The Qiyang Red Soil Station of the Chinese Academy of Agricultural Sciences (CAAS) has conducted research to uncover the impact of lime application on soil potassium and its key regulatory processes. The research findings highlight the importance of lime effects in soil potassium management within global agricultural ecosystems. The results of the study have been published in the journal "Catena".

Soil acidification hinders crop uptake of potassium and accelerates the leaching of soil potassium. Lime, as a commonly used management measure for soil acidification control, has direct and indirect regulatory effects on soil potassium. However, the quantitative impact of lime application on surface soil potassium at a global scale remains poorly understood, as well as its long-term effects on potassium transformation processes and crop effectiveness.

Based on published literature data and long-term field experiments at the Qiyang Red Soil Station, this study explores the influence of lime application on changes in soil potassium content and the main driving factors. Meta-analysis shows that lime application at a global scale can significantly reduce the content of exchangeable potassium (EK) in the surface soil (by 4.8%). The extent of reduction is closely related to soil properties, crop types, fertilizer systems, and experimental types. Further analysis reveals that the initial content of EK and pH value are the main regulating factors affecting the decrease in EK content (Figure 1). Long-term field experiments further demonstrate that the decrease in EK after lime application is closely related to crop potassium uptake and the conversion of different forms of potassium (Figure 2). The research results reveal the key role played by the initial content of EK and degree of acidification in regulating the exploration of subsoil potassium by crops when lime is applied. This provides scientific evidence for optimizing management measures in red soil areas of China to achieve sustainable utilization of soil potassium.

Figure 1: The impact of lime application on exchangeable potassium content in surface soil and factor analysis.

Figure 2: A conceptual diagram for soil potassium cycling acceleration after liming addition.

Dr. Han Tianfu from the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS), is the first author, and Researcher Zhang Huimin is the corresponding author. This research was supported by the National Natural Science Foundation of China, the Key Research and Development Program, and the Postdoctoral Scientific Foundation.

Paper Link: https://doi.org/10.1016/j.catena.2023.107408