ISHS Acta Horticulturae 619: XXVI International Horticultural Congress: Potatoes, Healthy Food for Humanity: International Developments in Breeding, Production, Protection and Utilization
MEASUREMENT OF LEAF WATER STRESS IN POTATO USING A NOVEL INFRARED THERMOMETRY METHOD |
| Author: | T. McBurney |
| Keywords: | Irrigation scheduling, soil moisture deficit, stress index, reference surface, Solanum tuberosum |
| Abstract:
A novel leaf water stress index method, based on a combination of thermal sensing of leaf temperature with continuous measurement of wet and dry critical reference temperatures, was adapted for use in potato crops. Reference surfaces were devised which matched the dynamic temperature responses of real leaves. Use of a low-cost infra red thermometer (IRT) tended to give a positive bias of 0.42°C (+/- 0.23°) compared with corresponding readings with an embedded fast-response thermocouple. However, correcting for the IRT bias made little difference to severe stress index values. The method was evaluated both in plants growing in containers under conditions of closely controlled soil moisture and in field plots subjected to two irrigation regimes. Stress index values taken at mid-day in sunny conditions tended to be above 0.7 in drought-stressed plants and below 0.4 in plants subjected to moisture deficits below the irrigation threshold. | |
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