Study On Soil And Water Conservation Effect Of Agricultural Land Soil And Water Loss Prevention Measures Of Loess Plateau In Western Shanxi

In this study, Zhongyang County in Western Shanxi province was the research object. Thecurrent situation of soil and water loss prevention of agricultural land was understood andgrasped to a certain extent by investigating the existing soil and water loss prevention measuresof agricultural land in3different type areas in Zhongyang County. Based on the study methodsof field investigation combined with laboratory experiments,we obtained the effects of soilimprovement, water conservaion and preveiton and control of soil erosion, etc. by analyzingand comparing the soil basic physical properties, soil hydrological characteristics, corrosionresistance of soil micro-aggregate and soil nutrient content, etc. of soil and water lossprevention measures of agricultural land in3different type areas. The agricultural land soil andwater loss prevention measures will be selected to fit to different type areas, and this willprovide scientific basis for the effective prevention and for the reasonable construction ofprevention measure system for soil and water loss in agricultural land. The main findings are asfollows:(1) The existing soil and water loss prevention measures of agricultural land inearth-rocky mountainous area mainly included2kinds: forest and grass measures (returningfarmland to forest and grass land) and agricultural technical measures (plastic film mulching).Based on the comparative analysis of soil basic physical properties, soil hydrologicalcharacteristics, corrosion resistance of soil micro-aggregate, soil nutrient content and etc. of3forest and grass conservation measures, it was found that soil porosity status, soil moisturecontent, water-holding capacity, soil infiltration properties and soil nutrient content of woodland were better than grass land and shrub land to a certain extent, but the corrosion resistanceof soil micro-aggregate was worse than grass land.By respectively comparing the soil and water conservation effects of mulching potato andnon-mulching potato, and mulching corn and non-mulching corn, it was found that mulchingimproved soil physical properties, the stability and corrosion resistance of soil aggregates, soil infiltration and the water storage and retention capacity, and increased the growth of crops. Butfor the local downslope tillage habits and non-completely covering, plastic film mulching wasmore easily to form surface runoff and intensify soil erosion under the heavy rainfall.(2) The existing soil and water loss prevention measures of agricultural land in loess hillyarea mainly included grass measures (returning farmland to forest and grass land, agroforestryand terrace ridge) and engineering measures (terrace).Wood land and shrub land exhibited advantages in improving soil physical and chemicalproperties, increasing soil water infiltration and water conservation and other aspects than grassland. But compared with grass land and shrub land, wood land was lower in soil water content.Therefore, the soil and water conservation effect of shrub land was better in this area.By the contrasting analysis of soil and water conservation effects of apple-green bean,walnut-corn and walnut-soybean agroforestry systems, it was found that soil basic physicalproperties, soil hydrological characteristics, corrosion resistance of soil micro-aggregate andsoil nutrient content of apple-green bean agroforestry system exhibited certain advantages thanwalnut-corn and walnut-soybean agroforestry systems, and secondly was walnut-soybeanagroforestry system. The performance of walnut-corn system was poor.0-40cm soil nutrientcontent of apple-green bean agroforestry system and walnut-soybean agroforestry system werehigher than walnut-corn system. So, from the effects of soil and water conservation,apple-green bean agroforestry system was the best agroforestry type among the3agroforestrysystems in the area.The terrace exhibited advantages in the aspacts of soil basic physical properties, soilhydrological characteristics, corrosion resistance of soil micro-aggregate and soil nutrientcontent to a certain degree than sloping land, but the differences were not significant. Thus, thenew terrace has played a certain role in water and nutrient retention and soil improvement, butthe effect was not obvious at present.By comparing the soil basic physical properties, soil hydrological characteristics,corrosion resistance of soil micro-aggregate and soil nutrient content of walnut ridge, lily ridgeand jujube ridge, it was foun that soil bulk density, porosity condition and soil texture of walnut ridge were better than the other two ridges, but the composition of soil aggregates and stabilityshowed a bit weaker than lily ridge. The soil moisture conditions, soil water storage capacityand soil infiltration capacity, and soil corrosion resistance of micro-aggregates of walnut ridgewere better than lily ridge and jujube ridge. The soil and water conservation effects of walnutridge was the best in loess hilly area.(3) The main agricultural land soil and water loss prevention measures in the river valleyarea was agroforestry.Based on the contrasting analysis of soil and water conservation effect of walnut-potato,apple-corn and walnut-corn agroforestry systems, it was found that the soil bulk density,non-capillary porosity, soil infiltration properties, water-holding capacity in non-capillaryporosity, corrosion resistance of soil micro-aggregate and etc. of walnut-corn agroforestrysystem were better than the other two types. The apple-corn agroforestry system was worse inthe aspects of soil moisture content, water-holding capacity in non-capillary porosity and soilinfiltration properties. The corrosion resistance of soil micro-aggregate of walnut-potato wasworse. So the soil and water conservation effect of walnut-corn agroforestry system was thebest among the3agroforestry systems in the river valley area.In summary, the3different type areas in Zhongyang County showed differentgeomorphological features, climatic conditions, water conditions and soil vegetation, so theagricultural land soil and water loss prevention measures and land use direction were alsodifferent. The loess hilly area with fragmented surface and ravines loess had the mostagricultural land soil and water loss prevention measures, but the agricultural land soil andwater loss prevention measures of river valley area was the least with the flat ground, thick soillayer, good soil water and fertility condition. The forest and grass measures was the major soiland water loss prevention measures of agricultural land in the3different type areas, but theiremphases were different. In earth-rocky mountainous area, eco-forest of soil and waterconservation was main. In loess hilly area developed both eco-forest of soil and waterconservation and agroforestry. But in the river valley area economic forest agroforestrymeasures was important. Therefore, the appropriate soil and water loss prevention measures ofagricultural land of different areas are different, and the soil and water conservation effects ofthe same measure showed different in different areas.