1968 Volume 37 Issue 1 Pages 57-66
Experiments were carried out to clarify the effects of nitrogen supplied in various growth stages on the growth and yield of green soybean, cabbage, turnip, and cauliflower in sand culture outdoors.
1. In green soybean, the beginning of flowering and harvesttime were delayed by withholding nitrogen in the former half of growth period. Especially, when the nitrogen supply was discontinued for 2-3 weeks immediately before flowering, the yield of pods was decreased. But there was no decrease in yield in treatments withholding nitrogen after flowering.
2. As to autumn sown cabbage, weight of head at harvesttime was considerably smaller in treatments withholding nitrogen during the rapid growth period or outer leaves, from early April to early June. But when nitrogen was not supplied after early June (rapid growth period of head leaves), and in winter months, there were no significant differences in the weight of heads as compared with the control supplied with nitrogen throughout all stages of growth.
3. In turnip, both growth of top and yield of roots were suppressed, if nitrogen supply was stopped at any stage of growth. But, in treatment withholding nitrogen for 2 weeks before harvesting, yield of roots was better than that of the control.
4. In cauliflower, growth of curd was suppressed when nitrogen was not supplied immedately before harvesting.