Negative effects of urbanization on agricultural soil easily oxidizable organic carbon down the profile of the Chengdu Plain, China

Abstract

Soil easily oxidizable organic carbon (EOC) is directly related to CO 2 density; dynamics in subsurface EOC have been observed globally in relation to rapid urbanization.However, in the context of rapid urbanization, the factors related to EOC and the response of the EOC pool to urbanization down the profile remain elusive. The aim of the current paper is to investigate possible changes in the distribution of EOC over the soil profile and the impact of land use, socioeconomic, and natural factors on these. The study used samples from 182 soil profiles (0-100 cm) taken in the periurban areas of the megacity Chengdu (a typical megacity with rapid urbanization).Main drivers of changes in soil EOC were analyzed by using spatial and regression analyses. Closer to the centre of the city, soil EOC levels were lower and land-use factors and socioeconomic factors contributed more to explaining variation in EOC levels in the 0-40-cm layer, whereas natural factors were most important at larger distance from the city. The effect of land-use factors and socioeconomic factors on EOC reached down to 60-cm depths. Moreover, an estimated 20% loss of EOC stock was observed close to the city in comparison with the surroundings, suggesting that the rapid process of urbanization was accompanied by a loss of EOC stock down the profile to depths of 60 cm, and the negative effects on EOC stock became more intensive as the distance to the city decreased. KEYWORDS easily oxidized organic carbon, impact factors, negative effects, rapid urbanization, soil profile

Aggregate‐associated soil organic carbon fractions in subtropical soil undergoing vegetative restoration

“…Moreover, SOC is essentially released from litter decomposition. Surface litter significantly changed the SOC input, which affects the EOC content (Luo, Hou, et al, 2020; Luo, Li, et al, 2020). For these reasons, the highest concentration of SOC fractions was found in SP types, which had the maximum content of <0.053 mm aggregates and biomass (Figure 4).…”

“…Recent studies highlight that vegetation restoration in the subtropical region has positive effects on soil organic carbon (SOC) sequestration by changing C inputs, turnover and stability (Deng et al, 2016). Thereby, vegetation restoration is indicated as a productive strategy (Luo, Hou, et al, 2020; Luo, Li, et al, 2020). Although effects on C stocks have been widely reported (Cook et al, 2016; Li et al, 2021), additional research is needed to clarify how and to what magnitude restorations affect SOC fractions.…”

Impact of suburban cropland intensification and afforestation on microbial biodiversity and C sequestration in paddy soils

“…Considering the possible interaction of soil depths versus land uses, two‐way ANOVA was used to test the interaction (test of between subjects effects) and confirm per data set (Levene's test for equality of variances and test for equality of means) (Luo et al, 2020), when there was a significant interaction between both factors ( p < 0.05), where variances were homogenous (Levene's test, p > 0.05), permitting pairwise comparisons of means (Tukey's post hoc tests, p < 0.05). Then, one‐way analysis of variance (ANOVA) followed by the Tukey–Kramer test was used to assess the significance of differences in soil chemical characteristics, bacterial, and fungal quantities (Figure S1) across different suburban croplands.…”

“…Considering the possible interaction of soil depths versus land uses, two-way ANOVA was used to test the interaction (test of between subjects effects) and confirm per data set (Levene's test for equality of variances and test for equality of means) (Luo et al, 2020), when there was a significant interaction between both factors ( p < 0.05),…”

Major Consequences of Land-Use Changes for Ecosystems in the Future in the Agro-Pastoral Transitional Zone of Northern China

“…Taking advantage of the carbon sequestration potential of natural ecosystems, especially of the grassland ecosystem-the main LULC in the APTZNC-could help in effectively mitigating regional climate change. Some scholars have studied the APTZNC in the city of Hohhot and found that the most active and fast-cycling component in soil organic carbon is the readily oxidizable carbon, a sensitive indicator of SOM dynamics, which can reflect the early changes of SOM [90,91]. The SOM in grassland is higher, whereas the readily oxidizable carbon is lower instead [92].…”