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、水资源与大气造成了沉重负担，若人口增长、肉类与能源消费及食物浪费的当前趋势持续，这类环境压力还将进一步加剧。因此，亟需兼具高生产效率与最低环境危害的耕作体系。过去十余年间，有机农业能否为全球粮食生产作出贡献，一直是学界广泛争论的议题。本研究重新审视这一主题，依托规模较此前三倍有余的全新元数据集（meta-dataset）——涵盖115项研究、超1000组观测数据——以及能够更好适配数据异质性与结构特征的新型分层分析框架（hierarchical analytical framework），对比有机与常规耕作的产量表现。研究发现，有机耕作的产量仅比常规耕作低19.2%（±3.7%），产量缺口（yield gap）较此前的估算值更小。更关键的是，与既往研究相比，我们发现作物类型与管理措施对产量缺口的影响完全不同。例如，本研究未发现豆科作物与非豆科作物、多年生作物与一年生作物，或是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时，两项农业多样化措施——间套作（multi-cropping）与作物轮作（crop rotations）——可显著缩小产量缺口，分别降至9±4%与8±5%。本研究基于大规模元数据集的稳健分析得出了上述极具前景的结论，这表明，对农业生态研究进行合理投入以优化有机管理体系，或可大幅缩小甚至消除部分作物或区域的产量缺口。