Spatial variability in soil organic carbon in a tropical montane landscape: associations between soil organic carbon and land use, soil properties, vegetation, and topography vary across plot to landscape scales

Abstract

Abstract. Presently, the lack of data on soil organic carbon (SOC) stocks in relation to land-use types and biophysical characteristics prevents reliable estimates of ecosystem carbon stocks in montane landscapes of mainland SE Asia. Our study, conducted in a 10 000 ha landscape in Xishuangbanna, SW China, aimed at assessing the spatial variability in SOC concentrations and stocks, as well as the relationships of SOC with land-use types, soil properties, vegetation characteristics and topographical attributes at three spatial scales: (1) land-use types within a landscape (10 000 ha), (2) sampling plots (1 ha) nested within land-use types (plot distances ranging between 0.5 and 12 km), and (3) subplots (10 m radius) nested within sampling plots. We sampled 27 one-hectare plots -10 plots in mature forests, 11 plots in regenerating or highly disturbed forests, and 6 plots in open land including tea plantations and grasslands. We used a sampling design with a hierarchical structure. The landscape was first classified according to land-use types. Within each land-use type, sampling plots were randomly selected, and within each plot we sampled within nine subplots. SOC concentrations and stocks did not differ significantly across the four land-use types. However, within the open-land category, SOC concentrations and stocks in grasslands were higher than in tea plantations (P < 0.01 for 0-0.15 m, P = 0.05 for 0.15-0.30 m, P = 0.06 for 0-0.9 m depth). The SOC stocks to a depth of 0.9 m were 177.6 ± 19.6 (SE) Mg C ha −1 in tea plantations, 199.5 ± 14.8 Mg C ha −1 in regenerating or highly disturbed forests, 228.6 ± 19.7 Mg C ha −1 in mature forests, and 236.2 ± 13.7 Mg C ha −1 in grasslands. In this montane landscape, variability within plots accounted for more than 50 % of the overall variance in SOC stocks to a depth of 0.9 m and the topsoil SOC concentrations. The relationships of SOC concentrations and stocks with land-use types, soil properties, vegetation characteristics, and topographical attributes varied across spatial scales. Variability in SOC within plots was determined by litter layer carbon stocks (P < 0.01 for 0-0.15 m and P = 0.03 for 0.15-0.30 and 0-0.9 m depth) and slope (P ≤ 0.01 for 0-0.15, 0.15-0.30, and 0-0.9 m depth) in open land, and by litter layer carbon stocks (P < 0.001 for 0-0.15, 0.15-0.30 and 0-0.9 m depth) and tree basal area (P < 0.001 for 0-0.15 m and P = 0.01 for 0-0.9 m depth) in forests. Variability in SOC among plots in open land was related to the differences in SOC concentrations and stocks between grasslands and tea plantations. In forests, the variability in SOC among plots was associated with elevation (P < 0.01 for 0-0.15 m and P = 0.09 for 0-0.9 m depth). The scale-dependent relationships between SOC and its controlling factors demonstrate that studies that aim to investigate the land-use effects on SOC Published by Copernicus Publications on behalf of the European Geosciences Union. 124 M. de Blécourt et al.: Spatial variability of soil organic carbon need an appropriate samp...

Comparative Analysis of Soil Variables in Different Land Uses of the Shazand Watershed, Iran

“…There was no significant difference (P> 0.05) among SOCs in different land uses, which agrees with Blécourt et al (2017) who stated there was no statistically significant difference among land uses in viewpoint of SOC in Xishuangbanna Region, China. However, it disagree with the findings of Falahatkar et al (2016) who expressed the mean values of the SOCs in the selected land uses in the Deylaman Region were significantly different (p < 0.05).…”

“…Effects of land use changes on soil properties is inherently regional and highly dependent on the soil type (Abu -Hashim et al, 2016), climate (Berhongaray et al, 2013;Yang et al, 2016), and topography (Ayoubi et al, 2012;Dessalegn et al, 2014;Falahatkar et al, 2016;de Blécourt et al, 2017). So, there is a need to assess the effects of different land uses on soil properties in different ecological regions.…”

Soil Organic Carbon Stock Variation under Different Soil Types and Land Uses in the Sub-Humid Noun Plain, Western Cameroon

“…in Yunnan Province in China [56], in the Cerrado of Brazil [57], and in the mountainous area of North-West Cameroon [6]. This significant variation in SOCS with respect to land use type observed in the Noun agricultural plain is similar to the findings reported by De Blécourt et al [16] in a study on the impact of land use change in Namibia and Zambia.…”

El Efecto de diversos atributos topográficos sobre el carbono orgánico en varios usos del suelo

“…Koning et al (2003) en la cordillera de los andes ecuatoriano también encontraron suelos de textura fina que reduce el contenido de CO a medida que disminuye la pendiente y aumenta la profundidad de muestreo. Por otra parte, el contenido de arcilla afecta de forma positiva al almacenamiento de CO (Ruiz Potma Goncalves et al, 2017), aunque los valores de arcilla aumentaron en 30-40 cm, se observó una relación inversa en los usos del suelo banano y cacao joven, donde el carbono disminuyó, resultados encontrados en otras investigaciones con pendientes > 20% (Beach et al, 2018;de Blécourt et al, 2017;Singh y Benbi, 2018). Los niveles de COS almacenados mostraron diferencias significativas en todos los usos de suelo por profundidad (Figura 3).…”

“…La pérdida del carbono orgánico del suelo (COS) en las regiones de montañas ubicadas en las zonas tropicales y subtropicales son atribuido al cambio en los usos del suelo (Wang et al, 2018). Los atributos topográficos del terreno como la pendiente, elevación, dirección, factor de transporte de suelo, radiación solar, índice topografico de humedad del suelo, entre otros, potencia su pérdida (de Blécourt et al, 2017;Singh y Benbi, 2018). Sin embargo, los atributos topográficos difieran en magnitud en los diferentes sistemas agrícolas, por ejemplo en la redistribución del agua sobre los cultivos en terrenos con alta pendiente se incrementa la infiltración y la escorrentía (Senthilkumar et al, 2009).…”