Extent to which pH and topographic factors control soil organic carbon level in dry farming cropland soils of the mountainous region of Southwest China

Chenglong Tu, Tengbing He, Xiaohui Lu, Ya Luo, Pete Smith

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Soil organic carbon (SOC) in agricultural land is influenced greatly by indeterminate human activity, making it difficult to understand the spatial pattern of SOC. Soil pH and topographic conditions are key indices in the Chinese Soil Genetic Classification System (CSGCS) and manage some critical factors that control the dynamics of SOC either directly or indirectly. To identify the extent to which pH and topographic factors control SOC levels in dry farming cropland soils of the mountainous region of Southwest China, we compared the differences along topographic gradients, and analysed the contribution of different factors in determining SOC status using analysis of variance (ANOVA) and linear regression. Our results indicated the SOC levels ranged from 10.46 g•kg− 1 to 37.60 g•kg− 1 and were significantly correlated with soil pH, landscape position, slope and elevation (p < 0.05). On a large scale, the combined effects of landscape position and elevation contributed to fluctuating SOC levels along the elevation gradient. SOC levels slightly, but significantly, decreased from base to summit. The difference of SOC levels along a 200 m elevation gradient exhibited statistical significance (p < 0.05). A slope range, from 0 to 42° was categorized into three groups, namely, 5° to 15° 15° to 30° and others. The slope range 15° to 30° had significantly greater SOC values than the other groups. These variables could all together explain approximately 40% of total variation in SOC, of which approximately 70% was attributable to soil pH, suggesting soil pH plays a key role in forming the spatial pattern of SOC levels in dry farming cropland soils of the mountainous region of Southwest China. The combined effect of landscape position and elevation could further explain 7.3% of SOC variation, which is more apparent than the effect of elevation alone.

Original languageEnglish
Pages (from-to)204-209
Number of pages6
JournalCatena
Volume163
Early online date26 Dec 2017
DOIs
Publication statusPublished - 30 Apr 2018

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organic carbon
soil
dry farming
variance analysis
human activity
agricultural land

Keywords

  • China
  • Dry farming cropland
  • Mountain
  • pH
  • Soil organic carbon
  • Topography

ASJC Scopus subject areas

  • Earth-Surface Processes

Cite this

Extent to which pH and topographic factors control soil organic carbon level in dry farming cropland soils of the mountainous region of Southwest China. / Tu, Chenglong; He, Tengbing; Lu, Xiaohui; Luo, Ya; Smith, Pete.

In: Catena, Vol. 163, 30.04.2018, p. 204-209.

Research output: Contribution to journalArticle

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title = "Extent to which pH and topographic factors control soil organic carbon level in dry farming cropland soils of the mountainous region of Southwest China",
abstract = "Soil organic carbon (SOC) in agricultural land is influenced greatly by indeterminate human activity, making it difficult to understand the spatial pattern of SOC. Soil pH and topographic conditions are key indices in the Chinese Soil Genetic Classification System (CSGCS) and manage some critical factors that control the dynamics of SOC either directly or indirectly. To identify the extent to which pH and topographic factors control SOC levels in dry farming cropland soils of the mountainous region of Southwest China, we compared the differences along topographic gradients, and analysed the contribution of different factors in determining SOC status using analysis of variance (ANOVA) and linear regression. Our results indicated the SOC levels ranged from 10.46 g•kg− 1 to 37.60 g•kg− 1 and were significantly correlated with soil pH, landscape position, slope and elevation (p < 0.05). On a large scale, the combined effects of landscape position and elevation contributed to fluctuating SOC levels along the elevation gradient. SOC levels slightly, but significantly, decreased from base to summit. The difference of SOC levels along a 200 m elevation gradient exhibited statistical significance (p < 0.05). A slope range, from 0 to 42° was categorized into three groups, namely, 5° to 15° 15° to 30° and others. The slope range 15° to 30° had significantly greater SOC values than the other groups. These variables could all together explain approximately 40{\%} of total variation in SOC, of which approximately 70{\%} was attributable to soil pH, suggesting soil pH plays a key role in forming the spatial pattern of SOC levels in dry farming cropland soils of the mountainous region of Southwest China. The combined effect of landscape position and elevation could further explain 7.3{\%} of SOC variation, which is more apparent than the effect of elevation alone.",
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N1 - This work is financially supported by National Natural Science Foundation of China (Grant No. 2013CB956702; 41571130041; 41261058; 41573012). Project on Social Development of Guizhou Province, No.20133127; Doctoral foundation of Guizhou Normal University. We would like to thank Mike Martin very much for his help and comments.

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N2 - Soil organic carbon (SOC) in agricultural land is influenced greatly by indeterminate human activity, making it difficult to understand the spatial pattern of SOC. Soil pH and topographic conditions are key indices in the Chinese Soil Genetic Classification System (CSGCS) and manage some critical factors that control the dynamics of SOC either directly or indirectly. To identify the extent to which pH and topographic factors control SOC levels in dry farming cropland soils of the mountainous region of Southwest China, we compared the differences along topographic gradients, and analysed the contribution of different factors in determining SOC status using analysis of variance (ANOVA) and linear regression. Our results indicated the SOC levels ranged from 10.46 g•kg− 1 to 37.60 g•kg− 1 and were significantly correlated with soil pH, landscape position, slope and elevation (p < 0.05). On a large scale, the combined effects of landscape position and elevation contributed to fluctuating SOC levels along the elevation gradient. SOC levels slightly, but significantly, decreased from base to summit. The difference of SOC levels along a 200 m elevation gradient exhibited statistical significance (p < 0.05). A slope range, from 0 to 42° was categorized into three groups, namely, 5° to 15° 15° to 30° and others. The slope range 15° to 30° had significantly greater SOC values than the other groups. These variables could all together explain approximately 40% of total variation in SOC, of which approximately 70% was attributable to soil pH, suggesting soil pH plays a key role in forming the spatial pattern of SOC levels in dry farming cropland soils of the mountainous region of Southwest China. The combined effect of landscape position and elevation could further explain 7.3% of SOC variation, which is more apparent than the effect of elevation alone.

AB - Soil organic carbon (SOC) in agricultural land is influenced greatly by indeterminate human activity, making it difficult to understand the spatial pattern of SOC. Soil pH and topographic conditions are key indices in the Chinese Soil Genetic Classification System (CSGCS) and manage some critical factors that control the dynamics of SOC either directly or indirectly. To identify the extent to which pH and topographic factors control SOC levels in dry farming cropland soils of the mountainous region of Southwest China, we compared the differences along topographic gradients, and analysed the contribution of different factors in determining SOC status using analysis of variance (ANOVA) and linear regression. Our results indicated the SOC levels ranged from 10.46 g•kg− 1 to 37.60 g•kg− 1 and were significantly correlated with soil pH, landscape position, slope and elevation (p < 0.05). On a large scale, the combined effects of landscape position and elevation contributed to fluctuating SOC levels along the elevation gradient. SOC levels slightly, but significantly, decreased from base to summit. The difference of SOC levels along a 200 m elevation gradient exhibited statistical significance (p < 0.05). A slope range, from 0 to 42° was categorized into three groups, namely, 5° to 15° 15° to 30° and others. The slope range 15° to 30° had significantly greater SOC values than the other groups. These variables could all together explain approximately 40% of total variation in SOC, of which approximately 70% was attributable to soil pH, suggesting soil pH plays a key role in forming the spatial pattern of SOC levels in dry farming cropland soils of the mountainous region of Southwest China. The combined effect of landscape position and elevation could further explain 7.3% of SOC variation, which is more apparent than the effect of elevation alone.

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