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Título:
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Nitrogen yield advantage from grass–legume mixtures is robust over a wide range of legume proportions and environmental conditions
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Autor/a:
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Suter, Matthias; Connolly, John; Finn, John A.; Loges, Ralf; Kirwan, Laura; Sebastià, Ma. T.; Lüscher, Andreas
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Notas:
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Current challenges to global food security require sustainable intensification of agriculture through initiatives that include more efficient use of nitrogen (N), increased protein self-sufficiency through homegrown crops, and reduced N losses to the environment. Such challenges were addressed in a continental-scale field experiment conducted over 3 years, in which the amount of total nitrogen yield (Ntot) and the gain of N yield in mixtures as compared to grass monocultures (Ngainmix) was quantified from four-species grass–legume stands with greatly varying legume proportions. Stands consisted of monocultures and mixtures of two N2-fixing legumes and two nonfixing grasses. The amount of Ntot of mixtures was significantly greater (P ≤ 0.05) than that of grass monocultures at the majority of evaluated sites in all 3 years. Ntot and thus Ngainmix increased with increasing legume proportion up to one-third of legumes. With higher legume percentages, Ntot and Ngainmix did not continue to increase. Thus, across sites and years, mixtures with one-third proportion of legumes attained ~95% of the maximum Ntot acquired by any stand and had 57% higher Ntot than grass monocultures. Realized legume proportion in stands and the relative N gain in mixture (Ngainmix/Ntot in mixture) were most severely impaired by minimum site temperature (R = 0.70, P = 0.003 for legume proportion; R = 0.64, P = 0.010 for Ngainmix/Ntot in mixture). Nevertheless, the relative N gain in mixture was not correlated to site productivity (P = 0.500), suggesting that, within climatic restrictions, balanced grass–legume mixtures can benefit from comparable relative gains in N yield across largely differing productivity levels. We conclude that the use of grass–legume mixtures can substantially contribute to resource-efficient agricultural grassland systems over a wide range of productivity levels, implying important savings in N fertilizers and thus greenhouse gas emissions and a considerable potential for climate change mitigation.
Coordination of this project was supported by the EU Commission through COST Action 852 ‘Quality legume-based forage systems for contrasting environments’. A contribution to the research leading to these results has been conducted as part of the AnimalChange project which received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under the grant agreement no. 266018. |
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Materia(s):
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-Climate change mitigation
-Climatic gradient
-Food security
-N fertilizer replacement |
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Derechos:
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(c) John Wiley & Sons, 2015
info:eu-repo/semantics/restrictedAccess |
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Tipo de documento:
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article
publishedVersion |
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Editor:
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Wiley
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