Summer 2006 - Vol. 6/No. 3
Part I: Growers review winter cover crops, conservation tillage
[Editorís Note: This article was originally printed in two parts, with Part I appearing in Vol. 06, No. 3 and Part II appearing in Vol. 07, No. 1. This HTML version contains the complete article.]
Several growers and UC Cooperative Extension personnel who cooperate on the SAFS project discussed
farming practices at Sano Farms in Firebaugh. L-R: Yolo County farm advisor Gene Miyao, Sano Farms farm
manager Jesse Sanchez, Yolo County farmers Bruce Rominger and Tony Turkovich, and UCCE vegetable crops
specialist Jeff Mitchell.
(photo by Z. Kabir)
Growers have been part of the interdisciplinary SAFS/CIFS team since the
project's inception at UC Davis in 1988. From the start, the project's
focus was to combine the best features of both on-farm and experiment station research. It was
established under controlled conditions on a research farm, yet considers the
practical applicability of its farming practices, which are regularly evaluated
by farmer cooperators. At least three growers representing organic and conventional
farming operations and two UC Cooperative Extension farm advisors have participated
in all major project decisions. One of the basic premises of the project was
that organic and low-input farming systems must be economically productive
to be adopted by farmers. Research at the SAFS project has long demonstrated
the importance of premium prices, and the need for cost-effective and reliable
fertility and weed management practices to achieve economic viability.
The SAFS project receives attention each year from farmers, industry, researchers,
and the general public. Ideas that were once considered to be impractical or
radical are gaining in popularity. As consumer demand for organic foods increases,
more growers are considering the transition to organic farming systems and
seek out the SAFS/CIFS team to get information and advice. Others are simply
interested in reducing costs or improving soil quality. Information and experience
generated by the project since 1989 is valuable in informing growers of some
of the agronomic, economic, and ecological consequences of their many options.
At a panel discussion at the SAFS field day in June 2004, four growers representing
diverse farm sizes and growing practices discussed the importance of crop and
system diversity in their operations (http://www.safs.ucdavis.edu/newsletter/v05n2/page3.htm).
We recently checked back with them and several other growers who have worked
with the SAFS project to discuss their use of conservation tillage and cover
crops, and what researchers could do to help other farmers adopt these practices.
Jeff Main. Jeff and Annie Main have farmed organically on
20 acres in the Capay Valley since 1984. They continue to plant a variety of
cover crops on their farm, where they grow 60 to 80 different tree and annual
crops. Cover crops can be used to provide much more than weed suppression and
nitrogen, Jeff Main said.
"Farmers have just scratched the surface on cover crops," he said. "There
are lots and lots of varieties. We don’t want to limit ourselves to what
we traditionally consider to be cover crops, i.e. legumes and grasses."
Main said he hasn’t made major changes in his farming systems, which
includes the use of deep-rooted cover crops instead of deep tillage.
"Good farmers would put more back into their soil if they could, but
if the resources aren’t there, obviously they cannot," he said. "Farmers
are innovators, but without time or money, it’s hard to expect innovation
and creative thinking."
Main noted that this year his farm must pay $600 for a new insurance policy "strictly
to cover our presence at the Davis Farmers Market for liability."
"It’s a brand new cost, forced on us," he said. "This
new coverage equals our cover crop budget for the whole farm. The trend
is toward more protection and more regulation, and every one costs more time
or money or both."
Charlie Rominger. Charlie Rominger is a partner in a 2700-acre
family farming operation in Yolo County, which is moving toward more
organic, more no-till and less conventionally farmed land. In 2005, they enrolled
in the federal government’s Conservation Security Program through the
Natural Resources Conservation Service, which pays farmers for using conservation
practices rather than for producing commodity crops. Some of the Rominger fields
qualified for incentive payments, but others did not.
"Even though on one field we had hedgerows, a tail-water pond and a
windbreak, we did not qualify for incentive payments because we used conventional
tillage at that site," Rominger said. "In order to expand our conservation
tillage, we bought a conservation tillage bed implement, which chews
up the residue but leaves most of it on the surface."
His biggest disappointment was that the federal conservation program couldn’t
"We made the changes, but then the government froze the budget for the
conservation program and we didn’t get the reward," he said. "Incentive
programs do encourage farmers to be innovative, but only if there is
Rominger said he has learned from conservation tillage research, and would
like to see research on a "true no-till farming system" for irrigated
row crops in the Sacramento Valley, including a more diverse crop rotation
Frank Muller. Yolo county farmer Frank Muller uses winter
cover crops and conservation tillage to various degrees on different crops
he farms both organically and conventionally with his large family operation,
Joe Muller and Sons.
"We do include winter cover crops on some target crops," he said. "We
use them ahead of our later planted tomatoes so we can follow best management
practices and not fight putting them in when the ground is too wet. But
we avoid practices that compromise our yield goal."
Muller said he is interested in learning about practices that help him save
money while producing the same or increased yields.
"You want your expectations to always be high—we want to incorporate
these more sustainable practices and hopefully increase yields," he said. "Once
our yield bar has been set, we will not lower our expectations."
He noted that his operation’s use of conservation tillage has been
very successful in some crops.
"We raise a lot of sunflower seeds," he said. We have our tillage
program down to one pass with a stalk chopper after the sunflower harvest
before we plant wheat. Without a doubt, we are successful using conservation
Muller noted at the other end of the spectrum, he uses more conventional
tillage in high value crops like tomatoes or peppers.
"With tomatoes we can’t have a lot of residue on top of the bed
because trashy conditions make harvest difficult," he said. "We’re
numbers people here. If it’s less cost effective in the big picture,
it doesn’t make sense."
Muller said his operation’s tillage has changed quite a lot in the
last few years; the number of field passes has been reduced 60 percent,
but many standard implements are still used.
He said if farmers can see that alternative farming practices consistently
provide greater returns, they would readily adopt them.
"People can see that some farmers are having success using cover crops
and reduced tillage, and they see diesel prices rising so they want to adopt
these practices," he said. "But we also have to see that they provide
The problem for him, Muller said, is that what works on one farm in one microclimate,
may not work for him.
"I’d like to see a project that focuses on maximizing return.
Researchers should identify the model of best management practices, including
conservation tillage and winter cover crops," he said. "The goal
of this project would be to create an economic model that is superior
to conventional models. Lower costs, higher yields, and greater environmental
benefits will draw a crowd."
Paul Underhill. Yolo County organic farm
partner Paul Underhill said he has increased the planting of fall cover
crops (grasses) on 220-acre Terra Firma Farm. The cover crops are irrigated
in October and mowed after they have "frosted down," which has worked well as
preparation for summer cash crops. Unfortunately, during 2006’s very
wet spring, winter cover crops like vetch are still green and won’t be
turned under in time for summer cash crops.
"Our vetch cover crops will work better this year if we wait to plant
the cash crops until fall and winter," he said. "That takes some
of the stress out of using winter cover crops."
He said the extended rain, which has made it impossible to incorporate or
mow winter cover crops on time, is what big growers fear—they can’t
get into fields and plant 500 acres of a cash crop quickly on saturated
"We like to plant cover crops before our biggest cash crops," he
said. "Our organic plants produce way bigger yields after winter cover
Although Underhill said it would be useful for smaller farmers to share the
use of expensive planting and mowing equipment for cover crops, he noted
that wet years underscore why it is hard to share equipment: "during the
few dry windows for mowing or planting, everyone wants to use the equipment."
He said he appreciates reading the SAFS/CIFS project research results and
was especially interested to see that researchers had documented a phenomenon
he and other organic growers have seen on their land—the use of cover
crops has helped build up soil nitrogen, but plants don’t seem to be
able to access it.
"We know we’re building up nitrogen in our soils, but we still
have to apply expensive organic nitrate fertilizer," he said. He said
he has been watching commercial microbial products such as "EM" and "Microlizer" that
purport to increase the availability of existing nitrogen in the soil, but
he would like university researchers to conduct "an objective test on
all those products."
"We know the nitrogen is in the 'nitrogen bank' in the soil, and we’re
trying to do 'withdrawals,'" he said. "We’d like to know if
these microbial products would help."
Tony Turkovich. Grower Tony Turkovich farms several thousand
acres in Yolo and Solano counties as a partner in Button & Turkovich Ranches.
He said his operation has used cover crops and conservation tillage for
many years in varying degrees.
"We grow a lot of alfalfa using conventional tillage to get it established,
but use minimum tillage on most of the other ground," he said. "We
have used no-till in corn and wheat, but we’re trying not to grow those
crops, which tend to be unprofitable."
Turkovich said that they do not generally plant cover crops before high value
crops like tomatoes and peppers, which must be planted early, although the
later-planted tomatoes are sometimes preceded by cover crops.
"The majority of our fields have cover crops, including the orchards," he
said. "This year we planted garbanzo beans on some fields, which although
they are harvested as a cash crop, also function as a winter cover crop."
"All told, around three-quarters of our fields have some kind of winter
cover crop," he said. "Cash crops that provide some of the benefits
of a winter cover are certainly a consideration in our crop selection."
Turkovich noted that in the north part of the state, farmers have traditionally
thought of winter cover crops as "big, lush, leguminous plants."
"But with diesel forecast to reach $3 a gallon, and many costs associated
with working the cover crops in, we’re rethinking the legumes and looking
at the cereal cover crops reported to be used more in the southern San Joaquin
Valley," he said.
He said he is interested in finding out more about plants that can be used
as cover crops "whose roots improve soil structure, but don’t have
as much above-ground biomass and therefore wouldn’t require significant
Turkovich said he’d like to see more research investigating new cover
crops that enrich the soil and improve water quality, as well as equipment
and techniques that growers can use to plant directly into residue, which would
reduce the need to spend time and money working plant trash into the soil.
"With fuel and fertilizer costs going up, conservation tillage is definitely
more attractive as a way to save field costs," he said. "Cover crops
need to be reevaluated in relation to the rising costs of fuel and fertilizer
and whether we can manage them in a cost-effective way."
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