Comparative sampling methods for foliar diagnose in perennial cotton in Paraíba State, Brazil

Abstract

In order to choose a suitable sampling method for foliar diagnose in first year's perennial cotton (Gossypium hirsutum marie galante Hutch), five experiments were conducted in two regions of Paraíba State, Seridó and Sertão, in a randomized complete block design with ten replications. Three sampling methods were evaluated at flowering time: a. Leaves opposite to a flower point (sympodial branches); b. Young mature leaves from monopodial branches; and c. Young mature leaves from the main stem (4^th or 5^th leaf). The nutrients N, P, K, Ca and Mg were determined in the leaf blade and petiole. The results showed that samples taken from the main stem had more significant values for N, P and Mg in the Seridó Region. No significant differences were found for the three sampling types in the Sertão Region.