Carbon Sequestration Potential of Agroforestry Systems in the West African Sahel.
Asako Takimoto, Univ. of Florida, 118 Newins-Ziegler, PO Box 110410, SFRC, IFAS, Gainesville, FL 32611-0410, Ramachandran P. Nair, Univ. Of Florida-118 Newins-Ziegler, Gainesville, FL 32611-0410, and Vimala Nair, Univ of Florida, Gainesville, FL 32611-0510.
In recent years, carbon (C) sequestration potential of agroforestry systems has attracted attention from both industrialized and developing countries, especially following Kyoto Protocol’s recognition of agroforestry as an option for mitigating green house gasses. However, very little information is available on the C sequestration potential of agroforestry systems in the semiarid and arid regions of West Africa. In addition to the already existing indigenous agroforestry systems such as the parkland system, improved practices and technologies are now being expanded into these dry regions for perceived benefits such as arresting desertification, reducing water and wind erosion hazards, and improving biodiversity. We hypothesize that the tree-based systems will retain more stable C in lower profiles of soil because of the deep roots of trees. Carbon stock in biomass and soil will be compared in the traditional parkland systems involving Faidherbia albida and Vitelleria paradoxa trees, and two improved agroforestry practices (fodder banks and boundary planting) in the Segou region of Mali (from 13o 20’ to 13o 25’ N and 6o 10’ to 6o 25’ W). The soil is sampled to a meter depth (0-10, 10-40, and 40-100 cm). The total soil C contents up to 1 m depth in the systems varied from 26.0 to 56.2 Mg ha-1. Soil samples are fractionated (wet sieving) into three particle size classes (250-2000, 53-250 and <53 µm); C content in each fraction is determined by isotopic analysis (12C to 13C ratio) estimations. The data are being analyzed to determine the source of C (C3 vs C4 plants, based on the isotopic ratio) in different fractions of soils at a given depth, and to assess the effect of improved agroforestry practices on C sequestration by different size fractions of soils at different depths.