施氮对间作条件下玉米、马铃薯根际微生物群落功能多样性的影响

Effects of Nitrogen Application Rates on Rhizosphere Microbial Community Functional Diversity in Maize and Potato Intercropping

通过田间试验,采用平板培养法和BIOLOG技术研究了不同施氮水平N0(0 kg·hm-2),N1(125 kg·hm-2),N2(250 kg·hm-2)和N3(375 kg·hm-2)对玉米//马铃薯间作作物根际微生物群落及代谢功能多样性的影响。结果表明,间作条件下,施氮(N1、N2、N3)处理显著提高了玉米、马铃薯根际细菌、放线菌数量及微生物总量,在N2处理微生物数量最高,却显著降低了真菌的数量。与N0处理相比,施氮均显著提高了间作条件下玉米、马铃薯根际微生物群落碳源利用率、丰富度和功能多样性,N3处理的玉米根际微生物群落的碳源利用率(AWCD)、Shannon-Wiener(H)、Simpson指数(D)、均匀度指数(E)及碳源利用丰富度指数(S)最高,而马铃薯在N2处理时最高,但对6类碳源的利用存在一定的差异。聚类和主成分分析表明,间作玉米、间作马铃薯各施氮处理土壤微生物在碳源利用上出现较大差异,土壤微生物群落代谢特征发生改变。表明适量施氮对调控间作作物根际土壤微生物群落结构和提高其功能多样性均具有积极作用。

Field trials were carried out to investigate the effects of different nitrogen application rates N0（0 kg·hm-2）, N1（125 kg·hm-2）, N2 （250 kg·hm-2）and N3（375 kg·hm-2）on the rhizosphere microbial population and metabolic function diversity of maize and potato under intercropping using plate culture method and BIOLOG technique. The results indicated that nitrogen（N1, N2 and N3）application in-creased the amounts of bacteria, actinomyces and total microbes, but decreased the quantities of fungi significantly in rhizosphere soil of maize and potato in intercropping, and the highest increment was with N2 treatment. In comparison with N0, nitrogen fertilizer application could increase significantly the diversities of soil microbial community, the utilization rate of carbon source, richness of soil microbial com-munity. And the A W CD value, Shannon-Wiener index（H）, Simpson index（D）, Evenness index（E）and Richness index（S）in rhizosphere soil of maize under intercropping were the highest at N3 treatment, while that of potato were the highest at N2 treatment, but the effects of dif-ferent N application rates on the ability of rhizospheric microbes in utilizing six types of carbon sources were different. Principal component analysis （PCA）and cluster analysis showed that there were differences in carbon substrate utilization patterns and metabolic characteristics of the soil microbes in maize and potato intercropping with different N application rates. It suggested that applying N could regulate the rhizo-sphere soil microbial communities and promote the functional diversity of crop intercropping.