Study Reveals Regulatory Mechanisms of Soil Organic Carbon in Central Asian Grasslands

A new study led by Prof. LI Yaoming from the Xinjiang Institute of Ecology and Geography of the Chinese Academy of Sciences has revealed the driving mechanisms and environmental thresholds that govern the storage of particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) in Central Asian grasslands. The study was published in Geoderma.

Central Asian grasslands, as a core part of the world's largest contiguous temperate grassland belt, play a crucial role in the global carbon cycle. However, a comprehensive understanding of how different soil organic carbon fractions form and stabilize across environmental gradients has remained elusive.

To address this knowledge gap, the researchers collected 1,548 soil samples from 355 sites across Central Asian grasslands. The researchers used interpretable machine learning methods and generalized additive models to quantify the influence of various environmental factors on MAOC and POC dynamics.

The researchers found that vegetation productivity primarily drives the accumulation of both MAOC and POC.

Furthermore, they found that MAOC dominates the soil carbon pool in these arid grasslands, remaining consistently and significantly higher than POC. This indicates that mineral stabilization is the paramount mechanism driving soil carbon storage across the region.

Interestingly, POC exhibits a pronounced threshold response to soil bulk density; levels exceeding a critical threshold strongly inhibit its accumulation. Meanwhile, MAOC is highly sensitive to soil pH and texture, and alkaline conditions significantly constrain its accumulation.

"Our findings could provide essential parameters for refining the simulation of carbon cycle processes within Earth system models," said WANG Guangyu, the study's first author.

This study provides a scientific basis for forming and implementing tailored grassland carbon management strategies.

Read the full article: https://doi.org/10.1016/j.geoderma.2025.117610

Contact

LONG Huaping

Xinjiang Institute of Ecology and Geography

E-mail: longhp@ms.xjb.ac.cn

Web: http://english.egi.cas.cn