微量元素是植株生长的基本营养元素。但只是所需量很少。术语“次要元素“和“痕量元素”也是用来描述这些元素的。硼、氯、铜、铁、锰、钼和锌都是这组的成份。大多数微量元素的作用还不太清楚,但株内有酶反应是众所周知的。酶是一组化合物,它能促进化学反应的发生。没有酶就不能发生这样的反应,或能发生而速度不同。因而,正常生长的植株必须依靠这些元素的适当平衡。在这样的化学反应中酶未耗尽也未破坏。由此原因,这些元素不需要很多,但它对植株正常生长正如主要营养氮、磷、钾一样是必须的。微量元素的含量通常是用组织试验来测定, Trace elements are the basic nutrients of plant growth. But only a small amount required. The terms “minor elements” and “trace elements” are also used to describe these elements. Boron, chlorine, copper, iron, manganese, molybdenum and zinc are the ingredients of this group. The role of most trace elements is not yet known, but in-house enzyme reactions are well known. Enzymes are a group of compounds that promote chemical reactions. No enzyme can not happen such reaction, or can occur at different speeds. Thus, normally grown plants must rely on the proper balance of these elements. In such a chemical reaction the enzyme is not depleted nor broken. For these reasons, these elements do not require much, but they are essential for the normal growth of plants just as the main nutrient nitrogen, phosphorus and potassium. The content of trace elements is usually determined by tissue test,