Question

Which of the following soil has maximum water holding capacity?
A. Loam
B. Clay
C. Sand
D. Silt

Answer 1

Hint: Soil with small and fine particles can retain a good amount of water. Whereas, soils that have low nutrition and larger particles tend to lose more amounts of water.

Complete step-by-step answer:
Water holding capacity of a soil is the amount of water that a soil can hold. It is mainly important in agriculture, where field capacity is defined as the water holding capacity of the entire soil in the field has reached a maximum. Water holding capacity is highest in soil with fine particles like that of silt and clay-sized particles, as they have a larger surface area that allows the soil to hold a larger quantity of water. Thus, the water holding capacity for the above-mentioned soil decreases in the following order:
Clay (with maximum water holding capacity) > Silt > Loam > Sand

Additional Information:
Sand has the lowest water holding capacity because they have coarse particles that leave a huge gap between the particles. Thus, a large amount of water and nutrients easily escape from the soil and cannot be retained within the sand.
Water holding capacity of soil can be increased by increasing the amount of organic matter in the soil as they act as natural magnets of water, pulling or driving a huge amount of water towards it. These Soil Organic Matter (SOM) are nothing but the dead and decayed plants and animals that not only add nutrients to the soil but also help in retaining the water in the soil.
The fine particles of soil not only help in retaining water but also help in retaining nutrients as the nutrient cations can easily adhere to the large surface area of these fine particles as seen in clay soil.

Note: Water holding capacity of a soil depends on the size of the soil particles, as smaller the size, greater will be its surface area and lesser free space between the particles that not only help the soil to absorb most of the water but also helps in retaining the water within the soil for a longer time.