Weed suppression greatly increased by plant diversity in intensively managed grasslands: A continental‐scale experiment

作者：John Connolly, Maria‐Teresa Sebastià, L. Kirwan, John A. Finn, Rosa Llurba, Matthias Suter, R. P. Collins, C. Porqueddu, Á. Helgadóttir, O. H. Baadshaug, Gilles Bélanger, Alistair Black, Caroline Brophy, J. Čop, Sigríður Dalmannsdóttir, Ignacio Delgado, A. Elgersma, M. Fothergill, B. E. Frankow‐Lindberg, An Ghesquiere, P. Goliński, Philippe Grieu, Anne‐Maj Gustavsson, Mats Høglind, Olivier Huguenin‐Elie, Marit Jørgensen, Žydrė Kadžiulienė, Tor Lunnan, Païvi Nykänen-Kurki, Àngela Ribas, F. Taube, Ulrich Thumm, A. de Vliegher, A. Lüscher · 发表于：Journal of Applied Ecology · 年份：2017 · DOI：10.1111/1365-2664.12991 · 被引用次数：671 · 研究领域：Soil Carbon and Nitrogen Dynamics、Ecology and Vegetation Dynamics Studies、Agronomic Practices and Intercropping Systems

Abstract Grassland diversity can support sustainable intensification of grassland production through increased yields, reduced inputs and limited weed invasion. We report the effects of diversity on weed suppression from 3 years of a 31‐site continental‐scale field experiment. At each site, 15 grassland communities comprising four monocultures and 11 four‐species mixtures based on a wide range of species' proportions were sown at two densities and managed by cutting. Forage species were selected according to two crossed functional traits, “method of nitrogen acquisition” and “pattern of temporal development”. Across sites, years and sown densities, annual weed biomass in mixtures and monocultures was 0.5 and 2.0 t DM ha −1 (7% and 33% of total biomass respectively). Over 95% of mixtures had weed biomass lower than the average of monocultures, and in two‐thirds of cases, lower than in the most suppressive monoculture (transgressive suppression). Suppression was significantly transgressive for 58% of site‐years. Transgressive suppression by mixtures was maintained across years, independent of site productivity. Based on models, average weed biomass in mixture over the whole experiment was 52% less (95% confidence interval: 30%–75%) than in the most suppressive monoculture. Transgressive suppression of weed biomass was significant at each year across all mixtures and for each mixture. Weed biomass was consistently low across all mixtures and years and was in some cases significa...