Simulating Nitrate Drainage Losses from a Walnut Creek Watershed Field

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2004-01-01
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Bakhsh, Allah
Hatfield, Jerry
Kanwar, Ramesh
Ma, Liwang
Ahuja, Lajpat
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Kanwar, Rameshwar
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Agricultural and Biosystems Engineering

Since 1905, the Department of Agricultural Engineering, now the Department of Agricultural and Biosystems Engineering (ABE), has been a leader in providing engineering solutions to agricultural problems in the United States and the world. The department’s original mission was to mechanize agriculture. That mission has evolved to encompass a global view of the entire food production system–the wise management of natural resources in the production, processing, storage, handling, and use of food fiber and other biological products.

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In 1905 Agricultural Engineering was recognized as a subdivision of the Department of Agronomy, and in 1907 it was recognized as a unique department. It was renamed the Department of Agricultural and Biosystems Engineering in 1990. The department merged with the Department of Industrial Education and Technology in 2004.

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1905–present

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  • Department of Agricultural Engineering (1907–1990)

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Agricultural and Biosystems Engineering
Abstract

This study was designed to evaluate the improved version of the Root Zone Water Quality Model (RZWQM) using 6 yr (1992–1997) of field-measured data from a field within Walnut Creek watershed located in central Iowa. Measured data included subsurface drainage flows, NO3–N concentrations and loads in subsurface drainage water, and corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] yields. The dominant soil within this field was Webster (fine-loamy, mixed, superactive, mesic Typic Endoaquolls) and cropping system was corn–soybean rotation. The model was calibrated with 1992 data and was validated with 1993 to 1997 data. Simulations of subsurface drainage flow closely matched observed data showing model efficiency of 99% (EF = 0.99), and difference (D) of 1% between measured and predicted data. The model simulated NO3–N losses with subsurface drainage water reasonably well with EF = 0.8 and D = 13%. The simulated corn grain yields were in close agreement with measured data with D < 10%. Nitrogen-scenario simulations demonstrated that corn yield response function reached a plateau when N-application rate exceeded 90 kg ha−1 Fraction of applied N lost with subsurface drainage water varied from 7 to 16% when N-application rate varied from 30 to 180 kg ha−1 after accounting for the nitrate loss with no-fertilizer application. These results indicate that the RZWQM has the potential to simulate the impact of N application rates on corn yields and NO3–N losses with subsurface drainage flows for agricultural fields in central Iowa.

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This article is from Journal of Environmental Quality 33 (2004): 114–123, doi:10.2134/jeq2004.1140.

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