Long-term manure fertilization enhances red soil organic carbon storage

Authors: ZOU, HONGQIN - Chinese Academy Of Agricultural Sciences; LU, CHANGAI - Chinese Academy Of Agricultural Sciences; ZHANG, LU - Chinese Academy Of Agricultural Sciences; XU, MINGGANG - Chinese Academy Of Agricultural Sciences; DUAN, YINGHUA - Chinese Academy Of Agricultural Sciences; Hale, Lauren

Submitted to: Applied Soil Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2025
Publication Date: 11/27/2025
Citation: Zou, H., Lu, C., Zhang, L., Xu, M., Duan, Y., Hale, L.E. 2025. Long-term manure fertilization enhances red soil organic carbon storage. Applied Soil Ecology. 217. Article 106644. https://doi.org/10.1016/j.apsoil.2025.106644.
DOI: https://doi.org/10.1016/j.apsoil.2025.106644

Interpretive Summary: Soil organic carbon (SOC) is a primary component of soil health and is critical for agricultural water productivity. In this study, five different fertilization regimes were used to investigate how microbial communities, dissolved organic matter (DOM), and soil physicochemical properties influence soil carbon sequestration. Soil fertilization by manure application, relative to mineral fertilization with and without stover return, resulted in the highest SOC accumulation in a multidecadal annual cropping system trial. SOC accumulation was driven by increased soil pH, phosphorus, nitrate content, recalcitrant DOM, and abundance of bacteria known to perform well in environments rich in nutrients and available carbon substrates. Together, these results provide insights into a mechanistic understanding for how manure impacts soil agronomic productivity in the long-term.

Technical Abstract: Soil organic carbon (SOC) sequestration in farmland is a critical process for soil fertility, yet the underlying mechanistic drivers of SOC storage under organic and mineral fertilization strategies remain unresolved, especially across multi-decadal scales. We analyzed soil samples from a 31-year field experiment with five fertilization regimes (non-fertilization, CK; mineral fertilization, NPK; NPK with stover return, NPKS; NPK with manure, NPKM; and manure alone, M) to investigate how microbial communities, dissolved organic matter (DOM) dynamics, and soil physicochemical properties influence SOC sequestration. Results revealed that mineral fertilization, stover return, and manure application all enhanced SOC content, yet the magnitude and mechanisms underlying these increases varied significantly among treatments. Compared to CK, the NPK and NPKS treatments increased SOC content by 38%–45%. These increases were attributed to a significant decrease in soil pH and the relative abundance of bacterial copiotrophs, but increases in soil Olsen-P (51–53 times) and nitrate content (43%–109%). These changes further increased tannin and condensed aromatic compounds by 240%–540%, and increased the chemical diversity, aromaticity, and transformation potential of DOM components. Manure amendments resulted in significantly higher SOC content, increased by 93%–116%. This was attributed to an elevation in soil pH, increased Olsen-P (138–157 times), nitrate content (227%–281%), and a rise in the relative abundance of bacterial copiotrophs (82%–92%). These alterations further promoted the formation of tannin and condensed aromatic compounds and increased the chemical diversity, aromaticity, and transformation potential of DOM, thereby enhancing the accumulation of SOC. Overall, these findings underscore the potential of manure amendments in optimizing SOC sequestration by altering microbial and chemical dynamics in red soils, and provide insights into sustainable agricultural practices for soil carbon management.