Abstract:
Continuous cultivation of staple crops to feed a growing population in the semi-deciduous agro-ecological zone
of eastern Ghana (SDAG) has led to degraded soils and decreased crop yields. Biochar constitutes a potential
remedy as it is often reported to improve soil health and increase crop yield of infertile soils. We thus conducted
an experiment over two seasons to evaluate the impact of rice straw biochar on yield, radiation interception and
water productivity of maize grown in the SDAG. The biochar was incorporated into the soil at rates of 0, 15 and
30 t ha−1 under irrigated and non-irrigated conditions. Maize grain yield (GY), accumulated intercepted photosynthetic
active radiation (IPAR) and water productivity (WP) were compared among treatments. Regardless
of season, the highest GY, IPAR and WP were achieved in plots amended with 30 t ha−1 biochar. A biochar rate
of 30 t ha−1 increased grain yield by 17% and 36% and IPAR by 19% and 25% in 2017 and 2018 seasons,
respectively, compared to a no biochar control. For both seasons, maize GY for the 15 t ha−1 treatment was
statistically similar to that of 0 t ha−1 treatment whether irrigated or not. Irrigation increased grain yield by 9%
and IPAR by 3% in 2017 and with 30% and 17%, respectively, in the dryer 2018 season. The effects of biochar
and irrigation were additive. Water productivity from the 30 t ha−1 treatment was significantly higher in the
non-irrigated than in the irrigated plots. Overall, in the SDAG, a biochar soil amendment rate of 30 t ha−1 might
be a viable solution for farmers to increase yield and enhance water productivity of maize. Future studies should
focus on the effect of biochar on the soil and crops over a longer time span in order to recommend viable
management options to the farmers in SDAG.
