Effect Of Biochar On Soil Hydrodynamic Parameter In The Loess Plateau

The water shortage and soil erosion in the Loess Plateau is serious. It great significant toimprove soil water holding capacity, and enhance soil water availability, for the agriculturalproduction of the Loess Plateau. Biochar has wide application in adjusting soil structure andimproving water and fertilizer performance in prospect, due to the pore and surfacecharacteristics of the biocha r. The application of biochar will become an effective approachof ecological environment control in the Loess Plateau.In this study, the effect of biochar with different sizes and different applicationrate on thesaturated hydraulic conductivity, water retention, evaporation and infiltration characteristics,of the five main soils in the Leoss Plateau were studied. The results are as follows:Through assaying soil saturated hydraulic conductivity with constant water head it wasfound that the saturated hydraulic conductivity of the soil is mainly depended on the soiltexture. In general, biochar can increased the saturated hydraulic conductivity of AnthrosolLou soil and aeolian sandy soil in, however decreased the one of the Heilu soil, Huangmiansoil and Shahuang soil. The impacts of biochar particle size and content on the soil saturatedhydraulic conductivity are not significant.Using the centrifuge method, and by the comparison, it was showed that the soil textureplays a dominant role in determining soil water holding capacity, and the effect changeed withsoil textures. Biochar made a little influence on soil water retension curve of Lou soil,improved the ability of water-holding capacity of sandy soil, and promote the water holdingcapacity of Shahuang soil and Heilu soil. The greater the amount of biochar, the moresignificant the effec will be. The tedency of Water retention curve changes is not obviousunder different biochar particle size. Using the van Genuchten model, the water holdingcapacity of the soils with different sizes of biochar and addition amount was simulated. For allthe treatments, the correlation coefficients were above0.99, Variation between the parametersfitted by the measured value was not significiant.By analysising impact of the biochar on evaporation and soil moisture, the results showsthat biochar can restrain soil water evaporation.evaporation and delayed the release of soil moisture. With the content of biochar Increased, and the particle size decreases, the moresignificant the inhibition is.By vertical one-dimensional water infiltration method the impact of biochar on soilinfiltration characteristics was studied and found that the water infiltration was maily dependon soil texture. The biochar can reduce the infiltration capacity of the sandy soil, while play arole in promoting the infiltration capacity of the clay. By simulation using Philip andKostiakov infiltration model, the experimental results showed that the Philip model is suitablefor the simulation of water infiltration into soil with biochar, and the variation tendency of thefitted parameters were irregular.