|Rotz, Clarence - Al|
|Van keulen, Herman|
Submitted to: American Society of Agricultural Engineers Meetings Papers
Publication Type: Proceedings
Publication Acceptance Date: 6/20/2003
Publication Date: 7/27/2003
Citation: Rotz, C.A., Oenema, J., Van Keulen, H. 2003. Whole-farm management to reduce nitrogen losses from dairy farms. American Society of Agricultural Engineers Meetings Papers. Paper No. 032154. Interpretive Summary:
Technical Abstract: Whole farm simulation provides a tool for evaluating the impact of nutrient conservation technologies and strategies on dairy farms. A farm simulation model was verified by simulating the production and nutrient flows of the De Marke experimental dairy farm in the Netherlands. Through calibration of parameters related to the base temperature for corn growth and the fiber intake constraint, maintenance energy requirement, and protein requirement of animals, the Integrated Farm System model satisfactorily reproduced the long-term feed production and use and the nitrogen and phosphorus flows of the De Marke farm. Technologies used on De Marke to increase nutrient use efficiency and reduce N loss included a low emission floor system in the housing facility, a covered manure storage, deep injection of manure on arable land, and underseeding of grass in corn to take up and carry excess soil N through the fall and winter seasons. Simulation of these techniques on representative farms in southern Pennsylvania illustrated that N loss from farms, primarily in the form of ammonia emission, can be reduced by about 35%. The cost of this technology package exceeded the value of the N saved, causing a reduction in annual net return of $80/cow for a 100-cow farm and $74/cow for a 1000-cow farm.