Background and aims

In agriculture, cropping and fertilization practices can significantly affect the soil microbial community, which in turn affects crop growth. Nevertheless, it remains uncertain how cropping and fertilization treatments influence the structure, function, and metabolic characteristics of microbial communities from bulk soil to rhizosphere soil.

Method

Here, a dual-factor experiment was carried out in the black soil of Northeast China, involving cropping (soybean—maize rotation and continuous maize cultivation) and fertilization (no fertilizer control, chemical fertilizer, and chemical fertilizer plus straw incorporation) treatments. After 10 years of experimentation, we collected the maize non-rhizosphere and rhizosphere soil and maize root samples, and conducted the quantification and amplicon sequencing of the 16S rRNA gene and ITS region, as well as metagenomic sequencing and metabolome analysis of soil samples.

Results

Our results revealed that fertilization exerts a greater influence than cropping practices on microbial community structures from soil to maize root by largely altering soil chemical properties, and on various metabolic genes and pathways. Crop rotation primarily mediated microbial community assembly by influencing specific functional groups. Compared to continuous cropping, crop rotation enriches beneficial bacteria, fungi and mycovirus, suppresses fungal pathogen abundance, and lowers fungal species diversity in the maize rhizosphere through balancing metabolites originating from a variety of plant and microbial sources. Crop rotation also imposes stronger homogeneous selections on the prokaryotic community than continuous cropping.

Conclusion

In summary, cropping and fertilization treatments shape the maize root-microbiome relationships with distinct mechanisms.

中文翻译：

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轮作和施肥以不同的机制塑造玉米根际土壤的微生物组

 背景和目标

在农业中，耕作和施肥实践可以显着影响土壤微生物群落，进而影响作物生长。然而，仍不确定耕作和施肥处理如何影响从大块土壤到根际土壤的微生物群落的结构、功能和代谢特征。

 方法

本研究在东北黑土上进行了种植（大豆—玉米轮作和玉米连作）和施肥（不控肥、化肥、化肥加秸秆还田）处理的双因素试验。经过10年的实验，我们收集了玉米非根际和根际土壤以及玉米根样品，并对16S rRNA基因和ITS区域进行了定量和扩增子测序，以及土壤样品的宏基因组测序和代谢组分析。

 结果

我们的研究结果表明，施肥对从土壤到玉米根部的微生物群落结构以及各种代谢基因和途径的影响更大，因为施肥很大程度上改变了土壤化学性质。作物轮作主要通过影响特定功能群来介导微生物群落的组装。与连作相比，轮作可以通过平衡多种植物和微生物来源的代谢物，丰富有益细菌、真菌和真菌病毒，抑制真菌病原体丰度，并降低玉米根际真菌物种多样性。轮作还对原核生物群落施加了比连作更强的同质选择。

 结论

总之，种植和施肥处理通过不同的机制塑造玉米根部-微生物组的关系。