The Hengyang Red Soil Experimental Station of the Chinese Academy of Agricultural Sciences (CAAS), also known as the "Qi Yang Station," has recently discovered that the proper application of lime in acidic red soil regions in southern China can improve soil quality, increase crop yields, and reduce greenhouse gas emissions. The related research findings were published in the journal, "Science of The Total Environment."

The improvement in agricultural production through continuous and heavy nutrient input like chemical nitrogen fertilizer under the upland red soil of south China deteriorates soil quality, and this practice in the future could threaten future food production and cause serious environmental problems in the regions. These issues have become major factors limiting the sustainable development of regional agriculture. The combined application of lime is a common method to control soil acidification and increase crop yields. While studies have shown that lime application can improve various soil nutrient indicators, these indicators do not directly reflect changes in soil quality. To the best of our knowledge, no study has been conducted evaluating the effects of the sole application of chemical nitrogen fertilizer and combined with lime on soil quality in the acidic soil of the study area. Previous studies have reported that the combined application of chemical nitrogen fertilizer and lime increased crop yield compared to the sole application of chemical nitrogen fertilizer, but the details of the mechanisms have not been studied and are unclear. Similarly, there is also limited research on the comprehensive impact of lime application on greenhouse gas emissions.

Based on long-term field trials at the Qi Yang Station, treatments with long-term sole fertilizer application and fertilizer combined with lime were selected. The research results indicate that compared to sole fertilizer application, the combined application of lime significantly increases soil pH values, enhances the content of exchangeable calcium ions, magnesium ions, available phosphorus, and alkaline nitrogen, which substantially improved soil quality index. The results of structural equation modelling from the current study demonstrated that the improvement in soil quality is a direct cause of increased crop yields. Meanwhile, combining chemical nitrogen fertilizer with lime reduce global warming potential relative to the solo application of chemical nitrogen fertilizer. Overall, this research provides scientific evidence that liming acidic soil in upland red soil in South China improved soil quality, crop yields, and mitigate greenhouse gas emissions, which offer a sustainable solution for environmental and agricultural management.

Kiya Adare Tadesse (PhD candidate) from the Institute of Agricultural Resources and Regional Planning (IARRP) of CAAS is the first author, with professor Huimin Zhang as the corresponding author. This study was supported by the National Natural Science Foundation and the Innovation Project of the Chinese Academy of Agricultural Sciences.

Original article link:

https://doi.org/10.1016/j.scitotenv.2024.173827