贵州省黎平县地处与湘桂交界的贵州东南边沿,属南亚热带湿润季风气候区。总耕地面积307,050亩,农业人口368,295人,人均占有耕地面积0.83亩,人均占有田面积0.77亩。为了在有限的耕地面积内取得最佳经济效益,我们从1984年起即开始进行油菜——西瓜——水稻三熟制的试验、示范 Liping County, Guizhou Province is located at the southeastern border of Guizhou with the junction of Hunan and Guangxi and belongs to the humid subtropical monsoon climate zone. The total area of ​​307,050 acres of arable land, agricultural population 368,295 people, the per capita arable land area of ​​0.83 mu, per capita land area of ​​0.77 mu. In order to achieve the best economic benefits in a limited area of ​​cultivated land, we started the trial of rape-watermelon-rice three-crop system since 1984, demonstrating