TY - GEN
T1 - Field scale application of a water quality modeling approach for alternative agronomic practices
AU - Nangia, V.
AU - Gowda, P.
AU - Mulla, D.
AU - Sands, G.
PY - 2005/11/28
Y1 - 2005/11/28
N2 - This paper evaluates the effectiveness of alternative agronomic practices at improving water quality in agricultural fields. A spatial process model was calibrated using monthly flow and NO 3-N losses from a 14 ha commercial farm in southeastern Minnesota. The study area was monitored for NO 3-N losses from 1999-2003. Spatial patterns in crops, topography, fertilizer applications and climate were used as input to drive the model. Monitoring data from 1999-2001 were used for calibration and data from 2002-2003 were used in validation of the model. For the calibration period, the observed and predicted flow and NO 3-N discharges were in good agreement with r 2 values of 0.86 and 0.86, respectively. During validation, the observed and predicted flow and NO 3-N discharges were in excellent agreement with r 2 values of 0.92 and 0.91, respectively. The calibrated model was used to evaluate the effects of rate and timing of N fertilizer application on NO 3-N losses. Reductions in NO 3-N losses are possible by changing the application timing from fall to spring. For an application rate of 180 kg/ha (160 lb/ac), there was an 8% reduction in NO 3-N losses when switching from a fall to spring application. Further reductions in NO 3-N losses require reductions in N application rates. A twelve percent reduction in nitrate losses was found when the application rate was reduced from 180 kg/ha (160 lb/ac) to 135 kg/ha (120 lb/ac).
AB - This paper evaluates the effectiveness of alternative agronomic practices at improving water quality in agricultural fields. A spatial process model was calibrated using monthly flow and NO 3-N losses from a 14 ha commercial farm in southeastern Minnesota. The study area was monitored for NO 3-N losses from 1999-2003. Spatial patterns in crops, topography, fertilizer applications and climate were used as input to drive the model. Monitoring data from 1999-2001 were used for calibration and data from 2002-2003 were used in validation of the model. For the calibration period, the observed and predicted flow and NO 3-N discharges were in good agreement with r 2 values of 0.86 and 0.86, respectively. During validation, the observed and predicted flow and NO 3-N discharges were in excellent agreement with r 2 values of 0.92 and 0.91, respectively. The calibrated model was used to evaluate the effects of rate and timing of N fertilizer application on NO 3-N losses. Reductions in NO 3-N losses are possible by changing the application timing from fall to spring. For an application rate of 180 kg/ha (160 lb/ac), there was an 8% reduction in NO 3-N losses when switching from a fall to spring application. Further reductions in NO 3-N losses require reductions in N application rates. A twelve percent reduction in nitrate losses was found when the application rate was reduced from 180 kg/ha (160 lb/ac) to 135 kg/ha (120 lb/ac).
KW - ADAPT
KW - Fertilizer management
KW - GIS
KW - Tile drainage
KW - Water quality
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M3 - Conference contribution
AN - SCOPUS:27844538434
SN - 1892769468
SN - 9781892769466
T3 - Proceedings of the 3rd Conference on Watershed Management to Meet Water Quality Standards and Emerging TMDL
SP - 364
EP - 372
BT - Watershed Management to Meet Water Quality Standards and Emerging TMDL - Proceedings of the 3rd Conference
T2 - 3rd Conference on Watershed Management to Meet Water Quality Standards and Emerging TMDL
Y2 - 5 March 2005 through 9 March 2005
ER -