Cropping systems trial provides unique analysis (Research Brief #43)
Posted September 1999
Can environmentally beneficial crop rotations also improve farm profitability? A long-term study underway in southern Wisconsin aims to find out. It blends systems research with strong farmer guidance to measure profitability, productivity, and environmental impacts of six cropping systems.
The Wisconsin Integrated Cropping Systems Trial (WICST) compares three cash grain cropping systems and three forage systems at two southern Wisconsin sites. The trial began in 1989 to answer questions about the sustainability of farming systems, particularly addressing those involving low plant diversity and high commercial inputs.
Researchers, farmers, extension faculty, and others designed the study to generate solid data on whether increasing the complexity of a crop rotation would decrease reliance on commercial inputs. They also wanted to determine whether a more diverse cropping system could increase profits and reduce negative environmental impacts.
The study compares the systems’ effects on soil fertility and structure, weed populations, groundwater contamination, and earthworm numbers. Researchers also compare the profitability of the systems, without including environmental costs (such as groundwater contamination) in their analysis.
The WICST steering committee selected high, moderate, and low purchased input grain and forage systems for the study. To capture real world conditions accurately, the steering committee set up field scale plots and modified systems over time to reflect market conditions and cultural practices.
With this study design, WICST researchers can measure interactions within the cropping sequence in a way that individual crop research cannot. Economic comparisons are based on the entire rotation, not just the most profitable crop in each. WICST also provides insight on costs and returns to be expected during a transition to a lower chemical input, more diversified system.
The trials are being carried out at the UW-Madison Arlington Agricultural Research Station in Columbia County, with well-drained Plano silt loam soils, and the Lakeland Agricultural Complex in Walworth County, primarily on poorly drained Griswold loamy variant and Pella silt loam soils.
Trial collaborators include the UW-Madison College of Agricultural and Life Sciences, the Center for Integrated Agricultural Systems (CIAS), the Michael Fields Agricultural Institute (MFAI), the UW Cooperative Extension Service, Lakeland Agricultural Complex, Arlington Agricultural Research Station, the Walworth County Board of Supervisors, AGSTAT Agricultural and Statistical Counseling, and farmers near both sites. Support for this study also comes from the W. K. Kellogg Foundation, the USDA Agricultural Research Service and the USDA Dairy Forage Research Center.
CIAS Director Rick Klemme, CIAS economist Don Schuster, and Josh Posner from the UW-Madison Agronomy Department analyzed the economic results from the trial. “Josh Posner deserves a great deal of credit for leading the formation of this project and for building the project’s network of collaborators,” observes Klemme.
The research team bases the trials on two types of farms: cash grain farms with no access to livestock manure, and dairy farms with forage cropping systems. This Research Brief describes the overall study design. The profitability of the cash grain and forage cropping systems will be discussed in upcoming Briefs.
The WICST cropping systems
Cash grain systems
- Cropping system 1 (CS 1) Continuous corn
- Cropping system 2 (CS 2) Corn-soybean
- Cropping system 3 (CS 3) Corn-soybean-wheat/clover
Dairy forage systems
- Cropping system 4 (CS 4) Three-year alfalfa, one year corn
- Cropping system 5 (CS 5) Oats/alfalfa-alfalfa-corn
- Cropping system 6 (CS 6) Intensive rotational grazing
The cash grain cropping systems
The three cash grain systems in the study are continuous corn, a corn-soybean rotation, and a corn-soybean-wheat/red clover rotation. The cash grain rotations are assigned similar machinery sets (and associated costs) based on a 1200-acre farm, with variations due to the tillage and harvesting requirements for each system’s crops. Survey information provided by WICST steering committee farmers determines what machinery is appropriate for each system.
All the crops in a given system are grown every year: in a two-crop rotation, half of the system’s crop land is planted to each crop; in a three-crop rotation, one-third of the crop land is planted to each crop.
The continuous corn system relies on high chemical inputs and uses only chemical fertilizers based on soil tests. Land is fall chisel plowed and prepared with a field cultivator prior to planting. Mechanical cultivation is used in addition to herbicides and insecticides for weed and insect control. Corn is planted in 30-inch rows in chisel-plowed soil with a conventional planter and is harvested for grain. “The continuous corn system was a fairly common system for southern Wisconsin farmers at the beginning of the trial due to a now defunct federal feed grain program,” Schuster says, “but now it is less common.”
The corn/soybean system uses a two-year rotation. Only chemical fertilizers are used with the nitrogen credit from the soybeans applied to corn. The WICST steering committee made this a complete no-till system in 1994. Herbicides and insecticides are used to manage pests in the corn and bean crops. A no-till planter is used to plant corn in 30-inch rows in the soybean residue. Soybeans are drilled in 7.5-inch rows into corn residue. The corn and beans are harvested for grain. This rotation is fairly common in southern Wisconsin.
The corn-soybean-wheat/red clover system is a three-year rotation with low commercial inputs. No manure or chemical fertilizer is used in this system. Soybeans and corn are both planted in 30-inch wide rows and are rotary hoed and cultivated for weed control. The wheat is fall seeded into the soybean residue without any herbicide or fertilizer, and red clover is frost seeded into the wheat in early spring. The clover provides the nitrogen for the subsequent corn crop.
In this system, herbicides have been used very sparingly: outside rows are sprayed to control grasses on the edge. Sprayed rows have not been used in the calculation of yields. Some years, herbicides were used to control thistles or to rescue a crop. While this system would not qualify as organic by the standards of any existing certifying agency, it is nevertheless a very low-input system.
Soybeans, corn, and wheat are harvested for grain. Wheat straw is also harvested. “Few cash grain producers are using this system,” Schuster observes, “but the steering committee wanted to explore a cropping system that would use low purchased inputs, address recurring pest problems in corn-soybean rotations, provide environmental benefits, and be economically competitive.”
The dairy forage cropping systems
Production of high quality forage is the goal for the three dairy forage cropping systems. The equivalent of ten tons of manure per acre per year is spread on the fields for all of these systems, based on a stocking density of one cow and one replacement heifer per three tillable acres. The manure is applied in the fall of the final sod year and the fall of the corn year. Hay is cut as haylage for the first and fourth cuts, and as baled hay for the second and third cuts. The equipment for these rotations is based on a 150-acre dairy farm.
The green gold alfalfa system has a three-year alfalfa stand, followed by one year of corn. To control competing weeds, an herbicide rather than a companion crop is used to establish alfalfa. This system also uses an herbicide to kill any remaining alfalfa and an insecticide before the corn is planted. The hay is cut four times a year and top dressed with potassium fertilizer.
The rapid turnaround alfalfa system establishes an oats-alfalfa stand in year one, follows that with an alfalfa stand in year two, and corn in year three. Corn is grown without herbicides or chemical fertilizers, and is cultivated with a rotary hoe and single-sweep cultivator. Fewer years in hay than the green gold system should reduce the probability of quackgrass infestation.
The researchers included an intensive rotational grazing system in the dairy forage system. Holstein heifers are moved frequently from plot to plot. This system has the lowest purchased inputs of all the systems in the study and has the lowest capital costs over the 150 acres.
The importance of WICST
“WICST is a unique study in that it allows systems comparisons,” Klemme says. “It establishes an outdoor laboratory for scientists who want to examine various agricultural and ecological questions over a range of cropping systems.”
WICST resource people
- MFAI (Agronomy)-John Hall, Walter Goldstein, Jim Stute (262) 642-3303
- MFAI (Communications)-Kat Griffith, (920) 748-3923
- UW Cooperative Extension-Lee Cunningham, (262) 741-3175
- UW-Madison Agronomy-Josh Posner, (608) 262-0876
- UW-Madison Agronomy (Agroecology)-Martha Rosemeyer,
- UW-Madison Agronomy (Weed Science)-Jerry Doll, (608) 263-7437
- UW-Madison CIAS (Economics)-Rick Klemme, Don Schuster (608) 262-7879
Published as Research Brief #43