1987年7月以来,华山农场近4000亩柑桔幼树和初投产树突发性地发生大面积黄化。究其原因,众说纷云。有说天气反常,有说黄龙病,有说栽培管理不当等等。面对现状,我们按品种、树龄、砧木、苗木来源和抽梢时期等分别统计各类黄化植株,对果园生态环境、气象因子、农药肥料使用及田间管理等进行详细调查分析,并取土壤和叶片样品检测化验。调查结果如下: Since July 1987, Huashan farm nearly 4000 acres of citrus young trees and initial investment in the production of trees suddenly occurred large area yellowing. The reason for this is that there are numerous arguments. There are said that the weather is anomalous, there is that Huanglong disease, there is that cultivation and management, and so on. Faced with the status quo, according to the species, age, rootstock, seedling source and the sampling period of the various types of yellow plants statistics, orchards ecological environment, meteorological factors, pesticide fertilizer use and field management conducted a detailed investigation and analysis, and take soil And leaf sample test assay. The findings are as follows: