Abstract Changes in agricultural land use over recent decades have exacerbated the pressures and impacts of agriculture on the environment. Researchers model these pressures and impacts using data on soils, climate and agricultural land use characteristics, which have to be represented at the spatial and temporal scales appropriate to the ecological or biophysical processes being studied. Representation of agricultural land use across large areas (several thousand of km2 or more) is hampered by lack of data on the diversity of farming practices and their spatial distribution, usually reduced to land cover. We propose in this article a methodological approach for combining generic and local information sources to characterise, across a large area, the diversity of crop managements and their spatial distribution, at a resolution appropriate to a specific environmental issue: assessment of nitrate contamination of groundwater. The approach involves four steps: (i) devise a system of spatial units that is appropriate to the research context and the available information sources, (ii) use multivariate analysis to characterise the diversity of crop managements obtained from a national database, (iii) conduct a survey, holding semi-directive interviews with experts and local actors to identify specific features that may locally modify this diversity, (iv) synthesise the statistical findings and survey results to establish a set of representative crop management "types". Illustrated in connection with the problem of diffuse nitrogen pollution of groundwater in the Seine-Normandie basin in France, it enabled to describe 919 crop managements out of the 18 main crops in the basin and especially highlighted the high diversity of practices on wheat with more than 200 crop managements. The knowledge produced on the diversity of crop managements and their spatial distribution was used for environmental modelling.

中文翻译：

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在区域尺度上表征作物管理的多样性和空间差异

摘要 近几十年来农业土地利用的变化加剧了农业对环境的压力和影响。研究人员使用有关土壤、气候和农业用地特征的数据对这些压力和影响进行建模，这些数据必须以适合所研究的生态或生物物理过程的空间和时间尺度表示。大面积（数千平方公里或更多）的农业土地利用情况因缺乏有关耕作方式多样性及其空间分布的数据而受到阻碍，这些数据通常仅限于土地覆盖。我们在本文中提出了一种方法论方法，用于结合通用和本地信息源，以在大范围内表征作物管理的多样性及其空间分布，以适合特定环境问题的决议：地下水硝酸盐污染的评估。该方法包括四个步骤：(i) 设计一个适合研究背景和可用信息来源的空间单位系统，(ii) 使用多变量分析来表征从国家数据库中获得的作物管理的多样性，(iii)进行一项调查，与专家和当地参与者进行半定向访谈，以确定可能在当地改变这种多样性的具体特征，(iv) 综合统计结果和调查结果，以建立一套具有代表性的作物管理“类型”。结合法国塞纳-诺曼底盆地地下水的扩散性氮污染问题进行说明，它能够描述流域内 18 种主要作物中的 919 种作物管理，并特别突出了小麦种植方式的高度多样性，其中包括 200 多种作物管理。关于作物管理多样性及其空间分布的知识被用于环境建模。