Effects Of Conventional Tillage On Soil Erosion

Cropland accounts for a large proportion of China’s arable land area and is an important agricultural resource.Crop planting and slope cropland management have a significant impact on the occurrence and development of soil erosion on slope cropland,and conventional tillage methods are an important cause of serious soil erosion on slope cropland.Conventional tillage method refers to the tillaging in which the soil surface is totally disturbed in the process of ploughing in spring and autumn,and the tillage method is generally ploughed to a depth of about 20cm,and its field management is extensive,and the soil erosion is serious.To improve the prediction of soil erosion on cropland and the accuracy of regional soil erosion investigation and evaluation,a new method was developed for the assignment of factor T of tillage measures.In this study,the T value in different soil and water conservation zones in China was calculated according to the definition of conventional tillage factors,and the effects of different planting densities of crops on soil erosion under the conventional tillage mode were studied by using natural rainfall in the field and indoor artificial simulated rainfall,and the quantitative relationship between crop cover and soil loss was established to correct the T value of tillage factors.The main conclusions reached in the study were as follows:1.Different planting densities mean different crop coverage.As the planting density increases,so does the crop cover.In addition,crop coverage also changes with time,in the early stage of crop growth,the difference in the coverage of each density treatment was larger,the change was more dramatic,and then tended to stabilize,and then gradually decreased after reaching the peak.For example,in the corn seedbed stage,the leaf cover of crop seedlings was small and low,after entering the seedling stage(coverage 10%～50%),the coverage increased greatly,the development period(coverage 50%～75%)continued to grow,and after entering the maturation stage(coverage 75%～harvest),the coverage was relatively stable,the crops were grown to the most vigorous maturity stage,the coverage reached the maximum,and then began to decrease.2.Ground cover could significantly decreased surface runoff and soil erosion.Under the natural rainfall plot experiment in the field the average annual runoff depth and erosion modulus of bare land were 7.99 mm and 7.56 t/hm2,respectively,and the average runoff depth and erosion modulus of cropped plots were only 0.31 mm and 0.06 t/hm2.Under the condition of artificial rainfall experiment p,the initial runoff time was delayed with the increase of crop cover,and the flow rate and sand yield decreased overall,with the average runoff depth and erosion modulus of bareland being 42.9 mm and 7.7 t/hm2,respectively,and the average runoff depth and erosion modulus of each planting density of the naked land control at the full breeding stage of maize were 33.6 mm and 3.5 t/hm2.3.Surface runoff and soil erosion are negatively exponentially related to crop coverage.Under artificial rainfall conditions,Y=43.41e-0.006x(R2=0.882,p<0.01),Y=8.29e-0.02x(R2=0.856.p<0.01).that means,as the coverage increases,the surface runoff and soil erosion gradually decrease,and vice versa.This relationship has important implications for the assignment of regional tillage practices.4.Proposed a new method for assigning the factor value T of the actual tillage measures in the regional cropland.When conducting a regional soil erosion survey,the calculation of the value of the tillage factor T can be calculated in the following three ways:(1)The coverage data is calculated using the formula Y=-0.0086x+0.9099,and the resulting T value is Tacalc.(2)If the coverage information cannot be obtained,look up the baseline value of the tillage measure factor T of the 8 soil and water conservation zones,and the T value obtained is Tbas.(3)coupling Tcalc and Tbas values,i.e.,Tadj=Tcalc×Tbas/Tequi.,and obtaining more reasonable tillage T value.