Plant analysis was one of the means used by scientists in the 1800s to determine the essentiality
of chemical elements as plant nutrients
(22). Further refinements and applications of plant analysis
led to studies of the relationship between crop growth or yield and nutrient concentrations in
plants
(23–26). Elemental analysis of leaves is commonly used as a basis for crop fertilizer recommendations
(27,28).
Plants can be tested for sufficiency of nutrition by analytical tests, which employ quantitative
analysis (total or specific components) in laboratories, or by tissue tests (semiquantitative analysis),
often applied in the field. With proper means of separation of constituents, quantitative tests may
measure nutrients that have been incorporated into plant structures or that are present as soluble
constituents in the plant sap. The tissue tests generally deal with soluble constituents.