Depth weakens effects of long-term fertilization on dissolved organic matter chemodiversity in paddy soils

Xueying Feng ¹, Xiaomin Wang ², Zhijun Wei ²

⁰State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China; University of Chinese Academy of Sciences, Beijing 100049, China; Changshu National Agro-Ecosystem Observation and Research Station, Institute of Soil Science, Chinese Academy of Sciences, 211135 Nanjing, China.

The Science of the Total Environment +

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December 25, 2024

View abstract on PubMed

Summary

Long-term fertilization, including straw return, boosts dissolved organic matter (DOM) diversity in topsoil. Microbial activity drives DOM changes, with diversity decreasing with soil depth.

Area Of Science

Soil Science
Biogeochemistry
Microbial Ecology

Background

Dissolved organic matter (DOM) is crucial for soil health and ecosystem function.
Long-term fertilization impacts on soil DOM chemodiversity and microbial communities across soil profiles are not well understood.

Purpose Of The Study

Investigate DOM composition and microbial communities in paddy soil under various long-term fertilization regimes.
Determine how fertilization affects DOM chemodiversity and its relationship with microbial communities across soil depths.
Clarify the factors influencing DOM molecular composition vertically within the soil profile.

Main Methods

Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) for DOM analysis.
High-throughput sequencing for microbial community profiling.
Analysis across distinct soil layers (0-100 cm) under different fertilization treatments (Control, NPK, NPKHS, NPKS).

Main Results

Fertilization significantly increased soil total carbon (TC), total nitrogen (TN), and nitrate (NO3-) content, especially in the topsoil.
DOM chemodiversity and bacterial diversity decreased with increasing soil depth.
Fertilization, particularly straw return (NPKHS, NPKS), enhanced DOM chemodiversity in the topsoil (0-20 cm) but had limited effect below this layer.
Microbial decomposition was identified as the primary driver of DOM composition changes across the soil profile.

Conclusions

Long-term NPK fertilization and straw return enhance DOM chemodiversity primarily in the topsoil by altering soil nutrient content.
Microbial communities play a key role in shaping DOM molecular composition throughout the soil profile.
Understanding vertical DOM composition is vital for paddy soil management and ecosystem stability.

Keywords:

Dissolved organic matter FT-ICR MS Fertilization regimes Microbial community Soil depth