Agronomic performance and silage quality of Massai grass fertilized with organic and inorganic nitrogen sources

Abstract In this study, we aimed to evaluate the effects of different nitrogen fertilization sources on the growth and biomass yield of Massai grass, as well as on the chemical composition of the resulting silage at harvest. A completely randomized design was used with three treatments and eight replicates: poultry litter (PL), cattle manure (CM), and urea. Productive and structural variables were analyzed, including canopy height, tiller population density (TPD), live leaf count (LLC), and total forage biomass. Chemical variables of the silage were also evaluated, including dry matter, moisture, mineral matter, organic matter, neutral detergent fiber (NDF), acid detergent fiber, crude protein (CP), ether extract, total carbohydrates, and nonfibrous carbohydrates. The type of nitrogen source significantly affected canopy structure (P < 0.05), with urea showing superior values for TPD and LLC. In terms of silage composition, significant differences (P < 0.05) were observed only for NDF and CP. The CM treatment exhibited the highest NDF (69.55%) and the lowest CP (5.90%) compared to those of the urea and PL treatments. Organic fertilization with PL or CM can enhance biomass production without compromising silage quality, and a nitrogen application rate of 300 kg N ha-1 yielded the best results for forage biomass.