Soil enzyme activities in vegetable rotation and continuous cropping system of under Shed Protection

The use of enzymatic activities as a microbial index of changes in soil biological properties and fertility is(widely) recognized.Enzyme activities are strongly affected by different cropping systems.A pot experiment was carried out using Jinyou 1 cucumber as the test plant to study effects of vegetable rotation and continuous cropping system on activities of Catalase,Urease,Invertase and Polyphenol oxidase under shed protection.The test soil was collected from the cucumber greenhouse with 2 years and 7 years continuous cropping and the greenhouse soil with 15 years,18 years and 21 years rotation,respectively.The results showed,the activity of Catalase,Urease and Invertase of rotating soil is higher than that of continuous cropping 7 years soil at the significant level(P 0.05);with the increasing of continuous cropping years,the activity of Catalase,Urease and Invertase decreased markedly,but the activity of Polyphenol oxidase increased pronouncedly(P0.05).The cucumber yield growing on continuous cropping 2 years and 7 years soil was 7.91 kg and 3.14 kg per pot respectively with statistical difference.The yield of cucumber growing on rotating 15 years, 18 years and 21 years soil was 6.65 kg,6.85 kg and 7.16 kg per pot respectively with no statistical difference.The yield cucumber growing on the soil with 2 years continuous cropping was significant higher than other treatments,while the yield with the soil under 7 years continuous cropping was the significant lower(P0.05).The cucumber yield coincided with activity variation of soil enzymes indicating that Catalase,Urease,Invertase and Polyphenol oxidase can be used as sensitive biological indexes for cultivation practicesmode.