Abstract
A mathematical model was developed to estimate sediment yield from sloping cropland composed of a ridge-furrow system or ridge-furrow and catch canal system. In the new model, the rill erosion model proposed by Takagi et al.(1986, 1989) was used for evaluating erosion in furrows and catch canals. Moreover, Yalin's (1963) equation was incorporated into the model to evaluate the sediment transport capacity of flow at the ends of furrows and catch canal. To verify the applicability of the model, experimental plots (main-plots and sub-plots) were prepared on sloping reclaimed cropland with decomposed granite soil in 1992 and 1993. Ridges on the main-plots in 1992 and 1993 were oriented nearly on the up-and-down slope and the contour, respectively. We observed runoff and sediment yield from experimental plots at rainfall events during the rainy season in each year. A value of parameter related to soil erodibility was determined by using the observed data of the sub-plots. The value was used in calculating sediment yield from the main-plots. Good agreement between the calculated and observed values was obtained. The results suggested that the model was suitable for predicting sediment yield from sloping ridged cropland.
