Assessing the Macronutrient Status of Some Selected Soils in Bayelsa State, South-South Nigeria

Abstract

Fertility status of soils within the south-south region of Nigeria varies both inter and intra states. Therefore, the study investigated the macronutrient status of some selected soils in Bayelsa State. Two farm sites in Opume (OPF) and Amassoma (AMF) with records of long term cultivation were randomly selected and soil samples randomly collected from each locality for physico-chemical analyses. Data collected were subjected to statistical analysis of means and a post hoc regression analysis to determine relationships between soils and analyzed parameters. Results revealed that soils were loam to sandy clay loam and acidic with low pH levels. Exchangeable bases (Ca²⁺, Mg²⁺, K⁺) were low in AMF soils compared to OPF soils except for Na⁺. Organic carbon and organic matter were moderately low in both soils, however, AMF had lower contents. Total N were found to be critically low (0.03%) in both soils. OPF had higher available phosphorus (5.09 mg/kg) while AMF had higher available sulphur (6.55 mg/kg). Base saturation was high moderate in OPF (50.44 %), however, not significantly different (p<0.05) from AMF. Similarly, Effective Cation Exchange Capacity (ECEC) was low in soils of both localities. Regression analysis showed that pH had significant positive relationships with sand, Org C, Org M, available P, TN, % B.S and the basic cations (r=0.534*, 0.841***, 0.837***, 0.855***, 0.736***, 0.856**) with a negative relationship with Exchangeable acidity and SO₄^2- (r=-0.799** and 0.844***). Org C, Org M and TN had significant negative relationships with silt at both localities (r=-0.592**, -0.592** and -0.491*) respectively. These results indicate clearly that the nutrient status of soils in the study areas are mostly controlled by pH and the textural distribution. It also indicates that improved soil management practices can improve the macronutrient status for increased crop production.