NUTRIENT STATUS AND MANAGEMENT OF SOME HYDROMORPHIC SOILS IN RIVERS STATE, NIGERIA FOR SUSTAINABLE CROP PRODUCTION

Nutrient status of some hydromorphic soils in Rivers State were studied for their potentials and probable constraints to crop production. A total of one hundred and twenty surface (0-15 cm) and sub-surface (15-30 cm depth) soil samples obtained from ten locations were subjected to routine laboratory and statistical analysis using standard methods. Random sampling technique was employed in the collection of soil samples. Results revealed that the sand component of the soils which ranged from 117 g/kg to 891 g/kg decreased with increased soil depth. The clay and silt fractions ranged from 24 g/kg to 231 g/kg and 28 g/kg to 701 g/kg respectively. The highest sand content was obtained at 0 – 15 cm topsoil. The results showed that nutrient status of some of the soils were low as revealed by their estimated levels of availability. The soils were acidic in reaction. Mean pH values were 4.2 in the surface soils and 3.7 in the subsurface soils. Total nitrogen, calcium, sodium and electrical conductivity were all less than the critical levels in soils but moderate to high in organic matter, available phosphorus, exchangeable potassium, base saturation and micronutrient (Fe and Mn). The main constraints of these soils to sustainable crop production were therefore, the low chemical fertility (high acidity, low exchangeable Calcium and Nitrogen concentrations). However, short season crops (vegetables) can be grown at subsistence level. Ordinarily, fertilizer and lime could be recommended as measures to increase yield of crops, but these inputs are both unaffordable and unavailable at critical periods. Therefore, the farmers are encouraged to harness cheap resources found on the farms such as mulch and bio-fertilizers, to improve soil nutrient status rather than rely on inputs that are normally not accessible.