Daylight crop water stress index for continuous monitoring of water status in apple trees

• Published in: Irrigation science 2016-05, Vol.34 (3), p.209-219
• Main Authors: Osroosh, Yasin, Peters, Robert T., Campbell, Colin S.
• Format: Article
• Language: English
• Subjects: Abiotic stress; Agriculture; air; Air temperature; Apples; Aquatic Pollution; Biomedical and Life Sciences; canopy; Climate Change; Correlation; Crops; Daylight; Drought; Environment; Field capacity; Fruit trees; Irrigation; Life Sciences; Malus; Malus domestica; Moisture content; Monitoring; Original Paper; rhizosphere; Root zone; Soil (material); Soil water; soil water content; soil water deficit; Solar radiation; Stresses; Sustainable Development; Trees; Vapor pressure; Waste Water Technology; Water availability; Water content; Water deficit; Water Industry/Water Technologies; Water Management; Water monitoring; Water Pollution Control; Water potential; Water stress; Wind speed
• ISSN: 0342-7188; 1432-1319
• DOI: 10.1007/s00271-016-0499-3

We studied the suitability of empirical crop water stress index (CWSI) averaged over daylight hours (CWSI d ) for continuous monitoring of water status in apple trees. The relationships between a midday CWSI (CWSI m ) and the CWSI d and stem water potential ( ψ stem ), and soil water deficit (SWD) were investigated. The treatments were: (1) non-stressed where the soil water was close to field capacity and (2) mildly stressed where SWD fluctuated between 0 and a maximum allowable depletion (MAD of 50 %). The linear relationship between canopy and air temperature difference (Δ T ) and air vapor pressure deficit (VPD) averaged over daylight hours resulted in a non-water-stressed baseline (NWSBL) with higher correlation (∆ T  = −0.97 VPD – 0.46, R 2  = 0.78, p