Research on slope vegetation method for Shirasu soil erosion

1995 Fiscal Year Final Research Report Summary

• Project/Area Number: 05660280
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Irrigation, drainage and rural engineering/Rural planning
• Research Institution: Miyazaki University
• Principal Investigator: HOSOYAMADA Kenzo faculty of agri., Miyazaki University professor, 農学部, 教授 (10040833)
• Co-Investigator(Kenkyū-buntansha): AKIYOSI Yasuhiro faculty of agri., Miyazaki University assoc. prof., 農学部, 助教授 (30041031)
• Project Period (FY): 1993 – 1995
• Keywords: soil erosion / volcanic ash soil / rainfall / biomass / non-woven fabric / bacteria

Research Abstract

(1)SOIL EROSION AND VEGETATION AT SLOPE COVERED BY NON-WOVEN FABRIC IN SHIRASU EROSION TEST PLOT,MIYAZAKI UNIV.CAMPUS
In 1995, annual precipitation was 2170 mm that is less compared with that of average year, and temperature in summer was high as renewing high record. So, vegetation was over growing. Soil loss from bare slope was 93.43 t/ha/year and nothing from non-woven fabric slope. Features of test results in this year were that vegetation of bush clover was remarkable and an invasion of Peneross family plant to the non woven fabric (no seeds) plot was also remarkable.
(2)VEGETATIVE STATES AT TEST SLOPES IN ACTUAL UPLAND FIELDS
Vegetatin of slope for erosion test plots at HAE No.1, No.2 in Tano cho was so vigorous as over growing at this October in the stage of 4 year expiration, especially thick growing of bush clover has been remarkable about 2 years after. Vegetation was inferior to some degree at straw turf slope and vegetation net slope (1 m width) in HAE No.2 plot, but stability for slope erosion was not much influenced. At test slope where non-woven fabric was put on the simple vegetation net in HAE No.4 plot, effect of non-woven fabric for vegetation was much. At TOKIYA No.2, No.3 plots situated in Shirasu district of kiyotake cho, vegetation was generally stable about 3 years after. In the lower part of slope of former plot, there are some imperfect vegetation slope, so continuous observation willbe necessary.
(3)MEASUREMENT OF BIOMASS C,N AND NUMBER OF BACTERIA AND FUNGI
It cleared that Biomass C,N total C and N obtained from soil samples of root zone covered by Non-woven fabric at MIYAZAKI UNIV.test plot increase in quantity, especially biomass C and total C were more in case of seeds containing.
In case of test fields HAE and TOKIYA, the measurements have been started from the biginning of 1994 and biomass in non-woven fabric slopes have progressed every year, especially biomass C progressed remarkablly. Biomass C to total C and biomass N to total N had high plus correlation respectively and also influence of microorganism by meteorological condition must be considered.