Available water capacity refers to the amount of water held in the soil that is available for plant uptake. It is an important characteristic of soil that determines its ability to provide water for plant growth. Specifically, available water capacity represents the portion of soil water that can be accessed by plant roots and used for the physiological needs of plants.
This capacity is influenced by various soil properties, including soil texture, structure, and organic matter content. Soil texture refers to the relative proportions of sand, silt, and clay particles in the soil, which directly affects water-holding capacity. Soils with higher clay content tend to have higher available water capacity compared to sandy soils.
Soil structure also plays a role in available water capacity, as it determines the pore space within the soil, which affects the movement and retention of water. Soils with good aggregation and well-developed pore spaces tend to have higher available water capacity.
Moreover, organic matter content influences available water capacity by improving soil structure and water-holding capacity. Organic matter acts like a sponge, increasing the soil's ability to retain water and making it more accessible to plant roots.
Knowing the available water capacity of a soil is important for irrigation management and crop selection. It helps determine when and how much irrigation is needed to replenish the water available to plants. Additionally, it assists in selecting appropriate plants that can tolerate the soil's water-holding capacity.
