Effects of nitrogen supplied in various growth stages on the growth and yield of strawberry

Abstract

The experiment was carried out to clarify the effects of nitrogen supplied in various growth stages from the transplanting time middle in October to the termination of harvest early in July, on the growth and yield of strawberry (var. Donner) in sand culture outdoors.The control plants supplied with nitrogen throughout all stages of growth were the highest in the number of flowers and yield of fruits.In the plants withheld nitrogen supply after late in April or late in February, the growth of tops and roots were inferior to those of the control. Their number of flowers and yield of fruits were also less.When plants were not supplied with nitrogen during the winter period from late in December to late in February, their number of flowers and yield of fruits were less than those in control plants, however, their yield was the highest among other treatments except the control.Both the number of flower clusters and of flowers decreased remarkably in the treatments withheld nitrogen supply from the transplanting time till late in December or late in February. When nitrogen was supplied afterward to the plants in these treatments, growth of tops and roots became vigorously, and runner production was also active. Although the fruit yields in these treatments were decreased due to their smaller number of flowers, their fruit set percentages, average fruit weight and soluble solid content of fruits were higher than those in the control.