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Ag Blogs -
Tom Tibbits
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Friday, 24 February 2012 09:48 |
Tales of a Kansas Farmer
Authors note: Much of this is my recap of the 2012 No Till on the Plains Winter Conference.
I went into the conference wanting to wrap my mind around utilizing
cover crops in no till better. I still have many questions, but they
might be best answered from experimenting.
Implementing
cover crops in no till cropping systems has been a concept introduced
to me at the No Till on the Plains winter conference a couple of years
ago. Cover crops are plants seeded and grown between cash crops. These
plants can be legumes that takes nitrogen from the air for the plant to
use, brassica's that are deep rooted that help break compacted layers of
soil and trap nitrogen, or grasses that hold soil and take up
nutrients.
Gabe Brown,
North Dakota farmer and rancher, was the first farmer that really got
me interested in this crazy idea. He had found that a complex blend of
plant species with varying root depths not only survived, but thrived in
through North Dakota droughts. In the initial presentation a few years
ago he talked about grazing cow/calf pairs for a month on a cover crop
blend, I think he estimated the weight gain on the calves generated $100
or more an acre, that really perked my interest. At his presentation
this past winter we told of a corn crop planted in a cover crop blend of
cereal rye, vetches, oil seed radishes, turnips and a variety of other
plants species. His cost of production was $1.10/bu he made one
herbicide application to terminate the rye and set back the vetch enough
to not compete with the corn and the cover crop blends provided all the
nutrients. The expenses for his cover crops were covered by grazing
them with cattle. He showed pictures of a corn crop that was planted
into some of the heaviest ground cover of I've ever seen, at around
tassel stage the trash was very deteriorated, at harvest the space
between the rows were bare with the exception of some vetch that looked
about a foot tall, and a couple of weeks later the vetch really started
growing.
So Gabe Brown had luck with his cover crops during North
Dakota droughts, but how would they deal with a Kansas drought? Gail
Fuller, east central Kansas and Ryan Speer, south central Kansas, each
gave presentations about their use of cover crops in last summer's
drought.
Fuller has had cover crops longer in his rotation and
felt early in the season his corn had the potential to be some of his
best ever. He showed pictures of it green where his neighbor's corn was
burned up from the drought, but relief from the drought came too late
for it. After harvesting as forage he planted cover crop blends back to
it to protect the soil and keep soil ecology working. The cover crops
looked like they had good growth in his photos.
Ryan Speer is
transitioning cover crops to his crop rotation and has experimented some
the past few years. Speer's dryland corn was horrible, I think he said
it yielded in the 15 to 20 bushel per acre range this year, but he
noticed his yield monitor jumped up to 60 to 70 bushel range in a spot
where there had been a plot of sun hemp between wheat crops three years
ago. He stated that evaporation in the fairly short fallow period, late
June to early October, is more than the water requirements of many of
the cover crops. Speer has also been having rye and radishes flown on to
irrigated corn fields late in the irrigation season. These are some
very sandy field and he's seen an increase in soil organic matter to
help increase both the water holding capacity and fertility of these
fields.
So how do I tell how much nutrients are these cover crops
are either tying up to be released when they decompose or nitrogen they
are "making" in the case of legumes? Ray Ward of Ward Lab,
recommends farmers either estimate how many tons of hay the cover crop
may make and determine protein value of the various plants or send a
vegetative sample from one square yard for a cover crop analysis. Many
cover crop advocates emphasizing some very diverse mixes so I feel
sending a sample would be more helpful.
How do cover crops effect
soil biology? Dr. Jill Clapperton soil biologist and president of
Rhizoterra Inc explained that poor soil biology produced poor crops in
terms of both crop yields and nutrient content. She went on to tell us
that most soil organisms are fed by the soil organic matter and when
cover crops are used there are more actively growing roots throughout
the entire growing season to keep producing soil organic matter. She
also stated that the more diverse mix of plants that are growing on top
of the soil the more diversity in soil organisms, since a monocropping
system is used for cash crops this leaves cover crops to be a major
source of plant diversity. Earth worms are one of the biggest and
easiest to recognize soil organisms and they absolutely dislike soils
that have had mechanical tillage performed. Mechanical tillage disrupts
the soil organisms that earth worms live on.
Fuller commented on
having part of a field that was poor even though soil tests revealed
that fertility was the same as the rest of the field. A mycorrhizea test
revealed that it was severely out of balance there. Clapperton
mentioned that Ward Lab and a few others are capable of testing for it
now. Determining which cover crops helps correct mycorrhizea problems is
a challenge.
I sat in a presentation of Dr. Jonathan Lundgren an
entomologist with USDA-ARS, stationed at North Central Agriculture
Research Laboratory, Brookings, South Dakota. He does extensive research
and studying of predator insects. He stressed that reducing soil
disturbance and careful scouting and using insecticides only when
thresholds are met are a help preserve insect predators. He felt cover
crop blends are helpful in recruiting more predators insects to fields
to reduce need for insecticides.
I ran into a neighbor, Craig
Ballou, he had a stop on a sunflower crop tour last summer at a double
crop sunflower field without commercial nitrogen fertilizer. The field
had been in a sun hemp cover crop between two wheat crops. It's a common
practice of no till farmers in my area to raise two continuous crops of
wheat. From past soil tests on double crop sunflowers in this rotation
the nitrogen left was the same as what he had applied so he decided to
not apply it. With our winter wheat growing season the soil doesn't warm
soon enough for the residual nitrogen from a legume to be available for
the wheat other than a possible protein boost.
Here
are Craig Ballou's double crop sunflowers on August 30th. No nitrogen
fertilizer was applied and Craig said they did very good, I could tell
he was proud of them when I asked him about them.
I feel
transitioning to cover crops is the next step in our no till rotation. I
feel it will be a fairly slow transition as we learn what mix of plants
and how to seed them in a timely manner. We will need to start on land
we own, partially to insure we receive the long term benefits of it and
to also prove to landlords that this crazy idea is viable.
- About Tom: I farm with my dad and granddad in north
central Kansas. We raise wheat, corn, grain sorghum, soybeans and oil
type sunflowers. I have been married for 16 years and have 3 young
children.
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- Visit Tom's blog at http://farmertimes.blogspot.com/
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