十多年前,在美国的加利福尼亚和佛罗里达,为了使柑桔苗木避免线虫和土地菌类的为害,经常用氯化苦和D—D剂进行土壤重蒸,或用蒸气消毒,希望使柑桔在消毒后的土壤中生长良好。但适得其反,在消毒后的土壤里栽种的柑桔生长反而受抑制,叶片缺绿、坏死、脱落,根系的生长也受到阻碍。起初,人们认为这些生长受抑制的现象,是磷、铜、锌等缺乏,或其他微量元素吸收过多引起的,但在消毒后的土壤里,并未发现这些成份的增减,也没有发现特别的 More than a decade ago in California and Florida in the United States, citrus seedlings were often re-steamed with chloropicrin and D-D agents or sterilized with steam in the hope of averting the infestation of nematodes and terrestrial fungi. Citrus Good growth in sterilized soil. But counterproductive, citrus growth planted in the sterilized soil on the contrary inhibited, leaves lack of green, necrosis, loss, root growth has also been hindered. Initially, these growth inhibitions were thought to be caused by the lack of phosphorus, copper, zinc, or excessive absorption of other trace elements, but no change in these components was observed or found in the sterilized soil special