Project tests introduction of chickens in organic fields In an effort to quantify the potential for chickens tobepart of safe and sustainable
Davis graduate student, acknowledged that using chickens to contribute to soil fertility on farms isn’t a new idea. But, she said, “there is currently little scien- tific information for using chickens on a bigger scale, especially in terms of food safety concerns.” TheCaliforniaproject fits intoanation- al effort, funded by the U.S. Department of Agriculture, that also involves re- searchers fromIowa StateUniversity and the University of Kentucky.
In the trials, chickens are introduced as part of a rotation that includes cover crops and a variety of vegetable crops. In California, chickens were placed on research plots inApril, following awinter cover crop of vetch, peas, fava beans and oat grass. Duan said the chickens are contained in “chicken tractors,” to protect them frompredators. Each 50-square-foot tractor—de- scribed as a floorless chicken coop on
wheels—can accommodate 29 birds. Built by two UC Davis students, the tractors consist of wood frames cov- ered with mesh and plywood. Each day, researchers move the tractors to a different part of the plot, where the birds can graze on cover crop residue and deposit manure. “The first day, the chickens were con- fused,” Duan said. “We had to go slowly. It’s a learning process for the chickens and us.” But ultimately, she said, the chick- ens appeared “excited to move to a new spot where they have fresh food to graze on.” Once the chickens have done their part on the plots, researchers plant vegetables amid the leftover cover crop residue and chickenmanure. This summer, UC said, the experi- ment in California will grow process- ing tomatoes. Subsequently, melons, eggplant, spinach and broccoli will be part of the vegetable rotation in California or the other states involved in the project. Other replications of the trial will have the chickens immediately follow the vegetable harvest, so they can graze on the crop leftovers before the cover crop is planted. Comparing the soil health, fertilizer needs, chicken quality and other factors will help the scientists optimize the rotation, Duan said. “Vegetable yield will be an important indicator of success,” she said. UC Cooperative Extension specialist Maurice Pitesky, a poultry specialist and a project lead, said soil samples will be tested to determine the presence or ab- sence of Salmonella bacteria after the chickens have been removed. Salmonella is a bacterium that can be part of poultry’s microbiome. If the bac- teriumcontaminates human food, it can cause illness. “Since Salmonella lives in the chick- en gastrointestinal system, when it gets into the soil, it will eventually be out-competed by bacteria more adapt- ed to soil than the gut of a chicken,” Pitesky said. Noting that there are many different types of Salmonella, he said only “a se- lect few” found in birds prove harmful to humans. “Nevertheless,” Pitesky said, “it is very important to test anduse various practic- es tomitigate the presence of Salmonella on land that will be used for cropproduc- tion following poultry.” Early results of soil tests in Iowa and Kentucky detected Salmonella in the soil where chickens grazed, but the bacteria disappeared very quickly, he said. After 24 days on pasture, the chickens become part of the project’s meat study. “We have broiler chickens that are raised for meat,” Duan said. “Some people believe chickens that graze and eat grass taste better and are more nu- tritious. It will be part of the study to look at the chickens’ meat quality.”
comme rc i a l organic vege- table produc- tion,University of California Cooperat ive Extension re-
searchershave joinedanationwideproject to diversify organic farms with chickens. Project coordinator Faye Duan, a UC
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California Foundation for Agriculture in the Classroom L e a r n A b o u t A g . o r g • 1 - 8 0 0 - 7 0 0 - A I T C
planting seeds for the future of agriculture
18 Ag Alert June 9, 2021
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