Effect of Biochar Application on the Physico-chemical Properties of Ferralitic Soils, Yield and Growth Parameters in Maize Cultivation: A Case Study in Wassande, Adamawa, Cameroon

Abstract

Biochar is a carbon-rich product obtained from thermochemical conversion of biomass mostly used for soil enrichment. This study aimed to assess soils fertilizing potential of biochar under maize cultivation in Wassande. The physico-chemical properties of the soil and biochar revealed an acidic soil (pH = 5.6) characterized by an average cation exchange capacity (CEC = 11.68 cmol/kg), a moderate sum of exchangeable bases (SEB = 7.5 cmol/kg) and a good saturation rate (V = 64.45%). Furthermore, the analyzed biochar demonstrated a basic pH (9.5), a moderate CEC (29.5 cmol/kg), a low SEB (2.5 cmol/kg) and a high saturation rate (V = 86.20%). The soil incubation with biochar at 10, 20 and 30% improved the nutrient release rate into the soil and performed significant improvement at 20%. Accordingly, at this optimal concentration, the pH values changed from 5.6 to 9.1, 7.8, 9.4 and 8.4, respectively within 1, 2, 4 and 6 months of incubation time. Similarly, the CEC parameter was progressed from 11.68 to 49.88, 21.14, 31.72 and 44.84 cmol/kg within the same treatment period. Thus, the saturation rate values were moved from 64.45% to 56.31%, 74.54%, 32.00% and 61.50%, while the SEB values were changed from 7.53 to 17.33, 15.68, 10.03 and 26.95 cmol/kg at the same periods of incubation. The field tests were performed on three random complete blocks (112.5 m2) with five different treatments: the control (TST), the treatment with chemical fertilizers (TNPK), the treatment with 20% of biochar at sowing (TBS), at germination (TBL) and at flowering stage (TBF). The results revealed that the soil amended with biochar was more suitable for maize growth and yield, especially when the biochar was applied at germination step. For this treatment, after 8 weeks, the plants reached an average height of 138.61±2.44 cm, with an average of 10.47±0.39 leaves per plant. The plot treated at germination stage showed the best yield (9.64 kg), followed by the plot improved under chemical fertilizers (7.41 kg) while the control soil yield was 5.22 kg. Therefore, these findings demonstrated that biochar is an excellent soil quality regulator, improving soil fertility and could be a versatile alternative to the current use of chemical fertilizers in farming practices.