Soil organic carbon priming co-regulated by labile carbon input level and long-term fertilization history

Lei Wu; Jun Wang; Hu Xu; Xinliang Xu; Hongjun Gao; Minggang Xu; Wenju Zhang

doi:10.1016/j.scitotenv.2023.166175

Soil organic carbon priming co-regulated by labile carbon input level and long-term fertilization history

Sci Total Environ. 2023 Dec 1:902:166175. doi: 10.1016/j.scitotenv.2023.166175. Epub 2023 Aug 9.

Authors

Lei Wu¹, Jun Wang¹, Hu Xu¹, Xinliang Xu², Hongjun Gao³, Minggang Xu¹, Wenju Zhang⁴

Affiliations

¹ State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Key Laboratory of Cultivated Land Quality Monitoring and Evaluation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China.
² Key Laboratory of Ecosystem Network Observation and Modeling, Chinese Academy of Sciences (CAS), Institute of Geographic Sciences and Natural Resources Research, 11A Datun Road, Chaoyang District, Beijing 100101, China.
³ Institute of Soil and Fertilizer, Jilin Agricultural Academy of Sciences, Gongzhuling 136100, China.
⁴ State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Key Laboratory of Cultivated Land Quality Monitoring and Evaluation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China. Electronic address: zhangwenju01@caas.cn.

PMID: 37562612
DOI: 10.1016/j.scitotenv.2023.166175

Abstract

Labile carbon (C) input and fertilization have important consequences for soil organic matter (SOM) decomposition via the priming effect (PE), thereby impacting soil fertility and C sequestration. However, it remains largely uncertain on how the labile C input levels interact with long-term fertilization history to control PE intensity. To clarify this question, soil samples were collected from a 38-year fertilization field experiment (including five treatments: chemical nitrogen fertilizer, N; chemical fertilizer, NPK; manure, M₁; 200 % manure, M₂; NPK plus M₂, NPKM₂), with strongly altered soil physiochemical properties (i.e., soil aggregation, organic C and nutrient availability). These soil samples were incubated with three input levels of ¹³C-glucose (without glucose, control; low, 0.4 % SOC; high, 2.0 % SOC) to clarify the underlying mechanisms of PE. Results showed that the PE significantly increased with glucose input levels, with values increasing from negative or weak (-2.21 to 3.55 mg C g^-1 SOC) at low input level to strongly positive (5.62 to 8.57 mg C g^-1 SOC) at high input level across fertilization treatments. The increased PE intensity occurred along with decreased dissolved total nitrogen (DTN) contents and increased ratios of dissolved organic C to DTN, implying that the decline in N availability largely increased PE via enhanced microbial N mining from SOM. Compared to N and NPK treatments, the PE was significantly lower in the manure-amendment treatments, especially for low input level, due to more stable SOM by aggregate protection and higher N and phosphorus availability. These results suggested that manure application could alleviate SOM priming via increased soil C stability and nutrient availability. Collectively, our findings emphasize the importance of long-term fertilization-driven changes in labile C inputs, SOM stability, and nutrient availability in regulating PE and soil C dynamics. This knowledge advances our understanding of the long-term fertilization management for soil C sequestration.

Keywords: Aggregate distribution; Carbon input level; Long-term fertilization; Nutrient availability; Priming effect.