红壤坡耕地玉米大豆间作的根际微生态效应

Rhizospheric microecological effects of corn and soybean intercropping in sloping farmland with red soil

[目的]本研究旨在明确红壤坡耕地玉米大豆间作的根际微生态效应。[方法]以云南典型的红壤坡耕地为研究对象,布置玉米大豆单间作大田小区试验,通过常规方法和Biolog测定玉米抽雄期根际土壤化学性质、酶活和微生物群落代谢功能多样性。[结果]与单作相比,间作玉米根际土壤微生物群落碳源代谢功能Shannon指数显著提高3.5%,Simpson指数显著降低13.1%(P<0.05);间作大豆根际Shannon指数和Mclntosh指数出现降低趋势,Simpson指数显著增加7.8%(P<0.05)。玉米和大豆根际土壤的过氧化氢酶活性在单作下无显著差异,间作下大豆根际显著高于玉米根际(P<0.05)。与单作相比,间作根际碱解氮含量均出现增加的趋势,pH、有机质和速效钾含量均出现玉米增加大豆降低的趋势。根际微生物群落碳源代谢功能Shannon指数与速效钾含量呈显著正相关(P<0.05),与酸性磷酸酶活性、pH呈极显著正相关(P<0.01);根际微生物群落碳源代谢功能Mclnoth指数与碱解氮、速效钾、速效磷含量呈显著正相关,与酸性磷酸酶活性、pH呈极显著正相关。[结论]红壤坡耕地原位种植条件下,玉米大豆间作的根际微生态效应明显。

[Objective]The present study was designed to better understand the rhizosphere micro-ecological effects of corn and soybean intercropping in sloping cropland with red soil.[Methods]Taking the typical sloping cropland with red soil in Yunnan as the research object,we conducted corn and soybean intercropping field plot experiment.Rhizosphere soil chemical properties and enzyme activity at tasseling stage were tested using the conventional method and metabolism diversity of the microbial com-munity was determined using Biolog.[Results]Compared with monoculture,the Shannon index of soil microbial community carbon source metabolic function in rhizosphere soil of intercropped corn was significantly increased by 3.5%and the Simpson index was significantly decreased by 13.1%(P<0.05);The Shannon index and Mclntosh index of intercropping soybean showed a decreasing trend,while the Simpson index significantly increased by 7.8%.There was no significant difference in catalase activity between corn and soybean rhizosphere soils under monoculture,while soybean rhizosphere was significantly higher than corn rhizosphere under intercropping.Compared with monocropping,the content of alkali-hydrolyzed nitrogen in the rhizosphere of intercropping was increased,and the pH value,the content of organic matter and the available potassium all showed a trend of increasing in corn and decreasing in soybean.The Shannon index of carbon source metabolism of rhizosphere microbial community was significantly and positively correlated with the content of available potassium(P<0.05),and was extremely significantly and positively correlated with acid phosphatase activity and pH(P<0.01).The Mclntosh index of carbon metabolism of rhizosphere microbial community was positively correlated with the content of alkali-hydrolyzed nitrogen,available potassium and available phosphorus(P<0.05),and extremely significantly and positively correlated with the activity of acid phosphatase and pH(P<0.01).[Conclusion]The rhizosphere micro-ecological effects of corn and soybean intercropping was obvious under the in-situ planting condition of sloping cropland with red soil.