Soil chemical properties dynamics as affected by land use change in the humid forest zone of Cameroon

摘要

The conversion of forests to other forms of land use has profound effects on the distribution and supply of soil nutrients. Understanding the effects of land use on soil is essential for addressing agroecosystem transformation and sustainable land productivity. Although soil carbon stock has been previously examined in the humid forest zone of Cameroon, the dynamic and interactions between other soil chemical properties has been poorly addressed to date. The present study used the quadrat approach to assess the effect of four land use types (secondary forest, fallow, cocoa plantation and mixed cropping) on soil chemical properties. Soil samples were collected at two different depths (0-10, 10-30 cm) in all land use types and analyzed for pH, total carbon, soil organic carbon, total nitrogen, cation exchange capacity (CEC), calcium (Ca), potassium (K), magnesium (Mg) and boron (B). Land use type significantly affected B, Ca, K and pH: in general, these properties were higher in cocoa plantation and mixed cropping than in secondary forest and fallow. All soil properties were significantly greater in the upper than in the lower soil depth. In addition, all soil properties differed significantly among sites and villages within sites. Pearson correlations between soil chemical properties were positive and generally significant in the four land use types, except for some correlations with B, pH and CEC. Despite the fact that some of the fundamental soil chemical properties (carbon, nitrogen, CEC and Mg) did not differ among the four land use types, high density tree-based production systems are recommended for the storage of these elements in the soils.