Plant testing is the determination of the concentration of an element in a
sample from a particular part of a plant at a particular stage of morphological
development. The plant analysis measures the elements that are incorporated
as complex compounds and those that are present as soluble ions in the
Why test a Plant?
The aim of leaf analysis is to relate the nutritional content of the plant to
the physical appearance, growth rate, yield and quality of the product. Leaf
analysis provides the nutritional status of a crop and can be used to identify nutrient
imbalances, deficiencies and toxicities. It integrates all the factors influencing nutrient
availability and uptake. It shows the required balanced nutrients. Testing of leaves also
predicts plant nutrient problems during the growing season and the remedy
can be taken without any loss in productivity.
Selection of Sample:
Selection of plant samples must be taken at the correct time of
year because nutrient concentrations within plants continuously change.
Generally, Leaves are taken from the plant for the analysis. As leaves fall, N, P,
and K concentrations decrease; Ca increases; and Mg first increases and then
decreases resulting in poor nutrition. However, leaf mineral concentrations are
relatively stable from four to six months after leaf emergence. Leaf sample
should consist of 100 leaves. The clean proper bag should be used for the
preservation of leaves. Do not select the sample from the dead and ailing plants
and do not select the sample from the damaged part of the leaf by the insects.
Immature leaves must be avoided.
The parameters that are necessary for the plant testing are
Total Nitrogen, Mineralizable Nitrogen, Chlorophyll content,
Available phosphorus, Potassium, Calcium, Magnesium, Sulphur, Organic
Carbon, Organic Matter, Sodium