Posição da folha e estádio fenológico do ramo para análise foliar do pinhão-manso

ABSTRACT Leaf analysis is an important tool for prediction of nutritional disorders and evaluation of nutritionalstatus of plants. This procedure only can be effective if samples are standardized regarding leaf positionand phenological stage of the branch. This study had the objective of defining the most appropriate leafposition and type of branch for nutritional diagnosis of Jatropha plants. A factorial combination of fiveleaf positions (1 st , 2 nd , 3 rd , 5 th , and 10 node from apex to base) and two types of branch (vegetative andflowering) was adopted in a completely randomized design with four replications. Each leaf sample wascollected in 4 secondary branches of 20 plants in the flowering phase. Leaves in the position 2 and 3 arethe most adequate for analyzing N, P, K, S, Cu, Fe, Mn, and Zn, because they present mean values morestable when compared to the other studied positions. Leaves in the position 5 and 10 are more adequatefor analyzing Ca and Mg. The phenological stage of the branch does not influence nutrient content,except of Cu and Fe.