Double Cropping Field Peas Offer Economic Sustainability for Midwest Swine Producers

2009 Annual Report for LNC05-257

Project Type: Research and Education
Funds awarded in 2005: $109,651.00
Projected End Date: 12/31/2009
Region: North Central
State: Iowa
Project Coordinator:
Dr. Jim Fawcett
Iowa State University

Double Cropping Field Peas Offer Economic Sustainability for Midwest Swine Producers


Project Outcomes: The feasibility of growing field peas in Southeast Iowa will be completed. Double cropped field peas will be evaluated for disease, insect susceptibility, yield and nutrition attributes and the economics compared to the standard corn-soybean rotation. Swine producers who grow and use field peas as a source of protein and energy in swine diets could potentially increase profits by more than $35,000.

Background: The typical Iowa swine farmer raises about 5000 head of hogs as well as corn and soybeans. In order to use soybeans as a protein source for the swine it is necessary to process the soybeans. Field peas have been grown successfully by farmers in other states and countries and used as a substitute for soybean meal. Inputs which require no processing, grown and used on the farm have generally improved farm profits.

Approach/Methods: Small scale ISU replicated research plots as well as field scale cooperator plots will be set up to evaluate variety selection, time of planting, harvesting techniques, and pest management of field peas. Feeding trials will evaluate the economical inclusion rates of field peas into swine rations.

Evaluation: Economic evaluation based on net return per acre, comparing field peas in a double-crop production system compared to the control which for this study is the current corn/soybean rotation with the purchase of soybean meal from off farm commercial sources. The second part of the evaluation will be the economic return to the producer feeding field peas compared to the control. Evaluation will be based on performance of the swine comparing health, cost/lb of gain, average daily gain, and feed efficiency.

Objectives/Performance Targets

In the short term, crop producers in Southeast Iowa will increase their knowledge of how field peas can fit into their crop rotational system, including information on variety selection, time of planting, harvesting techniques, and pest management. Pork producers will learn that field peas raised in the Midwest provide an excellent source of protein and energy for use in swine diets.

Intermediate term outcomes will be an increase in the profitability of crop and swine producers. Profits will also become more sustainable by introducing two new crops into the rotation. At current prices, the net profit from the wheat/field pea crop has the potential to be more than the net profit provided by either corn or soybeans. Swine producers will have an alternative protein/energy source for swine diets if soybean meal costs become prohibitive due to increased soybean pest problems, including soybean rust. Unlike soybeans, field peas do not have to be processed, so pork producers could grow and feed peas without them ever leaving the farm.

A long term outcome will be the widespread adoption of the new cropping system and the use of peas in swine rations throughout the Midwest, increasing the sustainability of agriculture.


A double cropping system utilizing spring planted field peas followed by soybeans was successful in 2005, with pea yields of 40-50 bu/A and double cropped soybean yields of greater than 20 bu/A in both field scale trials and small plot research. Yields of both crops were less in 2006, probably partly due to later planting dates in 2006 and to unusually warm weather in late May when the peas were flowering and setting pods. Yields were better in 2007 and 2008, but not as high as ’05 yields, perhaps partly due to excess spring rainfall. A winter pea variety planted in the fall of 2005 at the SE Iowa Research & Demonstration Farm yielded slightly better than the spring pea varieties, but did not mature any sooner. A different winter pea variety planted on two planting dates in the fall of 2006 suffered severe winterkill and was not harvested.

One cooperator experimented with double-cropped milo after spring planted peas in 2006 and achieved milo yields of greater than 60 bu/A, even with a July 10 milo planting date. Based on this success and the low yields of double cropped soybeans, the double cropped soybeans were replaced with double cropped milo in 2007. Yields of double cropped milo planted on July 3 were about 90 bu/A at the research farm in 2007. Milo yields were about half of this in 2008, probably due to the later planting date of July 15 due to the wet spring. The double cropped milo was not planted until August 1 in the large field near Amana in 2007, so little grain was harvested, but the forage was utilized for cattle feed.

The double cropping system of winter wheat followed by summer planted peas has not been successful in any year. Although winter wheat yields were good in all years, the best field pea yield achieved was 19 bu/A with a late July planting date of the variety “Admiral” in small plots in 2005. Pea yields in field scale plots have generally been less than 10 bu/A. Summer planted peas were not worth harvesting on the research farm in 2007 or 2008 and no large fields were planted in 2007 or 2008.

In 2007 and 2008, organic farmers investigated whether peas could be used as a nurse crop for establishing alfalfa and red clover. In 2007, a late freeze resulted in close to 100% kill of the red clover seeded with peas. Pea yields were fairly poor (18 bu/A) partly due to poor plant stands and lack of weed control. In 2008, the very wet spring resulted in the seedings being delayed until mid-April, which resulted in poor pea yields (17 bu/A), although alfalfa and red clover stands were acceptable.

Fairly extensive testing of field peas was done to give a basic understanding of nutritional levels. The Iowa peas were about 86% dry matter (14% moisture), which is a level that will store well. Crude fat averaged about 2%, although the 2005 spring varieties were less than 1%. Crude fiber was 5 to 6%. Ash was about 3% and crude protein averaged 20%.

Field peas are a good source of lysine (about 1.54%), which is commonly the first limiting amino acid in pig diets. Unfortunately, peas are low in methionine and tryptophan (0.20%,). Digestibility of these amino acids is lower in peas than in soybean meal. It may be advisable to add synthetic methionine and tryptophan to swine diets containing high levels of peas. Threonine average 0.74% in the winter, summer, and spring peas averaged about 0.74%. The amino acid levels in the Iowa-grown peas were similar to NRC table values. Field peas are low in fat compared with corn and contain twice as much fiber as corn. Therefore, peas are lower in energy than corn.

The first feeding trial was conducted the fall/winter of 2005-06 involving a 1200 head finishing site with two replications of each treatment – 1) corn-soy, 2) Eclipse (variety) 300 lbs/ton field pea inclusion, and 3) WFP 0097(variety) 300 lb/ton field pea inclusion. Due to an outbreak of Circovirus within the site only one replication of each treatment was used in the final analysis. Performance of pigs on all diets was affected by disease outbreak but field pea and corn-soy diets showed no difference in average daily gain (ADG), which averaged 2 lbs/day. Rations were balanced for caloric intake. Excellent results were obtained from feeding field peas. The feed efficiency of the WFP 0097 variety of field peas (2.26) showed a statistical improvement over the other two diets.

A feeding trial using market barrows comparing diets containing spring planted peas, summer planted peas, and winter peas with a standard corn/soy based diet was conducted at the ISU Swine Nutrition Research Farm, Ames, IA during the fall of 2006. All pigs were in good health during the experiment period. Initial body weights did not differ between dietary treatments, as part of the experimental design. There was no difference in final weight for pigs in the four treatment groups and no treatment effects on ADG across dietary treatments. The Adjusted Daily Feed Intake was influenced by dietary treatments. Pigs tended to consume less corn-soybean meal and spring pea diets than the winter and summer pea diets.

In this study, the results showed no decrease in performance of finishing pigs at the inclusion rate of 30% field peas in a corn-based diet. There was no adverse effect on growth rate or feed conversion among the treatment groups. The 30% field pea inclusion rate was enough to replace all the soybean meal and reduce the corn. In the diets containing peas, synthetic lysine, tryptophan and threonine were added to the pea diets to avoid deficiencies.

The feeding trials indicate that swine producers can increase their profits by utilizing field peas in the ration, especially with today’s very high corn and soybean meal prices. However, a profitable cropping system utilizing field peas in Iowa is yet to be found. An economic analysis of the cropping systems investigated on the SE Iowa Research & Demonstration Farm indicated that none of the rotations including field peas could compete with the corn-soybean rotation with the crop yields obtained in the trials. Intercropping systems, such as using peas as a nurse crop for establishing a legume or seeding peas with a small grain for a feed crop, may be the best utilization for field peas in Iowa.

A field pea-triticale intercropping trial was conducted investigating 3 seeding ratios of the pea/triticale mixture to a pure stand of field peas and triticale. The crop was seeded on tilled ground on April 4 and machine harvested for yield in late July. Plots were all 50 foot by 20 foot and arranged in a randomized complete block design with 4 replications. The five treatments were 1) triticale only seeded at 150 lb/A, 2) field peas only seeded at 180 lb/A, 3) triticale at 100 lb/A and field peas at 135 lb/A, 4) triticale at 75 lb/A and field pea at 180 lb/A, and 5) triticale at 150 lb/A and field pea at 90 lb/A. The triticale only treatment received a nitrogen application of 50 lb/A and the field pea only treatment received a paraquat application prior to harvest because of weed growth. Plant stand evaluations were made and grain samples were analyzed for nutritional content.

A farmer in Jones County interseeded field peas with triticale in a 15-acre field on March 28, 2009. Two seeding rates were investigated. One area was no-till drilled into soybean ground and another area no-till drilled into corn ground. Plant stand evaluations were made and the pea/triticale crop was machine harvested for yield in July. A grain sample was analyzed for feeding quality.

In 2009 the seeding rates of intercropping of field peas and triticale resulted in seeding ratios of 1:2, 1:1, and 2:1 of triticale to peas at the research farm and a 1:1 ratio in the farmer’s field. In general yields were poor in both the small plots and farmer’s field, probably because of a few very hot days in mid June that affected the flowering of both crops. The highest yield was with the 1:2 seeding ratio of triticale to peas, which yielded 27 bu/A.

Economic analyses were condcuted to determine the viablility of raising field peas in Iowa and including them in swine rations. The feeding trials indicate that swine producers can increase their profits by utilizing field peas in the ration, especially with today’s very high corn and soybean meal (SBM) prices. A simple financial formula which producers can use when determining whether field peas should be used in their rations is: (corn price $/bu X 420 lbs/56 + SBM price $/ton X 180 lbs/2000)/10 = price which can be paid for field peas. This would be a 30% inclusion rate of field peas replacing corn and soybean meal in the ration. Inclusion rates this high showed no performance difference in any of the trials.

However, a profitable cropping system utilizing field peas in Iowa is yet to be found. The economic analysis of the cropping systems investigated on the SE Iowa Research & Demonstration Farm indicates that none of the rotations including field peas can compete with the corn-soybean rotation even when using the best field pea, and double cropped soybean and milo yields obtained in the trials. The corn-soybean rotation showed an average net gain of $47.45/A in the two year rotation, compared to a net loss of $53.05 for the field pea followed by soybeans and a net gain of $3.11/A for the field peas followed by milo. Field peas grown alone would have a net loss of $59.60/A (when the $120 land charge is not split between 2 crops). Intercropping systems, such as using peas as a nurse crop for establishing a legume or seeding peas with a small grain for a feed crop, may be the best utilization for field peas in Iowa.

Impacts and Contributions/Outcomes

Midwest crop and swine producers learned about the possibility of increasing their economic sustainability by utilizing double-cropped field peas in swine rations by seeing the many articles that have appeared in the press about the project.

Area producers learned that although there is an economic advantage to including peas in swine rations, they cannot be economically grown in a double cropping system in Iowa. Some producers are continuing to investigate other systems for including peas in their crop rotations, including seeding them as a nurse crop for establishing red clover and alfalfa, and intercropping them with a small grain. Swine producers closer to an available pea market are investigating the economics of purchasing peas to include in their


Shaun Greiner
Swine Producer
2453 Kiwi Ave
Washington, IA 52353
Terry Erb
3265 320th St
Wellman, IA 52356
Office Phone: 3196462855
Tom Bonnichsen

Crop Producer
15771 Hwy 92
Letts, IA 52754
Steve Fouch
Organic Farmer
92nd Ave
Pleasantville, IA
Office Phone: 6418427167
John Stanton
1404 County Road D61
Bernard, IA 52032
Office Phone: 5638527206
Tom Miller
Project Planning Specialist (Agriculture)
Iowa State University Extension
209 South Marion Ave.
Washington, IA 52353
Office Phone: 3196534811
Rich Gassman
Crop Manager
Amana Farms
P.O. Box 189
Amana, IA 52203
Office Phone: 3196223791
Brad Dvorsky
Crop Producer
2038 Jordan Creek Rd NE
Solon, IA 52333
Office Phone: 3196243062
James Petersen
Organic Farmer
Quebec St
Knoxville, IA
Office Phone: 6418287490