AN APPLICATION STUDY ON THE ZERO FLUX PLANE METHOD
零通量面方法的应用研究

The method of Zero Flux Plane (ZFP) is a new method based on the distribution of soil moisture potential to find the plane where water flux is zero without using the hydraulic conductivity to study soil water movement,ZFP exists in the above-held capillary water zone and joint parts of various states of soil water movement.The three kinds of ZFP are maximum and minimum values and complex.With the position where the last maximum value ZFP disappears, it can determine the capillary front to be suspended approximate to the height of 1,2m at Yucheng Experimental Station.Not only can a period of total soil evaporation be measured with ZFP method, but also can the whole processes of water consumption for evaporation and soil water potential changes be studied. Wheat field evaporation at Yucheng Experimental Station is 22.3 mm, which is 1.9 mm higher than that of Lysimeter from March 20 to 30, relative error is 7.9 percent.There are many problems that tensometer is used to measure soil water potential for ZFP position and Neutron probe is used to measure soil water changes. There may be more possibility to produce accidental error. And further study should be done.The computation of infiltration to recharge groundwater estimated by ZFP method, on the theoretical basis, is reasonable. But, to compute infiltration by using soil water storage changes, whatever measurement and method of computation should be improved otherwise it can not meet the need of accuracy.Because there are many ways for infiltration, the infiltration computed by ZFP method is only a little part of it, which can not represent effective recharge of rainfall or irrigaton to groundwater, so that, the computation is unimportant in practice.