Today this article may seem too simplistic an explanation of basic irrigation concepts -- field capacity, permanent wilting point
, readily available moisture.
This water content is called the permanent wilting point
s] is 10 dS/m for a loamy sand (soil #2) the permanent wilting point occurs in this soil by the time the matric head reaches a value of only 10m (or 1 bar).
s] values (on the horizontal axis) and their corresponding matric heads at the permanent wilting point (on the linear, vertical axis).
Since direct measurement of water retention characteristics over a large area is expensive, time-consuming, and difficult, in this investigation some of the easily measured soil physical and chemical properties were determined in rainfed rice area and pedo-transfer functions were derived through regression equations to predict water content at field capacity, permanent wilting point
, and available water capacity.
The permanent wilting point
of our soil was calculated to be 0.