Pedological Characterization and Assessment of Agricultural Potential of Soils Developed from Volcanic Parent Materials in Three Districts of Mbeya Region, Tanzania | Chapter 01 | New Perspectives in International Plant and Soil Research Vol. 1
This study clarifies the morphology,
genesis, physico-chemical properties and classification of soils developed from
volcanic parent materials of Mbeya Region, Tanzania. Six typical pedons (MWK
01, IFIG 02, MKY 03, MWZ 04, KYE 01 and NDE 01), were identified, described and
33 soil samples analyzed for physical and chemical characteristics. Results
indicate that all pedons were very deep, with textures ranging between fine and
coarse. Soil moisture retention ranged between low and medium (78 - 101 mm/m).
Some pedons had volcanic ash layers of varying thicknesses and buried 2BC, 2Bwb
or 3Bwb horizons, typical of recent volcanic soils. Topsoils had low bulk and
particle densities ranging between 0.70 to 1.26 g cm-3 and 1.95 to 2.55 g cm-3,
respectively. Organic carbon (OC) content ranged from medium to very high (1.29
to 5.58%). The studied pedons had extremely acidic to very slightly acidic pH
ranging from 4.02 to 6.58. Cation exchange capacity (CEC) ranged from medium to
very high (16.8 - 41 cmol(+) kg-1 soil for topsoils and 21 - 42.6 cmol(+) kg-1
for subsoils). All studied pedons had pHNaF > 9.5, reflecting an exchange
complex dominated by amorphous Fe and Al oxides and/or humus complexes.
Phosphate retention capacity (PRC) ranged from 25 to 97% and one pedon (MWZ 04)
met the andic properties requirement of PRC ≥ 85%. SiO2, Al2O3 and Fe2O3 ranged
from 46.5 to 62.1%, 26.3 to 38.4% and 4.0 to 9.8%, respectively. On the basis
of computed Chemical Index of Alteration (CIA), the degree of weathering of the
studied pedons followed the trend NDE 01>MKY 03>MKW 01>KYE 01>IFIG
02>MWZ 04. According to USDA Soil Taxonomy, the studied pedons were
classified as Alfisols (pedons MKW 01, MKY 03 and NDE 01), Inceptisol (pedon
IFIG 02), Andisol (pedon MWZ 04) and Entisol (Pedon KYE 01), respectively
correlating to Alisols, Cambisol, Andosol and Umbrisol of WRB for Soil
Resources. The studied soils were generally rated as having low to medium
fertility. All the studied sites except Tenende plain (KYE 01) were rated as
moderately suitable for production of maize, beans, wheat and potatoes.
Moreover, Tenende plain was rated as moderately suitable for paddy rice and
marginally suitable for the other crops.
Author(s) Details
Prof. Balthazar M. Msanya
Department of Soil and
Geological Sciences, College of Agriculture, Sokoine University of Agriculture,
P.O.Box 3105, Morogoro, Tanzania.
Mr. Juvenal A. Munishi
Kondoa District Council,
P.O. Box 1, Kondoa, Tanzania.
Assoc. Prof. Ernest Semu
Department of Soil and
Geological Sciences, College of Agriculture, Sokoine University of Agriculture,
P.O.Box 3105, Morogoro, Tanzania.
Dr. Zacharia J. Malley
Sustainable Agriculture
& Natural Resources Management Africa (SANREM AFRICA), P.O. Box 2280,
Mbeya, Tanzania.
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