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Bioresource and Agricultural Engineering Commons™
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Full-Text Articles in Bioresource and Agricultural Engineering
Simulated N Management Effects On Corn Yield And Tile-Drainage Nitrate Loss, Robert W. Malone, Liwang Ma, Philip Heilman, Douglas L. Karlen, Ramesh S. Kanwar, Jerry L. Hatfield
Simulated N Management Effects On Corn Yield And Tile-Drainage Nitrate Loss, Robert W. Malone, Liwang Ma, Philip Heilman, Douglas L. Karlen, Ramesh S. Kanwar, Jerry L. Hatfield
Douglas L Karlen
Thoroughly tested simulation models are needed to help quantify the long-term effects of agriculture. We evaluated the Root Zone Water Quality Model (RZWQM) response to different N management strategies and then used the tested model with observed weather data from 1961–2003 to quantify long-term effects on corn (Zea mays L.) yield and flow weighted nitrate-N concentration in subsurface “tile” drainage water (Nconc). Fourteen years (1990–2003) of field data from 30, 0.4 ha plots in northeast Iowa were available for model testing. Annual crop yield, nitrate-N loss to subsurface “tile” drainage water (Nloss), Nconc, and subsurface “tile” drainage amount (drain) …
Tillage System Effects On 15-Year Carbon-Based And Simulated N Budgets In A Tile-Drained Iowa Field, Douglas L. Karlen, Ajay Kumar, Ramesh S. Kanwar, Cynthia A. Cambardella, Thomas S. Colvin
Tillage System Effects On 15-Year Carbon-Based And Simulated N Budgets In A Tile-Drained Iowa Field, Douglas L. Karlen, Ajay Kumar, Ramesh S. Kanwar, Cynthia A. Cambardella, Thomas S. Colvin
Douglas L Karlen
Tillage influences N fate and transport by changing soil structure, aeration, macropore continuity, plant-residue placement, and organic-matter mineralization rates. Our objective was to use 15-year N budgets to compare four primary tillage treatments for continuous corn (Zea mays L.) production on tile-drained Aquic Hapludolls (FAO: Haplic Phaeozems) in northeastern Iowa, USA. A carbon-based N budget used annual grain yield, grain-N concentrations measured in 1992, changes in surface-soil C content between 1977 and 1988 or 1992, surface-soil C : N ratios, and measurements of NO3–N lost in tile-drainage water. It accounted for 98, 104, 99, and 99% of the fertilizer N …