从1941年美国俄勒冈州就开始种植地三叶进行种子生产。其大部分种子田完全用于种子生产,而澳大利亚的则主要用来放牧绵羊。1940年 Duggan 在澳大利亚首次报道,绵羊放牧能增加地三叶的种子产量。他发现不需进行特殊的放牧处理,只是在地上部分生长过快而防碍种子生产时,进行适当放牧以阻止地上部分徒长。澳大利亚的许多试验 From 1941 the United States Oregon began planting three-leaf seed production. Most of its seed fields are used exclusively for seed production, while Australia is mainly used for grazing sheep. In 1940 Duggan reported for the first time in Australia that sheep grazing increased the yield of clover seed. He found that it was not necessary to carry out special grazing treatments, but only grazing on the ground to prevent the above-ground parts from lengthening when the aboveground parts grew too fast and hinder seed production. Many trials in Australia