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- Author or Editor: C.J. DeMoranville x
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Like many fruit crops, the difference between vegetative and reproductive production in cranberry is strongly influenced by nitrogen supply, as is fruit quality. However, the optimal supply for this crop has not been established. Further, there have been mixed results on whether or not cranberry can metabolize nitrate nitrogen. Within the past 6 years there has been an upsurgence in research on cranberry nitrogen nutrition and it has started to provide answers to some of these unknowns. Results from the lab of L. Peterson (U Wi - Madison) have shown that cranberry will take up nitrate nitrogen, however the uptake is minimal unless ammonium nitrogen is present. The work from Peterson's lab has also shown that there is some nitrate reductase activity in cranberry leaves, albeit at very low levels. Work that we have conducted and work by J. Hart's group (OSU) have been the basis for establishing optimal nitrogen rates and timings for cranberry in the different growing areas in North America. Overall, the work from these different groups has shown that except in extreme situations, 22 - 33 kg N/ha is optimal for cranberry production. However, timing of application varies widely due to weather conditions in the different growing areas.
Biennial bearing has long been thought to occur in cranberry (Vaccinium macrocarpon Ait). Researchers have shown that percent return bloom on fruiting uprights can range from 12% to 65% depending on year, bed vigor and cultivar. Resource limitation and/or hormonal factors in a fruiting upright may be related to flower bud initiation and, thus, percent return bloom the following year. This research was undertaken to determine the extent of biennial bearing by cranberry cultivar and growing region. Seven cultivars were studied; three found in all states (MA, NJ, WI, OR), two common to MA and NJ, and two different cultivars in WI and OR representing cultivars commercially grown in these areas. In the fall or winter of 1989/1990 six 2-m transects were randomly selected within a cranberry bed for each cultivar. Along the transect, 60 uprights that fruited in 1989 were tagged. In the summer of 1990, fifty of the uprights will be sampled to determine percent return bloom and percent set.
Biennial bearing has long been thought to occur in cranberry (Vaccinium macrocarpon Ait). Researchers have shown that percent return bloom on fruiting uprights can range from 12% to 65% depending on year, bed vigor and cultivar. Resource limitation and/or hormonal factors in a fruiting upright may be related to flower bud initiation and, thus, percent return bloom the following year. This research was undertaken to determine the extent of biennial bearing by cranberry cultivar and growing region. Seven cultivars were studied; three found in all states (MA, NJ, WI, OR), two common to MA and NJ, and two different cultivars in WI and OR representing cultivars commercially grown in these areas. In the fall or winter of 1989/1990 six 2-m transects were randomly selected within a cranberry bed for each cultivar. Along the transect, 60 uprights that fruited in 1989 were tagged. In the summer of 1990, fifty of the uprights will be sampled to determine percent return bloom and percent set.
This research was undertaken to document the extent of biennial bearing in flowering uprights by American cranberry (Vaccinium macrocarpon Ait) cultivar and growing region. Seven cultivars were studied: three found in all states considered (Massachusetts, New Jersey, Wisconsin, Oregon), two common to Massachusetts and New Jersey, and two other commercially grown cultivars, one each from Wisconsin and Oregon. There were significant cultivar, region, and cultivar × region interaction effects for both percent return bloom (%RB) and percent return fruit (%RF). Percent RB ranged from 74% for `Ben Lear' in Wisconsin to 14% for `Howes' in New Jersey. `Ben Lear' differed the most in %RB among regions, from 74% in Wisconsin to 14% in Massachusetts. However, in some regions, especially in Wisconsin, many blossoms did not set viable fruit. There was no significant difference in %RB among cultivars grown in Massachusetts or Oregon; however, cultivars grown in these regions did differ in %RF.
Biennial bearing of uprights has been documented for cranberry (Vaccinium macrocarpon Ait.). Percent return bloom (%RB) may vary from 14% to 74% depending on cultivar and growing region. Floral initiation for the following season in cranberry takes place during the same time period as flowering and fruit set for the current season. This research was undertaken to document the effect of fruiting or not fruiting in the previous year on %RB and %RF (return fruit) in two cultivars (Stevens and Ben Lear) and five growing regions (MA, NJ, WI, OR, WA). Previous year fruiting caused a reduction in %RB compared to non-fruiting in the previous year. The effect on %RF was even greater. For `Ben Lear', uprights that fruited in 1990 had 31%RB and 22%RF while those that did not fruit in 1990 had 67%RB and 54%RF. Both %RB and %RF in 1991 were about 49% lower for `Stevens' which fruited in 1990 than those that did not fruit in 1990. It is still not clear whether biennial bearing in cranberry uprights is a function of hormonal interaction and regulation or of resource limitation or both.
Nitrogen fertilizer application is a universal practice among cranberry growers. Cranberries only use ammonium nitrogen sources. This study was undertaken to discover how quickly cranberries in the field would take up fertilizer-derived ammonium nitrogen. Ammonium sulfate labeled with 15N was applied in field locations in Oregon, Massachusetts, New Jersey, and Wisconsin. Samples of current season growth were collected daily for 7 days beginning 24 hours after fertilizer application. In all cases 15N was detectable in the plants from treated plots by 24 hours following application. Additional nitrogen was taken up for the next 3 to 5 days depending on the location. With the exception of Oregon, the maximum concentration of 15N was found by day 7. Oregon was the coolest of the sites in this research. To determine a temperature response curve for N uptake in cranberry, cranberry roots were exposed to various temperatures in aeroponics chambers while vines were at ambient greenhouse temperatures. The optimum temperature for N uptake by cranberry vines was 18 to 24 °C. This research suggests that ammonium fertilizers applied by growers and irrigated into the soil (solubilized) are taken up by the plant within 1 day following application. Soil and root temperature is involved in the rate of N uptake.