More replenishment than priming loss of soil organic carbon with additional carbon input

Junyi Liang,Bo Liu,James M Tiedje,Ying-Ping Wang,James R Cole,Xiaoming Li,Lei Huang,Jianyang Xia,Zhongkui Luo,Liyou Wu,Jizhong Zhou,Zhenghu Zhou,C Ryan Penton,Konstantinos T Konstantinidis,Zheng Shi,Edward A G Schuur,Changfu Huo,Yiqi Luo

doi:10.1038/s41467-018-05667-7

Abstract

Increases in carbon (C) inputs to soil can replenish soil organic C (SOC) through various mechanisms. However, recent studies have suggested that the increased C input can also stimulate the decomposition of old SOC via priming. Whether the loss of old SOC by priming can override C replenishment has not been rigorously examined. Here we show, through data–model synthesis, that the magnitude of replenishment is greater than that of priming, resulting in a net increase in SOC by a mean of 32% of the added new C. The magnitude of the net increase in SOC is positively correlated with the nitrogen-to-C ratio of the added substrates. Additionally, model evaluation indicates that a two-pool interactive model is a parsimonious model to represent the SOC decomposition with priming and replenishment. Our findings suggest that increasing C input to soils likely promote SOC accumulation despite the enhanced decomposition of old C via priming.

Highlights

Increases in carbon (C) inputs to soil can replenish soil organic C (SOC) through various mechanisms
The magnitude of the net SOC accumulation was positively correlated with the nitrogen-to-C (N:C) ratio of the added substrates. These findings suggest that increasing plant productivity and the consequent increase in C input to soils likely promote SOC accumulation despite the enhanced decomposition of old C via priming
Our analyses showed that new C input induced priming, which on average stimulated C loss from the old SOC equivalent to 9.4% of the newly added C within 1 year (Fig. 2)

Summary

Introduction

Increases in carbon (C) inputs to soil can replenish soil organic C (SOC) through various mechanisms. It has been widely concerned that increased C input to soils due to rising atmospheric CO2 concentrations may limit or reduce SOC storage due to the priming effect, leading to a positive feedback to climate change[7,8,9,11]. Another important process, replenishment, has the potential to increase SOC via a variety of mechanisms[12,13,14,15]. The magnitude of replenishment was greater than that of priming, resulting in a net SOC accumulation after new C a CO2

Methods

Results

Conclusion