The Real Dirt
Dr. Jill
Clapperton
Rhizosphere Ecologist, Agriculture and Agri-Food Canada
Lethbridge Research Centre
5104 1st Ave S.,
Lethbridge, Alberta, T1J 4B1 Canada.
Email:
Clapperton@agr.gc.ca.
Phone: (403) 317-2221.
Soil is much more interesting than dirt!
You’ll see in this presentation that “when we are
standing on the ground, we are really standing on the roof top of another
world”. Living in the soil are plant
roots, viruses, bacteria, fungi, algae, protozoa, mites, nematodes, worms,
ants, maggots and other insects and insect larvae (grubs), and larger
animals. Did you know that the number
of living organisms below ground (known as soil biota) is often far greater
than that above ground? Together with
climate, these organisms are responsible for the decay of organic matter and
cycling of both macro- and micro-nutrients back into forms that plants can
use. Soil biota effect soil fertility
and hence the primary productivity of the ecosystem that they inhabit, soil
biological processes are responsible for approximately 75 percent of the
available N and 65 percent of the available P in the soil. Plants can take-up and use nutrients made
available through biological processes more easily and efficiently compared
with chemical fertilizers.
Microorganisms like fungi and bacteria use the carbon, nitrogen, and
other nutrients in organic matter, while microscopic soil animals like
protozoa, amoebae, nematodes, and mites feed on the organic matter, fungi,
bacteria, and each other. These activities
stabilize soil aggregates building a better soil habitat and improving soil
structure, tilth and productivity. In
agriculture, we modify the soil habitat with tillage and crop rotation
practices and so influence the ability of the soil ecosystem to provide
essential services such as decomposition and nutrient cycling. Agricultural practices such as crop
rotations and tillage affect the numbers, diversity, and functioning of the
soil biota, which in turn affects the establishment, growth, and nutrient
content of the crops we grow. For
example, including a perennial forage, or to a lesser extent, an annual forage, in the
rotation can enhance soil structural stability, increase soil organic matter -
to depth, and increase the number, diversity and activity of most soil
organisms. More importantly, our
research has shown that including forages or forage mixtures as cover crops,
increases the concentrations of micronutrients and P and Ca in the grain of the
following crop.
So let me introduce you to some of the organisms that
live in the soil, and how they affect the cycling and availability of nutrients
to crops, disease cycles, weed management, and soil. More detailed examples with mycorrhizal fungi and earthworms will
demonstrate the important role of soil biology in improving soil quality and
productivity. I’ll conclude with a
discussion of how we can manage soil biological fertility so we get more for
less.
Managing the soil as a habitat for soil biological
fertility
Soil is much more interesting than dirt. It is a complex inorganic and organic
matrix, the habitat for the highly diverse community of microorganisms, soil
fauna, and plants, which we learned about in the first session. Soil biota effect soil fertility and hence
the primary productivity of the ecosystem that they inhabit, soil biological
processes are responsible for approximately 75 percent of the available N and
65 percent of the available P in the soil.
Plants can take-up and use nutrients made available through biological
processes more easily and efficiently compared with chemical fertilisers. Soil fertility is largely dependent on the
processing of organic substrates – residues or soil organic matter (SOM)-
through the soil food-web. Soil biota
require the maintenance of a suitable soil habitat, with an adequate quantity
and quality of organic matter as an essential food source. In agriculture, we modify the soil habitat
with tillage and crop rotation practices and so influence the ability of the
soil ecosystem to provide essential services such as decomposition and nutrient
cycling. This can affect the nutrient
quality of the food and forages we produce, and ultimately human and animal
health. This more informal workshop
session will explore the use of specific soil and crop management practices
that enhance soil biological properties giving us the opportunity to take
advantage of soil biological fertility, and augment chemical fertilizer
regimes. So bring a pen and paper, and
willingness to participate in the discussion and activities. You will take home new ideas and a renewed
enthusiasm for farming.
Dr. Jill Clapperton - Biography
Dr. Jill Clapperton is the Rhizosphere Ecologist at
the Agriculture and Agri-Food Canada Lethbridge Research Centre in Lethbridge,
Alberta, Canada. She is an internationally respected lecturer presenting
research findings and promoting an understanding of how soil biology and
ecology interact with cropping and soil management systems to facilitate
long-term soil quality and productivity. Her research group studies soil food
webs, nutrient cycling, soil fauna- plant disease and rhizosphere interactions,
and soil biodiversity. Presently, the main focus of the Rhizosphere Ecology
Research Group is understanding the relationship between soil biological
nutrient cycling, plant nutrient uptake and nutrient quality of grains and
forage. Jill has a keen interest in promoting science in schools and
participates with other researchers and educators to develop soil ecology and
agriculture educational programs. The
Worm Watch program (www.wormwatch.ca)
Jill developed and initiated was cited by the National Science Teachers
Association for excellence in science education. In 2000, Dr. Clapperton received the Patricia Roberts-Pichette
Award for enthusiastic leadership and commitment to advancing ecological
monitoring, education and research in Canada.
Long-term Impacts of Tillage Erosion on Productivity
David A. Lobb
Department of Soil Science
University of Manitoba
Winnipeg MB R3T 2N2
lobbda@ms.umanitoba.ca
Introduction
In topographically
complex landscapes, tillage erosion causes the progressive downslope movement
of soil. Tillage practices which, in time, cause more soil to be moved
downslope than upslope result in the loss of soil from upper slope landscape
positions and the accumulation of soil in lower slope positions.
Tillage erosion is
described in terms of tillage erosivity and landscape erodibility. Large,
aggressive tillage implements, operated at excessive depths and speeds are more
erosive, with more passes resulting in more erosion. Landscapes that are very
topographically complex (short, steep, diverging slopes) are more susceptible
to tillage erosion.
Visual evidence of
tillage erosion includes: loss of organic rich topsoil and exposure of subsoil
at the summit of ridges and knolls; and undercutting of field boundaries, such
as fencelines and terraces, on the down-slope side and burial on the up-slope
side.
Significance of tillage erosion
The maximum rate of
soil loss by tillage erosion observed within topographically complex landscapes
is typically between 15 and 150 t ha-1 yr-1 (Lobb et al., 1995; Lobb and
Kachanoski, 1999a). Such rates are several times what is considered sustainable
for crop production. Tillage erosion has been found to account for the majority
of soil loss observed on convex slope positions. Estimates made using resident
137Cs indicate that between 70 and 100% of soil lost on these slope positions
is the direct result of tillage erosion (Lobb et al., 1995; Lobb and
Kachanoski, 1999a).
Using the tillage
translocation data of Lobb et al. (1995, 1999), the Tillage Erosion Risk
Indicator (TERI) model (Lobb, 1997), 1996 agriculture census data, and
landscape data from the National Soil Data Base, King et al. (2000) concluded
that approximately 50% of the cropland in the prairies was subjected to
unsustainable levels of tillage erosion (Table 1). A similar assessment was
made for water erosion by Shelton et al. (2000) and it was found that only
approximately 12% of the cropland was subjected to unsustainable levels of
water erosion. Within any given piece of cropland, water erosion results in
soil losses from approximately 50% of the area (back and foot slopes) and
tillage erosion results in soil losses from approximately 25% (shoulder slopes
and crests). These studies found that the risk of water erosion and the risk of
tillage erosion have decreased between 1981 and 1996. This decrease is due to
the adoption of conservation tillage practices. The analyses by King et al.
(2000) and by Shelton et al. (2000) were based on the assumption that the area
in conservation tillage in 1981 was negligible. The adoption of conservation
tillage since 1996 is believed to be minimal; consequently, soil degradation by
tillage erosion in the prairies remains widespread.
Agricultural and environmental implications
Severity and extent of tillage erosion. Tillage erosion occurs to some degree in all
topographically complex cultivated landscapes. Although tillage erosion
research has focused on "hilly" landscapes, tillage erosion can also be
significant on "flat" landscapes. The Red River Valley, a flat
landscape, is topographically complex even though its relief can be less than 2 m in 1,000 m. On such a flat
landscape, tillage implements with widths in excess of 20 meters are commonly
found. Surface drainage enhances the topographic complexity of these
landscapes. The infilling and required regular cleaning of these drains is the
consequence of tillage erosion. Tillage erosion can be severe on simple
hillslopes that are dissected with terraces, buffer strips, etc. Field boundaries dissect slopes, resulting in soil
loss by tillage erosion at the upper slope of each boundary and soil
accumulation at the lower slope. The total soil loss on a slope increases by a
factor equal to the number of dissections.
Tillage erosion occurs under any form of tillage.
Consequently, it is possible that unsustainable levels of tillage erosion may
exist even when conservation tillage systems are used. The chisel plough and
secondary tillage implements such as the tandem disc can be equally as erosive
as the mouldboard plough (Lobb et al. 1995, 1999). Even though the mouldboard
plough buries more crop residue it was found to result in less net
translocation of soil. As long as tillage is used,
there is the potential for the severity and aerial extent of this erosion to
increase.
Impacts
on soil-landscape variability. Tillage translocation and tillage erosion have contrasting effects on
the spatial variability of soil. Tillage erosion increases the variability of
soil properties within landscapes. As tillage erosion progresses, the
properties of the subsoil are expressed on convex areas. In some cases, it is
possible to see 'halos' in hilly landscapes where the white/yellow soil
material from the C horizon is exposed on the hilltops, the black/brown soil
material from the A horizon is exposed at the base of the hills, and the
red/brown soil material from the B horizon is exposed on the sides of the
hills. Tillage translocation reduces variability by spreading soil over great
distances. Soil can be mixed over a length in excess of 3 m per sequence of
tillage (Lobb et al., 1995); in fact, McLeod et al. (2000) has shown that a
single pass of a cultivator sweep operated at 15 cm depth and 5 km hr-1
can translocate soil as much as 4 m. Sibbesen (1986) demonstrated the
significance of the dispersion of soil and its constituents and developed a
model to predict the dispersion for long-term small-plot research. The
contrasting effects of tillage on spatial variability of soils was recognised
by Kachanoski et al. (1985).
Impact
of tillage erosion on crop production. Yield
losses of 40-50 % have been associated with severely eroded convex landscape
positions (Lobb et al., 1995). Assuming that the average annual yield loss on
convex slopes is one-half of this value, that this yield loss results from
tillage erosion, and that convex slope positions account for about 25 % of the
landscape of a region, tillage erosion can be expected to cause about a 5 %
annual loss in crop production. Such losses represent tens of millions of
dollars in intensive agricultural regions. The increased soil variability
caused by tillage erosion results in less efficient use of production inputs
and, therefore, increased production costs. Less efficient use of nutrients and
pesticides results in increased risk of environmental contamination. Soil
losses associated with tillage erosion may be the major cause for the need to
manage soil-landscapes variably, i.e. precision farming.
Impacts
on wind and water erosion. Tillage
erosion can increase soil erosion by wind and water by exposing subsoil that is
highly erodible to wind and water. Tillage erosion acts as a delivery mechanism
for water erosion, transporting soil to areas of concentrated overland water flow, i.e. rills and convergent
landforms. This delivery process has been examined by Lobb and Kachanoski
(1999a). Tillage erosion may be more significant than inter-rill erosion as a
delivery mechanism for rill erosion.
Impacts
on other biophysical processes. Tillage
erosion has potential significant impacts on biophysical processes other than
crop production and erosion by wind and water. The loss of topsoil that occurs
on the upper slope landscape positions and the consequential changes in soil
properties affect the hydrology of the landscape. Typically, the infiltration
capacity of these eroded soils is reduced resulting in increased overland water
flow to lowerslope positions. Furthermore, these eroded soils typically have a
reduced water holding capacity. Changes in soil moisture conditions affect
changes in soil temperature. In the process of redistributing soil within the
landscape, tillage erosion depletes nutrients such as carbon and nitrogen on
convex slope positions and accumulates and buries nutrients on concave slope
positions. These combined changes can be expected to have significant impacts
on biophysical processes such as the production and emission of the greenhouse gasses.
Estimation
of soil erosion. Changes in the concentration
of soil constituents, such as organic matter and resident 137Cs, are
commonly used as indicators of soil erosion. However, a decrease in
concentration can occur at a specific point in the landscape without a change
in soil mass at that point. The concentration of a
constituent in the soil translocated into a point by tillage is not necessarily
the same as that translocated out from that point. As a consequence of tillage
translocation, changes in concentration reflect soil losses at that point and
the surrounding area. This phenomenon, its impact
on the estimation of soil erosion using 137Cs and improved methods
to estimate soil erosion have been described by Lobb et al. (1995), Lobb and
Kachanoski (1999b).
Soil
erosion modelling. Soil erosion models that do not include the
process of tillage erosion do not adequately represent erosion on cultivated
land with complex topography. Schumacher et
al. (1999) have demonstrated the combined use of water and tillage erosion
models. In comparison to wind and water erosion models,
tillage erosion models are more universal because the erosive agent is not
related to climate.
Soil
conservation planning and policy. Preventative
and corrective soil loss measures that do not include the reduction of tillage
erosion will not be effective in controlling soil loss on convex upper slope
positions of cultivated landscapes. Given that it is these areas that are most
severely eroded, it would be negligent to ignore tillage erosion. A fully
integrated approach to soil conservation is required. Several soil conservation
practices are identified below.
For the
most part, agricultural soil conservation policies and programs have had two
primary objectives, to reduce soil losses within farm fields and to reduce
sediment delivery from farm fields. Many soil conservation policy and programs,
such as the National Soil Conservation Program, have been based on the
presumption that the process responsible for off-site sediment delivery (wind
and water erosion) is the same erosion process that is responsible for losses
in crop productivity; therefore, practices that reduce sediment delivery to
acceptable levels should result in sustainable levels of soil erosion within
fields. However, where tillage erosion operates within a landscape,
unsustainable levels of soil erosion may exist within a field even though
acceptable levels of wind and water erosion are achieved.
Soil conservation practices
The most effective
way to arrest tillage erosion and its adverse impacts is to eliminate tillage;
however, it is not always possible to do so. Where tillage is necessary, there
are several practices that can be used to reduce tillage erosion:
Reduce
tillage frequency and intensity. All
unnecessary tillage operations should be eliminated from a tillage system.
Tillage should be done when soil conditions are suitable to avoid correctional
tillage. The depth and speed at which a tillage implement is operated affect
its intensity and, therefore, its erosivity. Tillage implements should be
operated at minimum recommended depths and speeds.
Reduce tillage speed and depth variability. Operators should try to maintain a constant
tillage depth and tillage speed, even in topographically complex landscapes. To
maintain constant operating depth and speed in such landscapes requires more
power from a tractor than would be recommended for a specific tillage implement
by an equipment manufacturer/dealer. Implements are rated for required horsepower
assuming that they will be operated on level ground. Operation in excess of
recommended depth and speed results in greater translocation variability, and,
consequently, results in greater tillage erosion.
Reduce
the size of tillage implements. The larger the
implement is relative to landform size, the more rapid the landscape is
levelled. Tillage implements that are very long and/or very wide should be
avoided on landscapes that are highly erodible to tillage.
Use
less erosive tillage patterns. Where
possible, tillage should be conducted along the contour of the landscape. This
will reduce the variation in tillage depth and speed and, consequently, reduce
tillage erosion. Where tillage is conducted on the contour, a reversible or
rollover mouldboard plough can be used to throw the furrow upslope on every
tillage pass, leaving a back-furrow on the uppermost slope position. Moving
soil upslope with the mouldboard plough offsets the progressive downslope
movement of soil by other implements in the tillage system (Mech and Free,
1942). Reversible and rollover ploughs are not commonly used. Farmers who use
these one-way ploughs typically throw the furrow downslope to leave a smoother
surface for subsequent field operations and to reduce draught requirements.
However, this is not always the case; farmers who have recognised that tillage
causes their topsoil to accumulate at the bottom of slopes regularly, if not
always, throw the furrow upslope. Some farmers have been observed to take a
more aggressive approach; ploughing on an angle to the contour to throw the
furrow directly up the slope. However, ploughing on an angle to the contour
will reduce the effectiveness of plough ridges in controlling overland water
flow and water erosion. Ploughing on an angle to the contour may be necessary
on steep slopes. Mech and Free (1942) noted that difficulties may be
experienced turning furrows upslope while contour tillage if slope gradients
exceed 17%.
Restore
severely degraded land. Where
it is feasible, areas that are severely degraded by tillage erosion should be
restored by returning the topsoil that has accumulated in slope concavities.
This should be followed by the implementation of practices to reduce tillage
erosion. The Innovative Farmers Association of Ontario (Aspinall, 1997) and the
Chinook Area Research Association (CARA,1996) have evaluated this restoration
practice and have found it to be an effective method of regaining lost crop
production potential. In Europe in the 1940s, Lowdermilk (1953) observed the
common practice of hauling topsoil from the base of slopes back to the top
"to compensate for the downslope movement of soil under the action of
ploughing".
References
Aspinall, J.D., 1997. Remediation of an eroded knoll
in southwestern Ontario. J. Soil Water Conserv. 52, 308.
CARA, 1996. Reclamation of eroded knolls. Chinook
Applied Research Association. Project Report. 17: 1-5.
Kachanoski, R.G. Rolston, D.E., deJong, E., 1985.
Spatial variability of a cultivated soil as affected by past and present
microtopography. Soil Sci. Soc. Am. J. 49, 1082-1087.
King, D.J., Cossette, J.M., Eilers, R.G., Grant, B.A.,
Lobb, D.A., Padbury, G.A., Rees, H.W., Shelton, I.J., Tajek, J., Wall, G.J.,
van Vliet, L.J.P., 2000. Risk of tillage erosion. In: Environmental health of
Canadian agroecosystems. T. McRae, Smith, S., Gregorich, L.J. (eds) Agriculture
and Agri-Food Canada. Ottawa. pp. 77-83.
Lobb, D.A., 1997. Tillage erosion risk indicator:
Methodology and progress report. Agri-Environmental Indicator Project. AAFC.
Ottawa. 9 p.
Lobb, D.A., Kachanoski, R.G., 1999a. Modelling tillage
erosion on the topographically complex landscapes of southwestern Ontario. Soil
Till. Res. 51, 261-277.
Lobb, D.A., Kachanoski, R.G., 1999b. Modelling tillage
translocation using step, linear-plateau and exponential functions. Soil Till.
Res. 51, 317-330.
Lobb, D.A., Kachanoski, R.G., Miller, M.H., 1999.
Tillage translocation and tillage erosion in the complex upland landscapes of
southwestern Ontario. Soil Till. Res. 51, 189-209.
Lobb, D.A., Kachanoski, R.G., Miller, M.H., 1995.
Tillage translocation and tillage erosion on shoulder slope landscape positions
measured using 137Cs as a tracer. Can. J. Soil Sci. 75, 211-218.
Lowdermilk, W.C., 1953. Conquest of the land through
7000 years. USDA. Soil Conservation Service. Bulletin No. 99. Washington D.C.
30 p.
McLeod, C.J., Lobb, D.A., Chen, Y., 2000. The
relationships between tillage translocation, tillage depth and draught for
sweeps. In: Proceedings of 43rd Annual MSSS Meeting. MSSS, Winnipeg. pp.
195-199.
Mech, S.J., Free,
G.R., 1942. Movement of soil during tillage operations. Agr. Eng. 23, 379-382.
Schumacher, T.E., Lindstrom, M.J., Schumacher, J.A.,
Lemme, G.D., 1999. Modeling spatial variation in productivity due to tillage
and water erosion. Soil Till. Res. 51, 331-339.
Shelton, I.J., Wall, G.J., Cossette, J.M., Eilers,
R.G., Grant, B.A., King, D.J., Padbury, G.A., Rees, H.W., Tajek, J., van Vliet,
L.J.P., 2000. Risk of water erosion. In:
Environmental health of Canadian agroecosystems. T. McRae, Smith, S.,
Gregorich, L.J. (eds). AAFC. Ottawa. pp. 59-67.
Sibbesen, E., 1986.
Soil movement in long-term field experiments. Plant Soil. 91, 73-85.
Table 1. Risk of tillage
erosion on Canadian cropland† in 1981 and 1996
|
Province§
|
Cropland¶
(106 ha)
|
Proportion
of cropland (%) in various risk classes
|
|
Tolerable‡
|
Low‡
|
Moderate‡
|
High‡
|
Severe‡
|
|
1981
|
1996
|
1981
|
1996
|
1981
|
1996
|
1981
|
1996
|
1981
|
1996
|
|
B.C.
|
0.5
|
30
|
50
|
42
|
36
|
28
|
14
|
<1
|
0
|
0
|
0
|
|
Alberta
|
10.6
|
47
|
62
|
24
|
19
|
26
|
19
|
3
|
0
|
0
|
0
|
|
Saskatchewan
|
18.8
|
29
|
35
|
14
|
19
|
52
|
46
|
5
|
0
|
0
|
0
|
|
Manitoba
|
4.9
|
22
|
44
|
53
|
38
|
24
|
18
|
1
|
0
|
0
|
0
|
|
Ontario
|
3.4
|
33
|
41
|
21
|
35
|
43
|
24
|
3
|
<1
|
0
|
0
|
|
Quebec
|
1.6
|
68
|
75
|
21
|
16
|
11
|
9
|
0
|
0
|
0
|
0
|
|
New Brunswick
|
0.1
|
33
|
38
|
26
|
32
|
32
|
21
|
3
|
8
|
6
|
1
|
|
Nova Scotia
|
0.1
|
40
|
66
|
52
|
28
|
8
|
6
|
0
|
0
|
0
|
0
|
|
P.E.I.
|
0.1
|
50
|
50
|
29
|
30
|
10
|
10
|
11
|
10
|
0
|
0
|
|
Canada
|
40.1
|
35
|
46
|
23
|
23
|
38
|
31
|
4
|
<1
|
<1
|
0
|
† includes
seeded and summer fallow (tilled but not seeded); ‡ Tolerable
(sustainable) < 6 t ha-1 yr-1; Low = 6-11 t ha-1
yr-1; Moderate = 11-22 t ha-1 yr-1; High =
22-33 t ha-1 yr-1; Severe > 33 t ha-1 yr-1;
§ Newfoundland excluded based on the small area of cropland; ¶ average
values for 1981 and 1996
Figure
1. A landscape in
the prairie region that is severely eroded by tillage erosion. In the
foreground, note the calcareous subsoil tilled to the surface where it will be
incorporated into the surface layer.
Integrating
Livestock into No-Till Farming Systems
Gabe Brown
Farmer/Rancher
Bismarck, ND
Jay Fuhrer
NRCS – District Conservationist
Bismarck, ND
Integrating Livestock into No-Till Farming Systems
Brown’s Gelbvieh Ranch is a purebred
cow/calf operation located adjacent to I-94 in central North Dakota, two miles
east of Bismarck. Gabe, Shelly, Kelly, and Paul have an open-minded philosophy,
a willingness to try innovative practices and a dedication to being good land
stewards. These qualities have earned
the Browns the respect of their fellow cattlemen.
After purchasing the ranch, Gabe and Shelly
decided their first priority would be to improve soil health. Gabe is adamant that a successful ranch
starts with healthy soils. “We needed
to increase organic matter in our soils and enhance the biological activity
within the soil. To do this, we knew we
had to manage our range and cropland with this goal in mind.”
The Browns have worked hard to develop a
planned grazing system that has both increased the bottom line of the ranch and
paid great dividends to the environment.
Gabe says it is a labor of love though; it gives my family great
satisfaction to know that we are having a positive impact on the environment.
The Browns have increased their total
number of pastures from the original three to thirty-eight. This level of
management has allowed the Browns to maximize pasture recovery time. The native rangeland has flourished -
desirable grasses and forbs are abundant.
Gabe and son, Paul, are careful to graze a pasture less than 28 days
total in a year. Many are grazed less
than 14 days in a year. Some pastures
are grazed once a year, some twice, some for as short as three days, some as
long as 28 although never over 14 days at one time. It is totally dependent on the growth of the forage in the
pastures. Careful monitoring is
critical. They also rotate the time of
year each pasture is grazed. “We want
to insure the health of all desirable plant species in each pasture, both warm
and cool season,” Gabe explains. “Also
we make sure to stockpile grass in several pastures each year. This is our insurance policy if a drought
occurs.”
Marginal cropland was seeded back to tame
grasses in 1993. Although the stand was
good, production did not flourish due to low nutrient cycling, specifically the
availability of nitrogen. Soil tests
showed less than four pounds per acre. Gabe and Shelly searched for information
regarding what varieties of legumes could be interseeded into this tame
grass. Our goals for adding legumes
were as follows:
v Supply grasses with
nitrogen to boost plant vigor and forage production;
v Increase forage protein
content to benefit herd health and rate of gain;
v Add more residue to
the soil surface to increase infiltration, maximize efficient use of soil
moisture, and cool soil temperatures;
v Create a deeper
root zone to increase nutrient cycling;
v Increase wildlife
habitat
The tame grass/legume pastures on the Brown Ranch are unique to this region and
many tours of this system are given each year.
The Browns truly enjoy sharing their experiences with others.
Recently the Browns added to their tame
grass system by purchasing 120 acres that was previously in the Conservation
Reserve Program (CRP). They added a
well, installed a shallow pipeline, water tanks, and built perimeter and cross
fences to make six tame grass pastures from this 120 acres of former cropland. Although the opportunity existed to
re-enroll this land into CRP, Gabe is confident he can make a higher return on
investment by grazing the land. Gabe
feels proper grazing management will stimulate forage production and have a
positive impact on soil health and wildlife.
He looks forward to collecting data on this tract. “I have several neighbors interested in
seeing if grazing expired CRP is profitable.
This unit will compliment our native pastures extremely well,” says
Gabe.
Gabe has the same beliefs in his cropping
system as he has in his grazing system.
“I knew that the organic matter had been mined from the soils over the
past 100 years. We had soils testing
less than 2% organic matter. Today,
through zero-till and crop rotations, which include legumes, we have increased
organic matter in the soils to over 4% in some fields,” Gabe explains.
Livestock are used as a tool to manage the
cropping systems and increase soil health. The rotation evolves around crop
diversity which includes legumes, forages, companion crops, and cover crops.
Ground litter is constant; as crops are removed, a companion crop or cover crop
takes its place. Maintaining ground litter is becoming more challenging as soil
health improves. The livestock increase the cropping system profitability by
managing the residue in the fall.
A strong promoter of zero-till, which Gabe
has practiced since 1994, he credits zero till for increasing worm populations
and other micro and macro organisms in the soil. This, along with increased organic matter and litter on the soil
surface, means healthier soils, increased water infiltration, and more
efficient water utilization, creating a positive impact to the environment.
Wildlife diversity and population numbers
have also increased dramatically with the grazing system and zero-till cropping
system. The Browns carefully consider and include wildlife in all of their
management practices. The Browns take great pride in the fact that although
they are located only two miles from the city limits of Bismarck, wildlife is
not only abundant, it flourishes. Today, Ringneck Pheasant, Sharptail Grouse,
Hungarian Partridge, Canada Geese, many different species of ducks, a wide
array of songbirds as well as several species of raptors make their home on the
ranch. Whitetail deer abound and it is not uncommon to see over 20 of them any
given day on just the home section. Many other smaller mammals such as mink,
weasel, raccoons, coyotes, and fox abound as well.
By practicing the philosophy of using
livestock as a tool to improve natural resources, the Browns are insuring the
continued viability of the operation for ourselves, our children and future
generations.
Gabe Brown - Biography
Gabe
and Shelly Brown own and operate Brown’s Gelbvieh Ranch, located 5 miles east
of Bismarck, ND. The Brown’s have two children, Kelly and
Paul. They purchased the ranch in 1991
and built a 250 head purebred cow operation.
Gabe attended Bismarck State
College and graduated from North Dakota State University in 1983. Obtaining an
Animal Science degree and Agricultural
Economics minor.
The Brown’s started working
toward a sustainable cropping system, after purchasing a no-till drill in
1994. Gabe enjoys exploring legumes
that can be used in both his livestock grazing system and the no-till cropping
system, using soil health as the fertility indicator.
Gabe has been a Burleigh
County Soil Conservation District supervisor since 1999 and presently serves on
the North Dakota Private Grazing Lands Coalition mentor list. Gabe’s hobbies include hunting, reading, and
spending time with his family.
Jay D. Fuhrer -
Biography
Jay is a graduate of North
Dakota State University, in Agricultural Economics. He started a career with NRCS in 1980; past North Dakota work locations
include; Crosby, Mohall, Dickinson and Bismarck.
Soil Health is emphasized
for cropping and grazing systems, when working with farmers and ranchers. Information and education activities utilize
farmer and rancher speakers, for summer no-till cropping system and grazing
system tours, and winter workshops.
Working with Gabe Brown and
the Brown Gelbvieh Ranch toward soil health and sustainability has been, and
continues to be, a rewarding career highlight.
Cover Crop:
The Good and The Bad
S.L. Osborne1,
W.E. Riedell1, T.E. Schumacher2, and D.S. Humburg2
1USDA-ARS,
Northern Grain Insect Research Laboratory
2923 Medary Ave, Brookings, SD 57006
2South Dakota State
University, Brookings, SD 57007
(605) 693-5234
sosborne@ngirl.ars.usda.gov
Introduction
A sustainable agricultural system is one that, over the long term:
enhances environmental quality and the resource base on which agriculture
depends; provides for basic human food and fiber needs; is economically viable;
and enhances the quality of life for farmers and society as a whole (White et
al., 1994). Both large and small
farmers are seeking sustainable cropping systems that will provide consistent
returns for their efforts and investment (Clegg and Francis, 1994). Increased diversity of crops grown in
rotation and no-till farming practices are important components of sustainable
agriculture systems. This is because
crops grown in rotation have greater yield than when grown in monoculture (Dick
et al., 1986; Mannering and Griffith, 1981; Higgs et al., 1990) and that soil
loss to wind and water erosion is reduced when land is farmed under no-till
systems (Moldenhauer and Mielke, 1995).
Many of the advantages of no-till crop production are derived from the
residue mulch that remains on the soil surface after grain harvest. The residue mulch protects the soil from
wind and water erosion but also delays soil warming in the spring (Swan et al.,
1996). Cooler soil temperatures
translate into slower seed germination, reduced uptake of non-mobile soil
nutrients, and less vigorous early crop growth (Barber, 1984; Griffith and
Wollenhaupt, 1994). Under no-till
conditions, Drury et al. (1999) found that fall-seeded cover crops (red clover)
planted after wheat harvest allowed the following corn crop to have emergence
and yield equal to that of a corn crop following wheat under tilled
conditions. In contrast, Raimbault et
al. (1990) found that grain yields were consistently lower under no-till
treatments as compared with tilled treatments when the corn crop followed a
cover crop (winter rye), but that there were no tillage effects on yield in the
absence of cover crops. These
contrasting results suggest that cover crops add an extra dimension of
complexity and uncertainty to the no-till component of sustainable agriculture,
causing both no-till and cover crops to be viewed as risky practices by some
producers. A more comprehensive
understanding of soil and crop specific responses to crop rotation, tillage/residue
management practices, and cover crops is critical to understanding and
improving economies of production (Reeves, 1994).
Meisinger et al. (1991) outlined the importance of cover crops in
improving environmental quality. Cover
crops scavenge nitrogen from the soil profile and prevent it from moving below
the root zone during periods of time when the soil water is being
recharged. Under tilled conditions,
cover crops also help protect the soil from water and wind erosion. Hatfield and Keeney (1994) outlined some of
the knowledge gaps in cover crop use that need to be addressed through
research. They concluded that
development of cover crop systems for climates with short growing seasons
and/or low water availability was a priority.
Research to identify additional cover crops that fix nitrogen or have
other economic benefits was also identified as a priority. Additional information on the fate of
nitrogen recovered or fixed by the cover crop is needed to ensure that cover
crop decomposition and mineralization are synchronized with the N requirement
of the subsequent crop (Meisinger et al., 1991). The objective of this study was to evaluate the impact of cover
crops in no-till conditions on corn yield and quality compared to a
conventional tilled system without cover crops.
Approach
A field experiment was conducted in which different species (or
subspecies) of grasses and legumes (planted into spring wheat stubble) were
evaluated as cover crops in a three year rotation (soybean/spring wheat-cover
crop/corn) under no-tillage soil management. The experiment is located near Brookings, South Dakota on a silty
clay loam at the USDA, ARS, Northern Grain Insects Research Laboratory. Treatments included cover crops (14 different
cover crops), no-till fallow (no cover crop) and conventional tillage treatments
which were replicated four times within the experimental area. Cover crop species evaluated included
(common names): crimson clover, alsike
clover, red cover, sweet clover, annual ryegrass, winter rye, hairy vetch,
carneval field pea, Austrian winter pea, slender wheatgrass, non-dormant
alfalfa, sudangrass, buckwheat and barley.
All cover crops were planted in early August (following spring wheat
harvest) at recommended seeding rates for cover crop use. The following spring all plots were planted
to corn. The corn phase of the rotation
was planted on 29 May, 2001; 6 June 2002 and 12 June 2003.
Soil samples were collected prior to the first cover crop planting. The
0-24 inch samples was be separated into 0 – 6, 6 – 12 and 12 – 24 inch increments
before initial soil physical and chemical conditions were measured. During the course of the experiment, data
collection included growing environment (soil temperature, soil moisture,
rainfall, and air temperature, soil physical properties (soil bearing strength,
bulk density, water content at planting, and vane shear strength), total cover
crop growth, corn emergence and growth (stand counts and phenology), and corn
grain yield and quality (protein and oil content). For the purposes of this proceeding only data from the 2003
growing season will be discussed in respect to soil temperature and stand
establishment. Cumulative soil growing
degree days was calculated by summing the daily soil growing degree day calculated
with the following equations:
Daily Soil GDD(Base
10) = 
Results and Conclusions
One of the biggest concerns with no-till production practices is stand
establishment due to unfavorable soil conditions (excess soil moisture and/or
cooler soil temperatures) at the time of planting. Soil temperature was collected every half hour from approximately
the beginning of May until the beginning of July at a soil depth of 1.5
inches. Cumulative soil growing degree
days (Cº) were calculated for each treatment for the 15 days following corn
planting (Figure 1). Cumulative soil
growing degree days obtained for the 2003 growing season found that only five
of the cover crop treatments had significantly lower soil temperatures compared
to the conventional tillage. Cover
crops that over-winter and produce significant ground cover and above ground
biomass (alfalfa, alsike clover, hairy vetch, sweet clover and red clover)
significantly reduced spring temperatures.
Cover crop species that over-wintered and produced significant above
ground growth, but which grew in an upright manner (did not form a mat over the
soil surface) showed similar spring soil temperatures compared to the
conventional tillage. A visual illustration of the differences in growth
characteristic is illustrated in Figure 2.
The sweet clover on the left form a thick mat completely covering the
soil surface compared to the vertical growth of the slender wheatgrass on the
right. Species that did not over-winter
and the no-till fallow (no cover crop) treatments did not significantly reduce
spring soil temperature compared to the conventional tillage.
Stand counts for corn were performed to evaluate the effect of spring
soil temperature on stand establishment.
Data is reported for cover crop species that significantly decreased
spring soil temperature and the conventional tillage treatment (Figure 3). Initial stand counts revealed that emergence
was significantly delayed for corn planted into these treatments (alfalfa,
alsike clover, hairy vetch, sweet clover and red clover). The conventional tillage treatment reached
full emergence (16 plants / 10 ft row) a week after planting (19 June) while
the remaining species took an additional week to reach their maximum emergence. In contrast, stand counts for 19 June showed
that corn emergence beneath the five cover crop treatments were less then 50%
of the maximum emergence. Final
emergence counts for the five cover treatments were significantly less than the
conventional tillage treatment.
Corn grain
yield is expressed as a percent of the conventional tillage or no-till fallow
(no cover crop) grain yield to visually illustrate the impact on yield due to
the different cover crop treatments compared to conventional management
practices (Figure 4 and 5). Grain yield
was higher for all cover crop treatments (significantly higher for all except
buckwheat, annual ryegrass, winter ryegrass, slender wheatgrass and red clover)
compared to the conventional tillage treatment in 2002 due to extremely dry
conditions during the growing season (Figure 4). No-till soil management increases soil moisture retention, thus
resulting in increased yield compared to conventional tillage during that
year. Corn yield was significantly
reduced by the presence of alsike and sweet clover compared to the conventional
tillage and no-till fallow treatments in 2003 (Figure 4 and 5). Similarly the conventional tillage treatment
had significantly lower yields compared to the no-till fallow (no cover crop)
treatment during the dry growing season of 2002 (Figure 5).
Grain quality
was evaluated by determining protein and oil concentration. There were no significant differences in
protein or oil concentration for the 2001 growing season, and no significant
differences in oil for 2002. Protein
content was significantly affected in 2002 and 2003 (Table 1). Corn following spring legumes including
alsike clover, sweet clover and hairy vetch had a tendency to have higher grain
protein and oil concentration.
Table 1. Grain protein and
oil concentration analysis of variance by growing season, Brookings, SD
2000-2003.
------------------------------Mean
Square------------------------------
---------------------------------Protein----------------------------------
Rep 3 0.1347 0.0845 0.2691
Cover Crop 15 0.1677 0.1339 * 0.8783 **
Error 45 0.1247 0.0724 0.1078
------------------------------------Oil------------------------------------
Rep
3 0.0560 0.0480 0.0219
Cover Crop 15 0.0212 0.0137 0.3168 **
Error 45 0.0285 0.0179 0.0365
**, * - significant at the
0.01 and 0.05 probability levels, respectively; df - degree of freedom
No-till soil
management has the potential to preserve soil moisture, decrease soil erosion
and increase yield compared to conventional tillage systems. However incorporating cover crops adds an
additional management factor that if not managed properly can decrease the
following cash crop yield as illustrated in stand establishment and corn yield
differences obtained in this experiment.
No-till management increased corn yield in 2002 regardless of the cover
crop utilized due to extremely dry periods within the growing season. In contrast in 2003 the presence of some
cover crops significantly delayed stand establishment but not all had a
negative impact on corn yield. Proper
management and choice of cover crop species are important considerations when
including cover crops into current production systems.
References
Barber, S.A. 1984. Soil Nutrient
Bioavailability: A Mechanistic Approach. John Wiley and Sons, Inc., New York,
NY.
Clegg M.D. and C.A. Francis. 1994. Crop
management. p. 135-156. In: J.L. Hatfield and D.L. Karlen (eds) Sustainable
Agricultural Systems, CRC Press, Boca Raton FL.
Dick, W.A., D.M. Van Doren, G.N. Triplett,
and J.E. Henry. 1986. Influence of long-term tillage and rotation combinations
on crop yields and selected soil parameters. Research Bulletin 1180, Ohio
Agric. Res. and Dev. Center, Ohio State University.
Drury, C.F., C.-S. Tan, T.W. Welacky, T.O.
Oloya, A.S. Hamill, and S.E. Weaver. 1999. Red clover and tillage influence on
soil temperature, water content, and corn emergence. Agron. J. 91:101-108.
Griffith, D.R., and N.C. Wollenhaupt. 1994.
Crop residue management strategies for the midwest. p. 15-37. In: J.L. Hatfield
and B.A. Stewart (eds.) Crop Residue Management. Lewis Publishers, Boca Raton, FL.
Hatfield, J.L., and D.R. Keeney. 1994.
Challenges for the 21st century. p. 287-307. In: J.L. Hatfield and
B.A. Stewart (eds.) Crop Residue Management.
Lewis Publishers, Boca Raton, FL.
Higgs, R.L., A.E. Peterson, and W.H.
Paulson. 1990. Crop rotation: Sustainable and profitable. J. Soil Water Cons.
45:68-70.
Mannering, J.V., and D.R. Griffith. 1981.
Value of crop rotation under various tillage systems. Agronomy Guide AY-230,
Cooperative Extension Service, Purdue University, West Lafayette IN.
Meisinger, J.J., W.L. Hargrove, R.L.
Mikkelsen, J.R. Williams, and V.W. Benson. 1991. Effects of cover crops on
groundwater quality. p. 57-68. In: W.L. Hargrove (ed.) Cover Crops for Clean
Water. Soil and Water Conservation Society. Ankeny, IA.
Moldenhauer, W.C., and L.N. Mielke. 1995.
Introduction: Why the emphasis on crop residue management. p. 1. In W.C.
Moldenhauer and L.N. Mielke (eds.) Crop residue management to reduce erosion
and improve soil quality: North Central. USDA, NRCS, CRR-42.
Raimbault, B.A., T.J. Vyn, and M. Tollenaar.
1990. Corn response to rye cover crop management and spring tillage systems.
Agron. J. 82:1088-1093.
Reeves, D.W. 1994. Cover crops and rotation.
p 125-172. In: J.L. Hatfield and B.A. Stewart (eds.) Crops Residue Management.
Lewis Publishers, Boca Raton, FL.
Swan, J.B., T.C. Kaspar, and D.C. Erbach.
1996. Seed-row residue management for corn establishment in the northern US
corn belt. Soil Till. Res. 40:55-72.
White, D.C., J.B. Braden, and R.H.
Hornbaker. 1994. Economics of sustainable agriculture. p. 229-260. In: J.L.
Hatfield and D.L. Karlen (eds) Sustainable Agricultural Systems, CRC Press,
Boca Raton, FL.
Figure
1. Cumulative soil growing degree days for 15 days following corn planting,
Brookings, SD, 2003.
Figure
2. Above ground biomass growth for sweet clover (left) and slender wheatgrass
(right) photographed 15 May, 2003.
Figure
3. Stand establishment counts, number of plants emerged in ten feet of row, for
treatments in which soil growing degree days were significantly less then
conventional tillage, Brookings, SD 2003. (12 June planting date)
Figure
4. Corn yield expressed as a percent of the conventional tillage (CT) treatment
for all cover crops and no-till fallow (no cover crop) treatment, Brookings,
SD, 2001-2003.
Figure
5. Corn yield expressed as a percent of the no-till fallow (no cover crop)
treatment for all cover crops and conventional tillage treatment, Brookings,
SD, 2001-2003.
Shannon L. Osborne –
Biography
Education:
Ph.
D University of Nebraska, Lincoln,
Nebraska
Dissertation
Chair: Dr. J.S. Schepers
Major Field: Soil Fertility and Plant
Nutrition
Minor Field: Biometry
Date: December 1999
M.S. Oklahoma State University, Stillwater,
Oklahoma
Thesis Chair: Dr. W.R. Raun
Major Field: Soil Fertility
Date: May 1996
B.S. Oklahoma State University, Stillwater,
Oklahoma
Major Advisor: Dr. S.R. Henneberry
Major Field: Agricultural
Economics-Int. Marketing
Date: December 1994
Current Employment:
January 2000 – present: Research Agronomist, USDA/ARS,
Northern Grain Insects Research Laboratory, Brookings, South Dakota.
Responsibilities: plan, design and implement applied and basic field plot,
greenhouse, laboratory and on-farm research relating to the understanding of
crop rotations, tillage, residue management, cover crops and soil fertility impact
on crop production and soil productivity; the effects of spatial variation and
distribution of soil chemical and physical properties on crop growth and
yield; the identification of alternative crops and production methods for
integration into existing crop systems; develop cooperative research programs,
with ARS, university, and industry scientists.
Soil Carbon and
Greenhouse Gas Emissions Offsets:
An Economic Opportunity for Great Plains No-Tillers?
Gordon R. Smith, Ph.D.
Director, EcoLands Program
Environmental Resources
Trust
13047 12th
Avenue
Seattle, WA 98177-4108
voice: 206.784.0209; fax: 206.784.9662
email: gsmith@ert.net
Greenhouse Emissions
Greenhouse gases act like a blanket around the earth,
trapping some of the heat we get from the sun.
This greenhouse effect is essential to life on earth, keeping us from
being frigid like the moon. Human
activity has been increasing greenhouse gas levels in the atmosphere, and
warming the earth’s climate. If the
trend continues it will cause climate change that disrupts human
activities. The exact degree to which
observed warming is the result of human activity versus natural processes is
not known. But it is known that human
activities are causing as significant proportion of the warming that is
occurring. In the 20th
century, global temperatures increased by an average of about 1.1 degrees
Fahrenheit. Scientists estimate that
changes greater than 3.6 degrees Fahrenheit would cause changes in climate that
would be very disruptive to life as we know it. This change does not sound like much, but the temperature rise
would be enough to change what crops could be grown in many locations, and
would cause a 2-6 foot rise in sea level with flooding of coastal areas,
weakening or loss of the Gulf Stream, and increased intensity of storms. Warming is greater than average in the
arctic and in the interiors of continents.
Climate modeling indicates that limiting temperature
rises to 3.6 degrees Fahrenheit requires limit atmospheric concentrations of
carbon dioxide to about 450 parts per million.
Prior to industrialization, before about 1800, the concentration was
about 280 parts per million. As of year
2000 the concentration was about 370 parts per million, and rising at about 1.5
parts per million per year.
There are several gases that cause greenhouse
warming. The largest volume if
emissions and largest warming effect come from carbon dioxide. Other greenhouse gases that come from
agricultural activities are methane and nitrous oxide.
Current global carbon dioxide emissions are in the
range of 29 billion metric tons per year.
Limiting the atmospheric concentration of carbon dioxide to 450 parts
per million would require reducing emissions by more than 20 billion tons per
year. If emission reductions are not
started now, an even more precipitous drop in emissions will be needed in a
couple decades to avoid significant warming.
The potential market for emission mitigation is huge, if we were to
choose to avoid climate-changing warming.
Currently, total U.S. emissions of all greenhouse
gases are about 7 billion metric tons carbon dioxide equivalent per year. U.S. emissions are rising at about 1% per
year. In the U.S., agricultural
activities result in more than 500 million metric tons CO2 equivalent of
emissions, with about 60% of this warming effect from nitrous oxide from
nitrogen fertilizer. Nearly a quarter
is from methane from farm animals.
Emission Offsets
Emission offsets can be use to mitigate emissions,
such as emissions from burning coal in a power plant to generate
electricity. Offsets can be generated
in one location and used to mitigate emissions from another location because
greenhouse gases mix in the atmosphere.
To count as an offset, mitigation must have several attributes. An offset must have the following
attributes:
v Net reduction in emission or
removal of GHG from atmosphere
v An unused portion of an
emission allowance under an emission cap, or in the absence of a cap must be
mitigation that would not have happened otherwise (additional)
v Reliably quantified
v Owned by the seller (direct)
v Verified by an independent
party
Offsets may be reversible. For example, when carbon is sequestered in soil by switching from
plowing to no-till, that carbon comes from carbon dioxide in the
atmosphere. The sequestration can be
reversed by resuming plowing. If an
offset is based on something that is reversible, the continued existence of the
offset must be monitored. Emission
reductions are irreversible—you can not go back in time and emit more. Emissions can increase later. This could mean that no new emission
reductions are generated, but it would not emit tons that were not emitted in
earlier years.
There are several changes in agricultural practices
that can mitigate greenhouse gas emissions.
Mitigation can be reducing emissions or taking greenhouse gases out of
the atmosphere. Some changes in
agricultural practices that reduce emissions are:
v Precision nitrogen
fertilizer use reduces N2O
v Fuel use reductions lower
CO2 emissions
v Reduce irrigation power use
v Changes in livestock
management reduce CH4
v Biofuel reduces use of
CO2-intensive fossil fuels
Some changes in agricultural practices that remove
greenhouse gases from the atmosphere are:
v No or low tillage
v Increase residue
v Winter cover crops
v No summer fallow
v Improved grazing practices
v Vegetation buffers
v Convert marginal agricultural land to grassland or forest
On a per-acre basis, rates of generation of offsets
are generally modest. Rates vary by
practices and conditions. Generally,
rates range from less than one tenth of a ton carbon dioxide equivalent per
acre per year, to about a ton per acre per year. Growing trees can sequester a few tons per acre per year. For a local example, modeling predicts that,
in Hughes County South Dakota, doing dry land farming on a silt-loam soil with
a rotation of spring wheat, small grain, mechanical fallow, switching from
intensive tillage to no-till would sequester 0.18 tons carbon dioxide
equivalent per year.
Several practices change the equilibrium conditions
of lands, and generate new mitigation as the land is approaching the new
equilibrium. For example, when
switching from plowing to no-till, without any other changes, the soil organic
matter content rises and then stabilizes at a new, higher proportion. Sequestration is occurring as the rate is
rising, and then the sequestered carbon remains stored as long as the organic
matter content remains higher.
Changing agricultural practices to mitigate greenhouse
gas emissions can have several other environmental and economic benefits,
including:
v Improve soil quality
v Improve water
quality/decrease erosion & leaching
v Improve wildlife habitat
v Leverage conservation funds
Some changes that have a greenhouse benefit
sometimes cause negative effects on air quality. For example, if more nitrogen is applied to soil to increase
plant growth and speed carbon sequestration, that can cause increased emission
of oxides of nitrogen, which are air pollutants.
The Current Market
for Greenhouse Offsets
Currently, for most facilities in the U.S., there
are no limits on greenhouse gas emissions.
As a result there is little demand for offsets in the U.S. Some companies are reducing emissions
voluntarily. Most companies that are
reducing emissions are taking internal actions to reduce their own emissions,
but some are purchasing emission offsets.
The volume of purchases is low—a few million tons carbon dioxide
equivalent per year.
The market for greenhouse emission offsets is
growing rapidly in Europe because Kyoto Protocol limits on greenhouse gas
emissions are coming into effect.
Trading is up to about 10 million tons per week within the European
system, and expected to continue growing.
Offset prices are down because governments have given emitters very high
emission caps, so fewer companies think they will need offsets. Recent prices in the European market, for
certified offsets, were in the range of $9 per ton carbon dioxide equivalent.
Amounts of Offsets
which Farmers Might Sell
Many agricultural producers are interested in
earning revenue by selling greenhouse gas emission offsets. At the same time, most producers are
reluctant to make permanent commitments not to plow. This concern can be accommodated by renting offsets for a
specified time period, rather than selling them. Rented offsets must be replaced at the termination of the rental,
or counted as an emission. The buyer must
factor in the cost of replacing the offset at the end of the rental
period. For this reason, rentals are
valued less than permanent offsets.
Another factor that reduces prices paid for offsets
is advance payment. Many landowners
want to be paid in advance for offsets that will not be generated for several
years. Financial asset accounting
methods can be used to calculate what might be a fair price for rental of
offsets. The calculations become
somewhat complicated when the amount of offsets changes over time, the duration
of the rental is different for different tons, and the payment is made in
advance. An example illustrates
possible payments. In the example given
here it is assumed that:
v The price of permanent offsets does not change over time
v Annual interest rate = 6%
v Constant sequestration of
0.5 MgCO2/ac/yr (in 10 years, 5 tons would be stored)
v One time, up-front rental
payment for all sequestration and storage for life of project
v No discount for uncertainty,
performance risk, leakage, or non-additionality
Given these assumptions, the
up-front payments for sequestration would be as shown in the following
table. Payment amounts are given for 5,
10, or 15 year rentals, and for prices of $5, $10, and $15 per ton carbon dioxide equivalent.
|
$/ton CO2
|
5 year term
|
10 year term
|
15 year term
|
|
$5
|
$1.82
|
$5.54
|
$10.09
|
|
$10
|
$3.64
|
$11.09
|
$20.18
|
|
$15
|
$5.47
|
$16.63
|
$30.27
|
A farmer would have to choose whether or not the
commitment of not plowing is worth a payment of this size. Farmers may wish to choose annual payments,
where the obligation is only for one year.
Annual rentals are a fraction of the price of a permanent offset, just
as the annual rental price of an acre of farm land is a fraction of the price
of buying that land.
Farmers may wish to sell permanent offsets, such as
emission reductions from reduced fuel use resulting from switching from plowing
to no-till. In terms of tons of carbon
dioxide per acre per year, the amounts are small, but the reductions are
permanent and require no ongoing monitoring.
A common question is whether farmers who have been
no-tilling for several years can rent or sell offsets based on the
sequestration they have achieved over their years of no-tilling. We believe that, because farmers often stop
no-tilling, continuing to practice no-till is—in part—an action that is in addition
to what would have happened in the absence of a greenhouse gas emission offset
project. Recall that to count as an
offset, an mitigation must (among other things) be either an unused portion of
an emission allowance under an emission cap, or (if there is no emission cap)
be mitigation that would not have happened except for the project.
When a farmer in an emission offset project commits
to continuing to use no-till practices, to the extent that other farmers who
were no-tilling switch out of no-till, the farmer who continues no-tilling is
doing something over and above what others are doing. The amount of mitigation that is additional to what would have
occurred without the project, and the average behavior of others not in
greenhouse project but with similar starting conditions provides a measure of
what would have occurred otherwise.
With this calculation methodology, there are two parts of the equation:
the amount of carbon not released, and the proportion of this amount that
counts as additional and thus can qualify as an offset. Doing the math using a national average rate
at which farmers are observed to be stopping no-tilling, if a farmer has been
no-tilling for five years or more them may be able to substantiate more offsets
per acre than a farmer who is just starting no-tilling.
These methods for calculating the additionality of
tons stored prior to starting an emission offset project are not well
understood. Further discussion and
education within the greenhouse gas emission offset community is needed before
these methods will be generally accepted.
The Offset Buyer’s Perspective
In the absence of a cap on emissions, companies buy
offsets for a variety of reasons.
Reasons include:
v Voluntary GHG commitments
v Acquire low-cost mitigation
credits for long-term risk management
v Comply with contractual or
regulatory requirements
v “First-mover” advantage in
GHG credit market
v Competitive advantage in
marketing
v Public relations
Emitters can create or acquire emission mitigation
from a variety of sources. Agricultural
producers are just one of many sources of offsets. Many offsets are bought by electric utilities, to mitigate
emissions from power plants. Some other
mitigation options for electric utilities are:
v Fuel Switch from Coal to
Natural Gas
v Heat Rate Improvements
v Biomass Co-Firing
v Distribution Efficiency
Improvements
v Environmental Dispatch
v Demand Side Management
v Install Renewable Generation
v Landfill Methane
v Biological Sequestration
v CO2
Removal/Disposal from stack gases
If an electricity producer chooses to buy offsets on
the market, offsets produced by farmers are just one supply source of
many. When considering generating and
selling offsets from agriculture, both buyers and sellers should consider the
cost of generating offsets by other methods.
The graph below gives one utility company’s estimate of its costs of
creating or buying offsets different kinds of offsets. Many buyers will first obtain lower cost
offsets, and then move to higher cost offsets as larger quantities are needed.
Several barriers exist which hinder the creation and
sale of greenhouse gas emission offsets generated by changing agricultural
practices. On the supply side barriers
include:
v Standards not established
and accepted for: measurement precision, baselines, additionality, leakage,
permanence
v Measurement &
verification – few providers of services
v Few qualified aggregators
v Producers not familiar with
offsets
v Producers adverse to
long-term commitments
v High transaction costs
relative to value of offsets
Barriers to agricultural offsets also exist on the
demand side:
v Weak demand in U.S.
voluntary system
v Buyers not familiar with
agriculture
v Buyers prefer irreversible
offsets
v Buyers not use asset pricing
to value offsets
v Some agricultural offsets are
expensive
A key aspect of building sales of greenhouse gas
emission offsets from agriculture is establishing aggregators that can bring
together mitigation from many farmers.
Aggregators are required to bring together many tons so measurement and
verification costs can be spread across a large number of tons. Also, by pooling tons from many farmers,
aggregators can spread risk, making higher quality offsets.
Organizations that already have a relationship with
farmers are better positioned to be aggregators. Having an existing relationship with farmers can reduce the
transaction costs of establishing and managing contracts with individual
farmers. Organizations such as crop
marketing cooperatives are particularly well positioned to become aggregators.
Conclusions
In summary, several changes in land management
practices can both create greenhouse gas emission offsets and provide farmers
financial returns. However, revenue
from greenhouse gas emission offsets is likely to be modest relative to revenue
from crops. As a result, emission
mitigation practices must be compatible with continuing to earn the bulk of
revenue from crops.
Some of the most promising opportunities for
creating greenhouse emission offsets are:
v Tree planting
v No-till
Ø Sell fuel reductions
Ø Rent soil sequestration
v Fertilizer management
v Pasture management
v Irrigation management
For the foreseeable future, voluntary demand means
low prices for offsets. Offsets from
agriculture compete in the market with offsets from other sources. Many agricultural offsets are lower cost
than some other types of offsets, providing opportunity for agriculture. Producer organizations are well positioned
to aggregate and market offsets generated by farmers.
A challenge to marketing agricultural offsets is
developing broader understanding that offsets generated by continuing no-till
are additional to what would happen in the absence of emission offset projects.
Gordon R. Smith -
Biography
Gordon R. Smith is Director of the EcoLands Program of the Environmental
Resources Trust (ERT). ERT is a
national not-for-profit organization with the mission of developing markets
that improve the environment. A focus
of Dr. Smith's work with ERT is measurement and verification of greenhouse gas
emission offsets generated by changing land management. ERT also audits measurements performed by
others, and advises project developers.
Dr. Smith's work includes researching and testing tools for reliable and
cost-effective measurement of greenhouse gas offsets. He has authored
scientific and professional publications on measuring forest and soil carbon
sequestration, greenhouse gas offset accounting, and ecological management of
forests. He has also worked on
developing trading mechanisms for water pollution reductions, joint production
of timber and non-timber forest products, and development of Forest Stewardship
Council guidelines for certification of sustainable forest management. Dr. Smith has a Ph.D. in Forest Management
from the University of Washington, and a Master of Public Policy from Harvard
University. He is an active alpinist
and chair of the Rigging Committee of Seattle Mountain Rescue.
Marketing No-Till
Karl Kupers
Marketing Director
Shepherd’s Grain
Harrington, WA
History:
v
Sequence of events
leading to today
v
Conservationist in my
youth
v
Diversified farmer by
desire
v
No-tiller by accident
v
Educated no-tiller after
visit to Dakota Lakes Farm
v
Practicing no-tiller
v
Developer of Pacific
Northwest Direct Seed Association
Ø
Author of carbon
sequestration lease agreement 2002
v
Quit farming after 31
years
v
Marketer of No-till
crops
Ø
Final frontier of
advancing no-till
Future:
v
Regional marketing
v
3rd party verified
v
Transparent pricing
How to get there:
v
Be committed to
production process for yours and future generations sustainability
v
Recognize societies
desires for cleaner air and cleaner water
v
Use regulators funding
when applicable
v
Match your regional
market desires to what you are already doing
v
Form a group and play
the local, family, sustainable and even the oh poor me farmer card
v
Honesty, integrity and
relationships
v
Market your process
Karl Kupers – Hirst Farms*
- Biography
Background: (initial strategy,
evolution of strategy and enterprise structure, dynamics and resources involved
in getting started; amount of start-up capital required?)
Hirst Farms is a 5680 acre grain farm in the low rainfall (11-12 inches
per year) region of Lincoln County, Washington. Karl Kupers joined his father
working on the farm in 1973. Area agriculture is characterized primarily by
dryland winter wheat / summer fallow cropping systems and beef cow/calf
ranching.
In the mid- 1990’s, out of concern for soil health and sustainability,
Karl used a SARE Farmer Research grant to begin experimenting with alternative
crops and direct-seed cropping systems on a 40 acre test plot. He has also been
involved in on-farm cropping systems trials with WSU Extension and the Wilke
Research Farm (alternative dryland cropping systems trials). He gradually
translated these practices to the entire farm. The entire agricultural infrastructure
of Lincoln County emphasizes the production, export and marketing of wheat. So,
along the transition to more sustainable production systems, Karl recognized
that he had to develop a complementary marketing strategy. In order to capture
value and market share through his commitment to sustainability, Karl became
the first Food Alliance certified grain grower. Food Alliance certification and
market development efforts facilitated his marketing of grain direct to food
processors, such as artisan bakeries. Another way that Karl is marketing the
sustainability of his farm is through the Pacific Northwest Direct Seed
Association. PDSA has entered a carbon credit lease agreement with Entergy
(southern energy utility) for carbon sequestered through direct-seed cropping
systems.
Karl is becoming widely recognized and respected for his efforts to
improve the sustainability of dryland grain farming. He was profiled in SARE’s
The New American Farmer publication.
Organizational form / scale / leadership: (nature & legal form of the enterprise, number of members,
capitalization and other major financial indicators, amount of product,
leadership & decision-making structures, changes over time and reasons for
changes)
Karl, like his father, has always leased the farmland from landowners
that are between 3 and 5 generations removed from the farm. While these
landlords take pride in their farming heritage, none of them have technical
expertise in farming. Karl has taken the initiative to maintain transparency
with his landlords and to keep them informed about agricultural sustainability
and how he is trying to make their land and the farming more sustainable.
Consequently, his landlords have supported his decisions to pursue alternative
production and marketing systems. Recently, Karl purchased 1200 acres he had
been leasing to keep it in production.
In addition to building the sustainability of the land, Karl promised the
landlords that he would work out a transition of the farm to another farmer on
their behalf. In early 2000, Karl brought in Jim Hirst to begin the farm transition.
After three years of working together, Jim took over fiscal and operational
responsibility of the farm and is now the leaseholder. Attorneys and
accountants had questioned whether such a “non-family” transition on leased land
would work, but Karl says he and Jim hit it off well and the transition
actually came together more quickly than expected. Karl is now acting as the
“tractor driver” and the marketer for the grains and specialty crops.
To facilitate the marketing of crops, Karl has established a Limited
Liability Company called Columbia Plateau Producers with 11 other farmers in
the region. They market their grain as processed flour under the label “Shepherd’s
Grain”.
Nature of products and the “value chain”:
Karl has broken out of the rut of winter wheat / summer fallow
monoculture that dominates Lincoln County. He has shifted to alternative crops,
such as perennial grasses mixes for forage and CRP, safflower, sunflower,
canola, and mustard – all produced in direct-seed cropping systems. Karl’s
primary crop is still wheat.
The key difference that Karl’s new marketing strategy has created for his
“value chain” is that he now considers himself a flour producer and not a wheat
producer. Marketing flour as your end product requires a completely different
mindset and financial strategy. For instance, as a wheat grower, Karl used to
be paid for delivering wheat to the depot, but payments for flour are spread
out over the course of the year as the wheat is milled into flour. In addition,
direct marketing of a value-added product instead of a commodity has shifted
the burden of production from quantity to quality. As a commodity wheat
producer Karl says it’s “yield, yield, yield – quality be damned.” But when you
are direct-marketing a value-added end product like flour, you are very
concerned and take the extra steps to insure the quality of your product.
As is the key for many new successful marketing strategies, Karl’s value
chain is based on trust and relationship marketing. Karl credits Food Alliance
certification and partnership with opening many doors for marketing his product,
but the onus of making the sale is still on him. He is learning that patience
and persistence are critical qualities for successful relationship marketing.
Economics of the Enterprise:
Karl claims to earn 10 – 12% more than other grain farmers in the area.
He believes that the additional costs associated with innovation are more than
offset by the premiums received from direct marketing. He also believes that
the greatest economic benefits will be in the future, when the improved
fertility caused by his new production systems will improve productivity.
Direct-seeding and crop rotations have already significantly increased the
value of and created a demand for the land that he leases.
Currently, Karl direct markets approximately 50% of his products. His
goal is to have 100% of his crop contracted to direct markets before it is
planted.
Key opportunities & challenges engaged:
The challenges of farming sustainably in the dryer regions of Eastern
Washington have usually outweighed the opportunities. Karl has demonstrated
that making sustainability the goal of a farm is dependent on continual learning,
discovery and persistence. He notes that we can make things work if we get out
of the rut of ‘the way things are done.’
The greatest challenge and opportunity Karl faces is figuring out how to
fit all of the elements of sustainability that he has learned and is learning
into a comprehensive package and how to help other people understand this.
Directseeding, carbon sequestration, crop rotations, land tenure, Food Alliance
certification and relationship marketing are all pieces of the much larger
picture of sustainability. None of them alone is “the answer” to challenges of
farming. As enough of the pieces come together in a package, there is great
potential for improving the sustainability of agriculture. Each of the pieces
complements the others and learning how to see these complementarities is a key
to success. Recently, Karl has been thinking about how to link sustainability
all the way through the value chain of a product. As other units of the food
system, such as dairy farms, food processors and retailers, begin to value sustainability,
it makes sense to link them together to capture “life-cycle” sustainability of
a product. With this in mind, Karl has encouraged other links in his value
chain to become Food Alliance certified – so that there is third party verification
of sustainability from seed to consumer.
In addition to packaging sustainability, Karl is learning about the
importance of different concerns consumers have about the products they buy.
When he started direct marketing flour, he believed that his target market was
the “green” market. However, he has discovered that “local” is trumping every
other concern in marketing. Shepherd’s Grain products have been wildly
successful in Spokane, Washington – an Eastern Washington community not known
for concern about environmental issues. But the proximity of Spokane to the
Columbia Plateau Producers LLC has seemingly been the key. The issue of ‘what
is local’ is definitely changing with improved technologies, though – and that
has also had an impact on Karl’s success. He can now sit on his porch with his
cellular phone, wireless laptop and digital camera and talk with a buyer 300
miles away in Portland, Oregon – and for Karl that is still his local
community. He is now beginning to test how far his “local community” stretches.
Another challenge and opportunity that Karl thinks is important is
breaking out of the monoculture of winter wheat / summer fallow. While there
are certainly barriers to production in the low, winter-fed precipitation area
of Eastern Washington, Karl thinks that there are opportunities special to the
region, including proximity to large markets and the “benign” climate. The
cities of Seattle and Portland proper are home to 2.64 million consumers –
approximately $800 million dollars of baked good sales each year. When someone
claims that the market will be flooded if other farmers try to direct market,
Karl claims he’s more than willing to share! Another opportunity that Karl sees
is the fact that they don’t experience dramatic climatic shifts in Lincoln
County. A sever drought might cut production by 25%, a hailstorm might clip the
corner of the field and there is never a flood event too severe to farm - even
mild climatic shifts can devastate production in the Midwest or Canada. Karl believes
that in a benign environment like Eastern Washington, farmers can produce
products of more consistent quality and quantity than anywhere else in the
world, which is critical to developing direct markets.
Replicability in other settings:
Karl urges caution to other area farmers that are interested in
direct-seeding, because not all of the problems have been worked out.
Direct-seeding failed in the area already, when they tried it in a monoculture
of wheat without crop rotations. He believes you have to be absolutely
convinced about it, and that you need to be in good financial condition,
because you will see yield drags in your first few years. He also says that
while direct-seeding is a great weed management strategy in the long term, weed
problems can quickly ruin a transition.
Regarding the direct marketing of the grain and flour, Karl says that it
takes persistence, patience, and the ability to get out of traditional mindsets
(both for the grower and the potential buyer). Progress has been slower than
Karl expected, in spite of reports from buyers that he has been wildly
successful in his marketing efforts. He feels there is still a lot to be
learned and the need to coordinate multiple direct marketing efforts between
different types of farmers and ranchers. For instance, Karl believes both he
and Oregon Country Beef could both benefit from each other’s insight and
promotion of the other’s products when they are dealing with buyers.
Research, education/demonstration, or policy changes:
In terms of production research, Karl encourages continued research on
direct-seed systems and viable crops for the region. He comments that WSU and
ARS have made strides in that they are screening all of their most recent research
through direct-seed systems. He would like to see more varietal development,
especially for alternative crops.
He also appreciates research concerned with packaging the elements of
sustainability, such as work on the potential of carbon sequestration, the
visionary establishment of Food Alliance, and case studies on successes and
failures of direct marketing.
Conservation
Security Program
Jason Miller
Conservation
Agronomist
USDA-NRCS
jason.miller@sd.usda.gov
Do You “C” What I “C”?
Dr. Dwayne Beck
Dakota Lakes Research
Farm
South Dakota State
University
PO Box 2
Pierre, SD 57501
(605) 224-6357
dwayne.beck@sdstate.edu
www.dakotalakes.com
