Abstract
We investigated the effects of summer pruning and fertilization on the absorption of nutrients the following autumn when ‘Muscat of Alexandria’ grape was grown under forcing culture from December, using a soil-less culture system. After harvest between June and July, both summer-pruned and non-pruned vines received fertilizer treatments at three different levels (15 g, 10 g and 5 g nitrogen per m2, 15 g, 10 g and 5 gN). Fertilizer levels of all treatments in the autumn were fixed at the same level (12 gN). The color of leaves was significantly deeper from September to middle October after 15 g and 10 gN treatments compared with that after 5 gN treatment. Lignifications of shoots were most rapid after 10 gN treatment, followed by 15 gN treatment, and delayed after 5 gN treatment. Nitrogen applied in the autumn was more rapidly absorbed after 5 gN than after 15 g or 10 gN treatments. Most of the nitrogen disappeared by the beginning of December after 5 gN treatment. On the contrary, after either 10 g or 15 gN treatment, nitrogen partly remained in the nutrient solution through December. Phosphate was absorbed in the autumn with the same pattern in all treatments, and had completely disappeared by the beginning of December. Potassium absorption after 5 gN treatment was more rapid and larger than that after 10 g or 15 gN treatment. However, in all treatments, potassium partially remained through December, differing from nitrogen. Between summer-pruned and non-pruned vines, there was no difference observed in the absorption of nitrogen, phosphate and potassium in the autumn. These results indicate that the higher-level fertilizer application in summer significantly decreased absorption of nitrogen and potassium delivered from fertilizer applied the following autumn.
