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The study was carried out at MATI Mubondo Farm located at Kasulu district in Kigoma
region, Tanzania to examine soil morphological, physico-chemical and biological
properties, as well as carrying out soil classification, suitability assessment (potential and
limitations) for maize and beans production, and nutrients recommendation. The
reconnaissance field survey of 800 ha was conducted at the study area in late December
2019 to mid-January 2020. Six sampling units were identified based on soil variation and
features such as color, slope, vegetation and agronomic practices. Six profiles namely
MBD-P1, MBD-P2, MBD-P3, MBD-P4, MBD-P5 and MBD-P6 were excavated, studied
and 20 soil samples were collected and analyzed. All profiles were very deep, highly
weathered, well drained and clayey. Color ranged from very dusky red to dark reddish
brown. Topsoil bulky density ranged from 1.20 to 1.47 gcm -3 . The surface soil pH ranged
from 4.59 (very strong acid) to 5.6 (moderately acid) and subsoils pH ranged from 4.0
(extremely acid) to 5.45 (strongly acid). Topsoil OC ranged from 1.56 (medium) to 6.47
(high) and subsoil ranged from 0.35 (low) to 2.81 (medium) for subsoils. TN ranged from
0.13 (medium) to 0.31 (high) percent for topsoil and 0.04 (low) to 0.15 (medium) percent
for the subsoil. Available P for all the profile was rated low (0.67-7.19 mg kg -1 ) in topsoils
and 0.34-8 mg kg -1 in subsoils. CEC (cmol(+) kg -1 ) for the topsoils were 13 (medium) to 36
(high) and 5.2 (very low) to 22 (medium) for subsoils. BS of the top soil range from 10
(low) to 34 (medium) and subsoil range from 7.67 (low) to 41 (medium). Using the USDA
Soil Taxonomy, soils were classified as Typic Haplustox (MBDP1), Kanhaplic Rhondustalfs
(MBDP2), Typic Kandiustox (MBDP3 and MBDP4), Typic Ustorthents (MBDP5) and
Rhodic Kandiustox (MBDP6) and corresponding to Rhodic umbric Ferralsols (Clayic,
Dystric) (MBDP1), Umbric Ferralsols (Clayic, Dystric) (MBDP2), Rhodic Umbric Ferralsols
(Clayic, Dystric) (MBDP3), Rhodic Umbric Ferralsols (Clayic, Dystric (MBDP4), Rhodiciii
Cambic Ferralsols (Clayic Dystric) (MBDP5) and Umbric Ferralsols (Clayic, Dystric)
(MBDP6) in WRB. The quality of soils was rated marginally suitable (s2) and moderately
suitable (s1) for both crops due to the identified limitations. The most limiting factors for
the crop production being low pH, available phosphorus, total nitrogen and base saturation.
The low pH of the soil might have attributed to the deterioration of other soil chemical
properties in the farm. The study also generated the suitability map by kriging method
where by top soil macronutrients, CEC, pH and % BS were used in geographic information
system (GIS) environment. Nutrient recommendations were done for each soil unit by
referring the soil test results. The buildup and maintenance approaches for nutrient
recommendations were proposed. Soils were dominated by kaolinitic clay and sesquioxides
and had low inherent fertility. Routine soil analysis, nutrient amendments, suitability of
soils in quantitative terms and determination of nutrients available in grains and cobs of
maize were recommended. |
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