Studies on the fertilizer for florist crops. I

Abstract

This study was designed to obtain the nutritional requirement of Amaryllis (Hypeastrum hybridum) as an aid of bulb cultivation. The bulblets of nearly same size propagated by the artificial method in the previous winter were arranged. And three of them were planted per one pot on March 14, each treatment including twelve replicate bulblets. The different fertilizers were applied on the basis of triangular coordinates, with levels of 75, 150, 225 and 300 ppm of nitrogen, phosphorus, and potassium. (The rates are indicated in Table I.) Ammonium nitrate to supply nitrogen, calcium super phosphate to supply phosphate, and potassium sulfate to supply potassium were dissolved in water and applied at weekly interval from May 12 to Nov. 15. The number of leaves, and divided bulblets; the length of leaves; the diameter of bulb; and the weights of total plant, leaf, bulb, and root were measured, and the contents of nutritional ele-ments of each organ were analyzed after fertilizer treatment. The total nitrogen was determined by the Gunning method, total phosphorus by the photoelectric colorimeter, and total potassium by the flame photometer. The analysis of variance for the measurements shows significant differences among the treat-ments. The results of this study are summarized as follows: (1) The good fertilizer rates for Amaryllis growth were 4-4-4 and 3-2-4 plots. (2) Potassium was not effective for the top weight, but effective for the division of bulblet. (3) The plants with high nitrogen level and high potassium level absorbed more nitrogen and potassium than those with low nitrogen level and low potassium levels. However, such fact was not shown in phosphorus. (4) High potassium levels were not conducive to good plant growth unless the nitrogen level was also high.