the ability of soil to retain moisture against gravitational pull.
It is heavily determined by soil texture, pore size distribution, and organic matter content. Step 3: Detailed Explanation:
- Statement A evaluation: Sandy soils are dominated by large macropores. While these allow fast infiltration, they do not hold water against gravity, resulting in a very low water holding capacity. Thus, Statement A is incorrect.
- Statement B evaluation: Silty soils have intermediate pore sizes, giving them medium to high water retentive capacity. Thus, Statement B is correct.
- Statement C evaluation: Clay soils are dominated by tiny micropores. Although the individual pores are small, the total pore volume and specific surface area of clay particles are extremely high, giving clay soils the highest water holding capacity. Thus, Statement C is incorrect.
- Statement D evaluation: Clay soils have low macro-porosity, which causes water to drain slowly, leading to poor aeration and drainage. Thus, Statement D is correct.
- Statement E evaluation: Soil texture (proportion of sand, silt, clay) and organic matter (which acts like a sponge) are the two primary factors determining a soil's water holding capacity. Thus, Statement E is correct. Step 4: Final Answer:
The correct statements are (B), (D), and (E), which is option (C).
