Changes of soil carbon dioxide, methane, and nitrous oxide fluxes in relation to land use/cover management

Abstract

Conversions of land use/cover are associated with changes in soil properties and biogeochemical cycling, with implications for carbon (C), nitrogen (N), and trace gas fluxes. In an attempt to provide a comprehensive evaluation of the significance of different land uses (Alnus subcordata plantation, Taxodium distichum plantation, agriculture, and deforested areas) on soil features and on the dynamics of greenhouse gas (GHG) fluxes at local scale, this study was carried out in Mazandaran province, northern Iran. Sixteen samples per land use, from the top 10 cm of soil, were taken, from which bulk density, texture, water content, pH, organic C, total N, microbial biomass of C and N, and earthworm density/biomass were determined. In addition, the seasonal changes in the fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) were monitored over a year. Our results indicated that the different land uses were different in terms of soil properties and GHG fluxes. Even though the amount of the GHG varied widely during the year, the highest CO2 and CH4 fluxes (0.32 mg CO2 m(-2) day(-1) and 0.11 mg CH4 m(-2) day(-1), respectively) were recorded in the deforested areas. N2O flux was higher in Alnus plantation (0.18 mg N2O m(-2) day(-1)) and deforested areas (0.17 mg N2O m(-2) day(-1)) than at agriculture site (0.05 mg N2O m(-2) day(-1)) and Taxodium plantation (0.03 mg N2O m(-2) day(-1)). This study demonstrated strong impacts of land use change on soil-atmosphere trace gas exchanges and provides useful observational constraints for top-down and bottom-up biogeochemistry models.

Soil‐atmosphere exchange of greenhouse gases from typical subalpine forests on the eastern Qinghai‐Tibetan Plateau: Effects of forest regeneration patterns

“…In addition to climatic conditions, forest management practices/land use change could strongly influence soil‐atmosphere CO 2 exchange (Ju et al, ; Kooch et al, ; Wanyama et al, ). Our results revealed that soil CO 2 effluxes differed among the three forest types.…”

“…In addition to climatic conditions, forest management practices/ land use change could strongly influence soil-atmosphere CO 2 exchange (Ju et al, 2016;Kooch et al, 2016;Wanyama et al, 2019).…”

“…The coefficients of 16:1 ω5c and 18:1 ω7c in the stepwise regression equation were negative, indicating a positive effect of these PLFAs on CH 4 uptake ( Table 5). It has been reported that 16:1 ω5c and 18:1 ω7c are recognized as a signature for Type II and Type I methanogens, respectively (Dörr et al, 2010;Knief, Kolb, Bodelier, Lipski, & Dunfield, 2006). However, relatively few studies have detected CH 4 oxidation by the PLFAs of a15:0 (Dörr et al, 2010;Yao et al, 2015).…”

“…The Kolmogorov-Smirnov test and Levene's test were used to check the normality of the variables and the homogeneity of the variances (Kooch et al, 2016). A one-way analysis of variance (ANOVA) and Tukey's honestly significant difference test were performed to examine the statistical significance of forest types on mean and cumulative GHG fluxes and auxiliary indices (SOC, total N, C:N ration, soil pH value, and NH 4 + and NO 3 − concentrations).…”

“…Generally, forest regeneration patterns alter species composition, soil condition, and the microbial community; thus, it directly affects the sinks and/or sources of GHG (Tang et al, 2006;van Haren et al, 2013). To date, several studies have focused on soil GHG fluxes in forests originating from different processes (Kooch, Moghimian, Bayranvand, & Alberti, 2016;Liu, Zhang, Hu, & Tang, 2014;Sun, Zhang, & Wu, 2013;Tang et al, 2006;Ullah, Frasier, King, Picotte-Anderson, & Moore, 2008;Wanyama et al, 2019). However, the results of these studies vary greatly (Fang, Yu, Zhou, Zhou, & Dai, 2016;Tang et al, 2006).…”