Comparison of microbiological properties between soils of rice-wheat rotation and vegetable cultivation

A recent survey had been done in Jiaxing city of Zhejiang Province at Yangtze River Delta region to compare the difference of soil microbial properties among paddy soils with different cropping systems including continuous open-field vegetable cultivation, plastic-greenhouse vegetable cultivation and traditional rice-wheat rotation. The soil types included percolating paddy soil, permeable paddy soil, and waterlogged paddy soil. The results indicated that: 1) For all the three soil types, the microbial flora were markedly changed in continuous vegetable cultivation soils, especially in plastic-greenhouse vegetable cultivation soils, compared with rice-wheat rotation soils. The bacteria amounts in vegetable cultivation soils decreased dramatically, but the fungi and actinomyces amounts increased evidently. 2) Compared with rice-wheat rotation, the dehydrogenase activities in vegetable cultivation soils decreased significantly, especially in plastic greenhouse vegetable soils. 3) The microbial biomass C and total phospholipids contents (TPL) in vegetable cultivation soils greatly decreased compared with rice-wheat rotation soils. 4) Biolog analysis indicated that the kinds of carbon sources that could be metabolized by native microbes in plastic-greenhouse vegetable cultivation soils greatly decreased compared with open-field vegetable cultivation soils and rice-wheat rotation soils, revealing that microbial diversity had decreased. 5) The degradation of microbiological properties in continuous vegetable cultivation soils, especially in plastic-greenhouse vegetable cultivation soils might indicate the great decline of long-term productivity of soil and stability and sustainability of soil quality. 6) The main reasons might be associated with the environmental changes in vegetable cultivation and overuse of nitrogen and phosphorus chemical fertilizers, which caused soil acidification and secondary salinization.