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Full-Text Articles in Engineering
Assessment Of Aged Woodchip Bioreactor Physical And Hydraulic Properties, Shelby Duncan
Assessment Of Aged Woodchip Bioreactor Physical And Hydraulic Properties, Shelby Duncan
Electronic Theses and Dissertations
Denitrifying woodchip bioreactors are a critical tool for mitigating nitrate loading to downstream water bodies. The properties of the woodchip are a key factor in the design of the bioreactor which are usually designed to optimize that retention time of the water being treated. Retention time is affected by active flow volume, porosity, and flow rate. As a bioreactor ages, the carbon material will break down and, in some cases, sedimentation will occur within the bioreactor. Both processes will affect the porosity and hydraulic performance of the bioreactor. When flow through the bioreactor is significantly different than the original design, …
Impact Of Subsurface Drainage On Water Yield For Typical Soil And Weather In Eastern South Dakota, Govinda Karki
Impact Of Subsurface Drainage On Water Yield For Typical Soil And Weather In Eastern South Dakota, Govinda Karki
Electronic Theses and Dissertations
Subsurface drainage in agricultural land changes the field water balance by providing an alternate pathway for subsurface water. Determining the effects of subsurface drainage on downstream hydrology requires quantifying the components of the water balance. A number of studies have looked at the hydrological impacts of subsurface drainage. However, the effects are complex and difficult to generalize. The complex interaction involves the interrelation among variables such as soil type and properties, climate (rainfall and evapotranspiration), and drainage design configuration (drainage intensity and drainage coefficient), which all are local in nature. Additionally, most studies have been conducted in humid climates, whereas …
A Demonstration Study Of Drainage Water Management In Eastern South Dakota, Ashik Sahani
A Demonstration Study Of Drainage Water Management In Eastern South Dakota, Ashik Sahani
Electronic Theses and Dissertations
Subsurface drainage is a common water management practice for improving crop production in poorly drained soils; however, the practice is associated with several environmental concerns such as nutrient losses to downstream surface waters. These environmental concerns from subsurface drainage have prompted interest in drainage water management strategies such as controlled drainage. This study assessed the agronomic and environmental impacts of drainage water management in eastern South Dakota by using two demonstration plots for controlled and conventional drainage. Drain flow, nitrate and dissolved phosphorous concentration in drain water, shallow groundwater, crop yield, residual soil nitrate, soil moisture and temperature, soil penetration …
Simulation Of Flow And Water Quality From Tile Drains At The Watershed And Field Scale, Colleen Moloney
Simulation Of Flow And Water Quality From Tile Drains At The Watershed And Field Scale, Colleen Moloney
Open Access Theses
Simulation models such as the Soil and Water Assessment Tool (SWAT) have become widely used in determining the water quality impacts of various management practices. Ensuring that the algorithms accurately represent the processes simulated has become an important goal. Tile drainage is a standard practice in the Midwest, US in order to reduce risk of yield loss due to excess water. Multiple tile drainage and water table algorithms have been available in the SWAT model between the initial SWAT release and revision 638 used in this study. Testing of those algorithms is often limited. Furthermore, algorithms in the current version …
Annual Swine Manure Applications To Soybean Under Corn-Soybean Rotation, Allah Bakhsh, Rameshwar S. Kanwar, James L. Baker, John E. Sawyer, Antonio P. Mallarino
Annual Swine Manure Applications To Soybean Under Corn-Soybean Rotation, Allah Bakhsh, Rameshwar S. Kanwar, James L. Baker, John E. Sawyer, Antonio P. Mallarino
John E. Sawyer
The response of a corn-soybean rotation system receiving fall manure application to both corn and soybean is not well understood in terms of its impact on nitrate leaching to subsurface drainage water and crop yields. This field study was conducted from 2001 through 2005 with the key objective of determining the effects of manure application to both corn and soybean on NO3-N concentrations in subsurface drainage water and corn-soybean yields. The study was conducted on 0.4 ha plots instrumented with state-of-the-art subsurface drainage monitoring systems at the Iowa State University research center, Nashua, Iowa. Nitrogen application rates from liquid swine …
Empirical Analysis And Prediction Of Nitrate Loading And Crop Yield For Corn–Soybean Rotations, Robert W. Malone, Liwang Ma, Douglas L. Karlen, T. Meade, D. Meek, Ramesh S. Kanwar, Jerry L. Hatfield
Empirical Analysis And Prediction Of Nitrate Loading And Crop Yield For Corn–Soybean Rotations, Robert W. Malone, Liwang Ma, Douglas L. Karlen, T. Meade, D. Meek, Ramesh S. Kanwar, Jerry L. Hatfield
Douglas L Karlen
Nitrate nitrogen losses through subsurface drainage and crop yield are determined by multiple climatic and management variables. The combined and interactive effects of these variables, however, are poorly understood. Our objective is to predict crop yield, nitrate concentration, drainage volume, and nitrate loss in subsurface drainage from a corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) rotation as a function of rainfall amount, soybean yield for the year before the corn–soybean sequence being evaluated, N source, N rate, and timing of N application in northeastern Iowa, U.S.A. Ten years of data (1994–2003) from a long-term study …
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 …
Rzwqm Simulation Of Long-Term Crop Production, Water And Nitrogen Balances In Northeast Iowa, L. Ma, Robert W. Malone, Philip Heilman, Douglas L. Karlen, Ramesh S. Kanwar, Cynthia A. Cambardella, S. A. Saseendran, Lajpat R. Ahuja
Rzwqm Simulation Of Long-Term Crop Production, Water And Nitrogen Balances In Northeast Iowa, L. Ma, Robert W. Malone, Philip Heilman, Douglas L. Karlen, Ramesh S. Kanwar, Cynthia A. Cambardella, S. A. Saseendran, Lajpat R. Ahuja
Douglas L Karlen
Agricultural system models are tools to represent and understand major processes and their interactions in agricultural systems. We used the Root Zone Water Quality Model (RZWQM) with 26 years of data from a study near Nashua, IA to evaluate year to year crop yield, water, and N balances. The model was calibrated using data from one 0.4 ha plot and evaluated by comparing simulated values with data from 29 of the 36 plots at the same research site (six were excluded). The dataset contains measured tile flow that varied considerably from plot to plot so we calibrated total tile flow …
Alternative N Fertilizer Management Strategies Effects On Subsurface Drain Effluent And N Uptake, David L. Bjorneberg, Douglas L. Karlen, Rameshwar S. Kanwar, Cynthia A. Cambardella
Alternative N Fertilizer Management Strategies Effects On Subsurface Drain Effluent And N Uptake, David L. Bjorneberg, Douglas L. Karlen, Rameshwar S. Kanwar, Cynthia A. Cambardella
Douglas L Karlen
Demonstrating positive environmental benefits of alternative N fertilizer management strategies, without adversely affecting crop growth or yield, was a major goal for the Midwest Management Systems Evaluation Areas (MSEA) program. Our project objectives within this program were to quantify the effects of split- and single-N fertilization strategies on NO3-N concentration and loss in subsurface drain effluent and N accumulation and yield of corn (Zea mays L.) and soybean [Glycine max (L.) Merr.]. The study was conducted on glacial till derived soils in northeast Iowa from 1993 through 1995 using no-till and chisel plow tillage treatments. One-third of the 2,611 effluent …