WICST Core Systems Trial
The WICST question
By increasing farming system diversity, is it possible to:
- reduce the potential negative environmental impacts of farming
- lower input levels
- maintain or increase productivity and profitability?
The WICST cropping systems experiment
We designed a total of six cropping systems based on common existing
farming practices to evaluate these issues in 1989. To ensure the relevance
of the results for a commercial farm setting, our plots were large (0.8
a) and field operations were performed with conventional farm machinery.
Our cropping systems were not simply rotations, but rotations combined
with management strategies that were guided by a particular philosophy
(e.g., minimizing purchased chemical inputs).
Because of the importance of both animal-based and cash grain systems
in Southern Wisconsin, we included three cash grain and three forage systems
of varying levels of crop diversity and inputs.
The trial took place at two sites:
one with heavy and relatively poorly drained soils (Lakeland in Walworth
County), the other with lighter and better drained soils (Arlington in
Columbia County) to capture some of the variability of regional conditions.
- CS1 — continuous corn (low diversity, high-purchased-input
system)
- CS2 — corn-soybeans (moderate diversity, moderate-purchased-input
system)
- CS3 — corn-soybeans-wheat/red clover (high diversity, low-purchased-input
system)
- CS4 — corn-alfalfa-alfalfa-alfalfa (low diversity, high-purchased-input
system)
- CS5 — corn-oats/alfalfa-alfalfa (moderate diversity, low-purchased-input
system)
- CS6 — rotational grazing (high diversity, low-purchased-input
system)
What we found
The trade-offs.
The no-till corn-soybean system (moderate-purchased-input, CS2) had
the best yields and highest gross margins (crop income less variable costs—seed,
fertilizer, fuel) at both sites. The low-purchased-input rotation (CS3)
that added a small grain and cover crop to the corn soybean system was
the best system from an environmental standpoint but was slightly (9%)
less profitable. The corn and soybeans in CS3 were 14% less productive
than the simpler no-till corn soy system (CS2).
Among the forage systems, rotational grazing was the most environmentally
benevolent system and produced (on average) 87% of the dry matter of CS4
and CS5. On the other hand, the most productive system (CS4, intensive
alfalfa) was the least environmentally benign. The low-purchased-input
forage system (CS5) was again a solid all-around performer, equaling the
highest input system in profitability, with only slightly lower yields,
but better environmental performance.
Specializing in a single crop is costly.
The continuous corn system experienced high input costs ($164/a
direct costs versus $123 for CS2 and $76 for CS3), had erratic and only
fair corn yields (135 bu/a compared with CS2’s 147 bu/a and CS3’s 124
bu/a), showed unimpressive economic performance (average gross margins
of $127/a versus $187/a for CS2 and $170/a for CS3) and engendered high
environmental costs.
The primarily alfalfa system (CS4) was a much better economic performer
than continuous corn, but achieved little that the more diverse forage
system (CS5) did not. The alfalfa system also experienced more trouble
with pests and had a poorer environmental performance, particularly as
regards potential nitrate leaching.
Lower input systems are better for the environment.
The environmental advantages of the lower input systems generally
included greater energy efficiency (better energy output/input ratios),
reduced groundwater contamination, lower pesticide use and soil that was
slightly “healthier” in some measures. Rotational grazing (CS6), in particular,
stood out positively in a number of measures, e.g., soil ecology, soil
conservation, nitrate leaching.
Lower input systems are not “riskier” than the higher
input systems.
The lower input systems did not show significantly greater yield or
profitability variation than the higher input systems. They did encounter
different sources of risk however, stemming primarily from the challenges
of mechanical weed control in wet weather. Labor use in the low-input
cash grain system was also higher. The no-till corn and soybean system
used the least amount of labor resulting in a savings of nearly 25% compared
to continuous corn and 64% compared to the three-phase rotation In addition,
two bottlenecks occur in CS3: one in early summer while rotary hoeing
and cultivating, the second in the fall when combining soybeans and planting
wheat.
Leguminous cover crops are a viable alternative to
purchased nitrogen fertilizer.
A typical stand of red clover or hairy vetch will supply about 100 lbs.
of nitrogen per acre and offer several agronomic and environmental benefits
with modest additional cost (mainly seed) compared to inorganic nitrogen.
Forage rotations outperformed cash grain rotations.
Assuming a ready market for hay, the alfalfa-based systems (CS4
and CS5) were more profitable than the cash grain systems, produced high
yields with fewer inputs, and were more environmentally benign than the
cash grain systems.
We can’t always “have it all,” but WICST shows we
can do better.
Farmers in the Upper Midwest have a range of production options
available to them. Those who wish to reduce their impact on the environment
should be able to do so with little or no economic sacrifice by adopting
diversified systems with appropriate management strategies. Management
strategies that emphasize the long-term health of the resource base and
system profitability (rather than yield) can be achieved by significantly
reducing purchased chemical inputs. Some farmers may be willing and able
to substitute labor and managerial inputs for purchased chemical inputs,
thereby further reducing potential negative environmental impacts. More
drastic reductions in purchased chemical inputs (such as what we tried
on CS3 and CS6) will almost certainly lower productivity compared to the
most productive systems, but the economic results may be similar to or
only modestly lower than higher-input systems. Organic management of
the low-purchased-input systems — if organic price premiums continue —
offers the potential for significantly enhanced profitability of these
systems.
Management is key to success.
With any given cropping system, there are many possible management philosophies
and strategies. While our underlying philosophy remained the same for
each system over of the course of the trial, our specific management tactics
evolved over time as we gained familiarity with the strengths, weaknesses
and potentials of each under various conditions. In order to boost the
productivity of the lowest input cash grain system, we shifted from flying
on the wheat to adopting shorter cycle soybean varieties and drilling
in the wheat. Also, we tried food-grade soybeans and organic management
on some plots. As no-till drills became more popular in the region, we
shifted to an entire no-till system for the higher input corn-soybean
system. What is important is not adherence to a rigid formula for success,
or adoption of a particular set of practices or crops, but designing a
cropping system and management philosophy appropriate to a given situation,
and continuing to fine-tune it with prioritizing long-term health, productivity,
and profitability.
Projects that grew out of the core systems trial
Links to more information about the core systems trial
Core systems trial articles
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