Journal of
Soil Science and Environmental Management

  • Abbreviation: J. Soil Sci. Environ. Manage.
  • Language: English
  • ISSN: 2141-2391
  • DOI: 10.5897/JSSEM
  • Start Year: 2010
  • Published Articles: 311

Full Length Research Paper

Variability of soil organic carbon with landforms and land use in the Usambara Mountains of Tanzania

Joel Loitu Meliyo*
  • Joel Loitu Meliyo*
  • Selian Agricultural Research Institute, P.O. Box 6024, Arusha, Tanzania.
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Balthazar, M. Msanya
  • Balthazar, M. Msanya
  • Department of Soil and Geological Sciences, Sokoine University of Agriculture, P.O. Box 3008, Morogoro, Tanzania.
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Didas Nahum Kimaro
  • Didas Nahum Kimaro
  • Department of Engineering Sciences and Technology, Sokoine University of Agriculture, P.O. Box 3003, Morogoro, Tanzania.
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Boniface Hussein John Massawe
  • Boniface Hussein John Massawe
  • Department of Soil and Geological Sciences, Sokoine University of Agriculture, P.O. Box 3008, Morogoro, Tanzania.
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Proches, Hieronimo
  • Proches, Hieronimo
  • Department of Engineering Sciences and Technology, Sokoine University of Agriculture, P.O. Box 3003, Morogoro, Tanzania.
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LothS. Mulungu
  • LothS. Mulungu
  • Pest Management Centre, Sokoine University of Agriculture, P.O. Box 3110, Morogoro, Tanzania.
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Jozef Deckers
  • Jozef Deckers
  • Department of Earth and Environmental Sciences, University of Leuven, Celestijnenlaan 200E, Leuven, Belgium.
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Hubert Gulinck
  • Hubert Gulinck
  • Department of Earth and Environmental Sciences, University of Leuven, Celestijnenlaan 200E, Leuven, Belgium.
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  •  Received: 02 February 2016
  •  Accepted: 13 June 2016
  •  Published: 30 September 2016

Abstract

This study was carried out to assist in the formulation of conservation technologies for landscape sustained productivity in the Usambara Mountains, Tanzania. Conventional soil survey methods were used to develop a base map on which 55 soil profile pits were randomly located on representative landforms and land use mapping units. Soil samples were collected from topsoils for soil carbon analysis using the wet digestion method. Descriptive statistics and linear regression models were used to establish relationships between landforms, land use and soil organic carbon levels. Results showed that carbon levels ranged between 0.55 and 10.8% for bush land and forest plantations in the plain and plateau, respectively. Under cultivation, soil organic carbon (SOC) levels varied between 1.03 and 6.34% for mid-slopes and lower slopes of the plateau respectively. The average soil organic carbon in the vegetable growing valley bottoms was 4.5% while in the forest plantation was 5.5% with minimum and maximum of 0.8 and 10.8% respectively. Linear regression model analysis indicated that factors influencing variability of SOC apart from land use are: slope form, soil pH, electrical conductivity and CECclay. It was concluded that soil organic matter in the study area is mainly determined by elevation, slope form and type of land use and management. Introduction of soil erosion control measures and incorporation of crop residues to areas where soil organic matter has been depleted were recommended for sustainable crop production.

Key words: Soil quality, soil health, topographic variation, organic carbon.