| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
* Agricultural and Biological Engineering, Pennsylvania State University, University Park 16802
Cornell Cooperative Extension of Delaware County, Hamden, NY 13782
USDA Pasture Systems and Watershed Management Research Unit, University Park, PA 16802
1 Corresponding author: ltg106{at}psu.edu
Structural best management practices were implemented throughout the Cannonsville Reservoir Watershed (CRW) in an effort to reduce P losses to the reservoir. Yet long-term water quality control efforts within CRW are hindered by continuous P build-up in the soils resulting from dairy farm P imports exceeding exports. Addressing the P imbalance problems and maintaining economic viability of the farms requires a system-level redesign of farm management. One possible innovative strategy, precision feed management (PFM), reduces soil-P build-up by limiting feed and fertilizer purchases, and increasing high-quality homegrown forage production. This study applied the integrated farm system model (IFSM) to 2 CRW dairy farms to quantify the benefits of a PFM farm planning strategy in controlling P imbalance problems, and maintaining farm profit-ability and reducing off-farm P losses. The IFSM accurately simulated the 2 farms based on farm data supplied by farm planners; these scenarios were used as the baseline conditions. The IFSM simulations of more accurate feeding of P (based on P required in animal diets) integrated with increased productivity of grass-forage and increased proportion of forage in the diet reduced the P imbalance of 1 farm from 5.3 to 0.5 kg/ ha and from 9.6 to 0.0 kg/ha for the second farm. For both farms, soluble P lost to the environment was reduced by 18%. Feed supplement purchases declined by 7.5 kg/cow per year for dietary mineral P, and by 1.04 and 1.29 t/cow per year for protein concentrates through adoption of the PFM system. Moreover, when a land management practice of converting corn to grass was coupled with the precision feeding of P and improved forage management, IFSM predicted reductions of 5.8 and 9.3 kg/ha of converted land sediment-bound P in erosion loss each year. The model predicted slight purchase increases in corn grain to offset reductions in corn silage production and feeding rates, but no appreciable change in the farm P balance due to land conversion. The model-based studies conducted on a farm-by-farm basis complement farm planning efforts in exploring innovative farming systems. Moreover, the results set a benchmark for potential benefits of PFM strategies, economically and environmentally.
Key Words: forage management • phosphorus • precision feeding • simulation
This article has been cited by other articles:
|
|
 |
|
  R.B. Bryant, T.L. Veith, P.J.A. Kleinman, and W.J. Gburek Cannonsville Reservoir and Town Brook watersheds: Documenting conservation efforts to protect New York City's drinking water Journal of Soil and Water Conservation, November 1, 2008; 63(6): 339 - 344. [Abstract] [PDF]
|
|
|
|
|
|
L.T. Ghebremichael, T.L. Veith, J.M. Hamlett, and W.J. Gburek Precision feeding and forage management effects on phosphorus loss modeled at a watershed scale Journal of Soil and Water Conservation, September 1, 2008; 63(5): 280 - 291. [Abstract] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
