Abstract
We investigated the effects of summer pruning and fertilization on nutrient absorption and regenerated shoot growth after harvest of ‘Muscat of Alexandria’ grape grown under forcing culture from December using a soilless culture system.
The shoot regeneration in summer was slightly delayed in summer-pruned vines compared to non-pruned vines. The absorption of nitrogen, phosphate and potassium in summer-pruned vines during the post-harvest period in summer was also delayed. However, there was no difference observed between both treatments in total amount of nutrients absorbed from June to September. The leaf-area of regenerated shoot from each cane and the LAI on each vine in the summer-pruned treatment were smaller than those on non-pruned vines. The phosphate concentration in leaves in summer-pruned vines was lower than non-pruned vines in late September. On the contrary, those of nitrogen and potassium were not affected by summer pruning.
The total amount of nitrogen absorbed in summer was less with the low level fertilizer treatment (5 g nitrogen · m−2) than with either the middle or high level fertilizer treatments (10 g and 15 g nitrogen · m−2 respectively). However, there was no difference observed in the total absorption of nitrogen between the middle and high-level fertilizer treatments. The ratio of absorbed nitrogen to applied nitrogen was lower in the high-level fertilizer treatment than those in the low and middle fertilizer treatments. The fertilizer level clearly affected the nitrogen and potassium concentrations in leaves sampled in September, even though, differences in the fertilizer level did not affect the leaf-area and the LAI in this experiment. The nitrogen concentration in leaves was lowest receiving the low-level fertilizer treatment. The potassium concentration was highest in leaves receiving the high-level fertilizer treatment.
