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The fertilizer input in vegetables growth was far exceeded its necessary nutrient in conventional protected cultivation. As a result, soil quality degradation and prevented sustainable development of protected cultivation. And we must find new tillage methods to promote development of protected cultivation that can be sustained and stable developing. Through the research can provide some scientific and rational basis for development of protected cultivation. This study takes Shanghai Biofarm Organic Farm and Shanghai Wenjie Gardening Farm (conventional farms) as research object, used paired farm comparisons, compared the differences of organic and conventional farming systems. Through vegetable cultivation experiment, compared effects of organic farming system and conventional farming system under protected cultivation on vegetable yield, quality and soil fertility; through a comprehensive analysis of organic farms and conventional farms, compared the economic, social and ecological benefits. From the research we know that:The yield of organic farming system was less than conventional farming system. In monomer greenhouses, the yield of lettuce, celery cultivated by organic farm was lower than conventional farms respectively by 26.6%,11.4%. In the multi-span greenhouses, the yield of lettuce, celery cultivated by organic farm was lower than conventional farms respectively by 26.6%,11.6%. With the same cultivation method, there was no significant difference between the monomer greenhouse and the multi-span greenhouses on lettuce and celery yield.Under protected cultivation, lettuce and celery quality of organic farming was significantly better than conventional farming. The vitamin C, soluble sugar, soluble protein contents were higher, while nitrate content was low. With the organic farming system, lettuce and celery cultivated by single-span greenhouses and multi-span greenhouse had no significant differences in quality. With conventional farming system, the multi-span greenhouse cultivates lettuce which had a higher content of soluble sugar, soluble protein content and a lower content of nitrate, and its quality was superior to monomer greenhouses; there was no significant difference on celery quality cultivated by monomer greenhouse and multi-span greenhouse.With the organic farming system or conventional farming system, compared with the original soil, soil fertility in monomer greenhouse increase on the whole, while multi-span greenhouses decrease in general. In monomer greenhouse, the content of soil organic matter, total N, available K increase, the rate of increase of organic farming was larger than that of conventional cultivation. In multi-span greenhouse, the content of soil organic matter, total N decrease, the rate of increase of organic farming was smaller than that of conventional cultivation. In Monomer greenhouses, soil fertility of organic farming was significantly higher than those of conventional cultivation. The soil pH, organic matter, total N, available P, available K had a high content while nitrogen content was low; in multi-span greenhouses, soil fertility of organic farming was significantly higher than that of conventional cultivation, and the soil index was higher than the conventional cultivation. The various soil fertility indexes in monomer greenhouse soil are not difference with multi-span greenhouse soil under organic farming system. The various soil fertility indexes in monomer greenhouse soil were higher than multi-span greenhouse soil under conventional farming system, reach a significant difference. Organic farming had a greater role in improving the soil fertility than conventional cultivation.Different farm planting patterns varied significantly in economic, social and ecological benefits. Compared with conventional farms, the economic benefits of vegetable cultivation in organic farm was higher than conventional farms, with an average 37.7% higher than conventional farms. Organic farms can provides food which had a higher quality, more security and a strong marketability, help to improve the share of exports. Organic farming can solve the remaining problems in China’s rural labor force, so that China’s rural labor force can transfer locally to promote the farmers income. Compared with conventional farms, organic farm with a rich and diverse crop rotation, relay cropping, intercropping system, can establish a good ecological system, to promote the development of biological diversity.
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