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

Research Project

Project/Area Number	62560238
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	農業土木
Research Institution	Tottori University (1988) Kyushu University (1987)
Principal Investigator	TAKUMA Katsutoshi Tottori University ・ Associate Professor, 農学部, 助教授 (40032297)
Co-Investigator(Kenkyū-buntansha)	EGASHIRA Kazuhiko Kyusyu University ・ Associate Professor, 農学部, 助教授 (20038293) TAKAYAMA Masateru Kyusyu University ・ Professor, 農学部, 教授 (60038312)
Project Period (FY)	1987 – 1988
Project Status	Completed (Fiscal Year 1988)
Budget Amount *help	¥400,000 (Direct Cost: ¥400,000) Fiscal Year 1988: ¥400,000 (Direct Cost: ¥400,000)
Keywords	Soil Loss / Physical Properties of Soil / Floculation / Sedimentation / 受食性 / 凝集効果 / 相対濁度
Research Abstract	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