Effects of water supply and 3-methylphenol on soil microbial diversity and enzyme activity in wheat field intercropped with horse bean
供水及间甲酚对小麦间作蚕豆土壤微生物多样性和酶活性的影响

With pot experiment, this paper studied the effects of water supply levels (45%, 60% and 75% of soil water hold capacity) and allelochemical 3-methylphenol (300 x 10(-6) mol x kg(-1) soil) on the soil microbial diversity and enzyme activity in mono-cropped and horse bean-intercropped wheat fields during vigorous growth period. The results showed that with the decrease of water supply, the numbers of soil bacteria, fungi and actinomytes in the two fields decreased significantly, and 3-methylphenol enlarged this negative effect. 3-methylphonel had a negative effect on soil microbial diversity, but the increase of water supply could weaken this effect in intercropped field. The strongest allelopathic effect of 3-methylphenol was observed in mono-cropped field when the water supply was 75% of soil water hold capacity, while intercropping could maintain a relatively stable soil microbial diversity, compared to the mono-cropping with 3-methylphenol and low water supply. The allelopathic effect of 3-methylphenol was not significant on soil catalase activity, but significant on soil urease and phosphatase activities. Water supply level affected soil enzyme activity significantly, the lower the water supply level, the weaker the soil enzyme activity was. The interactions of water supply with 3-methyl phenol or cropping pattern were not significant, but intercropping could significantly affect the activities of soil catalase and phosphatase.