Importance of nutrient balance in determining yield and quality of crops is well established but there was no means to quantify it until the introduction of the Diagnosis and Recommendation Integrated System (DRIS) in which leaf analysis values are interpreted on the basis of inter-relationship among nutrients, rather than nutrient concentration themselves. The DRIS is based on the comparison of crop nutrient ratios with optimum values from a high yielding group (DRIS norms). The DRIS provides a means of simultaneous identifying imbalances, deficiencies and excesses in crop nutrients and ranking them in order of importance. The major advantage of this approach lies in its ability to minimize the effect of tissue age on diagnosis, thus enabling one to sample over a wider range of tissue age than permissible under the conventional critical value approach. Several researchers affirm that once DRIS norms based on foliar composition has been developed for a given crop; they are universal and applicable to that particular crop grown at any place and at any stage of its development.