佛罗里达大学盖恩斯维尔分校、莱克艾尔费雷德柑桔研究和教育中心、以及美国农业部奥兰多园艺研究实验室的科学家们已经对柑桔防冻工作进行过多年的研究。七十年代前,大多数的柑桔园防冻是采取在桔园内加温和机械鼓风等措施。但燃料价格的上涨使大多数柑桔园除了历来是在冷凉地区作为特殊用途或高价的应时鲜果栽培外,一般不再用加温法防冻。七十年代初以来,冻害已造成柑桔的平均价格上涨了近三倍,而加温燃料的价格却上涨了近五倍。由于燃料化费昂贵,因此,柑桔栽培者对选择何种发热装 Scientists at the University of Florida in Gainesville, Lake Elfeed Citrus Research and Education Center and the USDA Orlando Research Labs for Horticulture have been studying citrus antifreeze work for many years. Before the seventies, most citrus orchard antifreeze was taken in the orange garden and mechanical ventilation and other measures. However, the increase in fuel prices has caused most citrus groves to stop frost-freezing by heating in addition to the regular fresh-fruit cultivation that has traditionally been used for special purposes or at high prices in cold areas. Since the early 1970s, frost damage has caused citrus prices to nearly triplly, while prices of warming fuels have risen nearly fivefold. Due to the high cost of fueling, citrus growers choose what type of heat pack