Pedology of corn productivity indices for selected parts of Southern Highland Zone of Tanzania

Abstract

<p>Scientific investigations to determine land use planning and interpretations for corn productivity potential in the Southern Highland Zone of Tanzania were conducted. The assessment of soils corn growth potential has been conducted in four selected pedons namely; Uyole, Mbimba, Inyala and Seatondale. Pedological, physical, chemical characterization and an attempt to develop the pedotransfer functions were done. The results show that the soils have deep to very deep sola, subangular blocky structures, evidence of pedogenic clay movement, fine to coarse texture, bulk density ranged from 0.79 to 1.46 g/cm3, pH ranged from slightly acidic to slightly alkaline, cation exchange capacity ranged from 16.0 to 36.4 cmol (+)/kg, percent base saturation ranged from 20.3 to 121.6%, organic carbon from 0.13 to 1.52% and total N ranged from 0.01 to 0.11%. Extractable P ranged from 0.71 to 12.5mg/kg. Soil classes were Alfisols, Ultisols and Andisols according to USDA Taxonomic classification; and, Luvisols and Paeozems according to FAO world reference base soil classification system. The soils have shown low to medium fertility. Fertilizer application is required to supplement productivity. Three pedotransfer functions were developed for prediction of cation exchange capacity cmol (+)/kg, available water holding capacity (mm/m) and % soil organic carbon using the small data set available. The functions indicated good statistical power, a great potential of using large data set for precise prediction. Corn productivity indices were established through pedological characterization and soil classification that resulted in the following ratings: 72, 56, 62 and 48 for Uyole, Mbimba, Inyala and Seatondale respectively. Three pedons namely Uyole, Mbimba and Inyala showed good pedogenic potential for corn productivity. Whereas, Seatondale pedon indicated high pedogenic limitations for corn productivity.</p>