adequacy of phosphorus and nitrogen nutrition, respectively, 

 of the plants sampled. 



Plant or tissue analysis is a technique for nutrient assay 

 that has found widespread application in assessing the 

 nutrient status of soils for the production of agricultural 

 and horticultural crops (Bould, et al. , 1960; Reuther, 1961; 

 Smith, 1962; Chapman, 1966). Plant analysis is based on 

 the observation that the concentration of any essential 

 element in a plant can vary over a considerable range, 

 and that a primary factor determining the concentration 

 in a healthy plant is the availability of the element in 

 the environment. The essential relations on which tissue 

 analysis is based are shown in Figure 1 (Ulrich, 1961) . 



ADEQUATE ZONE 



TRANSITION 

 ZONE 



/ V. 



CRITICAL CONCENTRATION 





DEFICIENT 

 ZONE 



CONCENTRATION 



IN TISSUE 



Figure 1. Diagram of the relationship between plant yield and 

 the concentration of an essential element in specific plant 

 parts (From Ulrich, 1961) . 



