Many nutrient deficiencies produce characteristic visual symptoms in cereals. Visual symptoms may be the first clue that the nutrient supply is limiting plant growth. There symptoms in wheat are far more nebulous than in some other species. Symptoms on other species may also give an indication. However, different species have diverse nutrient requirements. Nutrient availability also varies among species, so a deficiency in another crop does note necessarily mean the nutrient is deficient in wheat.

For some nutrients, visual symptoms (i.e. those of copper deficiency in wheat during vegetative growth) are so characteristic that deficiencies can be confidently identified on the basis of those symptoms alone. For other nutrients, deficiencies or toxicities may produce foliar symptoms similar to those of other stresses. For example, copper deficiency during reproductive growth may produce a head tipping similar to that produced by either frost or drought at anthesis.

To distinguish between such stresses, further experimentation and/or plant and soil analyses are required. Analysis of an appropriate tissue will confirm for many nutrients whether the diagnosis of a nutrient deficiency or toxicity using visual symptoms was correct.

Table 1. Concentrations of nutrients in whole shoots and young leaves that are deficient, critical, adequate, and toxic for the growth of wheat. Values are a guide only.