Data from: Diversification practices reduce organic to conventional yield gap

Agriculture today places great strains on biodiversity, soils, water and the atmosphere, and these strains will be exacerbated if current trends in population growth, meat and energy consumption, and food waste continue. Thus, farming systems that are both highly productive and minimize environmental harms are critically needed. How organic agriculture may contribute to world food production has been subject to vigorous debate over the past decade. Here, we revisit this topic comparing organic and conventional yields with a new meta-dataset three times larger than previously used (115 studies containing more than 1000 observations) and a new hierarchical analytical framework that can better account for the heterogeneity and structure in the data. We find organic yields are only 19.2% (±3.7%) lower than conventional yields, a smaller yield gap than previous estimates. More importantly, we find entirely different effects of crop types and management practices on the yield gap compared with previous studies. For example, we found no significant differences in yields for leguminous versus non-leguminous crops, perennials versus annuals or developed versus developing countries. Instead, we found the novel result that two agricultural diversification practices, multi-cropping and crop rotations, substantially reduce the yield gap (to 9 ± 4% and 8 ± 5%, respectively) when the methods were applied in only organic systems. These promising results, based on robust analysis of a larger meta-dataset, suggest that appropriate investment in agroecological research to improve organic management systems could greatly reduce or eliminate the yield gap for some crops or regions.当今农业对生物多样性、土壤、水资源及大气均造成了沉重负担，若人口增长、肉类与能源消费及食物浪费的现行趋势持续，此类环境压力还将进一步加剧。因此，亟需研发兼具高产性与环境损害最小化双重优势的耕作系统。过去十余年，有机农业对全球粮食生产的贡献方式始终是学界热议的论题。本研究重新探讨该主题，所采用的全新元数据集（meta-dataset）规模较以往研究大三倍，涵盖115项研究、逾1000条观测数据；同时引入了可更好阐释数据异质性与结构的分层分析框架（hierarchical analytical framework）。研究结果显示，有机农业的产量仅较常规农业低19.2%（±3.7%），这一产量缺口（yield gap）较此前的估算值更小。更为关键的是，与既往研究相比，作物类型与管理措施对产量缺口的影响完全不同。例如，本研究未发现豆科与非豆科作物、多年生与一年生作物，以及发达国家与发展中国家之间存在显著的产量差异。与之相反，我们得到了全新的研究结论：仅在有机种植体系中应用的两项农业多样化措施——多熟种植（multi-cropping）与作物轮作（crop rotations），可显著缩小产量缺口（分别将缺口缩减至9±4%与8±5%）。此项基于大规模元数据集的严谨分析所得出的颇具前景的结果表明，对农业生态研究（agroecological research）予以适当投入以优化有机管理体系，或可大幅缩减甚至消除部分作物或区域的产量缺口。