ISHS Acta Horticulturae 792: V International Symposium on Irrigation of Horticultural Crops
COOLING THE CANOPY WITH SPRINKLER IRRIGATION TO REDUCE TIPBURN IN ENDIVE |
| Authors: | Sylvie Jenni, J.F. Dubuc, J.C. Desrosiers, K.A. Stewart |
| Keywords: | evaporative cooling, overhead irrigation, physiological disorder, heat stress, high temperature |
| Abstract:
Endive (Cichorium endivia L.) is a cool season crop, highly susceptible to tipburn under intense solar radiation and high air temperature conditions. This physiological disorder is often associated with low calcium levels in rapidly growing tissues. A field experiment was conducted during a warm and humid summer to determine the potential of sprinkler irrigation and the application of foliar calcium to reduce the incidence and severity of tipburn in endive. Intermittent sprinkler irrigation, applied when the air temperature at a height of 10 cm was above 28°C, reduced the air temperature around the plant by 3 to 11°C, compared with the temperature of the control. The warmer the ambient air temperature prior to sprinkling, the lower the temperature around the plant after sprinkling. Sprinkler irrigation significantly reduced the incidence of tipburn. Only 18% of the sprinkler-irrigated plants had tipburn symptoms, compared with 98% of plants in the control. Foliar calcium had no effect on the incidence of tipburn. However, foliar calcium reduced the severity of tipburn only in plants not under sprinklers: tipburn symptoms occurred in 16% of the leaves sprayed with foliar calcium, compared to 38% in leaves not sprayed with foliar calcium. Foliar calcium had no effect on the severity of tipburn in sprinkler-irrigated plots, where less than 2% of the leaves showed tipburn symptoms. | |
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