Climate Change Dominated Long‐Term Soil Carbon Losses of Inner Mongolian Grasslands

Abstract

Soil organic carbon (SOC) is the most critical component of global carbon cycle in grassland ecosystems. There has been growing interest in understanding SOC dynamics and driving forces of grassland biomes at various temporal and spatial scales. Up to now, estimates of long-term and large-scale changes in SOC of grassland biomes have been mostly based on modeling approaches and manipulative experiments, rather than direct measurements. During 2007-2011, we repeated 141 soil profiles of the sampling in 1963-1964 (up to 1-m depth) to quantify the long-term changes of SOC storage in the major grassland types of Inner Mongolia in order to tease apart the relative contributions of climate change and grazing. We found that SOC decreased in all soil types, except in the eolian sandy soils, from 1963 to 2007, with an average reduction rate of 1.8 kg C m −2 (~22.9% or 0.52% year −1) in the grassland biome of Inner Mongolia. We quantitatively clustered the soils into four groups using principal component analysis (PCA) and detected clear spatial dependency of the changes on climate and grazing. The climate change was responsible for 15.3-34.9% of the total SOC variations, whereas grazing intensity accounted for <9.5% of the changes. Our findings indicated that climate change, rather than grazing, was the primary forcing for the changes in SOC of Inner Mongolia grasslands. We presume that other driving forces, such as changes in nongrazing-resultant wind erosion and atmospheric nitrogen deposition, might have played a role albeit their effects need to be further examined.

Temperature effects on carbon storage are controlled by soil stabilisation capacities

“…In this context, long-term surveys can be extremely valuable. For example, a recent study in Chinese grasslands was able to detect warming-induced soil C losses since the 1960s and, consistent with the global analysis presented here, coarsertextured soils lost far greater amounts of SOM 28 . Experimental soil warming studies also offer opportunities for further determining the factors controlling soil C storage and predicting rates of C release, although recent syntheses have produced conflicting overall findings 29,30 .…”

Long-Term Benefits of Cenchrus fungigraminus Residual Roots Improved the Quality and Microbial Diversity of Rhizosphere Sandy Soil through Cellulose Degradation in the Ulan Buh Desert, Northwest China

“…Soil organic carbon plays an extremely important role in the global carbon cycle process [ 48 ]. Xin et al found that organic carbon in 0–100 cm soil was lost at a rate of 48.4 Tg C year −1 between 1963 and 2007 [ 49 ]. There is a significant positive correlation between plant root traits (root biomass, underground plant carbon, nitrogen, and phosphorus content) and microbial residual carbon [ 50 ].…”

Effects of different grassland use patterns on soil bacterial communities in the karst desertification areas

“…Karst desertification, which is similar to desertified landscapes, has attracted much attention from the international community (Xiong et al, 2002 ). It has been shown that the establishment of artificial grasslands is an important initiative to rapidly repair the damaged ecological environment of rocky desertification (Wang et al, 2019 ), which is of great significance to promote ecological reconstruction and economic development (Fang et al, 2018 ; Xin et al, 2020 ; Bai and Cotrufo, 2022 ). However, due to the different utilization of artificial grassland, desertification may change the microbial community structure formed by long-term evolution and then change the soil microbial–soil–plant nutrient relationship (Pei et al, 2021 ), ultimately having a profound effect on grassland ecosystems and their functions (Liu et al, 2022 ).…”