Dave Lockwood, Jim Wills, Dennis Deyton, Gary Honea, and R. Allen Straw

This year marked the third year of this blueberry project. Canopy volume was determined to estimate growth. Temperature and moisture were measured beneath the plastic at the Plateau Experiment Station (PES) in Crossville, the Highland Rim Experiment Station (HRES) in Springfield, and the Middle Tennessee Experiment Station (MTES) in Spring Hill. The Knoxville Experiment Station plot was discontinued due to poor performance. MTES had the highest canopy volume measurement with 27.3 cubic feet followed by PES with 19.8 cubic feet, and HRES with 18.1 cubic feet. Only MTES was statistically different from the other two. Regarding treatments the black ground cloth had the highest canopy volume with a mean of 28.6 cubic feet and the bare treatment was the lowest with 16.0 cubic feet. The mean canopy volume by variety was 32.3 cubic feet for the Tiftblue (Rabbiteye) and 11.4 cubic feet for the Bluecrop (Highbush). The statistical analysis indicated a significant difference between the two varieties.

There is growing interest in producing blueberries across the state of Tennessee. Blueberry consumption has not been as high in Tennessee as in some northern states. However, with the influx of people from northern areas into Tennessee who bring with them a taste for blueberries as well Tennessee natives who are finding out about the many good qualitites of the blueberry that relate to health, the potential for increasing blueberry production is very good. Two of the basic types of blueberries are the Highbush and the Rabbiteye. Research was needed to evaluate at least one variety of each type and to evaluate various production systems for a period of five to ten years.

Two varieties of blueberries were selected for the trial that were expected to do well in Tennessee. The Rabbiteye variety selected was Tiftblue and the Highbush variety was Bluecrop. The Bluecrop plant pollinator was Duke. The Tiftblue plant pollinator was Centura. The experimental design was randomized complete block with a split plot factorial arrangement of treatments. There were five treatments: raised bed with no mulch, raised bed with sawdust mulch, raised bed with black woven polyethylene ground cloth, raised bed with black woven polyethylene ground cloth and with sawdust on top, and raised bed with black woven polyethylene ground cloth painted white. All treatments were on raised six inch beds four to five feet wide with trickle irrigation and the capability to fertigate through that irrigation system. The five treatments were replicated four times. Pollinators were placed in border rows on each side of the plots, at one end of each treatment rows, and approximately midway down the row of each treatment. Each treatment row consisted of five plants

of each variety and two pollinators for a total of 12 plants. Initially research blueberry plots were placed at the four UT experiment stations: Knoxville Experiment Station, Plateau Experiment Station, Highland Rim Experiment Station, and the Middle Tennessee Experiment Station. Due to poor performance the plot at KES was discontinued . As at the other experiment stations the soil was amended with sulfur to bring the pH down into the proper range of 5.2 to 5.5. Within a year the pH again rose to above 6.5 and could not be lowered with the methods used. A combination of low pH and misapplied cultural practices resulted in a loss of over half the plants in that particular plot. Plots at each station were basically the same with minor variations commensurate with the limits of the individual locations. The first year the plot at the Knoxville Experiment Station was instrumented to record temperature and moisture at 12-13 cm ( 5 in ). In 2002 the other three remaining locations were instrumented as well to record temperature and moisture in the root zone. The fruit and blooms were pruned the second and third year to enhance plant development. Beginning next year, the fourth year, the plants will be allowed to produce and yield will be recorded.

Results and Discussion

The first year mortality was evaluated. The second and third year canopy volume was determined. The results of the canopy volume determinations are presented below. Table 1 depicts the canopy volume by experiment station location for 2001 and 2002. Table 2 depicts the canopy volume by treatment for those same two years, and Table 3 depicts the canopy volume by variety. The results of the temperature and moisture are not available for this year.

Table 1. Canopy volume by experiment station location in 2001 and 2002.

Means within a column followed by the same letter are not significantly different at the 0 05 level of probability, Duncans’s multiple range tests.

Table 2. Canopy volume by treatment for 2001 and 2002.

Means within a column followed by the same letter are not significantly different at the 0 05 level of probability, Duncans’s multiple range tests.

Table 3. Canopy volume by variety for 2001 and 2002.

Means within a column followed by the same letter are not significantly different at the 0 05 level of probability, Duncans’s multiple range tests.

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Copyright © 1999 by The University of Tennessee. All rights reserved.

This research represents one season's data and does not constitute recommendations.  After sufficient data is collected over the appropriate number of seasons, final recommendations will be made through research and extension publications.