How to determine surface soil water content(SWC) quickly and accurately is fundamental in studying eco-hydrological processes and their modeling.Here we use laboratory experiments to determine surface SWC using soil surface gray level(SGL) values.A negatively exponential relationship exists between SGL and SWC,i.e.,SGL increases with the decrease of SWC.SGL can be estimated based on initial SGL value(surface gray level when SWC=0),SWC,and a surface roughness coefficient characterized by mean soil particle size.The variation range of SGL was larger than that of SWC,indicating that changes in SWC were enhanced in SGL,and that SGL would thus be sensitive to changes in soil water.At the 95% confidence level,SWC can be determined by using the relationship between SWC and SGL established by the experiments.The determination of SWC has a high precision when SWC was between dry and saturated.
ZHU YuanJun1,2,WANG YunQiang1,2 & SHAO MingAn1,2 1 State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau,Institute of Soil and Water Conservation,Northwest A & F University,Yangling 712100,China
