Laboratory Simulation Experiments On Soil Erosion From Grass-covered Surface Under Concentrated Flow And The Effects Of PAM On The Germination Of Alfalfa

Laboratory simulation experiments are one of the most effective ways to research soil erosion, and lays scientific foundation for soil and water conservation practice. The rule of grassland erosion is an important field in soil erosion.Most of the existing experiments on grassland erosion are in fields. Field experiments are effected by weathers, landforms, social conditions and so on. To collect long-term and complicated deals' data is much more difficult than laboratory simulation experiments. Fast growing and effective grasses are needed in soil and water conservation on sloping land.A new facility was manufactured to used in the laboratory simulation, and a new experiment way was brought in the simulation experiments.Grass roots reinforce the soil strength withstanding water flow flush and to effectively reduce soil erosion. Laboratory experiments were conducted for the soil erosion reduction under different grasses, as effected by different flow rates and under different slope gradients. 3 flow rates-2, 4 and 8 L/min, 5 slope gradients-5, 10, 15, 20 and 25 degrees as well as 4 surface covers-rye, alfalfa and Tall Fescue and bare soil (control) were used in the experiments. The data of grassland erosion was measured in 5 periods of time in different times of grasses growing periods. Experimental data were used to relate soil erosion with slope gradients of different surface covers under different flow rates in different periods. The models developed were then used to estimate the effectiveness of soil erosion reductions of surface covers as compared with bare surface.PAM, as soil amendment, can effectively stabilize the structure of soil aggregates, reduce soil surface sealing and crusting, improve soil conditions, which might be favorite to seeds' germination. In this study, field plot experiments, with application rates of PAM of 0, 0.5, 1.0, 1.5 and 2.0 g/m2 were conducted to investigate the impacts of PAM application rates on the porosity ofsoil body and germination rates and time of alfalfa, under sprinkler irrigation. Quantitative analysis showed the soil texture and germination differences under different PAM application rates. Economical PAM application rate for high and even germination rate was suggested.