Effect of mineral and biological nitrogen fertilization on Thompson seedless grape transplants. I. Effect on vegetative growth

Abstract

The effects of 2 sources of N fertilizers (mineral and biological) on the vegetative growth of grape (cv. Thompson Seedless) transplants were studied in a pot experiment. The treatments were 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, M2 resulted in the greatest shoot length, number of leaves, total chlorophyll content, and fresh and dry weights of whole plant. B3 gave the highest values of shoot length, number of leaves, and total chlorophyll content. M2 × B1 and M3 × B1 enhanced plant growth (shoot length, number of leaves, leaf area, and fresh and dry weights of whole plant) over the control (M1 × B1). M1 × B2, M1 × B3 and M1 × B4 increased plant growth (shoot length, number of leaves, leaf area, and fresh and dry weights of whole plant) over the control. The combination between mineral N and biological N resulted in higher values for all parameters, especially when mineral N at 5 g per plant was combined with biological N at any rate. However, M2 × B3 registered the highest values of shoot length, number of leaves, leaf area, and chlorophyll content. The greatest fresh and dry weights of whole plant were obtained with M2 × B2 and M2 × B3. M2 × B3 was the most beneficial among the combination treatments.