Evaluation Effects of Organic Vegetable Planting on Soil Quality in Songhuaba Basin

In this study, two typical organic vegetable production bases in Songhuaba watershed of Kunming city were selected for the evaluation of the effects of organic vegetable production on soil quality. Organic base I includes three treatments YJ1-1、YJ1-2 and YJ1-3, which had been engaged in organic planting for 1 year, 3 years and 6 years, respectively. Organic base Ⅱ includes one treatment of YJ2, which had been engaged in organic planting for 10 years. And one nearby conventional vegetable production base was also engaged in the study as CF treatment. The results show that the comprehensive fertility index of YJ1-2 and YJ1-3 treatments were higher than 0.8, and both belonged to the excellent level. The total active organic matter content of YJ1-2 and YJ1-3 treatments were 1.30 and 1.48 g·kg^-1, respectively, which were significantly higher than that of the CF treatment. The carbon pool management index of YJ1-2 treatment increased by 38.0% compared with CF treatment, however, the differences of the index between other treatments were not significant. Organic planting significantly increased the soil microbial activity of YJ1-2, YJ1-3 and YJ2 treatments, while significantly inhibited the bioavailability of heavy metals (Cu、Cd and Ni). The soil properties of YJ1-1 treatment was not different from that of CF treatment, indicating that the engaging time of organic planting and the amount of input of organic materials were important factors affecting soil properties. Therefore, organic planting can be used as an effective way to improve the farmland soil quality and reduce the bioavailability of heavy metals.