ISHS Acta Horticulturae 470: II International Symposium on Pistachios and Almonds
FOLIAR NUTRIENT (N, P, K, B) APPLICATION EFFECTS ON ALMOND YIELDS |
| Authors: | R.D. Meyer, J.P. Edstrom, J. Deng, S. Cutter |
| Keywords: | foliar fertilizer, nitrogen, phosphorus, potassium, boron |
| Abstract:
The objective of this research was to evaluate the effect of foliar applications of nitrogen (N), phosphorus (P), potassium (K), and boron (B) on kernel (meat) yields and leaf nutrient concentrations. Several rates and frequencies of pre- and post-bloom foliar applications of N, P, K, and B were applied in 1995 and 1996 to Butte variety almonds (Prunus dulcis [Mill] D. A. Webb). Foliar fertilizer rates ranged from 0 to 5.6-1.5-1.9 kg N-P-K ha-1 (5-3-2 lbs N-P2O5- K2O A-1) at pink tip pre-bloom, 0 to 11.2–2.9–3.7 kg N-P-K ha-1 30 days after pre-bloom and 0 to 22.4–5.9–7.4 kg N-P-K ha-1 60 days after pre-bloom in addition to the soil applied 180–220 kg N ha-1 yr-1. Boron was applied at prebloom in 1995 and in the fall of 1995 and 1996 at 0.67 kg ha-1. Almond meat yields ranged from 1789–2253 kg ha-1 in 1995 and 1665–2426 kg ha-1 in 1996 with the control treatment yields of 2223 and 2046 kg ha-1. The boron treatment gave a significant yield increase in 1996 and the third highest yield in 1995. There were no consistent trends in either year for yields to improve with 1, 2 or 3 foliar nutrient applications of N alone, N+P+K, N+K, slow release N (CoRoN) alone, or N+P+K+sucrose (Fulcrum). Leaf levels of N, P, K, Ca, S, Zn, Mn and B in July and October of each year were not significantly different. There were no significant treatment differences in shellout percentage; meat, hull, or shell percentage; increase in tree trunk circumference or cross-sectional area. | |
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