Effect of Hydroxy-Al Treatment on Soil Loss and Evaluation of Effect of Soil Parameter

农用地土壤的流失不仅造成富含营养物质的表层土壤的流失，还造成附着在细粒土壤上的农药的径流，产生对下游地区水体污染的可能性。本研究的目的是利用羟基铝改善农业用地的物理性质，防止农业用地的土壤流失，并建立一种在含细粒土壤的沉降盆地中农业用地流出土壤的絮凝沉降处理方法。当CEC中羟基铝的添加量达到100%时，对重黏土物理性质的改善效果显著，即使在100%及以上的范围内，对重黏土物理性质的改善效果也不会增加太多。在土壤团聚体的形成、渗透性的增加和含水量的降低等方面证实了添加效应，更重要的是增加了土壤的空隙，增加了土壤的入渗能力，减少了地表径流。这些现象产生了减少水土流失和防止侵蚀的效果。其次，明确了花岗岩为母岩的砂质土和非花岗岩为母岩的红黄土的可蚀性参数。决定马沙土和红黄土可蚀性的土壤参数分别为机械组成和团聚体稳定性，并以此为指标制定了可蚀性评价标准。20 me/100g HCL和0.003 me/100g羟基铝对红黄土的絮凝效果较好。10 me/100g FeCl_3在流动中具有良好的效果，但在未添加时，红黄土的浓度仅降至0.65 ~ 0.75左右，仅靠化学药剂立即促进沉淀池的絮凝沉降是不合理的。综上所述，结合使用化学品对农用地土壤进行改良，可以在一定程度上防止土壤流失。少

The loss of soil from agricultural land brings about not only the loss of surface soil rich in nutritive substances but also the runoff of the pesticide adhered to fine-grained soil and generates the possibility causing the contamination of water in the downstream regions. This study was conducted for the purpose of the improvement in the physical properties using hydroxy-Al, the prevention of soil loss from agricultural land and the establishment of a treament method for the flocculation and sedimentation of the soil flowing out of the agricultural land in a setting basin inclusive of fine-grained soil.The effects for improving the physical properties of heavy clay soil are markedly developed until the adding percentage of hydroxy-Al to CEC reaches 100% but not increased too much even if the adding percentage is increased within a range of 100% or more. The adding effects were confirmed in the formation of a soil aggregate, an increase in permeability and a lowering in water content, … More because not only the voids of soil but also the infiltration capacity thereof were increased and surface runoff was reduced. These phenomena result in the effects for reducing soil loss and preventing erosion. Next, soil parameters dominating the erodibility of masa soil occurring from granite being a parent rock and that of red-yellow soil occurring from a rock other than granite were cleared. The soil parameters dominating the erodibility of the Masa soil and that of the red-yellow soil are respectively mechanical composition and aggegate stability and the evaluation standard of erodibility was set using said soil parameters. 20 me/100g HCL and 0.003 me/100g hydroxy-Al imparted a good result to the flocculation effect on the red-yellow soil. 10 me/100g FeCl_3 imparted a good effect in flow but the cocentration of the red-yellow soil was only lowered to a level about 0.65 - 0.75 that at the time of no-addition and it is unreasonable to immediately promote flocculation and sedimentation in the setting basin only by the chemicals. From the foregoing, it is considered that soil loss can be prevented to a certain extent by performing the improvement in the soil of agricultural land in combination with the use of chemicals. Less