钙是橡胶叶片及其他植物体中的重要营养元素之一,是在作物营养诊断中必须进行常规分析的内容之一。目前,经常使用的方法有四种。一是EDTA络合滴定法,是继草酸盐沉淀氧化还原容量法之后较为快速的方法。但是由于选用络合滴定指示剂不同,所呈颜色及终点的稳定亦各异。另外并有干扰离子的影响。再加之个人视辨能力不同及终点 Calcium is one of the important nutrition elements in rubber leaves and other plants. It is one of the contents that must be analyzed routinely in crop nutrition diagnosis. At present, there are four ways to use frequently. First, EDTA complexation titration, oxalate salt precipitation is followed by the more rapid method of redox capacity method. However, due to the selection of complex titration indicator is different, the color and end point of the stability is also different. In addition there is interference with the impact of ions. Coupled with the different personal visual acuity and end point