ISHS Acta Horticulturae 729: III Balkan Symposium on Vegetables and Potatoes
EFFECT OF CULTIVAR AND SOIL HEATING TREATMENT ON OFF-SEASON PRODUCTION OF WHITE ASPARAGUS (ASPARAGUS OFFICINALIS L.) |
| Authors: | G. Paroussi, T.V. Koutsos, E. Paroussis, T. Pritsa, D. Voyiatzis |
| Keywords: | asparagus, off-season, soil heating treatment |
| Abstract:
Heating was applied to warm up the soil by circulating hot water in two pipes placed beside the crowns of asparagus plants grown in low transparent plastic tunnel (H/Tu) and under the crowns (HUC) of asparagus plants grown outdoors. The hybrid cvs. ‘Dariana’, ‘Larac’ and ‘Steline’ were used for off-season production, before mid March. Off-season asparagus produced between February and mid-March, which is exported by about 95% in Germany, sells substantially more than in-season asparagus. Unheated beds of each cultivar were used in low tunnel without heating (Tu) and outdoors (O) as control treatments. Raised beds were covered with plastic mulch to ensure white spears and weed control. The heating system was activated in mid January and harvest started on February 7. harvest in the HUC treatment was earlier by about 20 days compared to the control (O) and by about 10 days compared to the tunnel either heated (H/Tu) or unheated (Tu). The number of marketable spears in February (grade A) in the HUC treatment was significantly higher, 374.3 g/plant, in comparison with the unheated beds outdoors, 12.41 g/plant and the H/Tu and Tu treatments, which were approximately 115.7 g/plant and 90.03 g/plant, respectively. The number of spears per plant in the HUC treatment was also significantly greater in comparison with all the other treatments. Similar results were found regarding the B grade spears of early yield. The total yield of the plants grown in the HUC treatment until the end of harvesting, at 8 of April, was significantly higher compared to the plants grown in the unheated beds outdoors, but there was no significant difference compared to the plants grown in the low tunnel either heated or unheated. ‘Dariana’ had the highest early and total yield among the cultivars tested but the difference was not significant. The highest percentage of non-marketable off- and in-season yield was noticed in the ‘Steline’ and in the HUC treatment. | |
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