title:  Costs and Benefits of Integrating Poultry into Cover Crop - Vegetable Rotations
Creators: name: Halmos , Viktor 
Publisher: name: University of Kentucky Libraries
Year: 2023
Subjects: classificationCode: 4
subject: FOS: Agricultural sciences

description: Integrated livestock systems were once common leading up to the 20th century where livestock generated manure that was then used to fertilizer crop production in a closed- or semi-closed system. However, with the industrialization of agriculture in the mid to late 20th century, specialization drove simplified systems that segregated livestock from cropping systems. This segregation led to nutrient surpluses occurring in livestock operations, and nutrient demands in cropping systems creating a plethora of environmental issues. With the increased awareness of environmental issues, a renewed interest in integration has driven producers and researchers to experiment with integration again. For research, the emphasis has been on cattle, sheep, goats, and agronomic crops (corn, soybean, cotton, wheat, peanuts, oats, canola, sorghum).

Despite this increased interest, little scientific research has investigated the costs and benefits of the rotational integration of poultry and vegetable systems. In my thesis, I investigate the effects of integrating poultry at three differing stocking densities to better understand their effects on vegetable yields, cover crop biomass, and arthropod abundance in an annual vegetable, cover crop system. Across three years of a rotational integration study (spring vegetable, summer cover crop, fall poultry, winter cover crop), I found that spring vegetable yields increased following fall poultry, but only under a higher stocking density. Additionally, I find that manure deposition in the higher stocking density can largely replace the need for pre-plant fertilizer. Poultry had complex impacts on cover crop biomass throughout the rotational system. Fall pastured poultry integrated on cover crops reduced summer cover crop biomass as they are moved across the pasture. This effect is largely due to the trampling and consumption of vegetation by the broiler chickens. However, I found that the winter cover crop biomass in the spring was higher in the poultry plots compared to the no-poultry control plots likely through the poultry manure stimulating cover crop growth. Finally, I found complex annual impacts of poultry integration effects on arthropod communities across multiple taxonomic groups. Insect communities fluctuated in population in the fall rotational sequence stemming from the bottom-up effects of manure deposition and the top-down effects of insect habitat destruction occurring when poultry are integrated with the cover crop. The fresh manure attracted large populations of flies (Diptera) that then recruited large numbers of predatory beetles (Staphylinidae) as seen in pitfall traps. Additionally, the destruction of vegetative habitat (cover crop) by the poultry caused a loss of insect population as seen in sweep net samples. Overall, the heightened insect populations did not persist into the spring and summer rotational sequences.

Overall, this study demonstrates that poultry stocking density plays an important role in increasing vegetable yields and decreasing fertilizer input reliance. Furthermore, manure deposition from poultry is shown to increase cover crop biomass in the following time points and also increases arthropod populations that then decrease in numbers as the manure resource diminishes.
description: © 2023 Viktor Halmos