Vertisols Pedological Characterization: Soil Morphology, Properties, Classification and Fertility Levels

A detailed pedological characterization of vertisols was carried out from in Itigi district central Tanzania from 2022 to 2023 to adequately attain data relevant for agricultural planning and executing soil fertility studies across the district. Six sites were selected, named as IPD-P1, DML-P1, ITIG-P1, KTR-P1, SJR-P1 and TKR-P1 and considered as benchmark sites of existing vertisols in the district with reference to existing soil information and a prior conducted reconnaissance soil survey. Four samples from each site making a total of 24 samples were collected and analyzed with standard laboratory procedures for understanding their chemical and physical properties. The soil profiles were adequately very deep dominated by clayey. The pH level in all soils were between slightly acidic (< 6.4) to moderate alkaline (> 8.2). Available P, K and Zn were generally low (> 2.1 cmol(+) /kg, >17.4 cmol(+) /kg, 0.79 cmol(+) /kg respectively) in all study profiles.  Levels of Exchangeable bases in all study profile were adequately available in which Ca dominated over others (<15 cmol(+)/kg. With the use of USDA soil taxonomy, profiles were classified as IPD-P1 (vertic chromic gypsitorrests) DML-P1 (vertic chromic calcitorrests) ITG-P1 (vertic chromic gypsitorrests) KTR-P1 (vertic chromic calcitorrests) SJR-P1 (vertic chromic gypsitorrests) and TKR (vertic chromic gypsitorrests). The six studied profiles had slight variations among them and within their horizons in terms of physical and chemical properties, and therefore this enhances the need of carrying soil characterization for effective fertilization recommendations.