Boron Nutrition of Almonds


01 Mar 1998

1997 Annual Interpretive Summary

Boron nutrition of nut crops, 1997

In 1994 a study was initiated to determine the effect of boron (B) nutrition on flowering, fruit set, and yield of almond following a similar (and very successful) study with pistachio. Spraying B at a rate of 1-2 lb Solubor/100 gal on B deficient almond trees significantly increased fruit set and yields in 1995 and 1996. Of special note is the fact that often almond trees responded positively to supplemental B sprays without showing visible B deficiency symptoms. Results in 1997 suggest an optimal application is to mix 3 lb Solubor with compatible insecticides and fungicides to reduce application costs and to spray postharvest.

Research initiated in 1996 on prunes produced little useful information due to a very poor cropping year. The prune research was terminated and the research effort transferred to walnuts based on greater market opportunity. Field research in 1997 with foliar B treatments dramatically increased walnut set and retention, reduced or totally eliminated pistillate flower abortion (PFA) and increased ultimate nut yield. Boron is fundamentally essential for the flowering process and since 80% of all agricultural products develop from the flowering part of plants, the implications of this research are very wide ranging. CA-13F