Pecan Response to Nitrogen Fertilizer Placement

Application method and placement can improve the efficiency of applied nitrogen (N) per unit of yield, potentially minimizing N loss and increasing the profit margin for pecan producers. The following treatments were evaluated for their effect on pecan leaf N concentration, pecan yield, nut quality, agronomic N use efficiency (AE(N)), and alternate bearing intensity (I); 1) emitter-adjacent application of liquid urea ammonium nitrate (UAN) (28N-0P-0K) with 5% sulfur (S); 2) broadcast application of dry ammonium nitrate (34N-0P-0K); 3) broadcast-band application of dry ammonium nitrate; 4) broadcast ground-spray application of liquid UAN; and 5) untreated control (2009-12). Leaf elemental tissue analysis, pecan yield, quality, and alternate bearing intensity indicate that pecans can be effectively fertilized with N using any of the application methods used in the current study. Based on AE(N), it appears that pecans can be effectively fertilized at a lower field rate of N than is currently recommended and that the volume of fertilizer applied to pecan orchards can be significantly reduced by minimizing the area in the orchard to which N fertilizer is applied and eliminating excessive applications to vegetated row middles, which apparently offer little additional benefit to pecan leaf N, pecan quality, or yield.