Nutrient imbalance in soils is an emerging threat to sustainable agriculture: intensive cultivation, use of poor quality groundwater, depletion of soil organic matter and excessive use of fertilizers are major reasons for poor soil fertility worldwide. This necessitates correct diagnosis of plant nutrient deficiencies to avoid further use of pesticides in cases where pests or pathogens that are not in fact the cause of poor crop healthy. Nutrient deficiencies in field crops generally occur because of low nutrient levels in the soil. Consider nutritional problems in relation to all conditions affecting plant growth, not exclusively in terms of the amounts of nutrients contained in or added to the soil. The presence of adequate quantities of plant nutrients in the soil is no guarantee that they will be absorbed by the plant roots. Nutrients may be present in forms not available to the plants, or other factors may prevent plant uptake. Unusually low or high soil pH levels can affect nutrient availability. Poor growing conditions, excessively wet or dry soils, cold weather, or soil compaction can significantly restrict root growth and access to soil nutrients. Differences in soil conditions within a field can provide additional evidence of the possible limiting nutrient. Both soil testing and tissue analysis should be used to corroborate nutrient levels in the soil and the plant.