The Yellow River Delta region contains extensive saline-alkali land, where poor soil structure and low nitrogen use efficiency are key constraints to agricultural development. To address this challenge, the research team fromYantai Institute of Coastal Zone Research, Chinese Academy of Sciences,conducted field experiments using biochar derived from maize straw combined with the nitrification inhibitor DCD. They systematically investigated the effects of different treatments on soil aggregate structure, nitrogen forms, enzyme activities, and microbial communities.

Research reveals the synergistic mechanism by which biochar combined with the nitrification inhibitor dicyandiamide (DCD) improves soil structure, nitrogen transformation, and soybean-wheat rotation yield, providing both theoretical and practical support for the sustainable utilization of coastal saline-alkali soils. The study was published in Soil & Tillage Research, systematically elucidated the synergistic mechanism of co-application of biochar and the nitrification inhibitor dicyandiamide (DCD) for enhancing soil structure, nitrogen transformation, and soybean-wheat rotation yield in saline-alkali land. This research provides crucial theoretical and practical foundations for the sustainable utilization of coastal saline-alkali soils in China.

The results demonstrated that the integrated application of biochar and DCD significantly improved soil aggregate structure, promoted the formation of micro-aggregates (0.25–0.5 mm), and increased the Mean Weight Diameter and Geometric Mean Diameter, thereby enhancing soil structural stability.Concurrently, the treatment strengthened the storage and transformation capacity of soil organic nitrogen (SON), promoted microbial immobilization of inorganic nitrogen, and improved the soil's nitrogen supply capacity. Principal component analysis indicated that the combined application significantly enhanced the activities of key nitrogen-transforming enzymes, such as protease, urease, and nitrate reductase, boosting the mineralization potential of SON. Analysis of the microbial community structure further revealed a dual pathway of “inhibition of nitrifying bacteria + activation of fungal mineralization”, which optimizes the nitrogen transformation process. Ultimately, these synergistic effects led to a significant increase in the annual soybean-wheat yield and a substantial improvement in nitrogen use efficiency.

Fig.1 Biochar integrated with the nitrification inhibitor dicyandiamide facilitates soil improvement and crop yield enhancement in saline-alkali land.

This research provides the first systematic elucidation of the synergistic mechanism between biochar and DCD in the amelioration of saline-alkali soils. The results demonstrate that the integrated use of these amendments not only improves soil physical properties but also optimizes the pathways of nitrogen supply and transformation, thereby presenting an innovative strategy for achieving green agricultural intensification in saline-alkali areas.

The related findings, entitled “Biochar integrate dicyandiamide modified soil aggregates and optimized nitrogen supplying to boosting the soybean-wheat yield in saline-alkali soil”, have been published in the renowned international journal 《Soil & Tillage Research》. The first author is Assistant Professor Chunxiao Yu, and the corresponding author is Professor Guangmei Wang, both from the Yantai Institute of Coastal Zone Research. This work was supported by the Natural Science Foundation of Shandong Province, the National Key Research and Development Program, and the Key Research and Development Program of Shandong Province.

Link to the paper: https://authors.elsevier.com/c/1l-n8c13yd5tR