ISHS Acta Horticulturae 571: Workshop Towards and Ecologically Sound Fertilisation in Field Vegetable Production
NITROGEN AND WATER STRESS AFFECTS SPROUTING IN BULB ONIONS STORED OVER WINTER |
| Authors: | J.N. Sorensen, K. Grevsen |
| Keywords: | Allium cepa L., drought, fertilization, keepability, storage |
| DOI: | 10.17660/ActaHortic.2002.571.8 |
| Abstract:
In the production of bulb onions in Denmark, a ban on the use of maleic hydrazide is in consideration due to the risk of leaching into the drinking water reservoirs. An environmental friendly alternative to the chemical inhibitors is to prolong the natural dormancy of bulb onions by altering the pre-harvest growing conditions. Plants of onions were grown at various N supplies or imposed to drought stress conditions just prior to harvest. After harvest and drying the onions were stored at 1°C until April, May or June the following year. During a 40-day shelf-life period at 15°C the sprouting was recorded at 3- to 4-day intervals. In plants grown at low N supply, the harvest time was postponed and the yield was reduced. A surplus supply of nitrogen did neither influence the harvest time nor the yield. In contrast, drought stress during the final growth forced the onions to mature. This effect reduced the yield and increased the dry matter percentage of the bulbs. Sprouting was postponed if plants had been grown at low N supply or harvested in dry soil. Onions cold stored until April started to sprout after 20 days at 15°C. Correspondingly, onions stored until May started to sprout about 10 days after removal from storage. At storage until June, sprouting was initiated at the end of cold storage. | |
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