Balancing Biomass Yield and Nutritional Quality of Brachiaria ruziziensis through NPK (20:10:10) Fertilization in Cameroon’s Humid Tropics

Abstract

The rising global demand for livestock products underscores the need to enhance forage quality and yield, particularly within tropical farming systems. This study evaluated the impact of five application rates of NPK 20:10:10 fertilizer (0, 150, 200, 300, and 400 kg/ha) on the growth performance, nutrient composition, and biomass yield of Brachiaria ruziziensis in Buea, Cameroon. A completely randomized block design (CRBD) was employed with four replications per treatment, maintaining a uniform plant density of 80,000 plants/ha across all plots. Data were collected over three harvest periods, assessing fresh and dry biomass as well as nutrient parameters. A non-destructive linear regression model was developed to estimate actual leaf area (Y = 1.403X + 1.14). Fertilizer application significantly improved plant height, leaf number, tiller count, and stem diameter compared to the control (P ≤ 0.01). The treatment (400 kg/ha) had the highest plant height (86.8 cm), leaf number (463), tiller count (83), and dry biomass (34.7 tons/ha). Fertilizer treatments also significantly influenced nutrient concentrations of nitrogen, phosphorus, potassium, calcium, and magnesium (P = 0.05). Notably, the 300 kg/ha treatment optimized forage quality, producing the highest crude fibre (13.7%), crude protein (12.9%), nitrogen (2.2%), and phosphorus (2964.5 mg/kg) concentration and this was not significantly different from the treatment 400 kg/ha. The 400 kg/ha treatment recorded the highest potassium (2703 mg/kg), calcium (117.5 mg/kg) and ash content (8.6%). In conclusion, the 300 kg/ha gave the optimum biomass yield, the best balance between yield and nutritional quality. This rate is recommended for Brachiaria production and thereby enhancing sustainable livestock production in tropical humid regions such as Buea, Cameroon.