Effect of okoro [(Albizia zygia (J.F.) Macbr)] leafy biomass and NPK fertiliser on the growth and yield of sweet pepper (Capsicum annum L.)

Abstract

Agricultural productivity and sustainable crop management are pivotal aspects of global food security and economic stability. The quest for efficient and environmentally friendly practices in crop production has led to a surge in research exploring the utilisation of organic materials alongside conventional fertilisers to enhance crop growth and yield. An experiment was conducted over a growing period of three months, starting in August 2023 at the research field of Kwame Nkrumah University of Science and Technology, Kumasi-Ghana, to investigate the effects of Albizia zygia leafy biomass in combination with NPK fertiliser on the growth and yield of sweet pepper (Capsicum annum L.). A randomised complete block design was employed with four treatment groups replicated four times, including various combinations of A. zygia leafy biomass and NPK fertiliser, alongside control groups of sole fertiliser application and untreated plots (T1). The treatments were as follows: T1 = No biomass, no NPK (control); T2 = 0.5348 kg of A. zygia leafy biomass per 4.86 m2 (1100.5 kg/ha of A. zygia leafy biomass); T3 = 0.2463 kg of NPK per 4.86 m2 (506.7 kg/ha of NPK); and T4 = 0.2674 kg of A. zygia leafy biomass per 4.86 m2 + 0.1231 kg of NPK (550.3 kg/ha of A. zygia leafy biomass + 253.4 kg/ha of NPK). The assessed parameters were plant height, number of leaves, number of branches, fruit yield and fresh fruit weight. Significant variations (p ˂ 0.05) were observed in the growth parameters (plant height, number of leaves, number of branches) and yield attributes (fruit yield and fresh fruit weight) of sweet pepper among the treatments. The combined application of A. zygia leafy biomass and NPK fertiliser (T4) exhibited increased effects on plant height, number of leaves, number of branches, fruit yield and fresh fruit weight compared to individual treatments and control groups (p ˂ 0.05). Notably, the treatment combining A. zygia leafy biomass and NPK fertiliser (T4) demonstrated a substantial increase in plant height (44.58 cm), a significant improvement in the number of leaves (42.98) and a remarkable enhancement in the number of branches (11.33) compared to the sole applications and the control group. Furthermore, the combined treatment significantly increased (p ˂ 0.05) the yield parameters, including fruit yield and fresh fruit weight per hectare, showcasing an increase of 8796/ha and 23.91 t/ha, respectively, compared to sole fertiliser application and the control. The findings from this study demonstrated that the incorporation of A. zygia leafy biomass, either solely or in combination with NPK fertiliser, positively impacted the growth and yield of sweet pepper plants. These results highlight the potential of A. zygia leafy biomass as a valuable organic amendment for sustainable and enhanced crop production, offering promising implications for agricultural practices aimed at improving yield and plant growth.