Pedological investigation and characterization in Kitanda village, Mbinga district, Tanzania
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Date
1997
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Publisher
Sokoine University of Agriculture
Abstract
A pedological investigation was carried out in Kitanda village, Mbinga district
(Tanzania) with the objectives of characterizing the soils in terms of their physical, chemical
and mineralogical composition, classifying the soils of the village and assessing the
potentials and constraints of the soils. Soil profiles representative of six mapping units
covering an area of 5563 hectares were studied and classified according to FAO-UNESCO
and USDA Soil Taxonomy systems.
Results indicate that most soils are red to dusky red, well drained, clayey, friable,
slightly sticky to sticky and plastic. Soils of the river valleys are brown to dark grey, poorly
drained, sandy clay loam to clay, slightly sticky and plastic. Soil pH ranges from slightly
acid (6.1) to very strongly acid (4.8). Organic carbon ranges from very low (0.1%) to very
high (5.5%). Cation exchange capacity (CEC) ranges from low (6 cmol(+)/kg) to medium
(24 cmol(+)/kg). Base saturation ranges from 28% to 67%. Soil clay fractions are dominated
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by kaolinite and oxides of aluminum
and iron. Most soil properties correlate well with
landform. Pedogenically the soils are old, highly weathered and have a high potential for
fixation of phosphorus. Soil micronutrient levels are optimal except for Zn in the moderately
dissected piedmonts.
Soils classify as Umbric Leptosols, Dystric Leptosols, Ferric Acrisols, Ferric Lixisols,
Rhodic Ferralsols and Dystric Fluvisols respectively for hill summits (H1), hill shoulders
(H2), strongly dissected slope facet complex (H3), strongly dissected piedmonts (P1),
moderately dissected piedmonts (P2) and river valleys (V).
The hilland has mostly shallow stony surface soils, steep slopes and high risk to
soil erosion hence unsuitable for mechanized agriculture, but suitable for afforestation,
development of catchment systems and tree crops. Piedmont soils are physically suitable
for most crops grown in the area but are low in base saturation, nitrogen, and
micronutrients especially zinc. The river valleys are poorly drained, low in base saturation.
nitrogen and phosphorus but high in micronutrients. Due to perennial water availability
these valleys are suitable for vegetable growing. Most of the studied soils have low to
medium water retention capacities.
It is recommended that fertilizer application in most soils includes nitrogen.
phosphorus, potassium and micronutrients due to their low supply in the soils. Rates for
phosphorus should consider P-fixation. For most soils timeliness of cultural practises like
tillage and planting will help avoid moisture stresses to crops. Soil management and
conservation practises like the local tie ridge (ngoro) and conventional ridge cultivation
systems are also recommended.
Description
Dissertation
Keywords
Soils, Land use, Soil classification