Pedological investigation and characterization in Litembo village, Mbinga district, Tanzania
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Date
1997
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Sokoine University of Agriculture
Abstract
A pedological investigation was carried out in Litembo village, Mbinga district
(Tanzania) to identify the various soil types and characterize them in terms of their
physical, chemical and mineralogical properties. The soils were classified according
to FAO-Unesco and USDA Soil Taxonomy systems. On the basis of soil and other
ecological parameters the potentials and constraints of the land resources were
assessed.
Standard soil survey methods and laboratory procedures were utilised to
generate both field and laboratory data.
Results indicate that Litembo village has four major landforms i.e. plateaux,
hills, piedmonts and valleys Most piedmont soils are deep to very deep having dark
brown to dark reddish brown sandy clay topsoils and dark red to red clayey subsoils.
The hills and plateaux have shallow sandy clay loam soils. All the studied soils are
well drained to excessively well drained except those of the valley bottoms which are
poorly drained.
Topsoil bulk densities range from 0.99 to 1.2 Mg m'3 whereas subsoil values
are slightly higher. Total porosity ranges from 56 to 72% in the topsoils and from 40
to 53% in the subsoils. Topsoils have lower penetrometer resistance (PR values 0.1
to 0.28 MPa) than subsoil (PR values 3.97 - 5.52 MPa). Available water capacity
(AWC) of most topsoils ranges from 15 to 25% by volume and the values decrease
slightly with depth. AWC per meter range from 125 to 177 mm which is medium to
high.
General soil fertility status is poor. Soil reaction is very strongly acid to strong
acid with pH values between 4.4 and 5.4 in topsoils and 4.4 and 6.0 in subsoils. Total
nitrogen ranges from very low to medium (< 0.03 - 0.3); phosphorus, bases, CEC
and base saturation are low. OC ranges from low to very high in topsoils and very
low in subsoils. The clay mineralogy is dominantly kaolinitic with accessory amounts
of gibbsite and goethite. The piedmont soils classified as Ferric Acrisols, Haplic
Acrisols and Humic Acrisols, plateau soils classified as Humic Acrisols; soils of the
as Dystnc Leptosols and Haplic Acrisols and valley bottom soils as Umbric Fluvisols.
From the results of this study it is concluded that Litembo soils developed
under intensive leaching environment, facilitated by a mountainous/hilly topography.
Fertility status is poor, and due to steep slopes and weak soil structure Litembo soils
are prone to erosion. The traditional farming system (ngoro) seems to control soil
erosion on steep slopes. It is recommended that steep slopes should be planted with
trees that will protect soil from erosion. Use of the traditional farming system (ngoro)
should be encouraged. Due to low soil fertility status, use of fertilizers both artificial
and organic manures is recommended Non-acidifying fertilizers should be preferable
because of the low soil pH values. The study area lacks climatic data. More research
in this line is recommended. Research on different land use alternatives which can
sustainably be applicable in the village should be carried out.
Description
Dissertation
Keywords
Soil formation, Soil survey, Soil morphology, Pedogenesis