ISHS Acta Horticulturae 401: International Symposium on Growing Media & Plant Nutrition in Horticulture
MANAGEMENT OF MINERAL ELEMENTS OF ROSES GROWN IN CLOSED ROCKWOOL SYSTEMS |
| Authors: | C.M.J. Bloemhard, J. van Moolenbroek |
| Abstract:
The fertilization of rockwool grown roses is based on the guide values recommended by IKC. Experiments were carried out to check these guide values. After the first year several adjustments were necessary. The concentrations of potassium and calcium became too high, while the concentrations of ammonium and magnesium seemed to be low. After adjustments the guide values were checked again the second year. The values of NH4, K and Ca agreed with the values of the first year. In a second experiment the water and mineral balance sheet for roses was checked. The experiment was carried out on a commercial holding from March 1992 until May 1993 in a recirculation system. The absorption of water by the crop amounted to 772 mm/year. The total supply of nutrients in kg/ha/year was 906 N, 263 P, 1117 K, 204 Mg, 668 Ca and 332 S. In the drain to waste was in kg/ha/year 265 N, 53 P, 429 K, 77 Mg, 299 Ca and 148 S. The input of mineral elements was not in balance with the output of mineral elements: 19% N, 50% P, 22% K, 42% Mg, 35% Ca and 50% S were unidentified. | |
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