MINERAL NUTRITION OF FOUR CULTIVARS OF BEARING AND NON-BEARING MACADAMIA TREES IN VILLANUEVA, LARA STATE, VENEZUELA, AND ITS VARIATION IN TIME

Leaf nutrient composition of macadamia (Macadamia integrifolia) was assessed over three years at the Villanueva locality, Lara State, Venezuela in order to determine the annual concentration patterns of the macro and micronutrients in the foliar tissue. Two-year old non-bearing trees and twelve-year old bearing trees of four different cultivars (246, 333, 508 and 660) were tested in a farm located at 9º40’ North latitude and 1200 meters above sea level. Replicated sixty-leaf samples were taken from each of two trees at three-month average intervals during a forty-month period. Nitrogen, potassium and iron levels were statistically higher in January and lower in July, while the opposite occurred for phosphorus, calcium, manganese and zinc. The cv. 660 averaged the highest values for nitrogen and no differences were found among cultivars for the other nutrients. Young non-bearing trees presented the highest values for N, P and Mn and the lowest for Ca and Cu, thus reflecting a selective age effect. Mean N, P and K levels for bearing and non-bearing trees were ranked as sufficient according to the Hawaiian standards. Levels of Ca, Mg, Mn, Zn and Cu were within or in the lower limit of the standards proposed for Australia. Since the plants exhibited normal growth and appearance with good yield and high quality fruits, they were considered to be in good nutritional status. The results can be useful as guides for assessing the nutrient status of macadamia under these growing conditions.