Comparative Effects of Maize Cob Biochar and Inorganic Fertilizer on Soil Properties and Maize Productivity

Abstract

Declining soil fertility is a major constraint to sustainable crop production in sub-Saharan Africa, and sole reliance on inorganic fertilizers raises concerns about long-term soil health. This study evaluated the effects of maize cob biochar and NPK fertilizer, applied individually and in combination, on soil properties, growth, and yield of maize ( Zea mays L.) in Akure, Nigeria. The experiment was conducted using a randomized complete block design with three replicates. Treatments included control, biochar (1.5 and 3.0 t/ha), NPK fertilizer (100 and 200 kg/ha), and a combined application of 1.5 t/ha biochar with 100 kg/ha fertilizer. Growth parameters measured included plant height, leaf area index, internode length, and stem girth, while yield indices and post-harvest soil chemical properties were also assessed. Results showed that all treatments significantly improved maize performance compared to the control. Biochar alone produced the highest growth values and yield components, including cob weight (375.12 g), number of seeds per cob (707.80), and seed weight per cob (203.53 g), compared to the control (161.50 g, 104.73, and 37.49 g, respectively). The combined treatment also recorded high values (313.52 g, 670.50, and 169.94 g). Biochar improved soil properties, increasing organic carbon (0.89%) and organic matter (1.52%) relative to the control (0.69% and 0.19%), while fertilizer enhanced available phosphorus (5.39 cmol/kg). The study concludes that integrating maize cob biochar with inorganic fertilizer is an effective and sustainable strategy for improving soil fertility and maize productivity.