Effects of Foliar Applications of Nitrogen, Boron, and Zinc on the Rate of Fruit Set and Some Quality Aspects of Almonds

Abstract: One of the yield reducing factors in orchards is considered to be the deficiencies of nutrient elements especially micronutrients which are particularly difficult to correct and are of utmost importance in producing acceptable yields. Almonds (Prumus dulcis) fruit fall is one of the numerous problems faced by the growers a problem caused by deficiencies of nitrogen, zinc and boron in particular. A completely randomized factorial block experiment with 18 treatments and three re plications was carried out on a total of 108 local Azar variety almond trees during 2003 in Shabestar location. The first factor consisted of urea nitrogen at two rates of 0, and 0.5% , the second factor consisted of boron at three rates of 0, 0.2%, and 0.4% applied as boric acid, and the third factor consisted of zinc at three levels of 0, 0.3% and 0.6% applied as zinc sulfate. The greatest rate of initial fruit set (24 %) was obtained with the (0.2 %) applicat ion of boron at 2000 mg/kg and also with zinc at 5000 mg/kg. The highest rate of final fruit set (15 %) was obtained with the second and third rates of application of boric acid. The largest single almonds in grams were obtained with the second and third rates of boric acid. The highest percentage of nut content (15.6%) was obtained with boron at 2000 mg/kg. The longest almonds were obtained with the third rate of boron application. The widest with the second and third rates of boron. The highest percentage of nut content (14.5 %) was obtained with the third level of zinc application. The highest percentage of oil content (54 %) was obtained with the second and third rates of zinc application compared with the control. The largest single nut was obtained with the combined foliar applications of urea (5000 mg/kg) and boric acid (2000 mg/kg) and the highest percentage of hard shells was obtained with the combination of foliar applications of second nitrogen rate along with the second and third rates of boric acid. Similarly the greatest protein content (23 %) with foliar application of urea and third rate of application of boric acid.. Keywords: NitrogenBoronZincInitial fruit setFinal fruit set.