The american cranberry (Vaccinium macrocarpon) is a wetland plant native to North America. The plant is adapted to sandy, nutrient-poor, low pH soils and thus, like blueberry (Vaccinium sp.), its nutritional requirements are low compared with many other perennial fruit crops. Research conducted over the past 30 years has defined the annual requirements for nitrogen [N (20–60 lb/acre)], phosphorus [P (<20 lb/acre)], and potassium (40–120 lb/acre) based on tissue testing, plant growth demands, potential for remobilization, and determination of removal in the crop. These three nutrient elements are those most commonly applied to the crop in fertilizers. However, much of the work on nutrient rate requirements was conducted on native cultivars and there is an expectation that requirements of newer hybrid cultivars are greater. In Massachusetts, cranberries are grown in coastal watersheds and often depend on small lakes as their water source for irrigation, harvest, and winter flooding. Since cranberry production is heavily dependent on water use, the interaction of nutrient management and water management has become a primary focus area for research and extension, particularly for N and P, the nutrient elements most frequently associated with environmental pollution. Recent preliminary research examining cranberry farms with varied configurations (e.g., water passes through the bog and exits via a long channel, water recirculates back into the supply water body) has indicated that the cranberry bogs may act as either a source or sink for N depending on configuration and management activities. In a study of cranberry farms where P use was reduced to an average of <10 lb/acre, P concentration in harvest flood water declined by as much as 85% while crop production was sustained. Site variation in output of N and P in cranberry drainage and flood waters indicates the need for further research into the variables that control these processes, including soil types, site hydrology, nutrient application rates and forms, and water-management activities.
Conversions of parts per million on soil test reports to pounds per acre
