Twentieth Century Crop Statistics, 1900-2017

The Twentieth Century Crop Statistics, 1900-2017 data set consists of national or subnational maize and wheat production, yield, and harvested area statistics for all available years for the period 1900-2017. It combines a new digitization of crop statistics from Italy, Spain, Indonesia, China, Mexico, Uruguay, Chile, Sweden, and Morocco with existing, publicly available, digitized data sets from India, Australia, the United States, Canada, Southern Brazil, Argentina, England, Austria, Belgium, Croatia, Czech Republic, Finland, Germany, Spain, Portugal, France, the Netherlands, and South Africa. All units are converted to hectares (ha) for units of harvested areas, tonnes for units of production, and tonnes/ha for units of yield. A ratio of 1/36.744 is used to convert wheat bushels to tonnes, and a value of 1/39.368 is used to convert maize bushels to tonnes. In all cases, the Harvest_year reported in the data set is the harvest year for the crop. To provide a unique crop yield data set that spans the twentieth century for many of the world's major bread baskets.本数据集为1900-2017年二十世纪作物统计数据集（Twentieth Century Crop Statistics, 1900-2017），涵盖1900至2017年间所有可获取年份的国家级或亚国家级玉米、小麦总产量、单产及收获面积统计数据。数据集整合了意大利、西班牙、印度尼西亚、中国、墨西哥、乌拉圭、智利、瑞典及摩洛哥的作物统计数据全新数字化成果，以及印度、澳大利亚、美国、加拿大、巴西南部、阿根廷、英格兰、奥地利、比利时、克罗地亚、捷克共和国、芬兰、德国、西班牙、葡萄牙、法国、荷兰与南非的现有公开可获取的数字化数据集。所有收获面积单位均统一转换为公顷（hectares，缩写ha），总产量单位统一转换为吨（tonnes），单产单位统一转换为吨/公顷（tonnes/ha）。其中，小麦蒲式耳（bushels）转换为吨的换算系数为1/36.744，玉米蒲式耳（bushels）转换为吨的换算系数为1/39.368。本数据集中记录的收获年份（Harvest_year）均为对应作物的实际收获年份。本数据集旨在构建一套覆盖二十世纪、涵盖全球多数主要粮食主产区的独一无二的作物单产数据集。