Quantified Soil Evolution Under Shifting Agriculture in Southern Cameroon

Abstract

In the tropical rain forest zone of Southern Cameroon, shifting cultivation and perennial plantations of cocoa are the main farming systems practiced by small-scale farmers to ensure subsistence food crop production and a small income. This research used scientific modeling tools to produce quantitative information on the evolution of soils under this shifting agricultural system. An analysis of farming system led to the development of a conceptual model of the spatio-temporal dynamics of shifting agriculture, including transition matrices of rotational cycles that guided the sampling strategy for the study of soil evolution under the system. The study of soil variability showed that 30-35% of the total variance of some topsoil (0-20 cm) properties was due to the influence of land use practices. Five soil properties (pH, calcium, available phosphorus, bulk density and organic carbon) that are the most sensitive to these agricultural practices were empirically modeled and linear/quadratic fractional rational functions were successfully fitted to time series soil variables to derive quantitative measures on temporal changes in soil with land use. Data and methods produced are useful for soil quality assessment and spatio-temporal dynamic simulation in order to guide decision-making for sustainable land-use planning and soil resources management.

Impact of Fallowing on the Emergence of Weed Species, Soil Nutrient Dynamics and Yield of Maize (<em>Zea mays</em> L.)

“…This is because the carbon cycle is intrinsically linked to other elemental cycles, alterations in biomass production affect the cycling of soil nutrients-particularly macronutrients such as N and P that are frequently limiting. This agrees with the results of Nziguheba et al (1998); Yemefack et al (2002); Olabode et al (2007), who stated that T. diversifolia and C. odorata are high-quality organic sources with low to moderate carbon/nitrogen ratio, rich in soil nutrients (Liasu and Achakzai, 2007), while Atayese and Liasu (2001) reported T. diversifolia and C. odorata among the plants that improved the absorption of nutrients.…”

“…T. diversifolia and C. odorata are fast-growing weeds with the rapid conversion of biomass to organic matter (Ojeniye et. al., 2012) and in turn provide essential nutrients required for plant uptake and improved aggregate stability (Yemefack et. al., 2002).…”

“…These changes in particle size distribution explained the high bulk density. During fallow, clay particles tend to increase and aggregate stability while bulk density decreases (Yemefack et. al., 2002).…”

Does Sentinel-1A Backscatter Capture the Spatial Variability in Canopy Gaps of Tropical Agroforests? A Proof-of-Concept in Cocoa Landscapes in Cameroon

“…The vegetation cover is predominantly secondary forests, remnant primary forest areas, and agricultural lands. Farming practices are mostly extensive via shifting cultivation--slash and burn agriculture--and cocoa agroforestry expansion into forest areas [9,48]. The Efoulan locality, the headquarter of the district, is situated 32 km from Ebolowa and 43 km to Lolodolf (main towns) in the tropical humid forest zone.…”