No-Till Case Study, Richter Farm: Cover Crop Cocktails in a Forage-Based System
Regular hay and silage cutting leads plant residues diminishing at the detriment of soil health but a farming family in North Dakota profess to have a solution, reports the National Sustainable Agriculture Information Service.Introduction
Brothers Marlyn and Patrick Richter farm
2,600 acres of cash grains and forages on
their diversified dairy and beef cow operation
in Menoken, North Dakota, near Bismarck.
Their farm includes a feedlot for custom background
feeding of 450 beef cattle, a dairy operation
of 120 Holstein cows, and a herd of 160
Black Angus cow/calf pairs for beef production.
The Richters also raise their own dairy and beef
replacement heifers. At any given time, the Richters
may have 750 or more cattle on their farm.
The Richters use their cropland as the main source
of feed for their cattle, with most of the cropland
devoted to forage production, such as hay and
silage. About half of their crops are used to feed
their cattle, and the other half of their crops are
sold for cash off the farm.
Most of their cropland is rain-fed, with an average
of 15.4 inches of annual precipitation. They
do have one pivot irrigation system on a 128-acre
parcel of land.
The Richter farm has fragile sandy and sandy
loam soils, many of which are classified as Highly
Erodible Land (HEL). Their farm has a history
of wind erosion, and in the 1950s and 1960s
tree windbreaks were installed on the cropland
to help minimize soil loss. However, even with
this conservation method, they still had wind
erosion occurring. When they started a no-till
system in 2001, their primary goal was to reduce
wind erosion.
They did see some improvements in their soil by
switching to a no-till system. When they first
started no-till, their soil organic matter levels were
between 0.9% and 1.8%. Nine years later, their
soil organic matter levels average between 1.8%
and 2.6%.
Even after converting to no-till, however, the
Richters found it difficult to maintain enough
residue on the soil surface. Because so much of the
crop biomass was taken off the field for silage or
hay, there was not enough residue left on the soil
to protect it and to feed the soil biology. Marlyn
Richter refers to this problem as “The Stockman’s
Challenge.” Most stockmen want to take
the entire crop off the field to feed their livestock.
The challenge is to have the patience and foresight
to leave enough residue on the field to protect the
soil. This residue will improve soil health and the
overall health of the entire farm in the long run.
The lack of residue on the Richters’ fields presented
some problems. First of all, without the
armor of soil residue, their evapotranspiration
(ET) rates and soil temperatures were too high.
Soil temperatures taken by NRCS during past
growing seasons routinely exceeded 100°F on bare
soils. In contrast, similar soils with surface residue
recorded readings below 85°F. Their hot soils were
losing more water to evaporation than necessary.
The Richters also wanted more organic matter
to hold nutrients in the soil during large rain
events. Because their soils are sandy and have
little organic matter, a heavy rain of two inches
or more would cause the nitrate in the soil to leach deep into the soil profile. This caused their
crops to turn yellow as the nitrate flushed out of
the root zone.
The Richters planned to improve their soil organic
matter levels by planting a diverse cover crop mixture
that would provide a high-carbon residue.
However, they were concerned that the cover crop
would use too much soil moisture and thereby
decrease the yield of any subsequent crop. The
Richters’ soils are sandy, ranging from 3.7 to 6.1
inches of available water capacity in the top four
feet of soil. This compares with 9 inches of available
water capacity in the neighboring loamy soils.
The Richters hoped that improving organic matter
levels would increase the water-holding capacity
of their soil.
Average Available Water at Field Capacity, Richter Farms
2007 Cover Crop Cocktail Following Early Forage Harvest
In order to address several resource concerns, the
Richters planted a diverse cover crop cocktail on
72 acres of cropland (Table 2). They planted this
cover crop in early July of 2007 after a crop of oats
and peas that had been chopped for silage in June.
The Richters had several resource concerns:
- Crop Diversity – incorporating a variety of species to stimulate increased soil microbial activity.
- Soil Organic Matter – the cover crop provides a second set of roots in the soil, increasing the amount of organic material to be converted to soil organic matter.
- Nutrient Cycling – using deep-rooted species to capture deep nitrogen and release near the soil surface for shallower-rooted crops.
- Surface Residue – provide additional residue for erosion and temperature control.
- Residue Management – utilizing livestock to harvest half the cover crop, leaving the other half on the soil surface for the soil biology; managing residue in a manner that allows it to be returned to the soil surface.
2007 Cover Crop Cocktail Mixture
In order to evaluate the performance of the cover
crop, the Richters designed a test to compare it
with two other treatments. Their goal was to evaluate
the feasibility of producing a cover crop as
well as to evaluate the performance of the subsequent
grain crop in 2008. The brothers conducted
these three field tests on a 120-acre parcel that
had all been harvested for pea and oat silage in
June of 2007.
Field 1 was 72 total acres and contained the cover
crop cocktail with no manure added. Field 2 was
16 acres and had no cover crop but did have an
addition of 10 tons of manure per acre in the late
summer of 2007 (July 15 to August 15). Field
3 was 32 acres and had no cover crop and no
manure addition. All fields were adjacent to each
other, with windbreaks running from east to west
throughout the parcel.
Field Treatments and Observations
Prior to seeding, all three fields were sprayed with
glyphosate for weed control. Marlyn seeded Field
1 with the cover crop cocktail on July 7, 2007.
By August 2, Field 1 had a good canopy cover and
stood about two feet tall. In September, Fields 2
and 3 received another application of glyphosate
for weed control. However, Field 1 received no
additional herbicide because the cover crop provided
enough weed suppression.
By October 1, Field 1 was just over waist high and
ready to graze. Most of the cover crop growth was
still green, with little frost damage.
Cover crops can be terminated in various ways,
including mechanical harvesting, rolling, spraying
with herbicide, winter-kill, or grazing. The
Richters decided to graze the cover crop to get
the added benefit of an additional forage source
for their beef cows and calves. The trampling of
cattle hooves also provides an extra benefit in
improving nutrient cycling by bringing more of
the biomass in contact with the soil surface for
breakdown by the soil microbes. Grazing also
creates various levels of plant structure for erosion
protection, with some of the plant material
left standing and some trampled on the surface.
Because the main purpose of the cover crop was
to add residue, they only wanted to take half of
the cover crop for grazing. The other half would
be left for soil armor and as a means of stimulating
the soil biology. Leaving half of the cover
crop residue was the Richters’ way of solving The
Stockman’s Challenge.
Grazing the Cover Crop
The Richters turned 141 cow-calf pairs onto Field
1 on October 1. Prior to grazing, they weighed
each calf. The calf starting-weight average prior
to grazing the cover crop was 580 pounds.
The cattle grazed for 17 days and left Field 1 on
October 17. After this grazing period, the calves
were weighed again. The average ending weight
was 632 pounds, which translates to an average
weight gain of 52 pounds per calf, or 3.1 pounds
per calf per day, a very good rate of gain, especially
when compared with native grazing land
at that time of the year.
As Marlyn and Patrick noted the grazing preferences
of the cattle in the cover crop, they made
several observations. The cattle had definite preferences
and grazed the cover crop in the following
order:
- Millet heads
- Millet leaves
- Soybean, cowpea, sunflower
- Brassica leaves (turnip and radish)
- Brassica roots
While the cows were grazing the cover crop, a fecal sample was taken to find out whether the dietary needs of the livestock were being met (Table 3).
Fecal Sample Analysis, Field 1, October 5, 2007
The ratio of digestible organic matter to crude
protein is used as a measure of rumen efficiency
in cattle. An acceptable range for this ratio is
between 4:1 and 7:1, with 4:1 being ideal. This
ratio for the Richter cattle was 4.39:1, indicating
that the cover crop was not too lush, nor was it
too dry for cattle consumption.
Not only did the direct grazing benefit the soil,
it also helped the bottom line. There was no cost
to harvest and store the forage. Nor was there
the added cost of moving the manure from the feeding area and applying it to the fields. Direct
grazing saved the Richters time and money, which
is an added benefit of the cover crop.
Cover Crop Budget Analysis
The Richters calculated the gross income from grazing the cover crop at $111 per acre, as shown in Figure 2.
The total expense for the cover crop was $45 per acre. This consisted of the seed cost of $20 per acre, the cost of seeding at $13 per acre, and the cost of one glyphosate application prior to seeding at $12 per acre.
Together, this income and expense result in a $66 per-acre net income.
While the Richters gained about $66 in measurable
returns, they also gained some intangible
benefits, including the recovery time for their
native grazing land. While the cattle grazed the
cover crop, the land usually grazed at this time
had an opportunity for regrowth.
In Marlyn and Patrick’s opinion, the cover crop
was worthwhile for the grazing benefit alone. But
the story doesn’t end there. The benefits of the
cover crop carried forward to the 2008 field corn
crop. Let’s look at the next chapter in this story.
2008 Field Corn Crop
In the spring of 2008, after the cover crop year,
the Richters made some observations of the three
crop fields in their test. First of all, there was no
noticeable wind erosion in Field 1. In contrast,
Fields 2 and 3 did have some observable wind
erosion, particularly on the sandier knobs farther
away from the windbreaks. Also, there was little
weed pressure in Field 1 and significant weed
pressure in Fields 2 and 3.
Next, they observed about three times the earthworm
population in Field 1 compared with Fields
2 and 3.
In addition to these visual observations, they also
measured the available water and water capacity
in each field. They were concerned that the
cover crop might have used too much soil moisture
and that Field 1 would have decreased corn
yields as a result.
However, analysis of each field showed no significant
difference in available water capacity
between the field with the cover crop and the
fields without cover crops.
On May 5, the Richters planted Pioneer 39D80
corn in all three fields at a rate of 19,000 plants
per acre.
Throughout the growing season, they received
almost 15 inches of rain in the intervals shown in
Table 5. The year 2008 started out as one of the
driest in Burleigh County history, but by December
it was close to an average year, with the same
amount of rainfall in the growing months as they
normally receive during the entire year.
Estimated Inches of Available Water
All three fields received the same fertility treatment during 2008. Commercial fertilizer (21-24- 12) was applied to all three fields at a bulk rate of 200 pounds per acre. (Recall that manure had been applied to Field 2 in 2007, but not to Fields 1 and 3.)
2008 Precipitation, Bismarck Municipal Airport, North Dakota
2008 Corn Harvest Yield Data
2008 Corn Harvest Gross Income per Acre
2008 Corn Expense Summary per Acre (in dollars)
The Richters applied glyphosate to all three fields
for weed control right after corn planting in
May. All three fields were sprayed again in June.
However, in July, Field 1 did not receive another
glyphosate application, while Fields 2 and 3 did.
Why? Field 1 had enough cover crop residue left
to suppress weed growth until the corn developed
a canopy in late June. Fields 2 and 3 did not have
this residue and required the additional herbicide
application.
The corn was harvested for grain on October 31,
2008, and a weigh wagon was on hand to help
record yield and moisture data from each field.
The Richters deliberately decided to harvest this
crop for grain instead of silage, in order to leave
more residue on the field (See Table 6).
Corn Crop Budget Analysis
While Field 2 had the greatest yield, the budget
analysis shows that Field 1 was actually more
profitable. The gross income for each field is presented
in Table 7.
Most of the expenses were the same for all fields.
However, less herbicide and no manure were
applied to Field 1, which significantly reduced
the cost of production (See Table 8).
When the expenses are combined with the gross
income, the net income results are:
2008 Corn Net Income per Acre
Even though Field 2 had the greatest yield, with
87.3 bushels per acre, it only returned $49.57 per
acre to the bottom line. In contrast, Field 1 had
the best income return with $62.27 per acre, even
though it yielded less, at 82.8 bushels per acre.
Field 3 couldn’t compete with the other two and
brought only $13.77 per acre to the bottom line.
Field 3 had the double threat of low yield and
high input cost.
Not only did the cover crop bring income to
the bottom line in 2007 through grazing, it also
helped the bottom line in the 2008 corn crop.
This was a positive double benefit in addition to
the improved soil health.
Further Benefits and Beyond
After the corn harvest in 2008, the Richters
decided to graze the cornstalk residue on all
three fields. They turned out 153 cows for 20
days, which saved them about $2,760 in direct
feed costs.
Both Marlyn and Patrick say that the value the
cover crop has brought to the health of their soil is
priceless. They see a benefit to the bottom line, but
the most important benefit is the improvement in
their soil health. They hope to continue using a
cover crop on each field every three to four years,
following a June-harvested forage crop. When
using a cover crop, they plan to leave at least half
of the residue for the soil health benefits. They
find that if a stockman is patient and willing to
put soil health as a top priority, the rewards will
come back to him in multiple ways.
The Stockman’s Challenge is to improve soil quality
while concurrently using the soil to provide
livestock feed. The Richter brothers showed that
using a multispecies cover crop cocktail resulted
in healthier soil and a healthier farm.
January 2013