As a sustainable development model, organic farming is more and more widely accepted which is friendly to the earth. The study was based on three typical organic farming plots: 1) vegetable fields in Fengxian County, Shanghai City; 2) rice farms in Lishui County, Jiangsu Province; 3) kiwifruit orchards in Yuexi County, Anhui Province. The following indices were simultaneously analyzed and compared by means of investigating on the spot and dynamic measuring in organic & conventional farming: 1) physical and chemical properties; 2) soil biological indices; 3) irrigating water and groundwater quality; 4) food quality and security indices. As a result, the ecological benefits of organic farming were comprehensively and objectively assessed which would provide evidence and reference to promote the development of organic farming in China.The three plots mentioned above showed that organic manures and green manures were frequently carried out and then the soil pores were increased in organic farming. Compared with conventional farming, the water content, hygroscopic moisture in soil of organic farming were obviously increased while soil bulk density was dramatically decreased. The ANVOA result indicated that two systems were significantly differed (P<0.01) Soil fertility was well maintained and improved in organic farming by various measures such as recycle of inner matter, rotation, return of legume and straw, utilization of organic and green manures. Various nutrients such as organic matter, nitrogen, phosphorus, and potassium were increased and transformed in organic productive system. Overall ANOVA, of Which system (organic and conventional farming) and place (Fengxian County, Shanghai City; Lishui County, Jiangsu Province and Yuexi County, Anhui Province) were sources of variances, indicated that significant variance was existed among soil organic matter(OM), total nitrogen(TN), available nitrogen(AN), total phosphorus(TP), available phosphorus (AP), available potassium (AK) (P<0.01) . As data showed that OM, TN, AN, TP, AP, AK in 0~20cm soil layer were more remarkably enhanced in organic farming than conventional agriculture.In conventional productive system biodiversity was enormously reduced resulted that soil was disturbed by mechanical plough-up as well as pesticide and artificial fertilizer were long-term added unreasonably. By contrast, organic farming could effectively conserve biodiversity and maintain stability of ecosystem by absolute prohibition of pesticide and artificial fertilizer. Pearson’s correlation analysis indicated that soil respiration (RSP), microbial biomass carbon and nitrogen (SMBC, SMBN) were positively related to OM, TN, AN. TP, AP and AK. As representative indices for microbial activity, RSP, SMBC, SMBN were reasonable to assess soil’s health. In addition, as the indicative specie of soil fauna community, earthworm was very important to decompose organic matter, recycle nutrientsand maintain fertility. Overall ANOVA, of Which system and place were sources of variances, indicated that significant variance was existed among RSP, SMBC, SMBN (P<0.01) . As data showed that EMD, EMB, RSP, SMBC, SMBN in 0~20cm soil layer were dramatically improved in organic farming.The three plots had excellent environmental conditions for the contents of Cu Pb Cd Cr Hg. Ni in which reached the first class standard of Environmental Quality Criterion in Soil (GB15618-1995). Compared with conventional agriculture, the contents of Cu in soil of organic farming were obviously increased while Pb Cd Ni remarkably decreased. In the plots of Fengxian and Lishui County, the contents of Cr Zn in soil of organic farming were a litter higher than conventional system. The reason was that Cr, Zn which came mainly from chick and pig manures were enriched in organic productive soil. By contrast, the contents of Cr Zn were lower in organic kiwifruit orchards in Yuexi County where fertility was maintained mainly by return of green manures. As prohibition of pesticide and artificial fertilizer, the threat of A
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