The Soil Fertility and Improvement Team at the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences (CAAS), has identified key factors regulating the accumulation of glomalin-related soil proteins (GRSP) under long-term fertilization across different climatic zones. Their findings offer scientific guidance for climate-specific fertilization management and soil carbon sequestration. The study was published in the international journal Soil & Tillage Research, titled "Long-term fertilization-induced increases in glomalin-related soil protein depend on phosphorus input and aggregate stability across climatic zones."

Glomalin-related soil protein (GRSP), produced by arbuscular mycorrhizal fungi (AMF), plays a crucial role in soil carbon sequestration and structural stability. However, how fertilization affects GRSP variation across different climatic zones and management practices has remained unclear. This study evaluated the impact of long-term fertilization regimes, including no fertilizer (CK), chemical fertilizer (CF), and organic fertilizer (OF), on AMF biomass and soil aggregate stability at 14 long-term fertilization sites located in temperate, warm temperate, and subtropical regions across China. The results indicated that total GRSP content ranged from 1.0 to 5.1 mg/g, with the highest levels observed in the temperate zone, followed by the subtropical zone, and the lowest in the warm temperate zone. Organic fertilizer significantly increased GRSP content, raising it by about 46% compared to CK, while chemical fertilizer had limited effects in temperate regions.

The magnitude of the fertilization-induced increase in GRSP followed the pattern: subtropical (CF: +35%, OF: +80%) > warm temperate (CF: +13%, OF: +67%) > temperate (OF: +27%). Using a mixed-effects model, the study identified phosphorus (P) input, AMF biomass, and aggregate stability as main regulators of fertilization effects on GRSP across regions. Overall, the fertilization response of GRSP was distinctly climate zone-specific.

This study proposes region-specific soil management strategies. In warm and humid areas, enhancing soil aggregate stability should be prioritized to improve the physical protection of GRSP. In mid- and high-latitude regions, optimizing the combined application of phosphorus and organic fertilizers is crucial to promoting GRSP synthesis and accumulation. These findings provide important scientific evidence for optimizing fertilization systems, improving soil quality, and advancing agricultural carbon sequestration in different climatic regions.

Figure 1: GRSP Response to Fertilization Across Different Climatic Zones

Yang Hongbo, a Ph.D. student jointly trained by CAAS and the University of Liège, Belgium, is the first author of the paper, with Researcher Zhang Wenju as the corresponding author. The research was funded by the National Natural Science Foundation of China (42177331) and the CAAS Soil Science Center (CAAS-CSAL-202302).

Original article link:https://doi.org/10.1016/j.still.2025.106950