Alfalfa is the most productive and widely adapted forage species.
Idaho alfalfa acreage was 1 million acres in 2011 (NASS 2012) which
was down 130,000 acres from 2010, and down from about 1.25 million
acres in 2003. Production
was 4.3 million tons with an estimated gross value of $958 million
in 2011, second in the US. Forage
yield and quality vary widely across Idaho environments and
operations. The Idaho Agricultural Experiment Station (IAES)
conducts alfalfa variety performance trials at several sites in
southern Idaho including the Kimberly Research and Extension Center.
Over 300 alfalfa varieties are available to US producers, and these
performance trials are designed to assist producers in choosing
Alfalfa varieties are tested for forage yield for at least three
production years on irrigated sites. All trials are planted as
randomized complete block experiments, with four or six
replications. Trials receive adequate fertilization, irrigation, and
weed control for optimum production.
2008 Kimberly Alfalfa variety trial was planted on September 2, 2008
at the University of Idaho’s Kimberly Research and Extension
Center. A 2011 trial was
planted in May 2011 at the Kimberly R&E Center, and in August at
the Brigham Young University-Idaho farm in Rexburg, ID in
cooperation with Greg Blaser, agronomist BYU-Idaho. Seedling-year
production results are limited in value for predicting future
seed industry contributes significantly to the variety trials.
Besides donating the seed, they pay a significant fee to
offset our costs of doing the work.
The Plant, Soil, and Entomological Science Department of the
University of Idaho also contributes significantly in salary and
equipment—the 5-ft forage harvester purchased for our use costs as
much as a big machine.
Forage variety trials give potential yields.
The yields are measured on fresh forage with a moisture
percentage of about 75%. Yields
are corrected to 100% dry matter but there is very little harvest
loss in our trials. Harvest
losses for raking, baling, and stacking dry hay can be as much as
20% of the total dry matter production.
We also intensely manage the plots and we don’t have
traffic on the plots 5-9 days after cutting.
Thus I would expect realistic hay yields about 80 to 90% of
these, however, green chop or haylage yields would be closer.
and potash fertilizer was applied pre-planting.
are listed in rank of highest average yearly yield.
This year yields were not statistically different, so LSD
values are not given. There
is a page full of good varieties!
put too much emphasis on 1-year's data from one location.
I suggest looking at results from the Intermountain region
of Northern California, Utah State University trials, and others
similar in climate.
forage quality data is ranked from highest to lowest neutral
detergent fiber digestibility (NDFD).
Digestibility is inversely related to yield, so
‘Vernal’ had the highest NDFD at 57.0%.
The “LSD” statistic given at the bottom of the table
tells us that varieties with differences less than that value in
that column are not significantly different.
The LSD for NDFD was 2.3 so Vernal was not different for
all varieties in order through 54.7% NDFD, or ‘WL363HQ’.
Trial: This was the
third production year. The
spring and summer was unusually cool with average daily air
temperatures 3 to 5 degrees below normal for May 2011. First
cutting produced an average of 3.0 tons/acre in 2011 compared to
3.24 ton/acre in 2010 and to 3.68 ton/acre average in the years
from 2003-2008. The 2nd,
3rd, and 4th cuttings were near normal
yields. The stands are
Varieties: Vernal is a
public check variety used in all trials.
Vernal should yield near the bottom of the list, however
this year at Kimberly it yielded near the middle, probably a
result of the lower fall dormancy and adaptation to cool weather.
Check 1 and check 2 are several year old commercial
is the most important economic factor for alfalfa profitability.
Average yield over a period of years and at several locations
is a good measure of disease resistance and plant persistence.
Generally, the top yielding 1/3 of the varieties are not
significantly different for yield.
University trials offer neutral testing of varieties but will
not test blends--if the source is different every year, there is no
point to test it. Industry
data can be valuable because it usually is for a longer period of
time, but you should ask for the complete data from the trial, not
just a section of it. Avoid
data with only one year or a single harvest.
Quality--Plant more than one variety, especially if you have large
acreage and are seeking dairy-quality hay.
Varieties with different maturities will reach the cutting
time up to about a week apart, allowing you to cut more hay at the
pre-bud or bud stage. Harvesting
at the correct maturity and agronomic practices (proper irrigation
and weed control) has a larger effect on quality than does variety.
selection is important but not the only factor affecting yield and
quality. Soil fertility
management, irrigation management, weed control, and harvest
management may affect your profit more than variety.
However, almost all newer varieties will yield more and be
more resistant to pests and diseases than the old public varieties!
of Variety Information
University of Idaho Forage Extension: http://www.extension.uidaho.edu/forage/
Hay and Forage Association: http://www.idahohay.com/
Alfalfa Alliance's: http://www.alfalfa.org
American Alfalfa Improvement Conference: http://www.naaic.org/
University of California, Davis: http://alfalfa.ucdavis.edu/
For information regarding the Idaho Hay and Forage Association, email