Production Research at the NWREC – Highlights
Strik (Project Leader), Emily Vollmer and Gil Buller (Research Assistants)
and Denise Nemeth (Ph.D. graduate student) in the Berry Crops Research
program at the NWREC are working on several blueberry projects that
are briefly highlighted here. More information on these projects
will be presented at meetings throughout the winter.
long-term goal of this project is to develop organic production
systems that maximize plant growth, yield and fruit quality, facilitate
weed, water and nutrient management and provide economic benefit
to growers. This one-acre trial was in its fifth growing season
in 2011. We don’t have results on treatment effects for this
year yet, because of the very late fruiting season. Cumulative yield
from years two-four (2008-10) was 48 percent greater on raised beds
than flat ground, corresponding to improved plant growth. So far,
yields for the best treatments have been similar to what is expected
for well managed conventional fields. Plants fertilized with the
high rate of feather meal or the low rate of fish emulsion had the
greatest yield. Plants mulched with yard debris compost topped with
sawdust or those grown with landscape fabric (weed mat) produced
greater yield than those mulched with sawdust.
Long-term Impact of N Fertilization and Sawdust Use in Elliott
We are studying the long-term impact of pre-plant incorporation
of sawdust and surface sawdust mulch and nitrogen fertilizer rate
on yield, fruit size, fruit firmness, soil nutrient status and soil
microbiology in Elliott. Nitrogen rates have been increased proportionately
as the planting has aged with rates of 50, 150 and 240 lb. N/acre
used in 2010 and 2011 (years seven and eight). Machine-harvested
yield was 10 tons/acre in 2010. We have found no significant effect
of N fertilization rate, sawdust incorporation before planting or
sawdust mulch on yield in any year of the study! However, plants
fertilized with the high rate of N have had smaller fruit size.
Higher N rates have also reduced soil pH and soil Ca over time and
use of sawdust is affecting soil organic matter and nutrient status.
Denise Nemeth is working with Drs. Strik, Lambrinos and Yang to
study the amount of carbon sequestration in this mature field and
the impact of use of organic matter and N rate on mycorrhizal infestation.
Fruit Set and Berry Development in Blueberry Cultivars
We are working with Duke, Liberty, Bluecrop, Bluejay, Legacy, Draper,
Reka, Aurora, Ozarkblue and Bluegold. Percentage of fruit buds on
one-year-old laterals ranged from 38 percent (Ozarkblue) to 54 percent
(Bluegold) and has varied from year to year. Flower number per bud
has been relatively consistent within cultivars ranging from six
to seven (e.g. Duke, Draper and Legacy) to more than eight (e.g.
Aurora, Bluegold and Ozarkblue). Percent fruit set has been high
(89 to 95 percent), but averaged about five percent lower in wet
springs than dry ones. Fruit firmness has been greatest for Draper
and lowest for Ozarkblue and Aurora, to date. Although there has
been as much as a three-week difference between cultivars in date
of full bloom, this has not been correlated with date of first harvest.
The number of growing degree days required from bloom to full blue
fruit ranged from 550 in Duke to 1,300-1,400 in Aurora. We are studying
the relationship between seed number and berry weight in these cultivars.
The Impact of Hand Harvest Frequency on Yield and Fruit
In 2010 we started a two-year study to compare bushes that are harvested
at a low, medium and high frequency (number of days between hand
harvests) for the impact on bush yield and fruit quality (berry
size, firmness, brix and total acidity) in several commercial cultivars.
In the bushes that are picked at a high frequency, fruit are picked
when they first turn fully blue. In contrast, fruit harvested at
a low frequency are left to hang on the bush longer. We have not
analyzed our data for this year yet.
We thank our advisory board members and the organizations that have
provided funding for these projects: 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
In-State Promotions Keep the Spotlight on Oregon Blueberries
to Discuss Assessment Hike
Korea Gets Fresh with Oregon
Answer to Fruit Safety Concerns
Wing Drosophila Update
Production Research at the NWREC Highlights
Dropped from Pristine and Cabrio Labels
Blueberry Day at the Ag Show, January 24, 2012
Offers Financial Assistance for Energy Audits