Vegetable lands in polytunnel greenhouse from coastal plain of eastern Zhejiang province with continuous cropping of 3-4 years,8-10 years,and more than 20 years,and rice-vegetable rotation cropping of 8-10 years and more than 20 years were selected for studying differences in soil microbial community and enzyme activities in vegetable lands with varying cultivation years and planting systems.Both newly-enclosed coastal land and reclaimed coastal land without vegetable cropping were also selected for compari...