Evaluating the Potential of Legumes to Mitigate N 2 O Emissions From Permanent Grassland Using Process‐Based Models
Year: 2020
Type: article
Abstract: A potential strategy for mitigating nitrous oxide (N 2 O) emissions from permanent grasslands is the partial substitution of fertilizer nitrogen (N fert ) with symbiotically fixed nitrogen (N symb ) from legumes. The input of N symb reduces the energy costs of producing fertilizer and provides a supply of nitrogen (N) for plants that is more synchronous to plant demand than occasional fertilizer applications. Legumes have been promoted as a potential N 2 O mitigation strategy for grasslands, but evidence to support their efficacy is limited, partly due to the difficulty in conducting experiments across the large range of potential combinations of legume proportions and fertilizer N inputs. These experimental constraints can be overcome by biogeochemical models that can vary legume‐fertilizer combinations and subsequently aid the design of targeted experiments. Using two variants each of two biogeochemical models (APSIM and DayCent), we tested the N 2 O mitigation potential and productivity of full factorial combinations of legume proportions and fertilizer rates for five temperate grassland sites across the globe. Both models showed that replacing fertilizer with legumes reduced N 2 O emissions without reducing productivity across a broad range of legume‐fertilizer combinations. Although the models were consistent with the relative changes of N 2 O emissions compared to the baseline scenario (200 kg N ha −1 yr −1 ; no legumes), they predicted different levels of absolute N 2 O emissions and thus also of absolute N 2 O emission reductions; both were greater in DayCent than in APSIM. We recommend confirming these results with experimental studies assessing the effect of clover proportions in the range 30–50% and ≤150 kg N ha −1 yr −1 input as these were identified as best‐bet climate smart agricultural practices.
Source: Global Biogeochemical Cycles
DOI: 10.1029/2020gb006561
Authors: Kathrin Fuchs, Lutz Merbold, Nina Buchmann, Gianni Bellocchi, Marco Bindi, Lorenzo Brilli, Richard T. Conant, Christopher D. Dorich, Fiona Ehrhardt, Nuala Fitton, Peter Grace, Katja Klumpp, Mark Liebig, Mark Lieffering, Raphaël Martin, Russell McAuliffe, Paul C. D. Newton, Robert M. Rees, Sylvie Recous, Pete Smith, Jean‐François Soussana, Cairistiona F. E. Topp, Val Snow
Institutions: Karlsruhe Institute of Technology, ETH Zurich, Institute of Agricultural Sciences, International Livestock Research Institute, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, VetAgro Sup, Unité Mixte de Recherche sur l'Ecosystème Prairial, University of Florence, Colorado State University, University of Aberdeen, Queensland University of Technology, Agricultural Research Service, Northern Great Plains Research Laboratory, AgResearch, Scotland's Rural College, Fractionnation of AgroResources and Environment, Université de Reims Champagne-Ardenne
Language: English
Subfield: Soil Science
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,500
OpenAlex ID: W3003306274