Soil Productivity Restoration And Evaluation Of Erosion Degradation In Weibei Dry Highland

The phenomenon of soil erosion in Loess Plateau of China is serious, which hastremendously restricted the development of agriculture. Due to the special nature of the soil inthe Loess Plateau, it is vulnerable to be eroded and washed, resulting in the depletion of soilnutrients, thicker texture, and a decline in soil fertility and yield. The soil type of Weibei areain the Loess Plateau is mostly Lou soil, which always has loose structure. The localprecipitation in spatial and temporal distribution is nonuniform and the form of precipitationis mostly rainstorm. The rapid precipitation striking and eroding soil is not only makes thesoil structure destroyed, but also take away the nutrient of the surface soil, resulting in soildegradation and productivity reduction, which has a serious effect on the development of thelocal agricultural economy. Soil productivity was observed through the method of theartificial simulation of different degree of eroded soil, and the fertilization and covered thetopsoil two recovery measures were selected to study the recovery of soil productivity. At thesame time, the PI model for soil productivity evaluation of two recovery measures wasutilized. Main conclusions were achieved as follows:1. Soil erosion could reduce the productivity, the stronger erosion force, the greater range ofreduction of the soil productivity. Soil erosion could change the physical traits of the soil andreduce the organic matter and other nutrient content in the soil. Plant height could reduce andcrop biomass and yield could decrease because of soil erosion. Corn biomass of degradedlands in the experiment reduced by2103.1kg/hm~2compared with control treatment and cornyield of degraded lands in the experiment reduced by1039.6kg/hm~2compared with controltreatment. Wheat biomass of degraded lands in the experiment reduced by531.8kg/hm~2compared with control treatment and wheat yield of degraded lands in the experiment reducedby233.3kg/hm~2compared with control treatment. The PI model was used to evaluate erodedsoil, which could draw a conclusion that the eroded soil productivity was lower than the soilproductivity under the control treatment.2. Covering the mellow soil could improve the physical properties of soil, and increase soilnutrient content, so as to increase the soil productivity. The test shows that plant heights underthe covering soil were higher than that under the control treatment. Biomass and yield had improved compared with the control treatment. Corn yield of covering10cm mellow soilrose by430.3kg/hm~2compared with the control treatment and corn yield of covering20cmmellow soil rose by483.6kg/hm~2compared with the control treatment. Wheat yield ofcovering10cm mellow soil rose by100.2kg/hm~2compared with the control treatment andwheat yield of covering20cm mellow soil rose by178.8kg/hm~2compared with the controltreatment. Biomass also showed the same phenomenon. The soil productivity of covering soilcalculated by the PI model was higher than that of under the control treatment.3. Fertilization also could improve soil structure to a certain extent, and increase the nutrientsin the soil to improve soil fertility. The yield of corn and wheat were both increased comparedwith the control treatment, which indicated that fertilization could to some extent make up forlosses because of erosion. Fertilizer mounts should also be changed with erosion at differentlevels, in order to restore soil productivity to aquire the greatest benefits. The research hadshown that the best fertilizer mounts of wheat and corn for erosion simulation of10cmtopsoil and20cm were both N600P300K300, which indicated to a certain extent that soil erosioncan severely reduce productivity, and sufficient quantity of fertilizer were needed tocompensate the loss of productivity. Productivity index evaluation indicated that differentamounts of fertilizer could increase the productivity of eroded soil.4. Fertilization and covering soil two different recovery measures were combined andproportioned, in order to explore the most suitable recovery measures of eroded soilproductivity. Through contrast with biological properties, yield and biomass, there was aconclusion that the best soil productivity was soil productivity of covering10cm mellow soilcombined with standard fertilizer or less fertilizer and soil productivity of covering20cmmellow soil combined with least fertilizer or less fertilizer under the corn land. The best soilproductivity was soil productivity of covering10cm mellow soil combined with standardfertilizer and soil productivity of covering20cm mellow soil combined with less fertilizerunder the wheat land. Productivity index evaluation also proved that the above four kinds ofmatching patterns of soil productivity were higher.