Available water capacity (AWC) of soil is important for studying soil humidity, irrigation management, ecological agricultural planning, evaluation of crop growth potential and simulation of change of globe land cover under affection of economical factors and climate changes. The survey of soil AWC is expensive due to cost consuming and time-consuming. Moreover, it is probably unfeasible because of extension of study area and spatial changes of soil. It is better way to estimate the soil AWC through a few m...