A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Engineering at the Asian Institute of Technology, Bangkok, Thailand.

Thesis (M.Eng.) - Asian Institute of Technology, 1978

This study deals with conservation measures on cultivated slope land of Taiwan and evaluation of soil loss equation factors. Background and principal conservation practices of this area were introduced before the study. Conservation practices was compared by means of efficiency. Bench terrace functions better than hillside ditch in soil and water control, under no cover condition. But hillside ditche are better than bench terrace after completely covered by bahia grass on slope areas. Universal soil loss equation was introduced with all the relevant factors. It is A = R K LS C P. An Application example of this equation in Taiwan was shown. b Rainfall factor (R-index) was evaluated by the equation R = a Rab. R is the R-index, of a station already calculated and Ra is monthly rainfall, a, b are parameters. The R-index equation of Pingtung areas is R = 0.0069 Ra 1.74 and that of Taichung areas is R = 0. 0049 Ra 1.7653 The R-·index of sourrounding rainfall station can be evaluated by these equation. An R=index iso-map of these areas is exhibited in Fig. 5.4. Soil erodibility factor K for slope land of Taiwan was evaluated by a soil erodibility nomograph, which had been modified according to soil mechanical analysis data. Finally, a slopeland soil conservation system consideration with a diagrammatic model was worked out. The factors of rainfall, soil erodibility topograph, creping system and control practices set the boundaries of the system to be synthetized. This gives a basic information for simulation system.