玉米间作和施氮对土壤微生物代谢功能多样性的影响

微生物功能多样性是土壤健康的重要指标,在多种生物地球化学过程中发挥关键作用.本研究基于多年田间小区定位试验,设置间作和单作2种种植模式和4个施氮水平(N0,0 kg·hm-2;N125,125 kg·hm-2;N250,250 kg·hm-2;N375,375 kg·hm-2),采用 Biolog-Eco微平板法,分析...

Effects of intercropping and nitrogen application on soil microbial metabolic functional diversity in maize cropping soil.

Soil microorganism is an important indicator of soil health and plays a critical role in biogeochemical processes. We collected soil samples from a multi-year in-situ field experiment with two cropping modes (maize monocropping and maize-potato intercropping) subjected to four nitrogen (N) levels (N₀, 0 kg·hm^-2; N₁₂₅, 125 kg·hm^-2; N₂₅₀, 250 kg·hm^-2; N₃₇₅, 375 kg·hm^-2). By using the Biolog-ECO microplate method, soil microbial metabolic activity, diversity and utilization of six carbon groups were analyzed. The results showed that N application significantly increased the average well color development (AWCD) values, Simpson and Shannon indices, with the highest value at N₂₅₀ in mono- and inter-cropped soils. Moreover, N application promoted the utilization of amino acids, amines and phenolic compounds, but decreased the utilization of polymers. Compared with monocropping at the same N level, intercropping improved the AWCD values, Simpson and Shannon indices, with a maximal improvement at N₂₅₀. Intercropping and nitrogen application significantly affected the metabolic activities of the six carbon-source groups. In addition, intercropping improved the utilization of labile carbon sources, such as amino acids and carbohydrates. Results of the redundancy analysis and linear regression showed that intercropping and N application elevated AWCD values by increasing soil temperature, water content, and soil organic carbon content. Therefore, the changes in soil physicochemical properties after intercropping were the main reason for the enhancement of microbial metabolic activity under N application.