Supplemental Foliar Nickel and Copper Applications Do Not Reduce Kernel Necrosis in Pecan Trees Receiving Excess Nitrogen

Abstract

Pecan [Carya illinoinensis (Wang.) K. Koch] fruit developed necrotic tissue at the basal end of the kernels in an orchard receiving large amounts of nitrogen (N) from nitrate-contaminated irrigation water. It was hypothesized that increasing canopy nickel (Ni) and copper (Cu) could mitigate negative effects of excess N and reduce the incidence of kernel necrosis. Nickel, Cu, and Ni + Cu were tank mixed with zinc (Zn) and applied as a canopy application at the parachute stage of leaf development followed by two additional applications at 2-week intervals. One study was conducted for 2 years, and a second study was conducted for 1 year using the same treatments. Foliar nutrient applications increased the leaf concentration of the applied nutrients. The amount of kernel necrosis was unaffected by treatment, and no consistently positive results could be attributed to the canopy treatments.

Keywords:

• Carya illinoinensis
• kernel necrosis
• nitrogen
• minor nutrient
• yield

Acknowledgments

This article was approved for publication by the Oklahoma Agricultural Experiment Station. Funding for this study was provided by the Samuel Roberts Noble Foundation, the Oklahoma Pecan Growers' Association, and the Oklahoma Agricultural Experiment Station.