Question

At $0^{o}C$ soil temperature, the rate of water absorption
A. Increases
B. Not affected
C. Decreases
D. Appreciable

Answer 1

Hint: The uppermost layer of the earth's crust is formed by weathering of rocks called soil. It is a mixture of living and non living materials. The nature and properties of soil is dependent on the climate, the weathering process, whether soil is transported or sedimentary and how soil development occurred.

Complete answer: Various characteristics of the soil such as soil composition, grain size and aggregation determine the percolation and water holding capacity of soil.
For the proper growth of a plant, the condition of soil must favor its growth. Adequate temperature, moisture and grain size of soil are required for the healthy growth of plants.
As a result of weathering, the mineral particles of different sizes are formed. The soil having high water holding capacity, high aeration and high root penetration is considered as the best soil for cultivation. Temperature and moisture are the most important factors that affect soil fertility.
Low temperature causes decreased permeability of the cell membrane of the root cell thus poor water absorption occurs in these conditions. As temperature increases, permeability of cell membrane also increases and due to increased kinetic energy of water, water is rapidly absorbed by the roots.
As $0^{o}C$ temperature is considered as the freezing low temperature, the rate of water absorption decreases at this temperature of soil.
Thus the correct answer is option C.

Note:
Soil is divided into various layers according to the size of particles and amount of organic matter present in it. Soil formation is a very slow process that takes about thousands of years for the production of just one inch of soil. The temperature and the moisture content of the soil are the most important climatic factors that regulate the process of decomposition by soil microbes. Warm and moist environment favours decomposition whereas low temperature and anaerobic environment inhibits decomposition.