The Innovation Team of Improvement and Amelioration of Soil Fertility at the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS) has made progress in the study of how nitrogen and phosphorus additions regulate the formation of soil organic carbon storage in farmland with different nutrient stoichiometry. The related findings were published in journal of Geoderma.

Microbial necromass carbon, as an important component of soil organic carbon in farmland, contributes over 50% to SOC (soil organic carbon) and is crucial for maintaining soil fertility. Nutrient input, as a vital fertilization measure in farmland ecosystems, can alter soil resource stoichiometry, thereby influencing microbial metabolic processes and necromass carbon formation. However, how nitrogen and phosphorus nutrient additions regulate the process and mechanism of microbial necromass carbon formation in soils with different nutrient stoichiometric characteristics remains unclear.

This study was conducted in collaboration with the Laiyang Field Scientific Observation Station of the Ministry of Agriculture and Rural Affairs at Qingdao Agricultural University. A microcosm simulation control experiment was adopted, combined with molecular markers (phospholipid fatty acids, amino sugars) and 13C stable isotope probe technology to quantify the assimilation process of exogenous carbon by soil microbes and the dynamics of microbial necromass carbon formation under nitrogen and phosphorus addition conditions. The results indicated that in low fertility soils (high C:N/C:P ratio), nitrogen and phosphorus additions alleviated microbial nutrient limitations, enhanced bacterial growth and metabolism, thereby promoting necromass formation. In high fertility soils (low C:N/C:P), phosphorus addition exacerbated the imbalance of soil microbial carbon and nitrogen, which was detrimental to necromass carbon formation. These research findings are crucial for optimizing nutrient management to promote microbial necromass carbon formation and thereby increasing organic carbon accumulation.

Figure 1: Mechanism of Nitrogen-Phosphorus Addition Regulating Soil Microbial Necromass Carbon Formation

Chen Yihui, a Ph.D. student at the Institute of Agricultural Resources and Regional Planning of the Chinese Academy of Agricultural Sciences, is the first author of the paper, with Researcher Zhang Wenju as the corresponding author. This research was supported by the Key Laboratory of Efficient Utilization of Northern Arid and Semi-arid Cropland, the National Natural Science Foundation of China, and the Innovation Program of the Chinese Academy of Agricultural Sciences.

Original Link: https://doi.org/10.1016/j.geoderma.2025.117323