Connolly John, Sebastià Maria-Teresa, Kirwan Laura, Finn John Anthony, Llurba Rosa, Suter Matthias, Collins Rosemary P, Porqueddu Claudio, Helgadóttir Áslaug, Baadshaug Ole H, Bélanger Gilles, Black Alistair, Brophy Caroline, Čop Jure, Dalmannsdóttir Sigridur, Delgado Ignacio, Elgersma Anjo, Fothergill Michael, Frankow-Lindberg Bodil E, Ghesquiere An, Golinski Piotr, Grieu Philippe, Gustavsson Anne-Maj, Höglind Mats, Huguenin-Elie Olivier, Jørgensen Marit, Kadziuliene Zydre, Lunnan Tor, Nykanen-Kurki Paivi, Ribas Angela, Taube Friedhelm, Thumm Ulrich, De Vliegher Alex, Lüscher Andreas
School of Mathematics and Statistics University College Dublin Dublin 4 Ireland.
Laboratory ECOFUN Forest Sciences Centre of Catalonia (CTFC) Solsona Spain.
J Appl Ecol. 2018 Mar;55(2):852-862. doi: 10.1111/1365-2664.12991. Epub 2017 Sep 27.
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 (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 significantly but not largely different from that in the equiproportional mixture. The average variability (standard deviation) of annual weed biomass within a site was much lower for mixtures (0.42) than for monocultures (1.77). . Weed invasion can be diminished through a combination of forage species selected for complementarity and persistence traits in systems designed to reduce reliance on fertiliser nitrogen. In this study, effects of diversity on weed suppression were consistently strong across mixtures varying widely in species' proportions and over time. The level of weed biomass did not vary greatly across mixtures varying widely in proportions of sown species. These diversity benefits in intensively managed grasslands are relevant for the sustainable intensification of agriculture and, importantly, are achievable through practical farm-scale actions.
草原多样性可通过提高产量、减少投入以及限制杂草入侵来支持草原生产的可持续集约化。我们报告了一项为期3年、涉及31个地点的大陆尺度田间试验中多样性对杂草抑制的影响。在每个地点，以两种密度播种了15个草原群落，包括4种单一栽培和11种基于多种物种比例的四物种混合物，并通过刈割进行管理。根据“氮素获取方式”和“时间发育模式”这两个交叉功能性状选择牧草物种。在不同地点、年份和播种密度下，混合物和单一栽培中的一年生杂草生物量分别为0.5和2.0吨干物质/公顷（分别占总生物量的7%和33%）。超过95%的混合物的杂草生物量低于单一栽培的平均值，在三分之二的情况下，低于最具抑制性的单一栽培（超亲抑制）。在58%的地点 - 年份中，抑制作用具有显著的超亲性。混合物的超亲抑制作用在多年间得以维持，与地点生产力无关。基于模型，整个实验中混合物的平均杂草生物量比最具抑制性的单一栽培低52%（95%置信区间：30% - 75%）。在所有混合物的每年以及每种混合物中，杂草生物量的超亲抑制作用都很显著。在所有混合物和年份中，杂草生物量一直较低，在某些情况下，与等比例混合物中的杂草生物量有显著但差异不大。一个地点内一年生杂草生物量的平均变异性（标准差），混合物（0.42）远低于单一栽培（1.77）。在旨在减少对化肥氮依赖的系统中，通过选择具有互补性和持久性性状的牧草物种组合，可以减少杂草入侵。在本研究中，多样性对杂草抑制的影响在物种比例差异很大的混合物中以及不同时间内一直很强。在播种物种比例差异很大的混合物中，杂草生物量水平变化不大。这些在集约化管理草原中的多样性益处与农业的可持续集约化相关，重要的是，可通过实际的农场规模行动实现。
