Effect of Nitrogen on Microbial Communities of Purple Mudstone Weathering Products in Southwest China: A Column Experiment

TL;DR

This study shows how adding nitrogen fertilizer changes soil chemistry and microbial communities in purple mudstone weathering products in Southwest China.

Contribution

The study reveals the specific effects of nitrogen application on microbial diversity and soil properties in purple mudstone weathering products.

Findings

Nitrogen addition increased bacterial evenness but decreased bacterial diversity (chao1 value).

Proteobacteria and Bacteroidetes increased, while Actinobacteria and Cyanobacteria decreased with nitrogen.

The N2 treatment (560 N kg ha−1) most effectively enhanced soil nutrients and microbial network complexity.

Abstract

Nitrogen application significantly affects microorganisms in agricultural ecosystems. However, it is still unclear how nitrogen application affects soil chemical properties and microbial communities in purple mudstone weathering products. In this study, a field soil column experiment was conducted in a typical purple soil area with four nitrogen fertilizer application gradients of 0 [CK], 280 [N1], 560 [N2], and 840 [N3] N kg ha−1. Nitrogen addition decreased the bacterial chao1 value and increased the bacterial evenness index. For both α- and β-diversity, the effect of nitrogen addition on bacteria was much greater than that on fungi. Nitrogen addition significantly increased the relative abundance of Proteobacteria, Gemmatimonadetes, Bacteroidetes, and Ascomycota and decreased the relative abundance of Actinobacteria, Cyanobacteria, and Basidiomycota. Both pH and TC are the most important soil chemical properties influencing the bacterial and fungal communities. With the increases in the nitrogen application rate, the co-occurrence network complexity increased and then decreased. In summary, nitrogen fertilizer application could significantly change the soil chemical properties, microbial community diversity, composition, and co-occurrence network of purple mudstone weathering products. Among them, the N2 treatment (560 N kg∙ha−1) can more effectively stimulate the soil nutrients, enhance microbial network complexity, and promote further weathering of purple mudstone.

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