Discrepancies in Karst Soil Organic Carbon in Southwest China for Different Land Use Patterns: A Case Study of Guizhou Province

Abstract

The assessment of soil organic carbon (SOC) in mountainous karst areas is very challenging, due to the high spatial heterogeneity in SOC content and soil type. To study and assess the SOC storage in mountainous karst areas, a total of 22,786 soil samples were collected from 2,854 soil profiles in Guizhou Province in Southwest China. The SOC content in the soil samples was determined by the oxidation of potassium dichromate (K2Cr2O7), followed by titration with iron (II) sulfate (FeSO4). The SOC storage was assessed based on different land uses. The results suggested that the average SOC density in the top 1.00 m of soil associated with different land uses decreased in the following order: Croplands (9.58 kg m−2) > garden lands (9.07 kg m−2) > grasslands (8.07 kg m−2) > forestlands (7.35 kg m−2) > uncultivated lands (6.94 kg m−2). The SOC storage values in the 0.00–0.10 m, 0.00–0.20 m, 0.00–0.30 m and 0.00–1.00 m soil layers of Guizhou Province were 0.50, 0.87, 1.11 and 1.58 Pg, respectively. The SOC in the top 0.30 m of soil accounted for 70.25% of the total within the 0.00–1.00 m layer in Guizhou Province. It was concluded that assessing SOC storage in mountainous karst areas was more accurate when using land use rather than soil type. This result can supply a scientific reference for the accurate assessment of the SOC storage in the karst areas of southwestern China, the islands of Java, northern and central Vietnam, Indonesia, Kampot Province in Cambodia and in the general area of what used to be Yugoslavia, along with other karst areas with similar ecological backgrounds.

Mediation effects of vegetation, land use and cover change and karst characteristics on hydrologic processes in heterogeneous karst basins

“…As demonstrated by this study, the acceleration of urbanization and population growth leads to increased water demand for industrial, agricultural, and domestic use, which reduces runoff. Interestingly, vegetation is consistently positively correlated with runoff (Figure 7), further validating the findings research of Zhang, Li, et al (2019) and Zhang, Huang, et al (2019). Due to the porous and fractures nature of rock matrixes in karst areas, vegetation enhances infiltration, and precipitation will lead to a continuous increase in the water content of the sub‐soil's surface layer within karst systems (Figure 10).…”

“…Under the disturbance of frequent agricultural activities, LUCC conversions can significantly alter the hydrologic processes and surface characteristics of the basin (Geng et al, 2023). The unique geological conditions in karst areas result in slow rate of soil formation, taking 2000–3000 years or even longer to form a 1 cm thick soil layer (Zhang, Huang, et al, 2019; Zhang, Li, et al, 2019). In consequence, anthropogenic land development such as CL expansion leads to decreased soil stability (Martínez‐Mena et al, 2020; Yuan & Li, 2023), further exacerbating water and soil erosion in the region.…”

Temporal variation in soil carbon in various paddy soil types in a cold temperate continental monsoon climate

“…The TOC, HOC, MOC and COC contents were analysed according to the procedure reported in previous studies (Bingqing et al, 2015;Huang et al, 2018;Zhang et al, 2006Zhang et al, , 2019. Specifically, the MOC was analysed as follows.…”

Organic Carbon in Wetland Soil: Seasonal Flooded Forest, Northeastern Thailand

“…Apparently, the SOC density showed the trends of being lower in the sub soil with little variability between locations, while top soil had a higher S O C density and more variability. Amber and Ken (2011) and Zhang et al (2019) suggested that SOC density is not only an important role in organic carbon storage estimating but the characteristics of organic carbon storage in different ecosystem are also reflected since horizontal consideration, the difference of canopy cover had significant. Our results indicate that SOC density in profile P4 was 1.98 times of SOC density in profile P5.…”