Soil Organic Carbon and Inorganic Carbon Accumulation Along a 30‐year Grassland Restoration Chronosequence in Semi‐arid Regions (China)

Abstract

Carbon accumulation is an important research topic for grassland restoration. It is requisite to determine the dynamics of the soil carbon pools [soil organic carbon (SOC) and soil inorganic carbon (SIC)] for understanding regional carbon budgets. In this study, we chose a grassland restoration chronosequence (cropland, 0 years; grasslands restored for 5, 15 and 30 years, i.e. RG5, RG15 and RG30, respectively) to compare the SOC and SIC pools in different soil profiles. Our results showed that SOC stock in the 0‐ to 100‐cm soil layer showed an initial decrease in RG5 and then an increase to net C gains in RG15 and RG30. Because of a decrease in the SIC stock, the percentage of SOC stock in the total soil C pool increased across the chronosequence. The SIC stock decreased at a rate of 0·75 Mg hm−2 y−1. The change of SOC was higher in the surface (0–10 cm, 0·40 Mg hm−2 y−1) than in the deeper soil (10–100 cm, 0·33 Mg hm−2 y−1) in RG5. The accumulation of C commenced >5 years after cropland conversion. Although the SIC content decreased, the SIC stock still represented a larger percentage of the soil C pool. Moreover, the soil total carbon showed an increasing trend during grassland restoration. Our results indicated that the soil C sequestration featured an increase in SOC, offsetting the decrease in SIC at the depth of 0–100 cm in the restored grasslands. Therefore, we suggest that both SOC and SIC should be considered during grassland restoration in semi‐arid regions. Copyright © 2016 John Wiley & Sons, Ltd.

Large‐scale soil organic carbon mapping based on multivariate modelling: The case of grasslands on the Loess Plateau

“…Vegetation biomass plays a non‐negligible role in determining SOC stocks (L. F. Chen et al, ). Vegetation recovery on the Loess Plateau favours SOC sequestration (Deng, Liu, & Shangguan, ; Deng & Shangguan, ; Deng, Shangguan, Wu, & Chang, ; Liu, Dang, Tian, Wang, & Wu, ). Pearson correlation coefficients and associated significance levels were utilized to identify the relationship between grassland SOC and biomass.…”

“…Zhang and Shangguan () studied the soil water content (SWC) in the Ziwuling forest region and found that grasslands exhibited a higher SWC than shrublands and forestlands. In addition, Liu et al () studied the Qiaozigou watershed and found that the SOC content in sediments was positively correlated with SWC ( p < .05). A high grassland SWC might favour SOC accumulation in mountain areas.…”

Leguminous species sequester more carbon than gramineous species in cultivated grasslands of a semi-arid area

“…Grasslands can have a significant effect in arid and semiarid areas' C cycle through changing soil C accumulation rates and turnover, soil erosion, and vegetation biomass (Deng et al, 2014a;Liu et al, 2017). Plants regulate SOC stock by controlling, assimilating, and accumulating C in the plant root system, and then through plant respiration and leaching release from soil to atmosphere (De Deyn et al, 2008;Garcia-Diaz et al, 2016).…”

Effect of Grazing Intensity on Soil and Plant δ15N of an Alpine Meadow

“…Soil mineral nitrogen was the dominant source of plant uptake nitrogen [20], herbivores appeared to have a strong influence on grassland N availability, and some studies showed that grazing could lead to an increase in soil δ 15 N [15,19,21], while no apparent and negative effects of grazing have also been reported [22]. Ammonia volatilization and gaseous N losses via denitrification resulted in the remaining soil and plant enrichment of 15 N in grazed grasslands [12].…”