No-till doesn’t cause disease buildup
BY DORIS CROWLEY
NEWARK, Del. When farmers
across the nation began climbing
onto the no-till bandwagon a few
years back, many scientists ex
pressed concern that this time- and
energy-saving production practice
might favor the build-up of certain
pest problems. Plant pathologists
worried that the vegetative mulch
which is no-till’s most charac
teristic feature would harbor
disease causing organisms and
cause serious future crop losses.
Fortunately, those fears haven’t
been borne out by experience - at
least not in Delaware, according to
Robert B. Carroll, a plant
pathologist at the University of
Delaware Agricultural Ex
periment Station.
A careful scientist, Carroll
shared the early concerns of his
colleagues about no-till. Today,
though he can’t say this cropping
system won’t ever lead to disease
build-ups, he’s ready to give it the
green light - at least for the
pathogens he’s studied. Several
years of research on soybeans and
recent work with com have con
vinced him that the increase in
diseases he’s seen on these crops is
due primarily to other causes.
Disease concern
“Most plant pathologists ex
pected no-till to increase plant
diseases,” Carroll explains. “With
no-tillage you permit crop debris to
remain on the soil surface, rather
than incorporating it, so we
thought this practice would cause a
build-up of many different
pathogens - particularly those
affecting root and basal stem
tissues of plants.”
Since sanitation - through burial
of potentially diseased vegetation
by plowing - has been a major
i ;
/iuf Mail today
/ W |Vjl NuPulse America, Inc
C 908 Stewart St.
W FEEDING EQUIPMENT Madison. WI 53713
Please send more information
i NAME
J ADDRESS
J CITY
means of plant disease control for
centuries, there was good reason
for this concern.
Research into the relationship
between no-till and plant disease
has been going on for about 10
years, but pathologists are just
beginning to feel comfortable with
their findings. Not all agree about
the results. And not all the results
agree. Some studies do show in
ceased problems with no-till under
certain circumstances.
“But,” says Carroll, “to a large
degree our fears have not been
justified. I think the encouraging
thing is that the picture isn’t all
bleak.”
Helps plants
Based on his observations, no
tillage may actually help plants
overcome the effects of some
diseases. This may be due to the
moisture-holding benefits of no-till
mulches. Since moisture stress
contributes to the development of
certain diseases, reducing stress
on plants may counter the effect of
a pathogen build-up in crop debris
left on the ground.
Carroll has investigated the
effects of no-tillage on two crop
diseases which are a serious
problem in Delaware - stalk rot of
com and Fusarium blight in
soybeans. Both can cause heavy
yield losses.
To determine the effect of no
tillage on stalk rot and standing
strength of field com, one of his
graduate students, Ken Byrnes,
conducted an experiment last
summer at the university’s
Georgetown substation on both no
till and conventional com. Plots
were planted into a hairy vetch
cover and irrigated at various
rates over the growing season.
Byrnes found that stalk standing
omputrac is priced to make computerized feeding affordable. Otten,
)ted to your present system to reduce the cost even more Computrac
doesn’t have to be more expensive to be better Call or write to find out how you can cut your feed bills.
STATE
strength and yield increased
significantly under no-till. '
Water makes difference
He also found that stalk rot and
lodging were not significantly
different under the two tillage
treatments, though adequate
water did make a difference.
Timely irrigation to minimize
drought stress generally resulted
in less stalk rot and greater stalk
strength in both no-till and tilled
plots.
Besides showing that com plants
may have better standability
under no-till, this study promises
to provide valuable information on
irrigation scheduling to avoid
lodging problems. It will be
repeated this summer.
Carroll also has been in
vestigating the possible effect of
no-till on Fusarium blight in
soybeans. Because Delaware
farmers began having trouble with
this disease at about the same time
they started to increase their no
till soybean acreage, it looked like
there might be a connection bet
ween the two events.
Monocropping
But after seven years of
laboratory, greenhouse and field
research, the plant pathologist no
longer associates no-till with the
spread of Fusarium blight. In-,
stead, he blames faulty
management practices like
monocropping and the use of
susceptible varieties.
“I’m fairly confident that a
major factor in the spread of this
disease is the continued cropping
of-soybeans in the same soils,” he
says. “Our observation and that of
our county extension agents has
been that Fusarium becomes a
problem where a farmer con
tinuously grows soybeans in the
you can afford
to cut feed bills
You not only save feed, you can actually increase
milk production by bringing each cow to maximum
production sooner and maintaining the peak longer
Computrac is easy to learn and easy to use, for stand alone
tenzed feeding or as part of an expanding farm management system.
You can't afford not to
ENDLESS MOUNTAINS
HARVESTORE SYSTEMS.
INC.
Towanda, PA 18848
1-717-265-2200
same soil. It’s the kind of pathogen
that builds up large populations in
the presence of a susceptible host
when conditions are right.”
He says the disease is less of a
problem on heavier soils in the
state. This may have something to
do with moisture stress and the
moisture holding capacity of the
soil. It may also depend on the
varieties grown. In a current
experiment station project being
funded in part by grants fromt he
Delaware Soybean Board and
Asgrow Seed Company, the
pathologist is screening soybean
varieties for resistance or
tolerance to Fusarium blight.
Carroll’s findings on the safety of
no-till from a crop disease stand
point should please Delaware
grain farmers; the state now leads
the nation in percent of no-till
acreage grown.
Despite his general optimism
about this cultural system in terms
of the diseases he has studied,
however, the plant pathologist still
feels it’s unwise to say ther may
HARRISBURG
production in Pennsylvania during
April totaled 768 million pounds,
down one percent from last year
according to the Pennsylvania
Crop and Livestock Reporting
Service. The number of milk cows
in the commonwealth during April
averaged 718,000 head, down 16,000
head from a year ago. Milk
production per cow averaged 1,070
Feed costs make up more than half the cost of producing milk.
Maybe you can’t do much about teed prices, but you can
increase feeding efficiency. With a Computrac feeding system,
you automatically adjust each cow’s feed ration to her specific
stage oflactation or adjust for the precise ration you want.
OMPUTRAC DEALERS
WESTERN PENN-JERSEY
PENNSYLVANIA PRODUCTS. INC.
HARVESTORE SYSTEMS. New Holland, PA 17557
INC. 1-717-354-4051
Slippery Rock, PA 16057
1-412-794-4093
Leads nation
Milk down one percent
Milk
never be disease problems related
to no-tillage.
“.Not enough studies have been
done yet with specific disease/
crop combinations to answer all
the questions,” he says. “Probably
every major crop disease situation
needs to be examined because
there can be subtle differences
which favor disease build-up in one
case and not in another.”
Such research could provide
ammunition for disease pest
management programs and be of
great benefit to farmers, the
scientist says. “If we had a good
data base on various important
disease/ crop combinations, that
information would fit very nicely
into any package of recom
mendations for disease control.
Thanks to Carroll’s work,
Delaware extension specialists
and county agents already can say
to farmers, “Yes, it’s safe to plant
your soybeans no-till without fear
of an increase in Fusarium
blight.” They can also advise
growers on management practices
which will reduce the incidence of
this disease.
pounds in April, up 15 pounds per
cow from a year ago.
United States milk production
during April totaled 11.7 billion
pounds, down two percent from the
previous year. Total milk cows
averaged 10.9 million head, 34,000
less than April 1983. Production
per cow averaged 1,075 pounds,
four pounds less than a year
earlier.