Water consumption of sweet cherry trees estimated by sap flow measurement

• Daily sap flow rate and monthly water uptake of sweet cherry trees were estimated.
• Sap flow ranged in fifth leaf 10–40, in eighth leaf 40–60 l day−1 from May to August.
• Crop basal coefficient varied between 0.4 and 0.9 depending on the phenological course.

Sapflow was measured applying heat balance method on sample trees of a high density (spacing 4 m × 2 m) orchard between the age of 4–7 years from 1 of May to 31 of August each year (2008, 2009, and 2011). Data from different 162 sample days were used in calculation of water consumption of sample trees and orchard. An automatic weather system was installed at the sweet cherry plantation to measure meteorological variables. The average daily water uptake of the 4-year-old trees were 24.2, 23.6, 22.7, and 10.9 l from May to August in 2008, while in 2011 the 7-year-old trees transpirated in May 55.6, in July 48.4 and in August 44.8 l per day. We found that the transpiration of trees in 4- and 5-year-old intensive sweet cherry orchard were 305 mm and 320 mm. The cumulative transpiration reached 523 mm for 3 months in 2011, while for the whole vegetation period 700–800 l water requirement can be calculated for local condition in intensive sweet-cherry orchards. The sapflow course showed typical characteristics on the investigated days with different weather conditions. The intensive water uptake began at about 6:00 a.m. and slowed down to minimum between 20:00 and 22:00 p.m. Transpiration of trees showed strong correlation to vapor pressure deficit, global radiation and air temperature, independently from the available precipitation. The crop basal coefficient (Kcb) – calculated as the rate of tree transpiration measured by SF and the referenced evapotranspiration – varied between 0.4 and 0.9. Our research results can contribute to harmonize the water supply and the plant's water use, and planning the irrigation.