Aims

Soil microbiomes and their interactions with crop plants are important drivers of agricultural health and productivity. Our objective was to examine short-term responses of soil microbiota to agricultural management (i.e. cover cropping and nitrogen fertilization).

Methods

Following three years of cropping, soil samples were collected from replicated field plots at two southern Minnesota field sites (Lamberton and Waseca). We used amplicon-based gene sequencing (ITS2 and 16S rRNA V4) to investigate short-term soil fungal and bacterial community responses to cover crops and urea-nitrogen (N) fertilization (0, 80, 100, and 120% of recommended rates) in a corn (Zea mays)-soybean (Glycine max) cropping system planted with and without cover crops.

Results

We found that rates of N-fertilizer applied, more than cover crops, significantly impacted soil chemical properties at both sites. Different cropping or N fertilization treatments did not lead to strong differences in fungal or bacterial alpha (local) diversity. At both sites, cover crop was a significant predictor of fungal community compositions and specific fungal and bacterial taxa were significantly impacted by cover crops. While, N fertilization was not a strong predictor of community compositions, urea-N additions, at any rate, resulted in changes in the relative abundances of the fungal phyla Glomeromycota in addition to a number of bacterial phyla.

Conclusions

Our findings suggest that after three years of cropping, fungal communities respond to cover crops, while bacterial community responses may depend on soil chemical conditions.

中文翻译：

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覆盖作物和施氮肥对农业土壤真菌和细菌群落的影响

宗旨

土壤微生物组及其与农作物的相互作用是农业健康和生产力的重要驱动因素。我们的目标是检查土壤微生物群对农业管理（即覆盖作物和施氮肥）的短期反应。

方法

经过三年的耕作，从明尼苏达州南部两个田地（兰伯顿和瓦塞卡）的重复田间地块收集土壤样品。我们使用基于扩增子的基因测序（ITS2 和 16S rRNA V4）来研究短期土壤真菌和细菌群落对覆盖作物和尿素氮 (N) 施肥的反应（推荐比率的 0、80、100 和 120%）在有和没有覆盖作物种植的玉米 ( Zea mays )-大豆 ( Glycine max ) 种植系统中。

结果

我们发现，施氮肥的比率比覆盖作物更多，对两个地点的土壤化学性质都有显着影响。不同的种植或施氮处理不会导致真菌或细菌 α（局部）多样性的强烈差异。在这两个地点，覆盖作物是真菌群落组成的重要预测因子，特定的真菌和细菌类群受到覆盖作物的显着影响。虽然施氮不是群落组成的强预测因子，但尿素氮的添加无论如何都会导致真菌门 Glomeromycota 的相对丰度发生变化，以及许多细菌门。

结论

我们的研究结果表明，经过三年的种植，真菌群落对覆盖作物做出反应，而细菌群落的反应可能取决于土壤化学条件。