Red Soil Experiment Station in Qiyang of CAAS of the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS) (hereinafter referred to as Qiyang Station) has made phased progress in the regulation of potassium distribution in red soil aggregates by exogenous organic carbon. This research is of great significance for guiding the efficient utilization of potassium resources in red soil. The relevant research results were published online in Soil & Tillage Research.

According to professor Zhang Huimin, soil organic carbon is the core of soil fertility, and soil organic carbon may affect the form and distribution of potassium in soil aggregates through soil aggregate components. However, there is a lack of in-depth research on the mechanism of how exogenous organic carbon input affects K distribution in soil aggregates.

On the basis of the previous research on the mechanism of acidification and improvement regulating the distribution of potassium in red soil aggregates, Qiyang Station further revealed the distribution law of aggregate components of potassium in the soil under different fertilization measures under the level of organic carbon through the addition of exogenous organic carbon simulation experiments. The correlation between soil organic carbon content and aggregate component potassium was further discussed.

The results showed that increasing soil organic carbon could increase the proportion of aggregates >2 mm, and the non-exchangeable potassium storage in aggregates >2 mm showed a trend of increasing with the increase of organic carbon content. Under the condition of increasing organic carbon, compared with the straw returning treatment, the >2mm agglomerates treated with pig manure could accumulate more potassium reserves. However, the >2mm aggregates treated with straw returning to the field have the potential to preserve a higher proportion of potassium reserves.

Associate Researcher Liu Kailou of Jiangxi Institute of Red Soil and Germplasm Resources and Associate Researcher Huang Jing of Qiyang Station are the co-first authors of the paper. The research was funded by the National Natural Science Foundation of China, the National Key Research and Development Program of China, the Natural Science Foundation of Jiangxi Province, and the Central Public Welfare Special Project.

Paper link: https://doi.org/10.1016/j.still.2022.105438