The impact of two drainage problems on cranberry yield was investigated. In the first case, a yield decline of 39% was measured for cranberries growing over clogged drains, and in the second case, an inadequate design of the drainage outlet was associated with a 25% yield reduction. This yield decrease vanished the following year after redesigning the outlet.

The rate of evapotranspiration from a mature cranberry bed in Wisconsin was measured using infrared thermometry. Values ranged from 0.8 to 6.2 mm d^-1, which were on average 1.05 of the equilibrium evaporation rate. These results are in good agreement with those measured earlier in Wisconsin by the Bowen-ratio technique. Estimates of stomatal conductance were extracted from the data, yielding values of at least 0.2–0.3 mol m^-2 s^-1, substantially higher than earlier reports for cranberry but typical of uncultivated plants. Our results give us good confidence that cranberry evapotranspiration in the continental climate of Wisconsin, at least, can be estimated from the equilibrium evaporation rate, i.e., the Priestley–Taylor potential rate, with α = 1.05.

Cranberry production is a water intensive practice that requires irrigation during summer months to achieve maximum yields. Previous studies have found that root zone tension maintained between -4 and -7.5 kPa allows for maximum yields without over irrigating. The present study looks at the effects of managing a water table to supplement overhead sprinkler irrigation with upward flow. Two drainage systems, controlled and free, were implemented in a cranberry bed constructed of fine sand. The controlled drainage system used existing drain tiles and a sump to maintain an artificial water table, while the free drainage system had no manipulation of the water table. Daily upward flow and water table level were measured in four locations, across the length of the bed, for each drainage system. Comparing upward flow with evapotranspiration (ET) rates, approximately 30% of maximum daily ET can be met by holding a water table between 500 and 600 mm. Numerical simulations indicate that water tables shallower than 500 mm allow for nearly full supply of ET, but at root zone soil water tensions too wet for the best productivity. Field results and model simulations indicate that water table management can be a useful tool in cranberry irrigation.

New recommendations in cranberry production suggest reducing overhead irrigation and the use of subirrigation as an alternative irrigation method, two strategies suspected to increase the risk of salt buildup in soil. Because very little is known about cranberry tolerance to salinity, this study was conducted to determine if deficit irrigation and subirrigation could cause salinity issues and affect plant yield. In a greenhouse, cranberry plants were submitted to eight different treatments combination from two irrigation methods (overhead irrigation and subirrigation) and four salinity levels created by increasing amounts of applied K₂SO₄ (125 (control), 2500, 5000, and 7500 kg K₂O ha^-1). Irrigation methods showed no significant difference in measured electrical conductivity of soil solution (EC_ss). Meanwhile, growth and yield parameters decreased significantly with soil salinity in both irrigation treatments, and an average EC_ss of 3.2 dS m^-1 during flowering caused a 22% drop in relative photosynthetic rate and a 56% decrease in yield when compared with the control. Cranberry seems to be salt sensitive, and further work should investigate EC_ss levels under different field and irrigation practices to make sure that it does not reach critical levels.

A recent study suggests a sensitivity of cranberry to saline stress. Consequently, monitoring of soil electrical conductivity may help growers to identify areas where plants could be under stress due to salt deposits. We used two different types of probes, a time-domain reflectometry (TDR; model CS645 probe) and a capacitive approach (model GS3 probe) to estimate electrical conductivity (EC) or conductance (G). The estimates were compared with measurements of EC in soil pore water using suction lysimeters in a sandy soil exposed to two different irrigation methods and a wide range of salt concentrations in a greenhouse. Linear regression analysis of TDR conductance versus measured EC in pore water gave coefficients of determination (R ²) between 0.24 and 0.98 and required specific calibration to accurately reproduce the suction lysimeter EC values. The GS3 probes had higher R ² values, between 0.54 and 0.98, and were generally easier to work, gave a better accuracy, and had a regression slope not significantly different from 1, result better than with the TDR probes. For both probes, data averaging increased the accuracy in estimates of soil solution EC, as did specific calibration of the probes for the EC values value within the range of 0–5 dS m^-1.

The commercial production of cranberries relies on abundant water resources for frost protection, soil moisture management, and harvest and winter flooding. Given water resource demands and regulations in southeastern Massachusetts, we sought to quantify the annual water requirement for the commercial production of cranberries. Based on 2 yr of monitoring across five sites, the mean water requirement for cranberries was 2.2 (±0.6) m yr^-1 (one standard deviation in parentheses). On average, the 3 mo maximum area threshold of 3.15 ha was within ∼20% of the value currently used to establish water permits for renovated cranberry farms in Massachusetts. Variation in the water requirement was primarily related to differences in the harvest and winter floods, which combined for two-thirds of the annual water requirement. The water requirement for the winter flood exhibited the greatest annual variation (54%), which was relatively low for the harvest flood (20%). Environmental variation was significantly related to water requirements for the winter flood, as well as seasonal irrigation, and should be carefully considered in agricultural water use regulations.

In cranberry production, efficient drainage systems are essential for the development of precision irrigation methods. Most cranberry fields are equipped with subsurface drainage systems used for water table control and excess water removal. Cranberries (Vaccinium macrocarpon Aiton) are highly sensitive to wet soil conditions, and decreases in crop yield are often caused by a malfunction of the drainage system. The main objective of this study was to identify the effect of soil hydrodynamic parameters on subsurface drainage efficiency and cranberry production. During the 2013 and 2014 cropping seasons, real-time measurement devices were installed in 15 fields in the Quebec region, to monitor water table drawdown. Characterization of the soil hydrodynamic properties was done on undisturbed soil cores collected from these 15 fields, and the relationships between drainage efficiency and soil properties were determined. The results of this study highlight the importance of soil hydrodynamic properties on water table drawdown and cranberry yield and showed that nearly 50% of the variance of water table drawdown and crop yield is explained by soil hydrodynamic properties.

Over the last few years, advanced knowledge in cranberry field hydrology has lead to substantial increase in production. Much of this progress has come from knowing the relationship between drainage capacity and soil profile properties. However, drainage problems can occur and an appropriate diagnosis remains essential for making recommendations adapted to each soil type. The objectives of this study were to (1) classify soil profiles under cranberry production and (2) identify diagnostic variables related to drainage capacity. To diagnose and classify drainage capacity, profiles were characterized for many physicochemical and hydraulic properties using a cluster analysis. Results indicate that a criterion can be defined and used to assess drainage capacity with respect to a soil classification scheme based on physicochemical and hydraulic properties. The methodology developed in this study provides a framework to identify local drainage problem and solutions based on soil characteristics.

A payback (PB) period calculation study was performed to evaluate the relevance of using a real-time tensiometer technology to manage irrigation in cranberries. By using wireless tensiometers collecting real-time information at different locations in the field, growers can avoid over or under irrigating some of their beds. They can also identify underlying subsurface hydrological processes that may affect crop growth. The study is based on a survey of problems encountered in the field and on the yield response associated with changes in irrigation practices in case studies and research experiments. It shows that the gains associated with the use of real-time wireless tensiometers and subsequent modifications made to drainage and irrigation in some of the beds generated a PB within a year, in most scenarios, with the price of cranberries between CAN$0.12 and $0.38 lb^-1, for farm operations covering 20–400 ha (50–1000 acres).

Recent research funding, as well as technological and management changes, has led to important scientific discoveries on irrigation and drainage of cranberry that could significantly impact on plant yield and water use. This paper integrates all this information into new proposed guidelines for irrigation and drainage management of cranberry. It explains the interaction of the different concepts, with the most recent ones published in this special issue. Cranberry yield is very sensitive to wet anaerobic conditions (soil matric potential >-4 kPa) or dry bed conditions (<-7 kPa) limiting capillary rise. It also appears that important water savings can be achieving by irrigating by a combination of overhead and subirrigation maintaining the top 15 cm of the bed within those soil matric potential limits and to meet an evapotranspiration demand up to 7.5 mm d^-1, provide frost and heat protection, and avoid salt accumulation, as this crop also appears sensitive to salinity stress. Finally, following plantings, soil properties appear to evolve dynamically and should be followed through profile observations, and combination of soil water potential and ground penetrating radar data, to identify potential yield limitations.