Soil properties, nutritional quality and yield of two maize varieties using different bio-chars as amendment on metal contaminated soil

The study assessed the yield of the two maize varieties and also determined the proximate composition of the maize grains and assessed the effects  of the Bio-chars on the physical and chemical properties of the soil. The field study was conducted within the vicinity of a metal recycling plant in Ile-Ife believed to have been contaminated with metal particulates and wastewater from the factory. Viable seeds of the two maize varieties (BR-9928-DMR-SR-Y and ART98/SW1) were obtained from the Institute of Agricultural Research and Training (IAR & T), Ibadan. The treatment were made up of the crop with: 100% maize stover (MS), 100% Milicia exelsa (ME), 50% MS + 50% AT, and each at the rate of ten tonnes per hectare as treatments. Zero Bio-char application served as control. The result indicate that the highest mean maize grain yield of 0.43 ± 0.28 t ha-1 with 100% maize stover Bio-char application was only significantly (p < 0.05) higher than 0.13 ± 0.08t ha-1 obtained from control plots. Lower values wereobtained with Br-9928-DMR-SR-R. Highest protein (9.94 ± 0.71%), crude fibre (2.60 ± 0.26%) and vitamin C (24.23 ± 2.26 mg kg-1) were obtained for the harvested ART 98 SW1 when compared with Br- 9928-DMR-SR-Y. Addition of Bio-chars soil enhanced the soil organic carbon, nitrogen, availablephosphorus and cation exchangeable capacity. The study concluded that the use of maize stover and M. exelsa Bio-chars at 10 t ha-1 as soil amendments enhanced the physiological performance, yields and proximate compositions of maize. It also enhanced the physical and chemical properties of the Bio-char amended metal contaminated soil. Keywords: Amendment, Bio-char, Contamination, soil properties, environment, maize, proximate composition, pollutio