The Agricultural and Ecological Functioning of a System Integrating Pastured Poultry and Raised-Bed Vegetable Production.

2005 Annual Report for GNC04-028

Project Type: Graduate Student
Funds awarded in 2004: $9,995.00
Projected End Date: 12/31/2006
Grant Recipient: University of Illinois
Region: North Central
State: Illinois
Graduate Student:
Faculty Advisor:
Benjamin Tracy
University of Illinois

The Agricultural and Ecological Functioning of a System Integrating Pastured Poultry and Raised-Bed Vegetable Production.


We examined several agro-ecosystem functions within an integrated pastured poultry and vegetable production system. Vegetable yields varied by crop. Diverse pastures were more resistant to weeds and had highest forage yields. Beneficial invertebrates were higher in grazed pastures throughout most of the season. Soil content of P, K, and total N, were increased by grazing and all pasture systems showed higher levels of total C than the tilled system. Additionally, the grazed systems improved profitability with additional income streams and reduced production costs. These results indicate that an integrated system offers a viable method for addressing agronomic and environmental concerns.

Objectives/Performance Targets

Short-term outcomes begin with the research objectives designed to increase knowledge of:

How pasture diversity affects forage, poultry, and vegetable productivity.

How pasture diversity and poultry grazing impacts insect and plant populations.

How this integrated system affects soil organic matter quality and nutrient mineralization potentials.

Short-term outcomes will also include:

Enhanced awareness of the system’s potential and limitations among each of the target groups.

Increasing farmers’ skill and knowledge necessary to adapt this system to their present operation.

Collaborating with local pastured poultry farmers, and implementing ‘backyard’ poultry projects in Urbana-Champaign, Illinois.

Intermediate-term outcomes would be:

The adoption and adaptation of this system into existing farms.

Influencing consumer choices to select for sustainably produced foods.

Long-term, systematic outcomes served by this work include an enhanced understanding of natural system agricultures and a broadening of agro-ecological restoration work.


Dressed weight of poultry was not affected by pasture type (p=0.60). Vegetable yields were affected by pasture type and grazing, but varied by crop. Pasture productivity, quality, and composition were affected by the grazing as well as the initial species composition. Diverse pastures were more resistant to weed invasion (< 2% of biomass), and the grazed mix yielded more forage biomass during peak production seasons than the ungrazed mix or monoculture pastures (p<0.05). Fall harvested forage from the grazed mix had highest levels of crude protein (23%), phosphorus (0.4%) and potassium (3.2%). Squash bug egg abundance was reduced in gardens surrounded by grazed compared to ungrazed pastures (p=0.038). Abundances of spiders, carabid beetles, and collembolans were higher in grazed pastures throughout most of the field season, and parasitic hymenopterans were most abundant within the garden areas surrounded by the grazed diverse pastures. The diverse pasture soil surface showed greatest abundance of worm casts (~1000/m2), indicating greater numbers or activity of these soil builders. Soil microbial biomass, and N and C mineralization potentials were not influenced by the treatments. Pasture soil content of P, K, and total N, were increased by grazing and all pasture-based systems showed higher levels of total C than the tilled system. Additionally, the grazed systems improved overall profitability by offering an additional income stream and reducing production costs compared to the tilled system. These results indicate that a system integrating rotational poultry grazing and annual vegetable production offers farmers a viable and flexible method for addressing both agronomic and environmental concerns.

Impacts and Contributions/Outcomes

The integration of pastured poultry in a farming system can help to maintain productivity, improve profitability, and restore land health. When paired with the diverse pasture composition, forage yield and quality was enhanced and invasion by weedy annuals was suppressed within the grazed systems. The potential to control a pest species was enhanced while the perennial plant habitat within the system was preserved.

Additionally, the population levels of three significant groups of arthropod predators were elevated within the grazed treatments. These organisms, considered in conjunction with greater abundance of decomposer organisms such as collembolans and earthworms suggest that these grazed systems are more trophically complex and nutrient cycles more tightly integrated.

Finally, the grazed systems exhibited a capacity to build fertility and stimulate nutrient cycling while protecting soils from erosion or depletion.

The potential to fulfill the qualifications of the Leopoldian definition of land health and to ensure the renewal of the farm and the farmland by securing the economic and environmental assets needed for a successful, sustained agriculture, appear to be present in this integrated system.

The mechanics of this system, and its principle of restoring ecosystem functions are, more so than the explicit details of the system, likely the key to creating agricultural systems with land health restoring capacities. The particular combination of broilers and raised beds are merely one manifestation of the myriad combinations that could prove to be successful on the farm. It will be the choices of independent farmers, who hopefully employ some of the principles illustrated here, that create the unique combinations of crops and systems that best suit and define their own individual perspective and farm.

Moreover, it will be a public that is aware of the contributions to land-health that conscientious farmers are making, and who are more directly connected with their food sources, which will help create the markets necessary to support this kind of agriculture.


Benjamin Tracy
Assistant Professor of Agroecology
University of Illinois
Department of Crop Sciences
1102 S. Goodwin Ave.
Urbana, Il 61801
Office Phone: 2172655313