Potential food production from forage legume-based-systems in Europe: an overview

peer-reviewedIntensification of EU livestock farming systems has been accompanied by the development of maize silage and intensively fertilised grasses at the expense of forage legume crops. However in the new context of agriculture, the development of forage legumes constitutes one of the pillars for future livestock farming systems with high environmental and economical performances. Yield benefits of grass-clover mixtures are equivalent fertiliser N inputs of 150 to 350 kg/ha, and productive grass-clover mixtures can fix 100 to 380 kg N per hectare symbiotically from the atmosphere. Animal intake of legumes is high and the rate of decline of legume nutritional quality with advancing maturity is less than for grasses, especially in the case of white clover, which makes mixed pastures easier to manage. Animal performances at grazing are identical or higher on clover-enriched pastures. Due to their high protein concentration, conserved forage legumes fit well with maize silage. Forage legumes increase the concentration of beneficial α-linolenic acid in ruminant products. Environmental balance of forage legumes is positive. Increasing the proportion of white clover at the expense of mineral N fertilisation can reduce the risk of nitrate leaching. Because forage legumes only require solar energy to fix N from the air, they also reduce energy consumption and associated impacts. They contribute to reduce the global warming potential of livestock systems by reducing emission of enteric methane and nitrous oxide from pasture and crop production. As an element of arable crop rotations, grass-clover leys suppress pests, diseases and weeds, improve soil structure and prevent soil erosion and nitrate leaching. Nevertheless, forage legumes have some limitations: expensive to harvest, difficulties of conservation, management of the associations. To take full advantage of forage legumes in the future, new research and development are required as well as financial support from the EU

Potential of legume-based grassland - livestock systems in Europe: a review

European grassland-based livestock production systems face the challenge of producing more meat and milk to meet increasing world demands and to achieve this using fewer resources. Legumes offer great potential for achieving these objectives. They have numerous features that can act together at different stages in the soil-plant-animal-atmosphere system, and these are most effective in mixed swards with a legume proportion of 30-50%. The resulting benefits include reduced dependence on fossil energy and industrial N-fertilizer, lower quantities of harmful emissions to the environment (greenhouse gases and nitrate), lower production costs, higher productivity and increased protein self-sufficiency. Some legume species offer opportunities for improving animal health with less medication, due to the presence of bioactive secondary metabolites. In addition, legumes may offer an adaptation option to rising atmospheric CO2 concentrations and climate change. Legumes generate these benefits at the level of the managed land-area unit and also at the level of the final product unit. However, legumes suffer from some limitations, and suggestions are made for future research to exploit more fully the opportunities that legumes can offer. In conclusion, the development of legume-based grassland-livestock systems undoubtedly constitutes one of the pillars for more sustainable and competitive ruminant production systems, and it can be expected that forage legumes will become more important in the future