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Articles 1 - 7 of 7
Full-Text Articles in Agriculture
Development Of A Data-Assimilation System To Forecast Agricultural Systems: A Case Study Of Constraining Soil Water And Soil Nitrogen Dynamics In The Apsim Model, Marissa S. Kivi, Bethany Blakely, Michael Masters, Carl J. Bernacchi, Fernando E. Miguez, Hamze Dokoohaki
Development Of A Data-Assimilation System To Forecast Agricultural Systems: A Case Study Of Constraining Soil Water And Soil Nitrogen Dynamics In The Apsim Model, Marissa S. Kivi, Bethany Blakely, Michael Masters, Carl J. Bernacchi, Fernando E. Miguez, Hamze Dokoohaki
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
As we face today's large-scale agricultural issues, the need for robust methods of agricultural forecasting has never been clearer. Yet, the accuracy and precision of our forecasts remains limited by current tools and methods. To overcome the limitations of process-based models and observed data, we iteratively designed and tested a generalizable and robust data-assimilation system that systematically constrains state variables in the APSIM model to improve forecast accuracy and precision. Our final novel system utilizes the Ensemble Kalman Filter to constrain model states and update model parameters at observed time steps and incorporates an algorithm that improves system performance through …
Cover Crops And Fertilization Alter Nitrogen Loss In Organic And Conventional Conservation Agriculture Systems, Rebecca E. Shelton, Krista L. Jacobsen, Rebecca L. Mcculley
Cover Crops And Fertilization Alter Nitrogen Loss In Organic And Conventional Conservation Agriculture Systems, Rebecca E. Shelton, Krista L. Jacobsen, Rebecca L. Mcculley
Horticulture Faculty Publications
Agroecosystem nitrogen (N) loss produces greenhouse gases, induces eutrophication, and is costly for farmers; therefore, conservation agricultural management practices aimed at reducing N loss are increasingly adopted. However, the ecosystem consequences of these practices have not been well-studied. We quantified N loss via leaching, NH3 volatilization, N2O emissions, and N retention in plant and soil pools of corn conservation agroecosystems in Kentucky, USA. Three systems were evaluated: (1) an unfertilized, organic system with cover crops hairy vetch (Vicia villosa), winter wheat (Triticum aestivum), or a mix of the two (bi-culture); (2) an organic …
Corn-Soybean And Alternative Cropping Systems Effects On No 3 -N Leaching Losses In Subsurface Drainage Water, Rameshwar S. Kanwar, Richard M. Cruse, Mohammadreza Ghaffarzadeh, Allah Bakhsh, Douglas Karlen, Theodore B. Bailey
Corn-Soybean And Alternative Cropping Systems Effects On No 3 -N Leaching Losses In Subsurface Drainage Water, Rameshwar S. Kanwar, Richard M. Cruse, Mohammadreza Ghaffarzadeh, Allah Bakhsh, Douglas Karlen, Theodore B. Bailey
Douglas L Karlen
Alternative cropping systems can improve resource use efficiency, increase corn grain yield, and help in reducing negative impacts on the environment. A 6-yr (1993 to 1998) field study was conducted at the Iowa State University’s Northeastern Research Center near Nashua, Iowa, to evaluate the effects of non-traditional cropping systems [strip inter cropping (STR)-corn (Zea mays L.)/soybean (Glycine max L.)/oats (Avina sativa L.)]; alfalfa rotation (ROT)-3-yr (1993 to 1995) alfalfa (Medicago sativa L.) followed by corn in 1996, soybean in 1997, and oats in 1998), and traditional cropping system (corn after soybean (CS) and soybean after corn (SC) on the flow …
Cropping System Effects On No3-N Loss With Subsurface Drainage Water, Allah Bakhsh, Rameshwar S. Kanwar, Theodore B. Bailey, Cynthia A. Cambardella, Douglas Karlen, Thomas S. Colvin
Cropping System Effects On No3-N Loss With Subsurface Drainage Water, Allah Bakhsh, Rameshwar S. Kanwar, Theodore B. Bailey, Cynthia A. Cambardella, Douglas Karlen, Thomas S. Colvin
Douglas L Karlen
An appropriate combination of tillage and nitrogen management practices will be necessary to develop sustainable farming practices. A six–year (1993–1998) field study was conducted on subsurface–drained Clyde–Kenyon–Floyd soils to quantify the impact of two tillage systems (chisel plow vs. no tillage) and two N fertilizer management practices (preplant single application vs. late–spring soil test based application) on nitrate–nitrogen (NO3–N) leaching loss with subsurface drain discharge from corn (Zea mays L.) soybean (Glycine max L.) rotation plots. Preplant injected urea ammonium nitrate solution (UAN) fertilizer was applied at the rate of 110 kg ha–1 to chisel plow and no–till corn plots, …
Nitrogen Fertilizer, Cropping Systems, And Iowa Groundwater, Robert Dehaan, Ronald Vos, Matt Schuiteman, Matt Van Schouwen, Harlan Kruid
Nitrogen Fertilizer, Cropping Systems, And Iowa Groundwater, Robert Dehaan, Ronald Vos, Matt Schuiteman, Matt Van Schouwen, Harlan Kruid
Faculty Work Comprehensive List
Summary presentation of research conducted over a 5 year period to determine which cropping systems best reduce nitrate leaching. Initial data was collected on nitrate concentration from individual wells in the Sioux Center, Iowa area which led to connections with the Iowa Department of Natural Resources Source Water Protection Program. A community group was then formed comprised of city representatives, Dordt College faculty, local farmers, Source Water Protection Program staff, and others. The group applied for and received a Leopold Center for Sustainable Agriculture grant to fund field experiments to identify cropping systems that retain nitrate and are workable for …
Best Management Practices To Minimize Nitrate Leaching For Irrigated Potatoes, Robert W. Hill, Ahmad Y. Ranjha
Best Management Practices To Minimize Nitrate Leaching For Irrigated Potatoes, Robert W. Hill, Ahmad Y. Ranjha
All Archived Publications
Nitrate nitrogen (N03-N) leaching is becoming an alarming threat to ground water in many areas in the U.S. In one study in North Carolina, over 9000 domestic wells were sampled for nitrate. Over 3 percent (288 wells) contained N03-N at levels exceeding the Environmental Protection Agency (EPA) safe drinking water standard of 10 mgIL (Jennings, et aI., 1991). Ground water quality concerns in central Nebraska surfaced in the mid 1950s when scientists observed increasing N03-N concentrations in the ground water of some river valleys (Olson et aI., 1962). In Utah also, excessive N03-N contamination has been found in private wells. …
Irrigation Management To Control Nitrate Leaching: What Is In It For The Framer?, Gilbert D. Miller, Jay C. Andersen
Irrigation Management To Control Nitrate Leaching: What Is In It For The Framer?, Gilbert D. Miller, Jay C. Andersen
Archived Natural Resources Publications
Managing irrigation application is an important tool in controlling the amount of nitrate that leaches out of the root zone.