摘要
SoilErosionofVarionsFarmingSystemsinSnbtropicalChinaZHANGBIN,ZHANGTAOLINandZHAOQIGUO(InstituteofSoilScience,AcademzaSznzca,P....
In order to optimise land use systems, to prevent erosion-induced degradation and to restore the degradedred soils in subtropical China, five cropping systems and four agroforestry systems were conducted in red soilswith a slope of 7° from 1993 to 1995. The results showed that erosion risk period occurred from April to June,and the annual runoff and the losses of soil and nutrients with sediment were alarming for two conventionalfarming systems, whereas they were negligible for the farming systems with ridge tillage. Enrichment ratiosof the lost soils from erosion were more than 1 .20 for all nutrients with much higher values for hydrolysable Nand organic matter. Compared with the control, the alley cropping systems also distinctly decreased runoffby 30% or 50%. However, the coverage of soil surface varied with alley cropping systems for the competitionof nutrients and soil water, which made a profound difference in runoff. The cropping systems of sweet potatointercropped with soybean, the alley cropping systems and the measures of mulching and ridge tillage werethe alternatives for red soil reclamation so as to prevent erosion-induced degradation.