Beef cattle producers seldom use fertilizers for their pastures in tropical regions of Brazil. Slowly, this is changing but because of the need for repeated applications, N fertilizer is rarely applied. The introduction of a forage legume is an appropriate solution for this problem, but until recently adoption has been very low as the legumes generally have not persisted in the sward. We report research on how grazing management can affect the persistence of stoloniferous legumes in pastures of Brachiaria spp. and the problems of establishing and maintaining crown‐forming legumes such as Stylosanthes spp. With suitable management, milk or bovine carcass yields can be equal or greater from mixed than from grass‐alone pastures fertilized with 120 or 150 kg Nha^‐1 year⁻¹. In addition to savings in CO₂ emissions from fossil fuels for the production and distribution of N fertilizers, nitrous oxide emissions from cattle excreta and legume residues are lower than those from N‐fertilized brachiaria grass monocultures. Other studies indicate that enteric methane emissions from cattle may be mitigated when forage legumes are included in their diet. The use of forage legumes in mixed pastures for tropical regions is emerging as a feasible strategy to keep meat and milk production at acceptable levels with reduced greenhouse gas emission rates.

中文翻译：

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巴西热带草牧场的豆类牧草及其对温室气体排放的可能影响：综述

肉牛生产者很少在巴西热带地区的牧场中使用化肥。慢慢地，这种情况正在改变，但是由于需要重复施用，因此很少施用氮肥。引入饲用豆科植物是解决该问题的合适方法，但是直到最近，由于豆科植物通常还没有坚持食用，因此采用率一直很低。我们报告了关于放牧管理如何影响腕带属植物牧场中豆科植物的持久性的研究。以及建立和维持冠状豆科植物（如Stylosanthes spp）的问题。通过适当的管理，混合后的牛奶或牛car体的产量可以等于或大于用120或150 kg Nha ^-1施肥的草场的产量 年^-1。除了节省用于生产和分配氮肥的化石燃料产生的CO ₂排放量外，牛粪和豆类残留物中的一氧化二氮排放量也低于氮肥的臂章草单一栽培中的一氧化二氮排放量。其他研究表明，如果在饲料中添加豆类饲料，则可以减少牛的肠内甲烷排放。在热带地区的混合牧场中使用草料豆科植物已成为一种可行的策略，可以将肉类和奶类生产保持在可接受的水平，同时减少温室气体的排放。