Study On Soil Nutrients 、 Enzyme Activities And Microbes In Non-irrigation Apple Orchard Under Different Mulching Managements

This study was taken from 2012 to 2015 with 11-year-old “Xinnonghong” apple(Malus domestica. Borkh) trees as experimental materials in Luochuan Apple Experiment Station of Northwest A&F University.The main research of this article was effect of different mulching patterns on soil properties,including soil available nutrients、 organic matter content, enzyme activity and topsoil microbial quantity. The mulching treatments were:①Full of Plastic Mulch ② Growing and Mulching Grass ③Ridging under Plastic Mulch ④Irrigation with Fertilizer under Plastic Mulch⑤ The cleaning tillage(CK). It was aimed to put forward a simple and practical method for non-irrigation apple orchards by comprehensive analysis different mulching treatments. Main research results are as follows:Different mulching treatments can raise the soil available nutrient content in 0 ~ 60 cm. Growing and mulching grass treatment can increase the soil organic matter content most significantly. Irrigation with fertilizer under plastic mulch can improve soil available nutrient content obviously. Organic matter content and available nutrient content declined along with soil depth decreasing.Compared with the cleaning tillage, the mulching managements had significant effects on increasing the activity of urease、sucrase and phosphatase, which mainly embodied in the topsoil. The sucrase activity of irrigation with fertilizer under plastic mulch was improved by 10.65%,the phosphatase activity of growing and mulching grass was impoved by 70.81% and the urease activity of irrigation with fertilizer under plastic mulch was improved by 66.27% compared with CK in topsoil(0 ~ 20 cm).The results show that the munber of bacteria was the largest which was followed by actinomycetes and the number of fungi was the least in topsoil of the orchard.Compared with CK,the microbe number of topsoil were significantly affected by different mulching patterns,especially, the treatment of growing and mulching grass had the most obvious effect in all treatments.The number of bacteria、actinomycetes and fungi were significantly increased by 66.29%、85.90% and 63.56% respectively.Further more,irrigation with fertilizer under plastic mulch was second only to growing and mulching grass.The organic matter was strongly and positively correlated with soil enzyme activity and the same relate among three soil enzymes.The correlation between organic matter and sucrase was 0.887 which reached a very significant level,and the same leave as phosphatase,which was 0.970.While the correlation of organic matter and urease was 0.587,which reached a significant level.