Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 10, 2005
Publication Date: December 4, 2006
Citation: Wood, B.W., Reilly, C.C., Nyczepir, A.P. 2006. Nickel deficiency in trees: symptoms and causes. Acta Horticulturae. 721:83-98. Interpretive Summary: Many plant maladies appear to be caused by nutrient element deficiencies, yet do not respond to fertilization by standard macro- or micronutrients. A nickel deficiency was found to be the cause of economically serious maladies in pecan and several other crops. A protocol was develop to identify deficiency symptoms, crops and circumstances were identified in which deficiency is most likely to be found, procedures were identified to correct deficiency, and a commercial nickel fertilizer product was developed for usage by farmers and gardeners. The nickel fertilizer and diagnostic methods will reduce crop losses.
Technical Abstract: This communication reports that the mouse-ear or little-leaf disorder and the associated replant disease of pecan [Carya illinoinensis (Wangenh.) K. Koch] is a Ni deficiency and is cured by timely foliar application of Ni (at 100mgL-1), thus documenting the first known example of Ni deficiency in orchard crops. Deficiency is inducible on soils with adequate Ni content by a) excessively high soil Zn, Cu, Mn, Fe, Ca, or Mg; b) root damage by root-knot nematodes; or c) dry and or cool soils at time of bud break. Symptoms associated with Ni deficiency, but varying with severity of deficiency, include early-season leaf chlorosis, dwarfing of foliage, blunting of leaf/leaflet tips, necrosis of leaf or leaflet tips, curled lead/leaflet margins, dwarfed internodes, distorted bud shape, brittle shoots, cold-injury-like death of over-wintering shoots, diminished root system with dead fibrous roots, failure of foliar lamina to develop, rosetting and loss of apical dominance, dwarfed trees, and tree death. In addition to pecan, Ni deficiency is exhibited by river birch; and based on symptoms and soil characteristics, it also appears to occur in certain other woody perennial crops (e.g., plum, peach and Pyracantha sp., and citrus). Its occurrence in two prominent ureide transporting hydrophiles raises the possibility that such species are most likely to experience Ni associated disorders than are other species. Observations implicate excessive soil accumulation of light metals from long-term fertilizer usage as a primary cause of Ni deficiency. These results raise the possibility that Ni is a contributing factor in certain recalcitrant maladies and replant disorders of certain woody perennial crops and support the role of Ni as an essential nutrient element for higher plants. Ni deficiency in field situations appears to be far more common than generally recognized; thus, meriting greater attention in horticultural production strategies and greater awareness by horticulturalists.