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- Author or Editor: Carolyn J. DeMoranville x
Levels of major elements (N, P, K, Mg, Ca) in `Early Black' cranberry (Vaccinium macrocarpon Ait.) tissues changed during the season (April to October). A distinct pattern was associated with each tissue type (old leaves, woody stems, new shoots, roots, fruit) and each element. However, the pattern for a given element in a given tissue was similar from year to year. For example, nitrogen levels in old leaves rose early in the season and then declined in old leaves as new shoot tissue was produced. The early-season rise in nitrogen levels in old leaves coincided with a decline in nitrogen in woody stem tissue. Changes in the amount of applied nitrogen led to changes in nitrogen levels in new shoots after a 2 year Iag. While N, K, Ca, and Mg content (% dry weight) in roots is lower than that in other tissues, there is great biomass of root tissue, so that root tissue represents a large pool of these elements. Roots, along with woody stems and old leaves may represent a reservoir of major elements for new shoot development early in the season, prior to fertilizer application. Levels of the major elements in new shoot tissue achieved a steady state in August, an indication that this is a good time to collect tissue for routine testing.
In Massachusetts, cranberry (Vaccinium macrocarpon) bogs were historically developed in existing wetlands and new plantings are now established in mineral soils that are converted into constructed wetlands. To streamline the interaction between cranberry farming and wetlands protection, the state has defined “normal agricultural practices” that are exempt from wetlands regulations under certain circumstances. As part of that process and to qualify for the exemption, farmers are required to have a conservation farm plan and demonstrate the use of best management practices (BMPs) on their farms. The University of Massachusetts Amherst Cranberry Experiment Station (UMass Cranberry Station) was engaged to bring together the U.S. Department of Agriculture, Natural Resource Conservation Service (NRCS) and cranberry industry representatives to define BMPs specific to cranberry farming practices. Initially, the documents were reviewed by scientists and regulators for soundness of science and rigor of environmental protection. A grower committee reviewed the proposed BMPs to determine if the BMPs could be implemented on real farms. The next stage of the project consisted of defining areas where more research was needed to formulate good BMPs. In particular, research projects were initiated to study nitrogen and phosphorus nutrition. This research has become the basis for nutrition BMPs, national cranberry nutrition guidelines, and standards used by NRCS for cranberry nutrient management plans. The cranberry BMP project has continued with a regular cycle of revision and additions based on grower-identified needs for horticultural and environmental guidance. This connection to the growers, along with the regulatory link, accounts for the widespread adoption of BMPs in the cranberry industry. Local NRCS estimates that 75% to 80% of Massachusetts cranberry growers have current conservation farm plans that include BMP implementation.
Competition between fruit and upright growth in cranberry has not been previously studied, but negative correlations reported between upright length/dry weight and yield indicate that sink demand from vegetative tissues may reduce fruit production. `Stevens', `Howes', and `Early Black' uprights and fruit were collected on either a weekly or bi-weekly basis through the growing seasons of 2002–04. The data indicated a shifting of resource allocation from leaf area and dry weight accumulation to fruit growth when about 1500 growing degree days (GDD, base 4.5 °C) had accumulated. Following the initial surge in fruit growth, leaf area and dry weight accumulation resumed at roughly 2300 GDD, resulting in a competition for resources with the developing fruit until after 3000 GDD. A lag phase in fruit diameter and dry weight accumulation was noted in some cultivars in some years, and may be partially due to the resumption of leaf growth. Roots, uprights, and fruit may all compete for resources during the hottest portion of the growing season.
Field conditions associated with commercial cranberry (Vaccinium macrocarpon Ait.) production were simulated in greenhouse studies to determine the effect of soil surface characteristics on dichlobenil activity. Sand was compared with organic matter, in the form of leaf litter, as the surface layer. A seedling bioassay using alfalfa (Medicago sativa L.), a dichlobenil-sensitive plant, was employed to determine root growth response on herbicide-treated soil. When the herbicide was applied to a sand surface, root growth was greater as time after application elapsed, indicating loss of herbicide activity. Conversely, the presence of organic matter on the surface prolonged the activity of the herbicide. Composition of the surface layer was more important than the depth of the layer in determining herbicide persistence. The influence of cultural practices, such as the application of sand or the removal of surface debris, on herbicide activity should be considered when planning weed management strategies for cranberry production. Chemical name used: 2,6-dichlorobenzonitrile (dichlobenil).
It has been speculated that cranberries are susceptible to chloride injury. If this is the case, it is possible that applications of high rates of 0-0-60 (KCl) fertilizer as a K source could be detrimental to cranberry productivity. Grower anecdotes of using 0-0-60 to “shut down the plants” persist. Supposedly, using 225+ kg·ha-1 of this material slows or arrests vegetative growth. In fact, growers have claimed it can overcome the production of rank vegetation that results when too much N fertilizer has been applied. Field plots were initiated to determine the suitability of KCl and to determine if high K rates could overcome the deleterious effects of excess applied N. Plots were set up in a split-block plot design with N doses [three each “normal” (28-34 kg·ha-1 N) vs. “high” (56-67 lb N/A)] in one direction and potassium/chloride treatments in the other direction (KCl or K2SO4 at 115 or 225 kg K2O; CaCl2 to give the equivalent Cl as in the high-rate KCl treatment, and a nontreated control) for a total of 36 2 × 2-m plots per each of three cultivar locations. Plots were treated and evaluated for three consecutive years. There were no significant differences in yield among the K2SO4 and KCl treatments, indicating that at rates as high as 225 kg·ha-1 K2O, 0-0-60 and 0-0-50 perform similarly. Further, treatment with CaCl2 had no significant effect on yield. In the third year, plots receiving no K treatment had significantly lower yield than those receiving either rate or form of K (single degree of freedom comparison, significant at 0.03). These results indicate that at the rates used in this study, KCl is an adequate K source. The effect of N rate was more pronounced than that of the K treatments. In years two and three, the low N rate strips had significantly greater yield compared to that in the high N rate strips. By year two, the high N strips were visually different, with rank overgrowth. There was no significant interaction of N rate and the K treatments. While there was a trend for greater difference between the 0 K and 115 kg K rates in the high N plots compared to the moderate N plots, the addition of K never entirely overcame the negative yield effects of high N rate.
Competition between reproductive and vegetative growth has not been studied in cranberry. The objective of this research was to assess the growth patterns of leaves and fruit in three cranberry cultivars to determine whether vegetative and reproductive growth compete for resources. ‘Stevens’, ‘Howes’, and ‘Early Black’ uprights and fruit were collected on a weekly basis in 2002 and on a biweekly basis in 2003 and 2004 from a research bog in Massachusetts. Although growth was affected by cultivar and year, data indicated a general shifting of resource allocation from leaf area and dry weight accumulation to fruit growth at ≈1500 growing degree days (GDD, base 4.4 °C), when the initial surge of fruit growth began. Leaf area and dry weight accumulation resumed at ≈2300 GDD, resulting in a competition for resources with the developing fruit until after 3000 GDD. A lag phase in fruit diameter and dry weight accumulation was noted in some years and some cultivars and may be partially the result of the resumption of leaf growth at 2300 GDD. Fruit and shoot growth appear to compete for resources in late July through early August in Massachusetts, when carbohydrate concentration of uprights and roots is extremely low.
Four nitrogen rates (0, 50, 100, and 150 lb/acre) and four spring pruning severities (none, low, medium, and high) were applied annually in all combinations at two commercial ‘Stevens’ cranberry (Vaccinium macrocarpon) farms in southeastern Massachusetts for 4 years (consecutive). Because runners generated from pruning vines are used to establish new plantings, determining the vine weight generated from each treatment combination was an important criterion for the economic analysis; these data were collected each spring. Mean pruning weight across nitrogen treatments at both locations, collected from the low, medium, and high severity pruning treatments, was 0.17, 0.35, and 0.54 ton/acre, respectively. Economic analysis of the data indicated that nitrogen rate largely determined net income revenues; pruning severity did not significantly affect net income. Nitrogen rates of 100 and 150 lb/acre led to declines in fruit yield and ultimately, in net income. Annual removal of 0.5 ton of vines per acre while applying 50 lb/acre nitrogen did not negatively impact net income values over the 4-year study period. When deciding on horticultural management options for vine propagation, growers should consider the impact of their fertilizer program on fruit yield.
A 2-year field trial examined the interaction of nitrogen rate, vine density, and weed management options for establishing new cranberry (Vaccinium macrocarpon) plantings. Utilizing the vigorous hybrid, `Stevens', the cost-efficiency of the treatment combinations was evaluated by combining cranberry and weed biomass data with various economic estimates. The most cost-effective production scheme for establishing new cranberry beds is to plant vines at a low density, use moderate rates of nitrogen, and apply an annual application of a preemergence herbicide. This combination produced substantial vine coverage at very low cost, reduced weed biomass by 85% compared to untreated plots, and gave the best weed control per dollar spent. Growers may opt for other reasonably successful combinations that involve higher labor costs if they can produce their own cuttings (reducing initial costs) or if they are farming with the intent to reduce overall synthetic inputs.
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.
Numerous observations of yellow vine syndrome of cranberry have been reported from commercial cranberry growers. The molecular mechanism resulting in yellow vine syndrome is unknown. We have previously reported on the shading effect as an approach to explore the mechanisms of yellow vine formation and proposed photoinhibition as a possible cause. To compare the photosynthetic performance of yellow vine-affected and normal cranberry leaves, we conducted chlorophyll fluorescence analyses over 1 period of 1 day and 3 weeks, respectively. Both experimental data sets indicated that the maximum quantum efficiency of photosystem II, the size of the quinone pool, the numbers of reaction centers (RCs) per chlorophyll absorption, and the photosynthesis performance index of the yellow vine samples are substantially lower than those of normal cranberry leaves. These results are in line with the data of yellow vine leaves, having 26% to 28% less in chlorophyll than the normal leaves as measured by spectrometric and high-performance liquid chromatography analysis. We concluded that yellow vine syndrome is associated with poor photosynthetic activity and is likely becoming a threat for the long-term growth and crop production of cranberries.