WICST 9th Technical Report
A COMPARISON OF LOW INPUT SYSTEMS ON WICST
Janet L. Hedtcke1, Joshua L. Posner1, and Jon O. Baldock2
INTRODUCTION
Marginal profits, increasing pest pressure, and concern for pollution hazard have resulted in
increased interest in including small grains in corn-soybean rotations and using less inputs. Data
from the WICST trials show environmental advantages of using a chemical free three-phase
system but yields were often lower than in the high input systems. Researchers have found that
expanded rotations plus low input levels can be quite competitive with shorter rotations and high
chemical inputs (Singer, 1998; Singer and Cox, 1998 and Clark et al., 1999). We decided to test
a ‘ChemLite’ approach adding reduced inputs to the 3-phase cash grain rotation and compare it
to the three phase organic system (CS3), and the no-till corn soybean system (CS2). The
ChemLite system would aim for half rates of N on cereals and half rates of post-emergent
herbicide on row crops (when necessary).
MATERIALS & METHODS
The Wisconsin Integrated Cropping Systems Trial (WICST) is a long-term trial that was initiated
in 1989 to compare production, economic, and environmental impacts of six cropping systems
common to the upper Midwest. Further description of the background details, design and
conduct of the main WISCT cropping systems can be found in Posner et al. (1995).
In 1995, a satellite trial was initiated at the Arlington site on a Plano silt loam soil (fine-silty,
mixed, mesic, Typic Argiudoll) to compare a reduced-chemical system of corn-soybeanwheat/red clover (hereafter referred to as ChemLite) to the No-till corn-soybean system and the
chemical free corn-soybean-wheat/ red clover system (hereafter referred to as ChemFree) of the
core WICST trial.
Inputs. A list of inputs and rates for the ChemLite system are shown in Table 1. Generally,
three inputs were added to ChemLite: starter fertilizer on the corn, N fertilizer on the corn and
occasionally the wheat, and post-emergence herbicides on the corn and soybeans. ChemLite
received half-rates of N fertilizer on the corn phase which averaged 80 lb N/a. Rotary hoeing,
cultivation and post-emergence herbicide was applied in 15” bands over the row or broadcast on
the whole field at half rates during the corn and soybean phases, depending on the equipment set
available at the time. Herbicides were applied as deemed necessary, and in some years, no
herbicides were applied. The No-till corn-soybean received inputs according to Best
Management Practices (i.e. 120 lb N/a on corn, pre- and post-emergent herbicides in both
phases).
The experiment was set up with two replicates adjacent to the main WICST experiment, which
was a randomized complete block. All plots were 0.70 acres and field-sized equipment was
used. Each phase of the rotation existed each year during the 8-yr trial to encompass different
environments. All effects in the model are fixed except year, which is random. To compare corn
and soybean phases, 95% confidence intervals were calculated for the two systems in WICST
1
2
Research specialist and Professor, respectively, UW-Madison, Agronomy Dept.
Statistician/consultant, AgStat, Verona, WI
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(ChemFree and No-till corn-soy) across the 8 years and 4 replicates and across the 8 years and 2
replicates in ChemLite. Wheat grain and straw yields were compared between ChemLite and
ChemFree using an independent t-test statistic. Preliminary tests showed variances to be
homogeneous between the core WICST plots and the ChemLite experiment for all the dependent
variables.
The Crop Rotations Options Program (CROP) software (Baldock et al., 1998) was used to
determine net returns (to labor, capital, and management) each year and for testing scenarios on
price premiums. A 1000-acre farm was used in CROP and yearly input prices, yields, and
commodity prices were entered for each system. Harvest-time commodity price (October price
without storage option) was used across systems without any governmental price supports.
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Table 1. Inputs for ChemLite System.
Year
1995
1996
Corn
Starter: 6-24-24 at 100 lb/a
N: 82-0-0 at 73 lb/a
Herbicide†: Accent 0.33 oz/a
Buctril 0.50 pt/a
Rotary hoe: 3 times
Cultivate: 2 times
Soybeans
Starter: none
N: none
Herbicide†: Basagran 0.50 pt/a
Resource 2.0 oz/a
Crop Oil 0.50 qt/a
28% N 0.25 gal/a
Rotary hoe: 3 times
Cultivate: 2 times
Starter: none
N: none
Herbicide: none
Rotary hoe: 3 times
Cultivate: 4 times
Wheat
Starter: none
N: none
Herbicide: none
Starter: 6-24-24 at 100 lb/a
Starter: none
N: 82-0-0 at 98 lb/a
N: none
Herbicide†: Accent 0.22 oz/a
Herbicide: none
Buctril 0.25 pt/a
NIS 0.1 qt/a Rotary
hoe: 3 times
Cultivate: 3 times
1997
Starter: 6-24-24 at 100 lb/a
Starter: none
Starter: none
N: 82-0-0 at 98 lb/a
N: none
N: none
Herbicide†: Accent 0.33 oz/a
Herbicide†: Poast Plus 0.75 pt/a
Herbicide: none
Buctril 0.50 pt/a
Crop Oil 0.25 qt/a
Rotary hoe: 3 times
Rotary hoe: 3 times
Cultivate: 7 times
Cultivate: 8 times
1998
Starter: 6-24-24 at 100 lb/a
Starter: none
Starter: none
N: 82-0-0 at 98 lb/a
N: none
N: none
Herbicide: none
Herbicide: none
Herbicide: none
Rotary hoe: 2 times
Rotary hoe: 2 times
Cultivate: 1 times
Cultivate: 3 times
1999
Starter: 6-24-24 at 100 lb/a
Starter: none
Starter: none
N: 82-0-0 at 98 lb/a
N: none
N: none
Herbicide: none
Herbicide: none
Herbicide: none
Rotary hoe: 1 time
Rotary hoe: 1 time
Cultivate: 2 times
Cultivate: 3 times
2000
Starter: 9-23-30 at 100 lb/a
Starter: none
Starter: none
N: 82-0-0 at 98 lb/a
N: none
N: none
Herbicide: None
Herbicide: none
Herbicide: Poast
Rotary hoe: 2 times
Rotary hoe: 2 times
0.75 pt/a
Cultivate: 2 times
Cultivate: 3 times
2001
Starter: none
Starter: none
Starter: none
N: none
N: none
N: none
Herbicide: Northstar 0.50 oz/a
Herbicide: none
Herbicide: none
Accent 0.33 oz/a
Rotary hoe: 1 time
Rotary hoe: 1 time
Cultivate: 2 times
Cultivate: 2 times
2002
Starter: 5-14-42 at 100 lb/a
Starter: none
Starter: none
N: 82-0-0 at 98 lb/a
N: none
N: 50 lb N/a (urea)
Herbicide: Buctril 0.5 pt/a
Herbicide: Raptor 2 oz/a
Herbicide: none
Accent gold 0.33 oz/a
Poast Plus 0.75 pt/a
AMS 3 lb/a
AMS 2.85 lb/a
NIS 0.1 qt/a
NIS 0.1 qt/a
Rotary hoe: 2 times
Rotary hoe: 2 times
Cultivate: 1 time
Cultivate: 1 time
† The rates shown are the amount per total acre. From 1995-1998, the applications were made in a 15-inch band
on 30-inch rows, thus the rate in the band itself was twice that shown. In 2001 and 2002, herbicides was broadcast
across the 30-inch row at half rate.
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RESULTS & DISCUSSIOIN
Agronomic Performance and Risk. Corn yields were similar for ChemLite and the No-till
corn-soy systems and both were statistically higher than ChemFree at p<0.05 (Fig. 1). However,
there was no significant difference between systems for soybean yield (Fig. 2). Wheat yields
were also not different between ChemLite and ChemFree averaging 58.2 bu/a of grain and 1.03
tons DM/a of straw. There was no year by system interaction for any crop yield so the 8-year
mean is reported.
Yield variability and the associated risk are important factors apart from mean yields. There was
more variability in ChemFree corn and soybean yields than the other two systems (Table 2).
There was a 2-fold difference in corn yield variability between ChemLite and ChemFree systems
(53 vs. 114 bu/a, respectively). However, soybean yields were less variable between ChemLite
and ChemFree systems (29 vs. 32 bu/a, respectively). In wet years (i.e. 1996, 2000), mechanical
tillage is less effective on weed control, which can reduce yields significantly. Forty-five percent
of the 18-bu/acre of corn advantage for the ChemLite system vs. ChemFree system occurred in
1996, which was a cool, wet spring. These conditions should not be regarded as rare because
similar conditions with similarly low ChemFree corn yields occurred in 1992, 1993 and 2000 in
the WICST core trial.
Economic Analysis. The 8-yr. average net return was highest for No-till corn-soy ($51/a/yr) and
lowest for ChemFree ($30/a/yr) with ChemLite very similar to No-till corn-soy at $49/a/yr. Net
returns on all three systems have declined over the trial period mostly due to decreasing
commodity prices. Corn, soybean and wheat prices decreased by 38, 26 and 45%, respectively,
from 1995-2001. Excellent yields and somewhat better commodity prices in 2002 have brought
net returns ‘out of the red’ for that year (Fig. 3).
Premiums can improve the economics of the low input systems.. Although the gap between
organic premiums and conventional is narrowing, organic grains are still enjoying more than
100% premium according to local elevators surveyed in 2001 (Peavy, Delong, QTI, pers. com.,
2001). Results from the CROP program, using the 8-yr average commodity prices, indicate that
with a modest organic premium of only 9% was needed for ChemFree to equal the No-till cornsoybean net returns3. Similarly, only a 1% ‘stewardship’ premium would bring ChemLite to
same net returns as the No-till standard. One can imagine that in the future, the 2002
Conservation Security Act will reward lower input cropping systems.
Environmental Impact. Soil test phosphorus was significantly higher (p<0.05) in ChemLite
and the No-till corn-soybean system than ChemFree (Fig. 4). Both these systems received starter
fertilizer (about 10 lbs P/a) to increase nutrient uptake in cold wet springs. Even without starter
fertilizer, STP was still quite high for ChemFree after 12 years of farming organically. This
underscores the excessively high P levels in the plots at the start of the trial, a condition similar
in most dairy farm fields. The year by system interaction was not significant.
Soil nitrates, measured after crop harvest, were significantly lower (28%) in the 3-crop systems
compared to the 2-crop system (Fig 5; p<0.0022). This can be explained by lower N inputs in
3
On-farm storage, transportation fees, and other fees associated with organic marketing not included in analysis.
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WICST 9th Technical Report
the expanded rotation due to N credit from green manure. In addition, the winter wheat phase
“traps” some of the fall nitrates in the soil profile.
There were obvious differences in soil erosion potential between No-till and the low input
systems (Fig. 6). Soil loss was well under ‘T’ for the No-till system at 1.2 tons/ac/yr. However,
ChemFree had the highest soil erosion hazard, followed by ChemLite, due to annual tillage and
repeated cultivations. On average, ChemFree had one more rotary hoeing and one additional
cultivation than ChemLite.
CONCLUSION
In terms of production, profitability and environmental impact, the ChemLite system performed
as well as or better than the standard corn-soy rotation. Managed organically, ChemFree is too
short a rotation to effectively control weeds. Even so, only a small premium (9%) is needed for
ChemFree net returns to equal the standard 2-crop system. Reducing inputs and increasing crop
diversity appears to be the best approach to meeting the twin goals of reduced environmental
impact and maintaining profitability.
LITERATURE CITATIONS
Baldock, J.O., D. Fisher, J. L. Posner. 1998. Crop Rotations Options Program. Software
University of WI, Madison, WI
Clark, S., K. Klonsky, P. Livingston, and S. Temple. 1999. Crop-yield and economic
comparisons of organic, low-input, and conventional farming systems in California’s Sacramento
Valley. American Journal of Alternative Agriculture. 14(3):109-121.
Posner, J.L., M.D. Casler, and J.O. Baldock. 1995. The Wisconsin Integrated Cropping Systems
Trial: Combining agro ecology with production agriculture. American Journal of Alternative
Agriculture. 10(3): 98-107.
Singer, J.W., and W.J Cox. 1998a. Economics of different crop rotations in New York. J. Prod.
Agric. 11(4):447-451.
Singer, J.W., and W.J Cox. 1998b. Agronomics of corn production under different crop
rotations in New York. J. Prod. Agric. 11(4):462-468.
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WICST 9th Technical Report
Table 2. Mean yield and standard deviation of crops in the 3 systems1.
Crop
corn
corn
corn
corn
corn
corn
corn
corn
average
min
max
Year
1995
1996
1997
1998
1999
2000
2001
2002
No-till c-sb
167.7
140.0
157.4
212.6
162.9
162.9
207.7
159.0*
171.3
140.0
212.6
ChemLite
146.5
149.6
158.8
199.8
160.0
154.5
190.8
173.1
166.6
146.5
199.8
ChemFree
155.6
83.4
147.6
197.8
155.6
132.8
155.4
157.8
148.3
83.4
197.8
soybeans
soybeans
soybeans
soybeans
soybeans
soybeans
soybeans
soybeans
average
min
max
1995
1996
1997
1998
1999
2000
2001
2002
58.1
53.7
51.9
63.6
59.2
56.3
51.6
54.5*
56.1
51.6
63.6
68.2
60.2
46.1
62.5
49.8
51.6
39.7
60.8
54.9
39.7
68.2
63.3
60.2
48.8
51.9
31.0
40.9
35.4
50.9
47.7
31.0
63.3
wheat grain
wheat grain
wheat grain
wheat grain
wheat grain
wheat grain
wheat grain
wheat grain
average
min
max
1995
1996
1997
1998
1999
2000
2001
2002
-
76.9
47.2
51.9
59.2
59.8
52.3
56.3
78.3
60.2
47.2
78.3
68.1
45.4
54.3
57.7
56.9
41.7
54.8
70.5
56.2
41.7
70.5
wheat straw
wheat straw
wheat straw
wheat straw
wheat straw
wheat straw
wheat straw
wheat straw
average
min
max
1995
1996
1997
1998
1999
2000
2001
2002
-
1.50
1.68
0.99
0.73
0.66
0.75
0.66
1.79
1.09
0.73
1.79
1.22
1.55
0.97
0.58
0.63
0.83
0.71
1.43
0.99
0.58
1.55
1
No-till c-sb and ChemFree means are from all 4 replicates in WICST core trial. Chemlite means are from 2
replicates.
* 3-rep average
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WICST 9th Technical Report
Fig. 1. Corn yields across systems with 95% confidence interval (1995-2002 average).
175
170
bu/acre
165
160
Chemfree
No-till corn soy
Chemlite
155
150
145
140
135
System
Fig. 2. Soybean yields across systems with 95% confidence interval (1995-2002 average)
65
bu/acre
60
Chemfree
No-till corn-soy
Chemlite
55
50
45
40
System
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WICST 9th Technical Report
Fig. 3. Net returns ($/acre/yr) on each system using CROP.
Chemfree (c-sb-w)
Chemlite (c-sb-w)
No-till (c-sb)
200
150
$/a/yr
100
50
0
1995
1996
1997
1998
1999
2000
2001
-50
-100
Net returns = $ left for labor, management, and capital
No government programs included in analysis
Fig. 4. Soil test P (ppm) in top 6 inches (1999-2002 average).
70
a
ab
No-till
Chemlite
b
60
lbs P/acre/yr
50
40
30
20
10
0
Chemfree
System
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WICST 9th Technical Report
Fig. 5. Fall soil nitrates to 3-ft. depth of each system (1999-2002 average).
90
a
lbs NO 3 --N/3ft a
80
70
b
b
Chemlite
Chemfree
60
50
40
No-till
System
Fig. 6. Soil loss estimates on a 4% slope, 150-ft run (RUSLE2, 2000).
10.0
ton/a/yr
8.0
6.0
4.0
2.0
0.0
No-till
Chemlite
Chemfree
System
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