Multielement testing of soil samples provides valuable understanding of its yield potential. Essential elements are divided into macronutrients (required in larger quantities because of their structural roles in the plant) and micronutrients (required in smaller quantities because they tend to be involved in regulatory roles in the plant). Primary macronutrients, such as potassium (K) are most often in short supply in soils, requiring replenishment in the form of applied fertilizer. Deficiencies of secondary macronutrients, such as calcium (Ca) and magnesium (Mg) are less commonly encountered. Micronutrients include iron (Fe), manganese (Mn) , zinc (Zn), copper (Cu), and boron (B). The presence of any of the essential elements in excessive amounts may result in toxic effects. Accurate and timely analysis of soil samples is vital so action can be taken to improve the soils fertility if a nu trient imbalance is present or if there is a risk of environmental pollution due to excess elemental concentrations Agilent 4200 微波等離子體原子發(fā)射光譜儀