Nitrogen Fertilization Using Conventional and Slow-Release Fertilizers at Multiple Levels in Lolium multiflorum Lam. Pastures

Abstract

Pastures are essential for sustaining dairy production, particularly in temperate climates where year-round grazing is feasible. However, comprehensive analyses of their productivity, efficiency, and cost evaluation remain uncommon. This study evaluated the productivity, quality, nitrogen fertilization use efficiency, and production costs of Lolium multiflorum Lam pasture on a farm in São Miguel Island. The research compared conventional nitrogen fertilizer with slow-release nitrogen fertilizer at application rates of 320 and 160 kg N ha−1, alongside a control treatment. A Latin square design with five treatments was employed to assess both agronomic and economic performance. The results showed that the type of fertilizer did not significantly influence productivity or quality, while nitrogen levels had a notable impact. Higher nitrogen doses increased dry matter yield and crude protein content. Fiber characteristics remained relatively stable, though neutral detergent fiber and acid detergent fiber levels tended to rise with increased nitrogen application. Nitrogen fertilizer use efficiency consistently exceeded 70%, regardless of the fertilizer type or application rate. Regarding production costs, conventional fertilizer was significantly more cost-effective than slow-release fertilizer, underscoring the importance of selecting economically viable options without compromising agronomic performance in forage production.