Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 30, 1995
Publication Date: N/A
Technical Abstract: The dairy forage system model (DAFOSYM) has been extended to include manure production, collection, storage, and application to crop land. The model simulates the growth, harvest, storage, and use of alfalfa and corn on representative dairy farms over many years of weather. The quantity and nutrient content of manure produced are a function of feed composition and consumption, milk production, and animal growth. Nutrient losses in manure handling, storage and application are subtracted, and the availability of N for crop growth is regulated by the conversion of organic N to mineralized N. The facilities, machinery, labor and fuel required are modeled to determine system costs. The integrated model provides a tool for evaluating and comparing the long-term performance and economics of alternative manure systems for dairy farms and their interaction with feed production. Manure systems using long-term storage with spreading, injection or irrigation have greater direct costs to the farmer than the daily haul system commonly used in the upper midwest. If long-term storage systems are required to protect the environment, the annual net cost of manure handling will increase up to $65/cow for small (60 cow) and $45/cow for large (250 cow) dairy farms.