Effect of Nutrient Sources and Their Interactions on Soil Oxidation-Reduction Reaction under Field Capacity and Waterlogged Conditions

Background and Objective: The two major sources of nutrients to soil are organic manure and inorganic fertilizers, these nutrient sources trigger various chemical reactions in the soil that have effects on soil fertility and plant nutrition. The oxidation-reduction reaction is also known as the redox reaction is one of the reactions affected. Materials and Methods: Consequently, the focus of this research is to evaluate the effect of fertilizers from inorganic and organic sources and their combinations on the redox potentials of soil. A factorial experiment (2×2×3) was set up on two texturally differentiated soils (clay loam and sandy clay loam), the treatments were arranged in a Randomized Complete Block design (RCBD) and replicated three times. The treatment combination involved two levels of NPK 15-15-15 (0 and 200 kg ha^–1), two watering regimes (field capacity and waterlogging) and three levels of poultry manure (0, 6 and 8 t ha^–1) a total of twelve treatments were obtained. Redox potential was measured using a redox potential meter while hydrogen potential (pH) was measured using a pH meter. Microsoft Excel 2010 edition was used to generate graphs. Results: Results from this study revealed that organic matter is a strong electron donor, soils containing organic materials became reduced moderately while coupled with waterlogging became highly reduced. Also, the pH of the soil was found to tend towards neutral under reduced conditions. Conclusion: It was concluded that the application of organic matter to soil can trigger a reduction process, this reduction process can also move soil pH towards neutral.