HR: 11:00h
AN: H42A-02 INVITED     [Abstracts]
TI: Nitrate losses in subsurface tile drainage as affected by tillage, crop rotation, and fertilizer management
AU: * Ma, L
EM: Liwang.Ma@ars.usda.gov
AF: USDA-ARS, GPSR, 2150 Centre Avenue, Building D, Fort Collins, CO 80526 United States
AU: Malone, R W
EM: malone@nstl.gov
AF: USDA-ARS, NSTL, 2150 Pammel Drive, Ames, IA 50011 United States
AU: Anapalli, S
EM: sassendran.anapalli@ars.usda.gov
AF: USDA-ARS, GPSR, 2150 Centre Avenue, Building D, Fort Collins, CO 80526 United States
AU: Ahuja, L R
EM: laj.ahuja@ars.usda.gov
AF: USDA-ARS, GPSR, 2150 Centre Avenue, Building D, Fort Collins, CO 80526 United States
AU: Heilman, P
EM: pheilman@tucson.ars.ag.gov
AF: USDA-ARS, SWRC, 2000 E. Allen Rd, Tucson, AZ 85719 United States
AU: Kanwar, R S
EM: rskanwar@iastate.edu
AF: Iowa State University, Department of Agricultural Engineering, Ames, IA 50011 United States
AB: Nitrate emanating from artificial subsurface drains in the U.S. Midwest has been implicated as a strong contributing factor to water quality problems such as hypoxia in the Gulf of Mexico. Balancing the amount of N needed for optimum plant growth while minimizing nitrate transport to ground and surface waters, however, remains a challenge. Field studies are limited that investigate the water quality effects of multiple management practices such as nitrogen application timing and amount. Agricultural simulation models may be one method to cost-effectively investigate the effect of a variety of management practices under a variety of conditions. The Root Zone Water Quality Model (RZWQM) was calibrated to long-term (1990-2003) data near Nashua, Iowa, which includes 36 plots with a variety of crop rotations, tillage, and manure and fertilizer applications. The model adequately responds to year-to-year climate variation and to plot-to-plot management variation within a year. The calibrated model will be used to populate a database that quantifies the water quality and yield effect of multiple agricultural management practices under several climate and soil conditions. A database such as this may be a useful tool that simply and objectively quantifies the tradeoffs of management alternatives, which may help accelerate adoption of best management practices.
DE: 1871 Surface water quality
DE: 1875 Unsaturated zone
DE: 3210 Modeling
SC: Hydrology [H]
MN: 2005 Joint Assembly