Many nutrient imbalances share similar symptoms. A good example is nitrogen an sulfur. When plants are deficient in either nutrient, leaves turn yellow. They can be distinguished by the location of yellow leaves though.
Multiple imbalances can occur at the same time. Your plants may suffer from multiple deficiencies at the same time, particularly if incorrect pH or another factor is causing the deficiencies. Your plants might also suffer from a toxicity and deficiency at the same time, especially since nutrient toxicities can result in deficiencies of other nutrients. As an example, excess phosphorus often causes zinc deficiencies.
Different plant species (or even cultivars) will respond to deficiencies and toxicities in different ways. Some types of plants are more tolerant of certain imbalances or may show different symptoms. For instance, strawberry leaves typically turn red as a result of phosphorus deficiency while corn leaves turn purple.
Other plant problems may cause symptoms that are similar to nutrient imbalances. Some diseases produce similar symptoms to nutrient imbalances but too much or too little water, soil compaction and insect attack can also mimic nutrient imbalance symptoms. Pesticide (including herbicide) damage can also produce similar symptoms.
Nutrient imbalances may be silent for some time. That is, a plant may be suffering from a deficiency or toxicity for some time before symptoms become visible. Sometimes, the first symptom of a problem is increased pest damage resulting from less than healthy plants.
Symptoms that you see may differ from 'typical' symptoms. Scientists can take photos of plants grown under laboratory conditions with an intentional deficiency or toxicity. In your garden or on your farm, symptoms may look different for any number of reasons including but not limited to: