大麻是张家口坝下地区主要经济作物之一,栽培历史悠久,解放后又有很大发展。但近年来由于当地不留种,外调种供不应求以及粮田面积增多等原因,大麻的种植有逐年缩减之势。因此,大麻留种就成为发展大麻生产极待解决的问题。当地麻农之所以不留种,主要是由于雌麻留种生育期延长,麻皮粗硬;其次是留种 Cannabis is one of the major cash crops in the area under the dam at Zhangjiakou. It has a long history of cultivation and great development after the liberation. In recent years, however, the cultivation of cannabis has been declining year by year because of the lack of species in the area, the out-sown demand for seeds and the increase in the area of ​​grain fields. As a result, the marijuana stay-at-home has become a matter of urgency for the development of cannabis production. The reason why the local nuisance-free nurture, mainly due to the extension of female-growing seasons, hemp hard; followed by the remaining species