Experiment Study On The Effects Of Shallow Flow On The Solute Transportation In The Slope Field Derived From Red Soil

The transportation mechanism of water and nutrient in slope field is the key content of soil degeneration and non-point contamination research on agriculture, and the crossing point of soil erosion, slope hydrology, slope agriculture and environmental science. It is helpful to predicting and controlling the nutrient and water content of slope field derived from the red earth and protecting eco-environment to study on the soil solute transportation mechanism in slope field derived from the red earth.The influence of bulk density on the characteristic of water solute transportation and the process characteristics of nutrient loss in red soil were studied, and the influence of hydraulic characteristics of shallow flow on soil erosion in slope field and the loss of Br" were also preliminarily investigated by the ways of soil column infiltration test and washing slope field by water from upper slope, using Br- as the tracer. The main results are listed as follows:1.Soil water transportation velocity and soil saturated hydraulic conductivity decreased with the increase of soil bulk density. But the dispersion coefficient and retardation factor increased with the increase of soil bulk density.2. Runoff time decreased and the loss of Br- and soil increased with the increase of slope.3. Runoff time decreased and runoff and soil erosion increased with the increase of runoff from upper slope. The effect of runoff on soil erosion was obvious. Soil erosion increased with the increase of flow. The loss of Br- were in direct proportion to the loss of soil.4. The flow velocity have obvious effect on soil erosion. The loss of soil increased with the increase of flow velocity, and there was obvious linear correlation between them. The effect of flow velocity on loss of Br- is more obvious than that on soil erosion. The slope had less effect on resistance coefficient. There was more effect on the soil erosion and Br- when resistance coefficient is less than 0.5. The higher the Raynolds Number was, the larger the loss of soil and Br-was,which showed that the turbulence of flow had more effect on slope soil erosion and solute transportion.