Influences of white clover returning to apple orchard on soil microbial community

In order to understand the effects of burying and covering white clover (Trifolium repens) in apple (Malus pumila) orchard on the soil microbial community, the soil microbial community functional diversity was analyzed by Biolog microplate method after 1, 3 and 6 months treatments which fresh white clover was buried or covered in apple orchard by litter nylon bag, respectively. The results indicated that both covering and burying white clover could significantly elevate (P<0.05) the soil microbial metabolism activities, the microbial Shannon-Winner diversity index(except 6 months) and richness index while significantly reduced (P<0.05)uniformity index and changed soil microbial community structure. The effects of covering white clover were greater than that of burying. And the time of white clover degradation also had effects on soil microbial community. Principal component analysis of soil microbial community showed that the major differences between covering and burying were the utilization of carboxylic acids, whereas the major differences of microbial metabolism activities between degradation periods were sugars. These results indicated that both covering and burying white clover can change the soil microbial community in apple orchards, and the effects of covering were greater than that of burying.