滨海地区石灰性土壤樟树失绿黄化症,主要起因于土壤条件,即土壤pH高,HCO3-多,土壤有机质含量低,从而影响了土壤中铁的活化和吸收;另一方面植株大量吸收磷素,使植株体内磷铁比失调,影响铁的运转,导致叶片失绿。建议用单叶叶绿素计读数SPAD值来描述樟树失绿黄化程度,当叶绿素计读数SPAD值大于30,即为正常;小于20即为黄化,介于20与30之间,越靠近30,黄化概率越小;越靠近20,黄化概率越大。 The calcareous chlorosis in coastal areas is mainly caused by soil conditions, that is, the soil has high pH, ​​HCO3-, and low content of soil organic matter, thus affecting the activation and absorption of iron in the soil. On the other hand, the plant largely absorbs phosphorus , So that plant phosphorus and iron than the imbalance, affecting the operation of iron, leading to green leaves. Proposed leaf chlorophyll meter reading SPAD value to describe the degree of chlorosis of camphor tree, chlorophyll meter reading SPAD value greater than 30 is normal; less than 20 is yellow, between 20 and 30, the closer to 30, The smaller the probability of yellowing; the closer to 20, the greater the probability of yellowing.