Effects of the interaction between biochar and nutrients on soil organic carbon sequestration in soda saline-alkali grassland: A review

Grasslands contain enormous soil organic carbon (SOC) reserves, and even minor fluctuations may have a great effect on the climate. N, P and S in soil organic matter (SOM) have important influences on SOC sequestration. The soil in soda saline-alkali grassland is characterized by high pH, high exchangeable sodium percentage (ESP), degraded physical properties and poor nutrients. N and P are the primary limiting elements, and nutrient addition is an effective path to support grassland plant growth. In addition, as a new method for improving saline-alkali land, biochar application can significantly improve soil nutrients and soil properties. The mechanism by which biochar and nutrients interact to influence SOC sequestration in strongly soda saline-alkali grassland remains unclear. From the perspective of ecological stoichiometry and microbiology, the influences of different biochar-nutrient combinations on the characteristics of SOMs were explored in this literature review; the influences of the interactions between soil microbial biomass, microbial residues and ecological stoichiometric characteristics of SOM on organic carbon accumulation were considered in the hope of providing a scientific basis for the improvement and appropriate fertilization of degraded grassland, and accurate prediction of changes in the reserves of SOC in the grassland ecosystem.