| Summary: | <p>The diagnosis of mineral deficiencies of crops is an important problem
in agricultural and horticultural practice. Although the appearance of
mineral deficiency symptoms may be of use, they usually appear when the
deficiencies are already severe. Sometimes the symptoms are not characteristic,
or else they may be masked when there are multiple deficiencies. Leaf
analysis of perennial crops has been successfully employed for diagnostic
purposes, particularly in the tropics. It is possible to standardize the
sampling techniques as regards to time of year, morphological position of
the leaves and physiological age. Under these conditions, analysis can be
used as a diagnostic tool and it affords a useful check on any fertilizer
policy adopted.</p>
<p>Where annual crops are concerned, the possibilities of leaf analysis
are much more restricted. Sampling and diagnosis has to be done at a stage
of development which is early enough to enable nutritional disorders to be
corrected. The chemical composition of annual crops may change during the
growing season as a result of climatic conditions, fluctuations in the
composition of the soil solution and the stage of development of the crop.
In making leaf analyses of annual crops we are therefore faced with the
problem of obtaining comparable samples of rapidly growing crops.</p>
<p>Potato plants, in particular, in the production of tubers remove
substantial amounts of nitrogen, phosphorus and potassium from the soil. In
Saskatchewan nitrogen and phosphorus often must be increased in the soil by
addition of these fertilizers. The objectives of this study were to relate
foliar nutrient levels to the levels of applied fertilizer, as well as to such
parameters as yield and quality.</p>
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