The Innovation Team of Improvement and Amelioration of Soil Fertility of the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS), has analyzed the long-term effects of lime application on soil organic carbon mineralization and its response to warming and external carbon input. Their research findings, titled "Long-term liming mitigates the positive responses of soil carbon mineralization to warming and labile carbon input," have been published in the "Journal of Environmental Management."

The prominent issue of soil acidification in southern red soil areas of China has become a major factor limiting the sustainable development of regional agriculture. Lime application, as a common measure to address soil acidification, effectively enhances soil fertility and crop yield. However, it also alters the physicochemical properties and microbial characteristics of the soil, thereby influencing the process of organic carbon transformation. Nevertheless, the long-term effects of lime application on regulating soil organic carbon mineralization in response to warming and external carbon input, as well as the microbiological mechanisms involved, remain unclear.

This study, based on the long-term positional experiments at the Qiyang Soil Quality Monitoring Station, utilized the incubation experiment, stable isotope tracing, and molecular biology techniques to investigate the mechanisms by which long-term lime application regulates acid soil organic carbon mineralization and its response to warming and carbon input. The results indicate that long-term lime application significantly reduces the response of organic carbon mineralization in red soil to warming. This is closely associated with increased bacterial α-diversity, a decrease in oligotrophic/copiotrophic bacterial ratios, and reduced activities of β-glucosidase and xylanase. Furthermore, compared with the unlimed soil, labile carbon addition has a limited impact on soil organic carbon mineralization and temperature sensitivity in the limed soil. These findings confirm the importance of acidification amelioration in enhancing the stability of soil organic carbon, and provide theoretical support for the improvement and fertilization techniques in acidic soils.

Figure 1: Response Mechanism of Lime Application in Regulating Organic Carbon Mineralization in Red Soil to Warming and External Carbon Input

Dr. Xiao Qiong, a postdoctoral researcher at the IARRP, is the first author of the paper, with Dr. Zhang Wenju as the corresponding author. The specific work was guided by Dr. Xu Xingliang from the Institute of Geography, Chinese Academy of Sciences, and Professor Iain P. Hartley from the University of Exeter, among others. This research received funding from the National Natural Science Foundation of China and the task of the Cultivated Land Science Center of the Chinese Academy of Agricultural Sciences.

Paper link: https://doi.org/10.1016/j.jenvman.2024.120498