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.

The American cranberry (Vaccinium macrocarpon Ait.) is an important part of the cultural heritage and economy of Southeastern Massachusetts, yet water quality concerns and wetland protection laws challenge its commercial production. Here, we report inputs and outputs of water, nitrogen (N), and phosphorus (P) for a 2.12‐ha cranberry bed over a 2‐year period from 2013 to 2015. Water‐budget analysis indicated that precipitation contributed 40%, floodwater 37%, irrigation 15%, and groundwater 8% of water inputs to the cranberry bed. Minor annual variation in surface water discharge (~90 mm·year−1 or 3%) contrasted with large decreases in net (= outputs − inputs) nutrient export, from 16.2 to 9.1 kg N·ha−1·year−1 for total (dissolved + suspended particulate) nitrogen (TN) and from 3.34 to 1.47 kg P·ha−1·year−1 for total phosphorus (TP) between Years 1 and 2. Annual variation in net TN and TP export was tied to decreases in spring and summer nutrient export and controlled by the combined effects of fertilizer management, soil biogeochemistry, and hydrology. The relatively high spring TN export in Year 1 was associated with coincident increases in soil temperature and rainfall. A second factor was the timing of fertilizer application, which occurred 1 day prior to a major summer storm (i.e., third largest daily rainfall since 1926) and was responsible for up to 15% and 9% of the Year 1 TN and TP export, respectively. Nutrient budgets, which balanced water and fertilizer inputs with water, fruit, and vegetative outputs, were consistent with the burial of 21.6 kg N·ha−1·year−1 and 7.27 kg P·ha−1·year−1. Field measurements indicated that burial would increase TN and TP in the shallow (0–5 cm) rooting zone by 14% and 6%, respectively, which seemed plausible based on the relatively young age of the bed (4–5 years) and new root growth patterns in Vaccinium plants.