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Retrospective Theses and Dissertations

Environmental Sciences

Water resources

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Full-Text Articles in Life Sciences

Soil And Runoff Phosphorus As Affected By Fertilizer And Manure Application , Brett Lee Allen Jan 2004

Soil And Runoff Phosphorus As Affected By Fertilizer And Manure Application , Brett Lee Allen

Retrospective Theses and Dissertations

Fertilizer or manure applications are increasing soil P in agricultural fields. This study assessed the impact of P application on soil P fractions and P loss with surface runoff based on P rate field trials and both indoor and field rainfall simulations. Bray P, Mehlich-3 (M3) P, Olsen P, total P (TPS) and soil P saturation (Psat) estimated by M3 or oxalate extractable P, Fe, and Al molar ratios increased with cumulative P application (0 to 1098 kg P ha-1 after 4 to 23 yr) at plots from 11 trials. Soil test P, TPS, and Psat were linearly correlated. Routine ...


Riparian Land-Use Impacts On Stream And Gully Bank Soil And Phosphorus Losses With An Emphasis On Grazing Practices , George Nick Zaimes Jan 2004

Riparian Land-Use Impacts On Stream And Gully Bank Soil And Phosphorus Losses With An Emphasis On Grazing Practices , George Nick Zaimes

Retrospective Theses and Dissertations

The tall-grass prairies, wetlands and forests that dominated the Iowa landscape have been replaced by annual row-crops and grass pastures that occupy more than 90% of the landscape today. Because of these changes, water reaches streams and gullies much faster and has led to incised streams and an extensive growth of gully networks. Stream and gully banks are major contributors of non-point source sediment and phosphorus. Reducing these pollutants is a priority to maintaining healthy streams. The objective of this study was to compare stream and gully bank soil and phosphorus losses under different land-use practices in three Iowa regions ...


Studies Of Solute Transport Through Fractured Till In Iowa , Martin Frederick Helmke Jan 2003

Studies Of Solute Transport Through Fractured Till In Iowa , Martin Frederick Helmke

Retrospective Theses and Dissertations

Fractures may provide pathways for agricultural chemicals to reach aquifers through till units that have traditionally been considered effective barriers to contaminant transport. Till units were studied at three sites in Iowa that represented three landform regions, till ages from 12.5 to >730 ka, and depths from 1 to 27.5 m. Fractures were present at all study locations and at all depths, including one site where fractures intersected an aquifer at 30 m depth. Laboratory experiments using eight large (0.40 to 0.45 m in length and 0.43 m in diameter), undisturbed columns of till showed ...


Quantitation Of Bound Pesticide Residues In Field And Wetland Soils , Larry Warren Wulf Jan 2001

Quantitation Of Bound Pesticide Residues In Field And Wetland Soils , Larry Warren Wulf

Retrospective Theses and Dissertations

A sequential extraction scheme was developed for the quantitation of extractable and bound pesticide residues in field and wetland soils. Extractable and bound fractions of pesticides in soil were measured in spiked field and wetland soils that were stored for periods of up to ninety days. Treatment conditions included microbiological control through the use of irradiated soil and biocide. Bound pesticide residue formation was also studied as affected by moisture level, dark and light storage, and concentration. The water column of wetland microcosms was dosed with pesticides to study sorption behavior of pesticides in intact wetland systems. Extractable pesticide degradation ...


Field And Laboratory Investigations Of Solute Transport Through Soil , Francis Xavier Mckeon Casey Jan 2000

Field And Laboratory Investigations Of Solute Transport Through Soil , Francis Xavier Mckeon Casey

Retrospective Theses and Dissertations

Two single tracer methods (basic and variance) and one multiple tracer method were developed to simultaneously estimate soil hydraulic properties and mobile/immobile solute transport parameters in situ. In this study, immobile water contents (thetaim) and mass exchange coefficients (alpha) were estimated with the multiple tracer method and the single tracer methods on the same five field sites. The theta im values estimated by the basic single tracer method were consistently lower than the multiple tracer method values. This was attributed to the assumption that alpha = 0 for the basic single tracer method. Furthermore, alpha values estimated by multiple tracer ...


Effects Of Liquid Swine Manure Placement And Rate On Phosphorus Loss With Runoff Water , Hadi Tabbara Jan 2000

Effects Of Liquid Swine Manure Placement And Rate On Phosphorus Loss With Runoff Water , Hadi Tabbara

Retrospective Theses and Dissertations

There is an increasing concern on the use of nitrogen (N) based manure application rate for corn production and its impact on soil phosphorus (P) buildup and the potential to release P to the environment. Therefore a field study was conducted to evaluate the effects of manure application rate and method of application on soil erosion and P loss with runoff water and sediment. Simulated rainfall was applied to 24 runoff plots to study two variables in triplicate. The first variable was application rate: liquid swine manure was applied at N recommended rate and twice the rate, and inorganic liquid ...


Spatio-Temporal Modeling In An Agricultural Watershed , Shabana Hameed Jan 1999

Spatio-Temporal Modeling In An Agricultural Watershed , Shabana Hameed

Retrospective Theses and Dissertations

Non-point source pollution in agricultural regions in the Midwest consists of two important components, namely, dislodgment of common pollutants, their movement across the landscape and subsequently transport through surface waters to their final destination. The objectives of this study were to: 1) model surface movement of agricultural pollutants for a succession of sub-watersheds in Bear Creek using AGNPS; 2) calibrate and validate the model for a small sub-watershed using available experimental plot data; 3) incorporate Monte Carlo simulation within the modeling process where field data was not available; 4) apply the calibrated and validated model to a small sub-watershed with ...


Characterization Of Preferential Solute Transport In Soil , Jaehoon Lee Jan 1999

Characterization Of Preferential Solute Transport In Soil , Jaehoon Lee

Retrospective Theses and Dissertations

The occurrence of preferential flow for rapid movement of solute through soil has been reported. However, there are not many practical methods to detect, quantify, and identify preferential flow. The characterization of preferential flow would improve our understanding of field water and solute behavior. A concept that separates water content into "mobile" and "immobile" domain has been successful in describing some forms of preferential solute transport. The mobile-immobile model (MIM) has three significant parameters- immobile water content (thetaim), mass exchange coefficient (alpha), and dispersion coefficient (D m). Although one can determine these parameters by applying inverse methods to effluent breakthrough ...


A Decision Support System For Planning And Management Of Sustainable Livestock Production In The Midwest, Irene Mary Crawford Jan 1999

A Decision Support System For Planning And Management Of Sustainable Livestock Production In The Midwest, Irene Mary Crawford

Retrospective Theses and Dissertations

Managing livestock operations in an environmentally sound way presents a major challenge to the livestock production industry. Excessive amounts of manure can cause major environmental problems if not properly managed. The contamination of surface and subsurface water supplies due to non-point source pollution from livestock production has increased public concern in regards to large livestock operations. Another source of pollution from livestock facilities is atmospheric pollution in the form of odor. Odorous gaseous, such as carbon dioxide, methane, ammonia, and other gaseous from livestock operations are a health hazard and nuisance to neighboring populations. Analysis of the environmental impacts of ...


Effects Of Variable Rates, Times And Methods Of Application Of Swine Manure On Nitrate-Nitrogen In Subsoil Water, Crop Yields, N Uptake And Recovery And Soil Residual Nitrate-Nitrogen: A Three Year Study , Sara Dominga Smith Jan 1999

Effects Of Variable Rates, Times And Methods Of Application Of Swine Manure On Nitrate-Nitrogen In Subsoil Water, Crop Yields, N Uptake And Recovery And Soil Residual Nitrate-Nitrogen: A Three Year Study , Sara Dominga Smith

Retrospective Theses and Dissertations

Land application of swine manure offers the alternative use of its nutrients for crop production but growing concerns exist when not properly managed because of potential water quality problems;The field experiment consisted of 48 plots (15.24 x 3.04 m), located in a Clarion-Nicollet-Webster soil association. Corn (Zea mays L.) was rotated with soybean (Glycine max L.). Treatments applied were a factorial combination of Nitrogen (N) rates (0, 84, 168 and 252 kg-N/ha) of liquid swine manure and Urea-Ammonium-Nitrate (UAN) with methods of application (manure in spring, fall and side-dress; manure with nitrapyrin in fall and UAN ...


Assessment And Simulation Of Atrazine As Influenced By Drainage And Irrigation: An Interface Between Rzwqm And Arcview Gis , Ana Sofia De Oliveira Nobre Azevedo Jan 1998

Assessment And Simulation Of Atrazine As Influenced By Drainage And Irrigation: An Interface Between Rzwqm And Arcview Gis , Ana Sofia De Oliveira Nobre Azevedo

Retrospective Theses and Dissertations

Atrazine is the most frequently detected herbicide in groundwater. For these reasons, atrazine's dynamics need to be studied, and work is needed to develop and calibrate mathematical models to help in determining best management practices to minimize contamination. This study was designed to make a small contribution in solving some of the environmental related problems;In the first part of this study, macroporosity of an agricultural soil in Iowa was characterized. This study confirmed that under saturated and partially saturated flow conditions, macropore flow was a dominant mechanism for water and chemical transport;Atrazine's movement through the soil ...


Nitrate Removal Capacity Of Constructed Wetlands , Richard Gregory Phipps Jan 1997

Nitrate Removal Capacity Of Constructed Wetlands , Richard Gregory Phipps

Retrospective Theses and Dissertations

Constructed wetlands at the Des Plaines Wetland Demonstration Project in Wadsworth, Illinois were examined for their capacity to remove nonpoint source loads of nitrate from an agricultural watershed. Three flow through wetlands received different loading rates of pumped river water with seasonably variable loads of nitrate and organic nitrogen. The nitrogen removal capacities of the wetlands were estimated using mass balance and sediment-water microcosms for the 1991 and 1992 field seasons. Concentrations of nitrogen and flow volumes were monitored at inlets and outlets and mass balances of nitrogen loads were calculated. The wetlands received two different loading rates in 1991 ...


Effects Of Emergent Vegetation On Wetland Microbial Processes , Charles Lee Rose Jan 1996

Effects Of Emergent Vegetation On Wetland Microbial Processes , Charles Lee Rose

Retrospective Theses and Dissertations

Wetland areas with varying amounts of emergent and free-floating vegetation may have very different microbial carbon and energy processing rates and and pathways. In Goose Lake Marsh, a natural prairie pothole wetland in central Iowa, transect measurements, continuous monitoring, and synoptic surveys were used to examine patterns light availability, temperature, dissolved O2 concentrations, dissolved CH4 concentrations, plant densities, litter densities, and CH4 flux due to diffusion and ebuliation within and outside emergent vegetation zones. Water column light availability was less than 2% of ambient light in emergent vegetated areas due to canopy cover, small floating plants (lemnids), and plant litter ...


Measuring And Modeling Alachlor Dissipation In Soil , Dee Anna Jo Weed Jan 1995

Measuring And Modeling Alachlor Dissipation In Soil , Dee Anna Jo Weed

Retrospective Theses and Dissertations

Field and laboratory experiments evaluated the overall dissipation of alachlor (2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl) acetamide) and the effect of no-till and chisel-plow tillages on alachlor leaching and dissipation. In the top 30-cm layer of field soil, the time to 50% dissipation (half-life) was 2 to 3 d, and the time to 90% dissipation ranged from 17 to 30 d. In no-till soil, alachlor dissipated slightly faster, and more was transported into the 10-to-30-cm soil layer. The tillage effect depended on weather that favored movement into and dissipation within the soil, rather than dissipation on plant residues and the soil ...


Sorption Kinetics Of Atrazine And Hydroxyatrazine In Freshwater Wetlands, Michael Patrick Matter Jan 1993

Sorption Kinetics Of Atrazine And Hydroxyatrazine In Freshwater Wetlands, Michael Patrick Matter

Retrospective Theses and Dissertations

No abstract provided.


Fertilizer Fate Under Golf Course Conditions In The Midwestern Region, Steven Kent Starrett Jan 1992

Fertilizer Fate Under Golf Course Conditions In The Midwestern Region, Steven Kent Starrett

Retrospective Theses and Dissertations

No abstract provided.


Effects Of Varying Concentrations Of Certain Major And Minor Nutrients On The Interaction Between A Blue-Green Alga And A Diatom, Howard David Markus Jan 1979

Effects Of Varying Concentrations Of Certain Major And Minor Nutrients On The Interaction Between A Blue-Green Alga And A Diatom, Howard David Markus

Retrospective Theses and Dissertations

No abstract provided.


Mathematical Models For Gully-Wall And Mineland-Soil Seep And Slip, Seyed Farhad Mousavi Jan 1978

Mathematical Models For Gully-Wall And Mineland-Soil Seep And Slip, Seyed Farhad Mousavi

Retrospective Theses and Dissertations

No abstract provided.


Growth Responses Of Selected Freshwater Algae To Trace Elements And Scrubber Ash Slurry Generated By Coal-Fired Power Plants , Robert Wayne Vocke Jan 1978

Growth Responses Of Selected Freshwater Algae To Trace Elements And Scrubber Ash Slurry Generated By Coal-Fired Power Plants , Robert Wayne Vocke

Retrospective Theses and Dissertations

No abstract provided.


Energy Balance In Crop Rotation With Different Levels Of Fertilizer, Akbar Mostajeran Jan 1978

Energy Balance In Crop Rotation With Different Levels Of Fertilizer, Akbar Mostajeran

Retrospective Theses and Dissertations

No abstract provided.