Soil organic carbon stocks in the dominant soils of the Miombo woodland ecosystem of Kitonga Forest Reserve, Iringa, Tanzania

Abstract

Few studies have determined the soil organic carbon (SOC) stocks in the Miombo woodlands ecosystem in Tanzania. Standard field and laboratory procedures were used to evaluate SOC storage in the Miombo woodlands ecosystem of Kitonga Forest Reserve Iringa, Tanzania. A study area of 52 km 2 was selected and ten soil profiles were studied. Representative sampling points were geo-referenced and soil samples collected from natural horizons to the depth of 60 cm. Results show that the total soil organic carbon stocks in soil profiles varied from 19.4 to 28.9 Mg C ha-1 in leptosols; from 45.6 to 80.1 Mg C ha-1 in fluvisols; and from 33.9 to 134.6 Mg C ha-1 in cambisols. The SOC increased significantly (p< 0.05) with increasing elevation, horizon thickness and % clay, but it decreased significantly (p< 0.05) with increasing slope gradient and increasing % sand. The areal distribution of the soil types was 61%, for cambisols, 19% for leptosols, 11% for fluvisols and 9% for natural forest which was not surveyed because of inaccessibility. Proper management of Miombo woodlands would increase the SOC storage and contribute to climate change regulation.