Your search found 2 records
1 Sands, G. R.; Podmore, T. H. 1996. An environmental sustainability index for agricultural systems. In ICID, 16th Congress on Irrigation and Drainage, Cairo, Egypt, 1996: Sustainability of Irrigated Agriculture - Transactions, Vol.1C, Q.47: R.3.02 Irrigation planning and management: Measures in harmony with the environment. New Delhi, India: ICID. pp.195-218.
Environmental sustainability ; Agricultural development ; Crop production ; Simulation models ; Indicators ; Soil properties ; Groundwater ; Case studies ; Irrigation water ; Water quality / USA / Colorado
(Location: IWMI-HQ Call no: ICID 631.7 G000 ICI Record No: H019561)
2 Nangia, Vinay; Gowda, P. H.; Mulla, D. J.; Sands, G. R.. 2008. Water quality modeling of fertilizer management impacts on nitrate losses in tile drains at the field scale. Journal of Environmental Quality, 37(2):296-307.
Water quality ; Simulation models ; Calibration ; Fertilizer application ; Nitrogen fertilizers ; Soyabeans ; Maize ; Subsurface drainage / USA / Gulf of Mexico / Mississippi River / Minnesota
(Location: IWMI HQ Call no: IWMI 631.8 G430 NAN Record No: H040829)
Nitrate losses from subsurface tile drained row cropland in the Upper Midwest U.S. contribute to hypoxia in the Gulf of Mexico. Strategies are needed to reduce nitrate losses to the Mississippi River. This paper evaluates the effect of fertilizer rate and timing on nitrate losses in two (East and West) commercial row crop fields located in south-central Minnesota. The Agricultural Drainage and Pesticide Transport (ADAPT) model was calibrated and validated for monthly subsurface tile drain flow and nitrate losses for a period of 1999–2003. Good agreement was found between observed and predicted tile drain flow and nitrate losses during the calibration period, with Nash-Sutcliff e modeling efficiencies of 0.75 and 0.56, respectively. Better agreements were observed for the validation period. The calibrated model was then used to evaluate the effects of rate and timing of fertilizer application on nitrate losses with a 50-yr climatic record (1954–2003). Significant reductions in nitrate losses were predicted by reducing fertilizer application rates and changing timing. A 13% reduction in nitrate losses was predicted when fall fertilizer application rate was reduced from 180 to 123 kg/ha. A further 9% reduction in nitrate losses can be achieved when switching from fall to spring application. Larger reductions in nitrate losses would require changes in fertilizer rate and timing, as well as other practices such as changing tile drain spacings and/or depths, fall cover cropping, or conversion of crop land to pasture.
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