Effects of interplantation of Trifolium repens in orchards on soil ecology and apple tree production

In view of the fact that the soil erosion,lower soil fertility and poorer fruit quality induced by traditional orchard-weeding activities,Trifolium repens was introduced and interplanted with apple trees in Yantai City of Shandong Province in 1999.Five pairs of plots,interplantation and traditional practice,were set up for comparison in different experimental sites,and soil ecosystem and growth of apple trees were observed on the plots.It was found three years later that the interplantation can not only improve the soil ecology by increasing soil nutrient contents,regulating soil temperature and strengthening soil-water conservation capability,but also promote growth of the apple trees,control of diseases, insects and weeds,increase fruit yield and improve fruit nutritional quality.