Hint: Soil is made up of a mixture of various components like organic matter, minerals, liquids, gases, and soil organisms. The various components of soil together support life. The water content of the soil refers to the soil moisture. Water retention in the soil is important for the growth of various plants.
Complete answer: Soil moisture is one of the important factors that determine the health of the soil. Various remote sensing methods can be used to measure soil moisture. Water in the soil affects soil formation, structure, stability, and erosion probability. When fields are irrigated then most of the water runoff or drain from the soil. Also, the pores present in the soil holds the water inside them. Due to gravity most of the water gets drained from the soil. A point reaches where the small soil pores get filled with water and the large pores get filled with water and gas. The specific surface area of the soil particles affects this water retention phenomenon. The various ions and chemicals present in the soil also affect the efficiency of water retention in the soil. Various adhesion and cohesion forces hold water strongly to humus and minerals present in the soil. The water stored or retained in large pores of soil is used up by plants for their growth. Also, water retention confirms soil moisture that helps to maintain the texture and stability of the soil.
Hence, the right answer is option D.
Note: The water in the soil is important for climate modeling. Also, numerical weather prediction requires soil water studies. Satellite data and hydrological models help in estimating the soil water. Insufficient soil moisture can cause damage to the yield of crops.