Blueberry Production Research Project
by Bernadine Strik, Emily Vollmer, Gil Buller, David Bryla and
Department of Horticulture, NWREC, USDA-ARS and Crop & Soil
Science Department, Oregon State University
This project, established as a certified organic planting at the
North Willamette Research and Extension Center, was initiated in
response to industry requests and was designed with input from an
advisory group that included growers using both conventional and
organic production systems, as well as leaders in the nursery and
fresh and processed fruit handling industries.
The long-term goal of this project is to develop organic production
systems for highbush blueberry that maximize plant growth, yield
and fruit quality, facilitate weed, water and nutrient management
and provide economic benefit to growers.
study was established at the Oregon State University NWREC in October
2006 and was certified organic in May 2008. Treatments consist of
two cultivars (“Duke” and “Liberty”), two
production methods (raised bed or flat ground), three weed management
practices (sawdust mulch + hand weeding; compost [yard debris] + sawdust
mulch + organic herbicides as needed; and landscape fabric [weed mat])
and two types and rates of organic fertilizer (feather meal and liquid
fish fertilizer at 25 or 50 lb. N/a in 2007-2009 and 45 and 90 lb.
N/a in 2010).
Blueberry Production research plots at the OSU North Willamette
Research & Extension Center. June 4, 2009.
Our key findings to date are briefly described here. We highlight
this planting at our annual Blueberry Field Day at the NWREC. More
detailed progress reports are available upon request.
Cumulative yield from years two - four (2008-10) was 48 percent greater
on raised beds than flat ground, corresponding to improved plant growth.
Although the soil at this research site is considered to be well-drained,
there was still an advantage to growing on raised beds. Yields for
the raised bed plantings have, in general, been similar to what is
expected for conventional fields, averaging about four tons/acre in
2010 (year four).
On average, plants fertilized with the high rate of feather meal or
the low rate of fish emulsion had the greatest yield, whereas fertilizing
with the highest rate of fish emulsion tended to reduce yield in both
cultivars to date. Leaf tissue %N was higher than recommended levels
in plants fertilized with the high rate of fish.Plants mulched with
yard debris compost topped with sawdust (compost+sawdust) and weed
mat produced greater yield than those mulched with sawdust in 2009
Duke and Liberty had lower fruit firmness when fertilized with the
low rate of feather meal than with fish emulsion or the high rate
of feather meal. Duke fruit were firmer and had higher percent soluble
solids (Brix) when fertilized with a high rate of fish emulsion. Our
goal is to determine why fertilizer is affecting fruit firmness.
Weed pressure has been consistently low with weed mat and high with
compost+sawdust. In 2010, for example, sawdust+compost mulched plots
required 83 hr/acre for hand-weeding and 20 hr/acre for contact herbicide
application (total of 103 hr/acre + $60/acre product) compared to
88 hr/acre to hand-weed in sawdust and 18 hr/acre in weed mat mulched
Percent soil moisture was maintained in a suitable range for good
plant growth through careful management of irrigation. In 2007-09
weed mat plots received approximately double the irrigation water
as sawdust mulched plots, but in 2010 there was less difference in
irrigation applied among treatments. Raised beds required more irrigation
water than flat ground plantings in 2007-09, but not in 2010. We think
these differences are mainly due to soil temperature as affected by
mulch type or depth and plant canopy size (shading). Soil temperature
was warmer under weed mat than under the organic mulches, particularly
in raised bed plantings.
Work on shoot growth rate, fruit bud set, tissue and soil nutrient
status, soil microbial content, weed management, production economics,
root growth and development of a compost suitable for blueberry were
also conducted in 2009-2010 and work is on-going so please stay tuned!
While this planting is still relatively young, growth and yield for
most treatments have been similar to what has been observed in conventional
systems. The best treatments so far have been growing plants on raised
beds with a low rate of fish emulsion or a high rate of feather meal
on either weed mat or compost+sawdust mulch. Economic returns to date
have been comparable to conventional systems, depending on the organic
production method used.
We thank our advisory board members and the organizations that have
provided funding for this project: The Oregon Blueberry Commission,
the Northwest Center for Small Fruits Research, the Washington Blueberry
Commission, the NIFA-OREI grant and industry contributors.
Message from the Chairman
Wing Drosophila Update
A Look Back …
Blueberry Production Research Project
Program Needs Industry Support
Growers to Receive GAP Certification Aid
Fresh Season Promotion On a Roll for 2011
Fees Jump a Bit
Move Increases Insulin Sensitivity
(Spotted Wing Drosophila)
Researcher Driving Blueberries up a Tree
Unveils New “Little Blue Dynamos” Positioning and Campaign
for Highbush Blueberries
World Acreage and
Crop Grant Supports Oregon Berry Festival;
Free Berry Vendor Space Available