STANDARDIZATION OF PLANT AND SOIL TESTING FOR FERTILIZER RECOMMENDATION
These features are especially important in vegetable production where the recommendations should be sometimes developed as quickly as possible. The standardization of analysis procedure enable next stage: the standardization of fertilizer recommendations for given growth conditions and the exchange of experience between different research and production centres as far as the critical figures and fertilizer recommendations are concerned.
Plant analysis is used for both purposes: controlling the nutrient status of plant (mostly in case of visual symptoms appearance or in case of developing the recommendations in respect to nitrogen topdressing) and checking the value of used fertilizer recommendations and critical figures for soil analysis.
In the plant analysis at first place the so-called index part is to be unified and the way of its sampling and preparing for analysis is to be established. It is important for organization reasons, to use the same index part for different nutrients. It seems that as such part may be recommended the petioles (or midribs) of the oldest, fully grown (however yet not drying) leaves. In this part the difference in the content of nutrient between worse and better nourished plant is the greatest. There is, however,