Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 4/25/2005
Publication Date: 7/15/2005
Citation: Wood, B.W., Reilly, C.C., Nyczepir, A.P. 2005. Correcting Ni deficiency in pecan and other crops [abstract]. Hortscience. 40(4):1065. Interpretive Summary: Nickel is an essential plant nutrient element that has been ignored by agriculture, even though Ni deficiency has now been documented in crops. Basic guidelines are presented that enable identification of those crops that are most likely to exhibit Ni deficiency, identify factors that contibute to Ni deficiency, and provide guidelines to Ni sufficiency level in foliage. This information will assist in the identification of crop losses to Ni deficiency and will provide insight into how to manage Ni nutrition of crop plants.
Technical Abstract: The recent discovery of the existence of nickel (Ni) deficiency in field plantings of pecan [Carya illinoinensis (Wangenh.) K. Koch] (Wood et. al., 2004) has led to efforts to identify appropriate management approaches to correct tree deficiency and to identify the causes for Ni deficiency. Evaluation of several inorganic and organic forms of Ni have indicated that solutions from all sources function well to correct deficiencies when timely applied as a foliar spray to affected trees at Ni concentrations >10 mg.L-1. Addition of urea, ammonium nitrate, or nicotinic acid to Ni spray solutions increased apparent foliar uptake from Ni sprays. The lower critical level of Ni, based on foliar analysis, appears to be in the 3-5 mg.L-1 dw range, with the upper critical level appearing to be >50 mg.L-1 dw. The cause of Ni deficiency in soils possessing plenty of Ni is associated with excessive amounts of one or more metals (e.g., Ca, Mg, Fr, Mn, Cu, and Zn) which inhibit Ni uptake and/or utilization. Root damage by nematode feeding and cool/dry soils during early spring also contributes to Ni deficiency. Foliar application of Ni to foliage in the autumn and subsequent appearance of Ni in dormant season shoot tissues indicates that Ni can be mobilized from senescing foliage to dormant season shoots and is therefore available for early spring growth. Evidence indicates that pecan has a higher Ni requirement than most other crop species because it transports nitrogenous substances as ureides. Thus, there is evidence that Ni-metalloenzymes are playing either a direct or indirect role in ureide and nitrogen metabolism. It is postulated that crop species that are most likely to exhibit field level Ni deficiencies are those which transport N as ureides. Candidate crops will be discussed.