Response of common bean (Phaseolus vulgaris L.) to nutrient amendments across variable agro-climatic conditions in Ghana

Abstract

Common bean (Phaseolus vulgaris L.) is an important crop with the potential to curb malnutrition in Sub-Saharan Africa (SSA). However, poor soil fertility is considered to be the major constraint for bean production in SSA. This study determines canopy spread, chlorophyll content, stomatal conductance, and seed yield of common beans in a field experiment conducted at Fumesua (rain-forest) and Akumadan (forest–savannah transition) agroecological zones. The study was conducted in the 2018 and 2019 cropping seasons using a split-plot arranged in a randomized complete block design with three replicates. The treatments consisted of the main plot factor namely varieties (Lv. “Semanhyia” and “Ennepa”) and the sub-plot factor P (75 kg ha−1), NPK (100 kg ha−1), ACARP organic fertilizer (4 t ha-1), ACARP plus NPK (2 t ha-1 + 50 kg ha-1), ACARP plus P (2 t ha-1 + 38 kg ha-1) and control (zero-amendments). Results showed that co-application of P, NPK, and ACARP fertilizer increased plant height and canopy spread by ≈9.54 and 11.25% compared with their sole application and the control, respectively. Similarly, the combined application of the organic and inorganic fertilizers increased chlorophyll content and stomatal conductance by 36.43 and 23.79% compared to their sole application and the control respectively. These observations translate into increased crop biomass and therefore seed  yield (≈ 42.54 - 46.58%). A significant variety and nutrient interaction were  observed in the number of pods per plant and seed yield, irrespective of the location. The results suggest that the growth and yield response of the crop may be optimized with the co-application of both P, and NPK with ACARP organic fertilizer. Key words: Crop productivity, fertilization, crop physiology, common beans.