摘要
In order to optimise land use systems,to prevent erosion-induced degradation and to restore the degraded red soils in subtropical China,five cropping systems and four agrforestry systems were conducted in red soils with a slope of 7° from 1993 to 1995,The results showed that erosion risk period occurred from Aproil to June,and the annual runoff and and the losses of soil and nutrients with sediment were alarming for two conventional farming systems,whereas they were negligible for the farming systems with ridge tillage.Enrichment ratios of the lost soils from erosion erer more than 1.20 for all nutrients with much higher values for hydrolysable N and organic matter.Compared with the control,the alley cropping systems also distinctly decreased runoff by 30% or 50%.However,the coverage of soil surface varied with alley cropping systems for the competition of nutrients and soil water,which made a profound difference in runoff.The cropping systems of sweet potato intercropped with soybean,the alley cropping systems and the measures of mulching and ridge tillage were the alternatives for red soil reclamation so as to prevent erosion-induced degradation.
