Water table control has been successfully tested to improve the sustainability of water management in cranberry production. In the province of Québec (Canada), three sites were investigated to determine the optimum water table depth below soil surface (WTD) using three criteria: (1) increasing yield without decreasing fruit quality; (2) minimizing the amount of water needed by the sprinkler system; and (3) avoiding hypoxic stresses in the rhizosphere. Our results show that the final yield, the berry sugar content, the total number of berries, the number of berries per upright, and the fruit set were maximized when the WTD was 60 cm. Sprinkler water savings of 77% were obtained where the WTD was shallower than 66 cm. In order to avoid hypoxic conditions due to poor drainage, the water level in the canals surrounding the beds should be lowered to 80 cm when a rainfall or a frost protection irrigation is anticipated. All sides of a block of beds must be surrounded by canals to ensure a uniform WTD and to avoid lateral hydraulic gradients that could cause peripheral seepage losses.

Cranberries were grown under controlled environmental conditions to determine the effects of soil waterlogging on cranberry gas exchange in three growth stages and to investigate the recovery time after waterlogging. Photosynthesis declined by 28% after the first day of waterlogging at the bud elongation stage and was 46% lower after the fifth day. At the flowering stage, the reduction in photosynthesis started to be significant only after the fifth day, whereas no reduction was observed at the fruit development stage. Stomatal limitations were responsible, in part, for the observed decrease in photosynthesis since stomatal conductance ( g _S ) declined by 68% and 45% after the fifth day of waterlogging during bud elongation and flowering, respectively. After water drained away in the saturated treatments, leaf photosynthesis remained lower than in the unsaturated control treatment for 1 to more than 10 days at the bud elongation stage. Our results demonstrate that short-term hypoxic soil conditions can alter cranberry gas exchange depending on plant growth stage, and suggest that adequate drainage or control of the water table depth is required to avoid the negative effects of soil waterlogging on cranberry yield.

The impact of irrigation thresholds based on soil water potentials on total anthocyanin content (TAcy) of cranberry fruit was studied at two sites. Two methods based on spectrophotometric measurements were compared: the acidic solvent extraction (ASE) method and the pH-differential method. TAcy was greater by 21–29 percent when irrigation was managed using a wetter threshold, −5.5 and −6.0 kPa, in comparison with a drier threshold, from −6.5 to −10.0 kPa. The pH-differential method resulted in significantly greater TAcy measurements than the ASE method, although the ASE method was faster and simpler to use.