Nutritional studies on tulips. III.

Seasonal changes in the absorption of three major elements and water

Abstract

(1) The large (15-16g) and the small tulip bulbs (2.0-2.2g) of cv. ′William Pitt′ were grown in a green-house by the gravel culture method, and the seasonal changes in the amount of absorbed nitrogen, phosphorus, potassium and water were examined.
(2) The changes of absorption of the three major elements went abreast with that of water; namely, the amount of three elements absorbed as well as that of water, was very little during the preemergence stage in winter, and after the emergence of the leaves above the ground in spring it rapidly increased following the growth of the top, and reached the maximum soon after the flowering, then it decreased up to the harvesting time.
(3) In the amount of absorption of each nutrient, nitrogen was the largest, and it was found that considerable amouns were absorbed even in the pre-emergence stage. Potassium absorption was next, and the absorption continued until the withering stage. Phosphorus absorption was the least. (cf. Figs. 2, 3)
(4) Compared with the total amount of three major elements absorbed, the small bulb showed a higher ratio in nitrogen absorption than the large one. The small bulbs required much less total amount of water and the nutrients for their growth than the large ones. The former consumed less water and the nutrients than the latter to get one gram increase in fresh weight of the neww bulb. This result seems to indicate that the small bulbs did efficient use of water and nutrients, as they absorbed less amount of those than the large ones to grow in equal weight.