Abstract #M137

# M137
Use of the Integrated Farm System Model to determine economic and environmental impacts of double cropping winter annuals with corn.
E. J. Ranck1, L. A. Holden1, K. J. Soder2, J. A. Dillon1,2, C. A. Rotz2, R. Goodling*1, 1The Pennsylvania State University, University Park, PA, 2USDA Agricultural Research Service, University Park, PA.

Many dairy farms struggle to remain profitable while reducing negative environmental impacts. Double cropping may improve profitability through increased DM yields per ha and increased manure nutrient application per ha, while reducing nitrogen (N) and phosphorus (P) pollution. The objective of this study was to evaluate the impact of double cropping winter annuals and corn on nutrient cycling, total feed cost, and net return to management as feed prices and the percentage of corn land double cropped changed. Farm simulations were done using the Integrated Farm System Model (IFSM) and crop, dairy, and financial data from 3 dairy farms that practiced double cropping in Pennsylvania during 2016 and 2017. Farms ranged from 336 to 511 ha with 233 to 663 cows. Farms were simulated over a 20-year time period using weather data from DuBois, Pennsylvania. Eight scenarios measuring intensity of double cropping and change in feed price for each farm were simulated. These included: current operation, 0, 50, and 100% of corn land double cropped, 30% relative feed price increase with and without double cropping, and 30% feed price decrease with and without double cropping at current operation level. Double cropping 100% compared with 0% of corn land improved total DM yield by 19% while reducing annual N leached and P runoff losses by an average of 4.5% and 9.2%, respectively, across farms. Double cropping provided a 1.3 and 1.8% increase in net return over feed costs and net return to management, respectively, across farms. When feed prices increased 30%, use of double cropping increased net return over feed cost and net return to management by 1.6 and 2.2%, respectively, across farms. When feed prices decreased by 30%, double cropping increased both net return over feed cost and net return to management by 0.1%, averaged over all farms. Simulation with the IFSM showed that use of double cropping improved profitability on farms during times of average to high feed prices. Loss of N and P decreased with double cropping, but use of N fertilizer with winter annuals reduced this benefit.

Key Words: profitability, environment, double cropping