Experimental Study On Parameter Distributions Of Soil Water Movement In Shiyang River Basin

The spatial variability of unsaturated soil hydraulic properties on basin scacle isprecondition to apply the soil water model in the big scales .It is also the demands tostudy the process of ecosystem hydrology and to resolve the realistic problems. Here we make the first step study on the spatial variability of unsaturated soilhydraulic properties based on the experiment and analyze exampled for Shiyang riverbasin.The main results are showed as follows: 1. The spatial scales of unsaturated soil hydraulic properties was divided, thestudy means for spatial variation was put forward, three key problems on the researchwas pointed out, i.e. the difficult to measure parameters, only one parameter formodels and characteristic and construction for spatial variation. 2. The one parameter model for the models of unsaturated soil hydraulicproperties were established based on the experiment.These models have high accuracyand can be used as the variation coefficient to describe the spatial variability of soilhydraulic properties of the big scales for unlimited by soil. The simple Philip modelhas one parameter, so it is can be used to calculate process of infiltration by only onedata and has the high accuracy. 3. The Pedo-Transfer Functions(PTFs) for parameters of one parameter models ofunsaturated soil hydraulic properties were established also.They have enough accuracyand can be used to estimate the parameters of soil hydraulic properties in bigscales.This means make the measurement of parameters very easy in big scales. PTFscan also used to study the affects on hydraulic properties of soil parameters. 4. The combination of the one parameter models and PTFs is not only estimate theparameters of soil hydraulic properties, but also estimate variation coefficient of soilhydraulic properties directly. This is the simple and beneficial method for theprofound research of the spatial variability of the soil water movement characteristic ofthe big scales. 5. The Pedo-Transfer Functions were established for parameters of Fractaldimension,Saturated infiltration coefficient and Permeate coefficient. It can be?3?estimate the parameters of highe accuracy. 6. Based on one parameter model and PTFs, the spatial distribution of theparameters were established of soil hydraulic properties and the physics and chemistryparameters of soil.