Abstract:
Soil fertility is an important factor in enhancing crop productivity. The study is aimed at
assessing the soil fertility status in selected rice growing areas in Kilombero district and
understand fertility variability among soils selected. Composite soil samples were collected in
these rice growing areas at 0–20 cm deep and characterized for soil fertility status. This was done
by analyzing twenty soil samples from rice growing villages of Kilombero district, whereby 20
soil samples were taken from 20 rice growing villages. The soil analysis included determination
of total N, OC, P, soil pH, textural classes, exchangeable bases and micronutrients (ZN, Cu, Mn
and Fe). The results showed that the soils surveyed are slightly to moderately acidic (pH 5.2 to
6.2). Results indicated that 80% of the soils were sand, 15% clay and the remaining 5% had
loamy textural classes. Organic carbon ranged from very low to medium (0.40-2.53%), total N
(0.11-0.32%). Also, results indicated that 50% of soils had P deficiency and 100% had
inadequate S levels. In addition, 90% of the soils had inadequate exchangeable K and
exchangeable Mg levels ranged from very low to medium (0.10-2.24 cmol(+) kg-1 ). Soils
indicate to had 95% very low Exchangeable Ca with low base saturation. The CEC ranged from
low to medium (7.0-21.60 cmol(+) kg-1). Extractable micronutrients such as Fe and Mn were
adequate but Zn and Cu were inadequate in 35% and 10% of the soils, respectively. Results
indicated that N, P, K, Ca and Zn were generally the limiting nutrients of which S and Na were
limiting in all selected soil. Generally, the categorization of nutrient status indicated poor fertility
in the studied soils. The results of the study area show deficient levels, however, there were
variations in nutrient deficiencies in selected soils. |
