Pedology at Four Representative Sites of Southern Highland Zone of Tanzania

Abstract

To study the soils of Southern Highland Zone of Tanzania, four representative pedons of some landscapes were characterized. Their names and identifiers are Seatondale, Mbimba, Inyala, and Uyole, respectively TzSea 01, TzMb 02, TzIny 03, and TzUy04. The pedons were formed from the weathering of among other materials, colluvial igneous rocks, alluvium, eluvial soils, laterite, lacustrine sands and silts, andesite, pumice, aeolian deposits, and metamorphic rocks including coarse grained and strongly foliated biotite gneisses. Twenty soil samples were taken for laboratory characterization. In addition to classical horizon by horizon descriptions and laboratory analyses, 12 core samples were taken for soil-water retention characterization. The available water holding capacity was rated as very low to low. Pedon descriptions and particle size analysis showed clay eluviation-illuviation was the predominant pedogenic process in all pedons. Soil pH was rated slightly acidic to slightly alkaline. Available P ranged from 0.71 mg/kg at Mbimba to 10.67 mg/kg at Seatondale. Exchangeable bases were variable across and within the profiles; at Uyole and Inyala they were high, while at Seatondale and Mbimba they were low and medium. Values of exchangeable bases showed decreasing trends with profile depths in all sites. C/N ratios ranged between 6 and 18, total nitrogen was rated very low to low in both A and B horizons. CEC soil ranged between 17.2 and 36.4 cmol (+) /kg. Organic carbon ranged from very low to high. The soils apparently developed from extreme and moderate weathering of parent materials. According to the USDA Soil Taxonomy, the pedons classified as Fine, Illitic, Active,

Minjingu phosphate rock solubilization and potential for use of Klebsiella variicola-MdE4 and Klebsiella variicola-MdG1 as biofertilizer for maize production

“…Despite its abundance in soils, phosphorus availability to plants in most tropical soils, including agricultural soils of Tanzania, is limited mainly due to fixation by kaolinitic clays and sesquioxides (Msolla et al, 2005;Mtama, 2018).…”