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Water retention curve is the relationship between the water content, θ, and the soil water potential, ψ. This curve is characteristic for different types of soil, and is also called the soil moisture characteristic . It is used to predict the soil water storage, water supply to the plants ( field capacity) and soil aggregate stability.
Available water capacity. Available water capacity is the amount of water that can be stored in a soil profile and be available for growing crops. [1] It is also known as available water content ( AWC ), profile available water ( PAW) [2] or total available water ( TAW ). The concept, put forward by Frank Veihmeyer and Arthur Hendrickson, [3 ...
Field capacity. Field capacity is the amount of soil moisture or water content held in the soil after excess water has drained away and the rate of downward movement has decreased. This usually takes place two to three days after rain or irrigation in pervious soils of uniform structure and texture. The physical definition of field capacity ...
Soil water (retention) Soils can process and hold considerable amounts of water. They can take in water, and will keep doing so until they are full, or until the rate at which they can transmit water into and through the pores is exceeded. Some of this water will steadily drain through the soil (via gravity) and end up in the waterways and ...
The specific heat of soil increases as water content increases, since the heat capacity of water is greater than that of dry soil. [89] The specific heat of pure water is ~ 1 calorie per gram, the specific heat of dry soil is ~ 0.2 calories per gram, hence, the specific heat of wet soil is ~ 0.2 to 1 calories per gram (0.8 to 4.2 kJ per ...
Cross-section of a hillslope depicting the vadose zone, capillary fringe, water table, and phreatic or saturated zone. (Source: United States Geological Survey .) Infiltration is the process by which water on the ground surface enters the soil. It is commonly used in both hydrology and soil sciences. The infiltration capacity is defined as the ...
where is void ratio, is porosity, V V is the volume of void-space (air and water), V S is the volume of solids, and V T is the total or bulk volume of medium. [1] The significance of the porosity is that it gives the idea of water storage capacity of the aquifer. Qualitatively, porosity less than 5% is considered to be small, between 5 and 20% ...
At a potential of −33 kPa, or −1/3 bar, (−10 kPa for sand), soil is at field capacity. Typically, at field capacity, air is in the macropores, and water in the micropores. Field capacity is viewed as the optimal condition for plant growth and microbial activity.