Effect of mineral and biological nitrogen fertilization on Thompson Seedless grape transplants. II. Effect on leaf mineral content.

Abstract

The effects of 2 sources of N fertilizers (mineral and biological) on the leaf mineral content of grape (cv. Thompson Seedless) transplants were studied in a pot experiment. The treatments consisted of 3 rates of ammonium sulfate (0, 5 and 10 g per plant, corresponding to M1, M2 and M3, respectively) and 4 rates of biological N (0, 50, 100 and 200 ml of the liquid culture of Azotobacter chroococcum, corresponding to B1, B2, B3 and B4, respectively). Generally, the mineral and biological N had significant effects on the mineral content of leaves (blades and petioles), and the optimum treatments for this parameter were M2, B3 and B4. M2 × B1 and M3 × B1 increased the contents of N, P and K over the control (1 × B1). The application of mineral N alone had no promising effects on Fe, Zn and Mn contents. M1 × B2, M1 × B3 and M1 × B4 increased the mineral content over the control, with M1 × B3 being the most effective. Mineral N was more effective when applied with biological N and vice versa, especially when mineral N was applied with B3 and B4. M2 × B3, M2 × B4 and M3 × B4 gave the highest values for N, P, K, Fe, Zn and Mn contents. The inoculation of A. chroococcum into the rhizosphere can provide a part of the N requirement of grape transplants. M2 × B3 was superior among the treatment combinations.