1974 Volume 43 Issue 1 Pages 1-6
Effect of autumnal application of N, P and K on photosynthesis and the translocation and distribution of photosynthates was studied with Delaware grapes grown in pots, using 14CO2. The effect of the same treatments on shoot growth and cluster development in the following spring was also studied. The treatments consisted of all possible combinations of N, P and K and no fertilization (control).
The results of the present study imply that in the growing of grape vines N, P and K are required to be applied all together in the fall from the standpoint of accelerating the photosynthetic rate and translocation of photosynthates to the roots and also of promoting the shoot growth and cluster development of the following year.
N fertilization increased cluster length, number of clusters per vine, number of flowers per cluster and fruit growth in the following spring. P fertilization increased cluster length and number of clusters, but decreased number of flowers, whereas K fertilization did not affect cluster length and number of clusters, but increased number of flowers. Among the treatments, the combined application of N, P and K was most effective for the growth of clusters and fruits. As to the shoot growth, the treatments including N were promotive, whereas P, K and PK treatments did not exhibit any obvious effects.
