Field scale application of a water quality modeling approach for alternative agronomic practices

V. Nangia, P. Gowda, D. Mulla, G. Sands

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

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).

Original languageEnglish (US)
Title of host publicationWatershed Management to Meet Water Quality Standards and Emerging TMDL - Proceedings of the 3rd Conference
Pages364-372
Number of pages9
StatePublished - Nov 28 2005
Event3rd Conference on Watershed Management to Meet Water Quality Standards and Emerging TMDL - Atlanta, GA, United States
Duration: Mar 5 2005Mar 9 2005

Publication series

NameProceedings of the 3rd Conference on Watershed Management to Meet Water Quality Standards and Emerging TMDL

Other

Other3rd Conference on Watershed Management to Meet Water Quality Standards and Emerging TMDL
CountryUnited States
CityAtlanta, GA
Period3/5/053/9/05

Keywords

  • ADAPT
  • Fertilizer management
  • GIS
  • Tile drainage
  • Water quality

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