The aim of this study was to evaluate the effects of application of two silicon sources via fertigation on nitrogen use efficiency and the production and crude protein contents of the forages BRS Zuri and BRS RB331 Ipyporã. Two experiments were carried out using both forages with treatments arranged in a 4 × 2 factorial design with four Si concentrations (0, 1, 2, and 4 mmol L⁻¹) and two sources of Si (stabilized sodium and potassium silicate, and potassium silicate) arranged in completely randomized blocks with four replications. Plants were grown in pots filled with dystrophic Red-Yellow Latosol samples with a content Si available of 5.1 mg dm⁻³. Two forage collections were carried out to evaluate silicon accumulation in shoots, number of tillers and leaves, leaf area, nitrogen use efficiency, shoot and accumulated dry matter, and nitrogen and crude protein contents. The correlation study showed that the increase in Si accumulation of the studied forages, promoted by the two sources of the element, correlated with the studied variables. The application of silicon via fertigation in the forages showed no interaction between concentrations and sources for the variables studied, but the effects of silicon do not depend on sources. The application of silicon via fertigation is an excellent choice for studied forages plants. This research proposes the application of Si via fertigation at a concentration of 2.7–2.8 mmol L⁻¹ as a new strategy to increase biomass production and protein content.

本研究的目的是评估通过灌溉施肥施用两种硅源对氮肥利用效率以及牧草 BRS Zuri 和 BRS RB331 Ipyporã 的产量和粗蛋白含量的影响。使用两种草料进行了两个实验，其中处理以 4 × 2 因子设计排列，具有四种 Si 浓度（0、1、2 和 4 mmol L ^-1）和两种 Si 来源（稳定的硅酸钠和硅酸钾，以及钾硅酸盐）排列在完全随机的块中，重复四次。植物在装有营养不良的红黄色 Latosol 样品的盆中生长，可利用的 Si 含量为 5.1 mg dm ^-3. 进行了两次草料收集，以评估芽中硅的积累、分蘖和叶子的数量、叶面积、氮利用效率、芽和累积干物质以及氮和粗蛋白含量。相关性研究表明，在两种元素来源的推动下，所研究牧草中 Si 积累的增加与所研究的变量相关。硅通过灌溉施肥在草料中的应用表明浓度和来源之间没有相互作用研究变量，但硅的影响不依赖于来源。通过灌溉施肥施用硅是研究草料植物的绝佳选择。本研究建议通过灌溉施肥以 2.7–2.8 mmol L ^-1的浓度施用 Si 作为增加生物质产量和蛋白质含量的新策略。