Influence of Environmental Variables on Carbon Mineralization in Diverse Soil Management Systems Under Maize Cropping in Kwara State, Nigeria

Understanding the influence of agricultural soil management practices on soil processes and the environment is vital for sustainable food production. Therefore, this study evaluated the impact of soil temperature and moisture on soil organic carbon mineralisation under synthetic (NPK) and organic (biochar) amendments in a maize cropping system in Ilorin, Southern Guinea Savanna of Nigeria. The objectives were to determine the C mineralisation and C sequestering potential under each amendment and assess how precipitation amounts and soil temperature influence carbon mineralisation. Two soil types (Anthrodensic Ustorthent and Typic Ustorthent) were used, and four treatments (control, NPK, biochar+NPK, and biochar) replicated thrice were laid out in completely randomised design on each soil. Soil respiration was measured in-situ by the alkali absorption method. Data collected was subjected to analysis of variance procedure for complete randomized design to determine significant differences in treatment means, correlation and regression analyses were also carried out to test the relationships amongst experimental factors and variable responses. Results showed that evaluated nutrient management options did not significantly influence C mineralisation. C mineralisation, however, differed between soils, with Typic Ustorthent having higher organic carbon (OC), total CO2 emission (82.35 mg) and mean CO2 emission rates (1.18 mg m -2 d -1 ). Correlation analysis showed differing relationships between soil temperature and C mineralisation under the different treatments and soils, with significant positive correlation (r=0.44; p= ≤ 0.05) recorded only under sole biochar treatment in the Typic Ustorthent. Rainfall amounts had no significant correlation with C mineralisation.