Improving Growth and Performance of Young Almond Trees in Nursery by Optimizing Mineral Nutrition

Short growing season restricts production of standard-sized fruit trees in nurseries at cold regions. Enhancing plant growth by optimizing program of mineral nutrition may solve the problem. This study evaluated efficiency of fertilizers [urea, sulfur coated urea (SCU), or foliar applications of a NPK compound fertilizer] for optimizing the growth of seedling rootstocks and grafted young almond trees at the nursery in a cold region. At the end of the first growing season, the growth and quality of the almond seedlings were evaluated and they were budded in September. At the following season, the treatments were repeated on the grafted trees and grafting success and performance of the young almond trees were evaluated. The result showed that application of 600 kg ha^-1 SCU and urea were the most successful treatments on enhancing the growth of the seedlings. Application of 400 and 600 kg ha^-1 urea and SCU, and 30 kg ha^-1 NPK resulted in the highest grafting success at the second season. The largest shoots of scion were found in the 400-600 kg ha^-1 urea and SCU treatments. The highest leaf greenness and chlorophyll concentration were found in the 600 kg SCU ha^-1 and 30 kg ha^-1 NPK treatments. The highest leaf potassium and phosphorus concentrations were found in 30 kg ha^-1 NPK treatment. The highest leaf nitrogen concentration was detected in treated plants with 400 and 600 kg SCU and 600 kg urea per hectare. According to the results, application of 400 kg ha^-1 SCU is recommended to obtain young standard-sized almond plants in the nurseries.