Farming, Saturday, July 8, 1995
I*l
Plant, First Cut Early To Fight Alfalfa Weeds
ANDY ANDREWS
Lancaster Farming Staff
LANDISVILLE (Lancaster ble by seeding alfalfa in April
Co.) —The early bird gets the first instead of May and harvesting 60
worm, so the story goes. Just so, days after emergence, said Dr.
early seeding of alfalfa and prompt Marvin Hall, associate professor
harvesting may be the best wea- of forage management at Penn
pons against weeds and their State, at the annual Penn Stale
effects on forage quality, accord- sponsored Weed Reid Day at the
ing to a Penn State forage expert Southeast Research Farm.
As the result of studies underta- On Thursday morning. Hall told
As tho result 0( studies undertaken by Penn State, fewer
weeds and grUMer yields could be possible by seeding
alfalfa In April instead of May and harvesting 60 days after
emergence, said Dr. Marvin Hall, associate professor of for*
age management at Penn State, at the annual Penn State
sponsored Weed Field Day at the Southeast Research
Farm.
Also at th« field day, Dr. Greg Roth, Penn State assistant
agronomy professor, indicated that he has received many
reports from around the state that there has been "lousy
stands in corn.” According to Roth, this could be the result
of insect and fungi'damage to the seed.
Herbicide Studies At Weed Field Da
ken by Penn State, fewer weeds
and greater yields could be possi-
Those attending had a chance to look at a “weed screen” to show the effects of dif
ferent herbicide treatments on a wide variety of weeds.
about 100 fanners and agri
industry representatives at the field
day that, by waiting too long to cut
newly seeded alfalfa in hot weath
er, the alfalfa can’t compete as
well against the weeds.
In the study, alfalfa was band
seeded at 15 pounds per acre into a
tilled seedbed in 1991 at the
research facility and in 1991 and
1992 at the Russsell E. Larson
Agriculture Research Center at
Rockspring at four times during
the growing season. In addition,
various weed control practices
were used.
Researchers observed the weed
severity and control at both loca
tions. using various herbicides at
different application types and
times. Weeds observed included
lambsquarters, pigweed, foxtail,
duckweed, and others, in a range
of 10 percent to 70 percent of total
dry matter harvested.
The question facing the
researchers: do weed control prac
tices in the study increase forage
yield and/or quality?
The research concluded, said
Hall, that "the answer is no, we
didn’t see an increase in yield or
quality," despite the various
chemical applications and under a
range of weed pressures. Even late
summer seeding showed no
improvement in forage quantity or
quality.
The key, according to Hall, may
be to plant and harvest early. Hall
indicated that alfalfa is very com
petitive against weeds early on in
the growing season and can recov
er from a cutting 60 days after
emergence.
This also applies to late summer
seeding. To compete against late
summer weeds. Hall suggests
planting in August versus
September.
But if alfalfa is to be seeded in
fields that lay fallow or were in
another crop, and the weed density
is “horrendous,” the question
remains: will using weed control
practices increase net economic
return per acre?
Hall said, “economically, can
we do it? That is the question.”
The conclusion: different seed
ing dates and weed control prac
tices did not result in consistent
differences in net economic return/
acre during the seeding year, first
production year, or for both years
combined. Early summer seedings
had similar economic returns per
acre in the year after seeding as no
weed control.
When alfalfa is either spring- or
summer-seeded and weed infesta
tions are light to moderate, weed
control practices are not economi
cally beneficial and may slightly
(Turn to Pago A 27)
Dave Messeramith, graduate research assistant In the
department of agronomy, right, provided some detail on the
bur cucumber study at Penn State. At left Is BUI Curran,
Penn State weed specialist.
conventional till com. Steve Cain, operations manager,
Agway In Pleasant Gap, Inspects weed emergence.
Ed Werner, research tech agronomist and master’s can
didate at Penn State, right, provided Information on an
ongoing study of economic threshold study of velvetleaf In
corn. At left is Bill Curran, Penn State weed specialist.