. In this context, the introduction of forage legumes in the pasture system is fundamental to fix nitrogen from the atmosphere and supply it to grasses, increasing its production and persistence, enhancing animal nutrition as it grazes, at the same time. Still, the use of plant mixes in the system brings further benefits to it, such as better utilization of fertilizers as well as enhances the nutrient cycle and soil coverage. However, there are still many gaps in our knowledge regarding intercropping legumes and grasses, especially the use of tropical legumes. The purpose of this review is compiles data about forage legumes as well as analyses them to find new tendencies and gaps on the knowledge to shed some lights on researches in this area. We also expect that this review will help researchers and producers to understand the role of forage legumes in a pasture system and that there will be an increase in its utilization worldwide, especially in the tropics, where nitrogen is easily leached and lost from the pastures. With emphasis on description of promising tropical legumes but still little used Arachis pintoi, Macrotyloma and Neonotonia whightii.

The present study aimed to assess the effects of combinations of doses of phosphorus and calcium on the yield characteristics of Macrotyloma axillare access NO 279 (family Fabaceae) in a Red-Yellow Argisol with average P level (24 mg dm-3). The experiment was carried out in greenhouse in Nova Odessa/SP, Brazil, from August to December 2015. A 52 fractional factorial design with 13 combinations for doses of phosphorus and calcium in mg dm-3: 0-0; 0-40; 0-80; 15-20; 15-60; 30-0; 30-40; 30-80; 45-20; 45-60; 60-0; 60-40; 60-80, in a randomized complete block design with four replications. Two cuttings were made on the plants. The phosphorus x calcium interaction and the isolated doses of calcium were not significant for the parameters assessed. The production of dry biomass of the aerial part, the leaf area, the number of leaves and the number of branches of Macrotyloma showed significant responses to the isolated doses of phosphorus applied in the primary growth. In the secondary growth, only the number of branches and the dry biomass production of the dead material responded to the doses of phosphorus. Phosphorus was a modulator of dry biomass production of roots and of the production of nodules and the number of nodules of macrotyloma. The content of calcium present in the soil, together with the increase of the value of base saturation to 50%, was sufficient for the establishment and growth of the legume. Therefore, a supplemental dose of this nutrient was not required.