Comprehensive evaluation of soil fertility and microorganisms factors for vegetables rotation and continuous systems in greenhouse

In this study,we analyzed the affect of soil fertility and microorganism on continuous crop-ping obstacles and these results may provided scientific evidence for mechanism of continuous cropping obstacles.Soil fertility,soil micro flora and microbial physiologic flora from the rhizosphere and bulk soil of strawberry and tomatoes rotation(RST),4 years continuous tomatoes cropping(CT4) and 10 years continuous tomato cropping(CT10) were analyzed respectively.Several main factors were analyzed by the principal component analysis(PCA).The results showed that the number of micro flora and microbial physiologic flora in rhizosphere were higher than bulk soils,which showed a significantly rhizosphere effect.The number of bacteria and actinomycetes decreased firstly and then increased as continuous cropping years increasing,while the number of fungi showed a linear increase trendency.Compare with RST,the CT4 and CT10 increased by 9.09% and 2.11%,74.58% and 57.72%in rhizosphere and bulk soils respectively.The number of nitrobacteria and aerobic nitrogen-fixing bacteria decreased as continuous cropping years increasing,while the ammonifying bacteria and aerobic cellulose degrading bacteria increased firstly and then decreased.Solution potassium bacterium,inorganic phosphor-bacteria and organic phosphor-bacteria decreased in rhizosphere and bulk soil.Among the three planting systems,RST in the rhizosphere soil is best,follow by CT4 in rhizosphere soil and RST in bulk soil,CT10 in rhizosphere and CT4,CT10 in bulk soils were the worst.Continuous vegeta-ble cropping can cause reduction of the soil quality,the longer the continuous cropping is and the more reduction of soil quality.