Study On Impact Of Soil And Water Conservation Of PAM In Purple Soil Region

Soil erosion has become a major issue in our country,as well as one of the world.Purple soil as a short development time of the lithological soil,prone to soil erosion.Purple soil arable land accounts for 78.7%in the Three Gorges reservoir area,most of them was slope land.Serious soil erosion and water loss of slope land in hilly region causing soil thin,nutrient loss,resulting in low productivity farmland,hampering the sustainable development of local agriculture seriously.PAM (Polyacrylamide,Polyacrylamide,referred as PAM) as a soil structure stabilizing agent,having soil physical properties improvement,water-keeping,sand reduction,fertilizer and other effect.In this study,the laboratory test and field test were combinated used to study the clay loam soil which was in the back of the mountain Southwest University a more systematic study of PAM on soil physical properties,nutrient loss and sediment reduction effect of water and so on,and PAM application in the field test results carried out.The main contents of the study results are as follows:1 PAM has a significant change to the effects of soil physical propertiesPAM had a regulatory application on soil bulk density and total porosity,bulk density reduced, total porosity increased.After application of PAM the soil water stable aggregate content increased, especially the increasing in aggregate＞0.25mm content of the soil.At the same time,saturated soil water content and average moisture content than the control significantly improved.After the imposition of PAM,field soil moisture conditions wer better than the control.2 PAM inhibit the loss of soil nutrients effectivelyThe soil after PAM treated,under repeated artificial rainfall,soil nutrients were significantly higher than the control.With the increasing use of PAM,the soil nutrient content increased.PAM on non-adsorption nitrate nitrogen process with the impact of runoff loss was not obvious,but significant changes in phosphorus concentration of runoff process over time,and subject to the power function decay.PAM imposed after the loss of nutrients in Daejeon situation obvious than that of the control,consistent with the indoor study.3 PAM has a significant effect of sediment reduction by waterThe higher concentrations of PAM,the shorter the time of the beginning of runoff,the smaller the runoff rate.PAM has a very good effect to reduce the runoff,as the PAM concentration increased runoff than that of the control respectively.At the same time,the erosion resistance of soil enhanced, rainfall runoff in the case could significantly reduce the runoff of silt content,and with the increase of PAM concentration in reducing sediment yield,soil erosion reduced by 2 to 6 times.Application of PAM to reduced the effects of sediment yield better than the effect of reducing runoff.