Micronutrient refers to the relative quantity of a nutrient that is required for plant growth. It takes part in metabolic activities, enzymatic process/catalysts etc. Thus these all directly and indirectly help in plant growth and development. There are 8 essential plant nutrient elements defined as micronutrients like boron (B), zinc (Zn), manganese (Mn), iron (Fe), copper (Cu), molybdenum (Mo), chlorine (Cl) and silicon (Si). They constitute in total less than 1% of the dry weight of most plants. Organic sources like farm yard manure, compost, vermicompost etc. may contain less quantity of these nutrients but presence of these help the plant in their growth and development. They also called trace elements or minor elements. They are required only in small amounts (5 to 200 ppm, or less than 0.02% dry weight). The visual symptoms may be caused by more than one nutrient. Deficiency of one nutrient may be related to an excess quantity of another. Nutrient deficiency symptoms are observed only after the crop has already suffered an irretrievable loss. When soil supplies more quantity of nutrient than the plant’s requirement, plant shows toxicity symptom.