Vol. 110 (1997): Proceedings of the Florida State Horticultural Society
Citrus

SURFACE DECONTAMINATION OF CITRUS LEAVES FOR MACRO AND MICRO NUTRIENT ANALYSIS

Published 1997-12-01

Keywords

  • foliar absorption,
  • micro-nutrient residue,
  • detergent and acid washing,
  • spring-flush

Abstract

Mineral nutrition status of the crop plants can be evaluated by leaf analysis. The value of leaf analysis largely depends on careful consideration of sampling, decontamination, and preparation of extract for various analysis. The recommended physiological stage for citrus leaf sampling is about 5- to 7-mo-old spring-flush. In most cases, foliar application of micro-nutrient is made during the flush emergence stage and later in summer. In this study, we evaluated the effects of recommended leaf washing procedure, i.e., detergent plus acid washing followed by several rinses in deionized water, vs. rapid rinse in deionized water alone on the concentrations of macro- and micro-nutrients in the leaves. The results showed no significant differences in most macro and micro-nutrient concentrations, except Cu, between the detergent plus acid washing vs. rapid rinse procedures. Therefore, under the conditions when the micro-nutrients foliar application was made in early flush stage and the leaves are sampled about 6 mo later and prior to the summer micro-nutrient application, a rapid rinse in deionized water was satisfactory for leaf surface decontamination of most mineral elements, except Cu. However, the critical time interval between the foliar spray of micro-nutrients and time of leaf sampling to minimize carry over of micro-nutrient residue on the leaf surface cannot be derived from this study.