Modeling carbon stock dynamics under fallow and cocoa agroforest systems in the shifting agricultural landscape of Central Cameroon uri icon

abstract

  • With increasing concerns raised by climate change, understanding biological processes within cocoa (Theobroma cacao L.) agroforest (CAF) and fallow systems is a prerequisite for developing actions related to emission reduction in the shifting agricultural landscape of Cameroon. Carbon (C) stocks and accretion were assessed and modeled in various C components (large trees, small trees, dead wood, litter, roots, soil, and total C) of fallow and CAF systems along a 50-year chronosequence. Several functions were empirically fitted to a time series of C stocks. Large tree, soil, and total C stocks were best described by a logistic growth function while that for small trees by a rational quadratic function. The best-fitted functions explained 72-96 % of C stock accumulation over time. Two metrics describing C stock accretion were derived from these functions: the point of maximum C growth and the C growth coefficient (GC). The rate of maximum growth of total C stock was reached after 12-13 years in both fallow and CAF, with maximum GCs of 6.9 and 6.3 Mg C ha(-1) year(-1), respectively. Over the 50-year period, the GCs of total C stocks varied between 0.2 and 6.9 Mg C ha(-1) year(-1), with quick accumulation within the first decade that then slowed until it levelled off after 45 years. Over a period of about 30 years, both systems sequestered a total of similar to 200 Mg C ha(-1). This indicates that cocoa agroforests, a main source of income for local populations, can also provide significant climate change mitigation services.

publication date

  • 2017
  • 2017