This article is based on a talk at the IPI-ISSAS 12th International Symposium on Management of Potassium in Plant and Soil Systems in China, Chengdu, Sichuan, China, July 25–27, 2012.
Citrus leaf nutrient status: A critical evaluation of guidelines for optimal yield in Israel†
Article first published online: 21 MAY 2013
Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Journal of Plant Nutrition and Soil Science
Volume 176, Issue 3, pages 420–428, June, 2013
How to Cite
Raveh, E. (2013), Citrus leaf nutrient status: A critical evaluation of guidelines for optimal yield in Israel. J. Plant Nutr. Soil Sci., 176: 420–428. doi: 10.1002/jpln.201200411
- Issue published online: 21 MAY 2013
- Article first published online: 21 MAY 2013
- Manuscript Accepted: 13 FEB 2013
- critical values;
- upper envelope curve
Maintaining orchards with trees at optimal leaf nutrient concentrations is one of the key issues for maximizing yield. Experiments for evaluating and updating guidelines are very rare since they require several years of field experiments with mature fruit-bearing trees. In the present paper, we first evaluated the Israeli guidelines for citrus by comparing them to the Israeli orchard leaf mineral status using a 10-year leaf-mineral database (results of 20 244 leaf analyses from commercial orchards all over Israel). Then, we created an updated guideline using a second database (the Israeli National Wastewater Effluent Irrigation Surveys database; INWEIS). This database summarizes yield and leaf mineral concentrations of commercial orchards from all over Israel. The data were collected from 122 orchards: 39 orchards of “Oroblanco” Pomelit (Citrus grandis), 33 orchards of “Michal” mandarin (C. reticulata), 30 orchards of “Star Ruby” grapefruit (C. paradise), and 20 orchards of “Shamouti” oranges (C. sinensis) over a 7-year period. Based on the first database, there was a disagreement between recommendations and the leaf nutrient status (e.g., the Israeli Ministry of Agriculture recommendations were higher than orchard median values), which indicated that the growers and/or the recommendations need to be corrected. Based on the INWEIS database, a new guideline was set. It was found that the optimal leaf nutrient concentrations for grapefruit trees are 1.7% to 2.1% dry weight (DW) for N, 0.08% to 0.010% DW for P, 0.37% to 0.48% DW for K, and 0.33% to 0.45% DW for Mg. For orange trees, the optimal leaf nutrient concentrations are 1.9% to 2.3% DW for N, 0.11% to 0.14% DW for P, 0.80% to 1.00% DW for K, and 0.19% to 0.26% DW for Mg. For mandarin trees, the optimal leaf nutrient concentrations are 2.0% to 2.4% DW for N, 0.09% to 0.12% DW for P, 0.55% to 0.69% DW for K, and 0.19% to 0.26% DW for Mg. Maintaining leaf nutrient concentrations within these ranges will support maximal yields of 110 to 120 t ha–1 for grapefruit, 65 to 70 t ha–1 for orange, and 60 to 70 t ha–1 for mandarin cultivars.