Foliar analysis: the basic principle Which is the basic principle of the foliar analysis? The basic principle of the foliar analysis to evaluate the supply of nutrients for the ground for the plant is based on the fact that the content of nutrients in leves of course is affected by the content of nutrients of the ground since the plants remove great part of the nutrients from the ground. , Plants thus grown in alone one with high text of nutrients tend to present greaters texts of these nutrients in the leaf if compared with the one it plants of the same species grown in one alone low text of nutrients. In the same line of reasoning, basses texts of nutrients in the leaf indicate low amount of these nutrients in the ground, or, the least, indicates that the nutrient, if present in the ground, is in a not available form to the plant. Thus, the availability of nutrients of the ground from the analysis of the content of nutrients in the leaf can be deduced..