Forage legumes intercropped with grasses add nitrogen (N) to the production system and may increase forage yields. However, both phosphate fertilization and the solubility of phosphorus (P) sources may affect this contribution. This study aimed to evaluate the response of Guinea grass (Panicum maximum) intercropped with legumes and fertilized with phosphate fertilizers of different solubility. Guinea grass was grown as a single crop, fertilized or not with mineral N, and intercropped with Java (Macrotyloma axillare), or dwarf pigeon pea (Cajanus cajan); phosphorus was applied as triple superphosphate (P-TSP) or Bayóvar (P-Bay), plus a control without phosphorus. The highest forage yield and N accumulation was observed in Guinea grass fertilized with N and P, with 70,364 and 60,036 kg ha⁻¹of dry matter, resulting in 977 and 1004 kg ha⁻¹ of N accumulated by the plants for P-TSP and P-Bay, respectively. The introduction of legumes increased the N accumulation but decreased yield of Guinea grass. The highest nitrogen use efficiency (NUE) was found with P fertilization, i.e., 56% and 54% for P-TSP and P-Bay, respectively. The use of legumes intercropped with Guinea does not improve the effectiveness of the reactive rock phosphate. Therefore, the introduction of legumes intercropping with Guinea grass may be an alternative to N fertilization only when P is not applied to low fertile soils. Broadcast and incorporated P fertilization by the time of Guinea grass sowing, not only increases forage yields but also results in higher NUE regardless of P fertilizer solubility.

间作草的饲草豆科植物在生产系统中添加了氮（N），可能会增加饲草产量。但是，磷酸盐施肥和磷（P）源的溶解度都可能影响这一贡献。这项研究旨在评估几内亚种豆科作物并用不同溶解度的磷肥施肥的几内亚草（Panicum maximum）的响应。几内亚草种为单一作物，不施用或不施用矿物氮，并与爪哇（Macrotyloma axillare）或矮矮豌豆（Cajanus cajan）间作）; 磷以三重过磷酸盐（P-TSP）或Bayóvar（P-Bay）的形式添加，外加不含磷的对照。在施用了氮和磷的几内亚草中观察到最高的牧草产量和氮积累量，其中干物质为70,364和60,036 kg ha ^-1，结果为977和1004 kg ha ^-1分别由植物为P-TSP和P-Bay积累的氮。豆科植物的引入增加了几内亚草的氮积累但降低了产量。磷肥的氮利用率最高（NUE），即P-TSP和P-Bay分别为56％和54％。与几内亚间作的豆科植物的使用不能提高反应性磷矿的有效性。因此，仅当不将P施用到低肥沃的土壤上时，才能将与几内亚草种间作的豆科植物作为氮肥的替代选择。在几内亚草料播种时进行播种并掺入磷肥，不仅提高了牧草产量，而且无论磷肥的溶解度如何，其氮素利用率都较高。