关键词: 间作, 连作, 根际土壤, 平均颜色变化率（AWCD）, 碳源

Abstract: To explore feasibilities and mechanisms of different cropping systems alleviating obstacles to mono-cropping of ppotato, a field experiment was carried out, consisting a plot of mono-cropping of potato as CK, a plot of intercropping of potato and corn, a plot of intercropping of potato and broad bean, and a plot of intercropping of potato and buckwheat. Changes in soil nutrient contents and microflora in the rhizosphere of monocropping potato were investigated. Results show that all the three intercropping plots were significantly lower than CK in total nitrogen, total phosphorus, readily available phosphorus and readily available potassium in rhizospheric soil and in soil pH . The decrease in readily available P was particularly significant, reaching at least 45%. Intercropping altered microbial community structure as indicated by significant decrease in the total counts of fungi in the rhizospheric soil. Besides, intercropping also significantly affected carbon source utilization capacity of the rhizospheric microbial community. Especially the intercropping of potato with broad bean and with corn was 13.39% and 4.30% higher than CK in AWCD (average well color development) after 120 hours of incubation of rhizospheric microbes.On the whole, the microbial community in the rhizospheric soil of potato plants in all the treatments was higher in carbohydrate utilization rate, but lower in aromatic compound utilization rate. Intercropping significantly enhanced carbon metabolism of the soil microbial community in the rhizosphere of potato, thus helping sustain stable production of potato. Therefore, intercropping may be used as an approach to improving rhizospheric micro-eco-environment of monocropping potato and alleviating obstacles to potato monocropping.

Key words: intercropping, continuous cropping, rhizospheric soil, average well color development (AWCD), carbon source