土壤的无机部分中存在着约九十种化学元素,除十种而外,其它统称微量元素或痕量元素。而微量元素之中只有十三个元素为动物、植物或微生物所必需,一般称为“必需元素”,即硼、钼、锰、锌、铜、铁、钴、钒、铬、氟、氯、碘和硒,可能还有钡、锶、钨和溴等。铁在土壤中属于常量元素,在植物体中则属于微量元素。这些元素的含量一般为n×10~(-4)—n×10~(-3)%。 There are about 90 kinds of chemical elements in the inorganic part of the soil, with the exception of ten kinds, the other collectively referred to as trace elements or trace elements. Of the trace elements, only thirteen elements are necessary for animals, plants or microorganisms and are commonly referred to as “essential elements”, ie boron, molybdenum, manganese, zinc, copper, iron, cobalt, vanadium, chromium, Iodine and selenium, possibly barium, strontium, tungsten and bromine. Iron is a constant element in the soil, while in the plant body is a trace element. The content of these elements is generally n × 10 -4 - n × 10 -3%.