Biological Engineering Commons^™

Human Health Effects Assays, Ronald C. Sims, J. L. Sims, R. R. Dupont

Biological Engineering Faculty Publications

Environmental health risk assessments based upon animal study results, epidemiology, quantitative structure activity relationships (QSARs), dose-response relationships, risk perception, and expert systems approaches, and the evaluation of mechanisms of carcinogenesis represent the focus for 1987. The term "biological risk assessment" was discussed by Clayson¹ to describe that part of risk assessment concerned with the relevance of specific animal results to the induction of human cancer. Guidelines for health assessment of suspect developmental toxicants addressed evaluation of data from animal testing studies.² Animal toxicity data on 200 chemicals and epidemiologic data on 30 chemicals was included within a data …

Biological Transformation And Detoxification Of 7,12-Dimethylbenzanthracene In Soil, K. Park, Ronald C. Sims, W. J. Doucette, J. E. Matthews

Biological Engineering Faculty Publications

Biological transformation and detoxification of 7,12-dimethylbenz(a)anathracene (DMBA) were studied in a nonacclimated sandy loam soil. Parent 14C DMBA biodegraded extensively (62% to 20%), accompanying an increase of metabolite 14C fraction (4% to 53%). Incorporation of DMBA into non extractable soil residue ,4C increased from 12 to 17%, but the increase was not statistically significant. DMBA was transformed into several metabolic products in the soil system, including 4-hydroxy-, 5-hydroxy-, and 10-hydroxy-DMBA and 7,12-dihydro 12-methyl-7-methylene-benz(a)anthracene-12-ol. High polarity transformation products of DMBA demonstrated a negative mu tagenic response with the Ames mutagenicity assay, strain TA 100, for both low and neutral pH soils. …

Fate And Transport Of Organics In Soil: Model Predictions And Experimental Results, B. D. Symons, Ronald C. Sims, W. J. Grenney

Biological Engineering Faculty Publications

Laboratory batch reactors were used to generate quantitative information about the fate of polynuclear aromatic hydrocarbon (PNA) compounds in soil systems. First-order degradation rates and equilibrium partition coefficients determined in laboratory studies were used in the Vadose Zone Interactive Processes (VIP) mathematical model to predict the fate and behavior of the PNA compounds as a function of time and soil depth. Predicted model results were compared with independent laboratory soil column studies for model validation. The VIP model provided a good approximation of the degradation and transport of the seven PNA compounds evaluated after 6 months of incubation in soil. …

Nebraska's Modified-Open-Front Farrowing Houses Design And Operation, Gerald R. Bodman, Donald G. Levis, Duane E. Reese

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Two modified-open-front non-mechanically ventilated farrowing houses with creep boxes were operated over a two year period. Annual energy requirements were in the range of 10.6 to 10.9 cents per crate per day. No adverse effects on pig performance were realized. In most instances pig performance exceeded national standards of excellent performance—survival rates in excess of 90% and 21-day pig weights of 5.9 to 6.8 kg (13 to 15 lb). The study verified that another alternative is available to producers who do not want additional mechanical equipment to operate and maintain.

Size Distribution Of Sediment As Affected By Surface Residue And Slope Length, John E. Gilley, S. C. Finkner, G. E. Varvel

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Runoff samples for determination of size distribution of sediment were collected under simulated rainfall conditions at selected downslope distances on plots covered with sorghum and soybean residue at rates ranging from 0.00 to 6.73 t/ha . The effects of surface residue and slope length on size distribution of sediment were evaluated. Substantial movement of sediment in the form of aggregates was found for each of the residue treatments. Significant differences in size distribution of sediment occurred between residue treatments. For a given residue rate, differences in sediment size distribution were found between sorghum and soybean residue. Size distribution of sediment …

Conservation Tillage: Perceived And Actual Use, Elbert C. Dickey, Paul J. Jasa, Bryn J. Dolesh, Lisa A. Brown, S. Kay Rockwell

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A mail survey of farmers in Nebraska showed their perceived use of conservation tillage was about 55%. However, using the 30% residue cover criterion that the Conservation Tillage Information Center uses to define conservation tillage, a field survey of seven counties in 1984 showed that actual use of conservation tillage was less than 5%. Fewer than 20% of the producers surveyed had more than 20% residue cover remaining after tillage and planting. The field survey also showed disk tillage systems were used by almost 70% of the producers. The moldboard plow was used by only 15% of the producers, thus …

Slope Length And Surface Residue Influences On Runoff And Erosion, John E. Gilley, S. C. Finkner, G. E. Varvel

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Runoff rate, runoff velocity , sediment concentration and soil loss rate of rills or overland flow channels were measured at selected downslope distances on plots with varying rates of sorghum and soybean residue, runoff rate, runoff velocity and soil loss rate usually increased with downslope distance. In general, the presence of greater amounts of crop residue reduced sediment concentration and soil loss rate along the entire slope length. Substantial variations in runoff rate, runoff velocity, sediment concentration and soil loss rate were found with downslope distance on some residue treatments.

Slot Injection Of Herbicides, Paul J. Jasa, Elbert C. Dickey, Thomas R. Peterson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Injection of thiocarbamate herbicides into a slot created by a coulter was evaluated during a 3-year study in southeastern Nebraska. Control of shattercane, the dominant weed, with the slot injector was similar to conventional double disk incorporation. In both tilled and untilled surface conditions, the slot injector placed the herbicide into the soil with minimal disturbance of the soil and residue. Herbicides which are normally broadcast applied were band applied, reducing chemical costs by two-thirds.

A Mathematical Model For The Fate Of Hazardous Substances In Soil: Model Description And Experimental Results, W. Greeney, C. Caupp, Ronald C. Sims

Biological Engineering Faculty Publications

A mathematical model (VIP) was developed and implemented for evaluating the fate of a hazardous substance in the unsaturated zone of the soil. The model simulates vadose zone processes including volatilization, degradation, adsorption/desorption, advection, and dispersion. Four physical phases in the vadose zone are considered including water, oil, soil grains, and soil-pore air (unsaturated pore space). The Vadose Zone Interactive Processes (VIP) model is appropriate for sites under RCRA and CERCLA (Superfund) categorization since site-specific soil-waste processes affecting transport of hazardous chemicals through the vadose zone are incorporated in the model. A RCRA land treatment system was chosen as the …

The Rate Of Benzo[A]Pyrene Apparent Loss In A Natural And Manure Amended Clay Loam Soil, M. P. Coover, Ronald C. Sims

Biological Engineering Faculty Publications

A study was conducted to evaluate the rate of Benzo[a]pyrene apparent loss from a previously uncontaminated agricultural clay loam soil and to determine the effect of cow manure, as organic substrate amendment, on B[a]P apparent loss. Soil microcosms were spiked with 10 μg/g B[a]P and incubated at 20°C. Triplicate sets of microcosms were periodically removed from incubation and solvent extracted. Concentrations of B[a]P in the soil were determined by HPLC analysis of the extracts. Under the conditions of this study manure was an ineffective amendment for increasing the rate of B[a]P apparent loss in the Durant clay loam soil. In …

The Effect Of Temperature On Polycyclic Aromatic Hydrocarbon Persistence In An Unacclimated Agricultural Soil, M. P. Coover, Ronald C. Sims

Biological Engineering Faculty Publications

A laboratory study was conducted to investigate the effect of temperature on the persistence of polycyclic aromatic hydrocarbons (PAHs) incubated in an unacclimated agricultural sandy loam soil. Soil microcosms were spiked with 16 priority pollutant PAHs and placed in incubation chambers at 10, 20, and 30°C. Triplicate sets of microcosms at each temperature were periodically removed from incubation over the 240 day study period and solvent extracted. Concentrations of PAHs in the soil were determined by HPLC analysis of the extracts. Substantial loss of three-ring compounds was observed at all temperatures whereas there was very little apparent loss of five …

Runoff And Erosion As Affected By Sorghum And Soybean Residue, John E. Gilley, S. C. Finkner, G. E. Varvel

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A rainfall simulator was used to measure the effects of varying rates of sorghum and soybean residue on runoff and erosion. In general, increased surface cover caused reduced runoff, sediment concentration and soil loss. Substantial reductions in erosion resulted from the use of small amounts of crop residue. Regression equations were obtained which related surface cover to residue mass. Equations describing relative runoff, sediment concentration and soil loss as a function of surface cover were also developed. Runoff, sediment concentration and soil loss were all found to be highly correlated to surface cover.

Size Distribution Of Sediment As Affected By Corn Residue, John E. Gilley, S. C. Finkner, R. G. Spomer, L. N. Mielke

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Size distribution of sediment was measured under simulated rainfall conditions at selected downslope distances on plots with corn residue rates ranging from 0.00 to 6.73 t/ha. The formation of rills caused increases in the percentage of larger sized sediment material. Greater surface cover usually resulted in an increase in the percentage of smaller sized sediment.

Considerable variation in the size of sediment from both rill and interrill areas was found with downslope distance. On interrill regions, the presence of residue served to reduce sediment size along the entire plot length. Transport of aggregated sediment occurred on each of the residue …

Tillage Systems For Row Crop Production, Elbert C. Dickey, Paul J. Jasa, Alice J. Jones, David P. Shelton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Selecting the tillage system best suited to a particular farming situation is an important management decision. Formerly, the traditional system was a moldboard plow operation followed by several secondary tillage operations before planting. This system can be appropriate for poorly drained soils having little or no slope and low erosion potential. However, plowing has several disadvantages . The potential for soil erosion is high on sloping lands, and labor and fuel requirements can be substantially higher than with other tillage and planting systems.

Today, conservation tillage systems are used to reduce preplant tillage operations, thus reducing soil erosion and moisture …

Runoff And Erosion As Affected By Corn Residue: Prt Ii: Rill And Interill Components, John E. Gilley, S. C. Finkner, R. G. Spomer, L. N. Mielke

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Hydraulic and soil loss variables were measured under simulated rainfall conditions at selected downslope distances on plots with corn residue rates ranging from 0.0 to 6.7 t/ha. Application of corn residue produced substantial reductions in runoff rate, runoff velocity, sediment concentration and soil loss rate along the entire slope length. On those plots subject to rilling, runoff rate, sediment concentration and soil loss rate usually increased with downslope distance.

Rill and interrill sediment concentration and soil loss rate were also measured at selected slope lengths. lnterrill sediment concentration changed little with downslope distance while greater interrill soil loss rates were …

Sediment And Dye Concentration Effects On Fluorescence, S. C. Finkner, John E. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Because of the relatively large sediment concentrations sometimes found on upland regions, adsorption of fluorescent dye onto sediment may be of concern. A laboratory study was conducted to identify the effects of sediment and dye concentration on adsorption. Sediment and dye concentration were both found to significantly affect adsorptive dye loss of rhodamine WT and sulpho rhodamine B.
Regression equations were developed which related dye adsorption to sediment and dye concentration. For a particular soil and dye material, regression equations may be used to correct for adsorptive dye loss. Sulpho rhodamine B is recommended as the dye of choice for …

Runoff And Erosion As Affected By Corn Residue: Part I. Total Losses, John E. Gilley, S. C. Finkner, R. G. Spomer, L. N. Mielke

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The effects of verying rates of corn residue on runoff and erosion from a loess soil in southwestern Iowa were measured using a rainfall simulator. Consistent reductions in runoff, sediment concentration and soil loss resulted from increased residue application. Small amounts of surface cover produced substantial reductions in erosion. A regression equation relating surface cover to residue weight was obtained. Equations describing relative runoff, sediment concentration and soil loss as a function of surface cover were also developed using regression analysis.

Estimating Residue Cover, Elbert C. Dickey, Paul J. Jasa, David P. Shelton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Crop residue management through conservation tillage is one of the best and most efficient methods farmers have to control soil erosion. Each year about 140 million tons of topsoil are eroded from Nebraska farmlands. Recent research shows that farmers can greatly reduce this loss by maintaining a residue cover of at least 20 to 30 percent after all tillage and planting operations. Leaving this amount of residue can reduce water caused erosion by 50 percent of what it would be from a cleanly tilled field, while leaving more residue will reduce soil losses even further. Conservation tillage and residue management …

Soil Erosion From Tillage And Planting Systems Used In Soybean Residue: Part I - Influences Of Row Spacing, David P. Shelton, Paul J. Jasa, Elbert C. Dickey

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A rainfall simulator was used to compare soil losses from various tillage and planting systems used in residue from soybeans which had been grown in both wide and narrow spaced rows the previous season. Up and- down hill tillage and planting treatments ranging from a double disk system to no-till planting were evaluated using replicated plots on a silt loam soil in the Nora Series having a 10% slope.

Tillage and planting systems used in soybean residue from narrow spaced rows had soil erosion and soil erosion rates that were reduced by approximately 50% compared to the same systems used …

Soil Erosion From Tillage And Planting Systems Used In Soybean Residue: Part Ii - Influences Of Row Direction, Paul J. Jasa, Elbert C. Dickey, David P. Shelton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A rainfall simulator was used to compare soil losses from tillage and planting systems used in residue from soybeans. The study was conducted on a silty clay loam soil in the Wymore Series with a 5% slope and on a silt loam soil in the Nora Series with a 10% slope. Tillage and planting treatments, ranging from a moldboard plow system to no-till planting, were evaluated both up and- down hill and on the contour using replicated plots.

For the first rainfall event after tillage and planting, the average soil loss for all systems on the contour was 3.0 t/ha …

Review And Evaluation Of Current Design And Management Practices For Land Treatment Units Receiving Petroleum Wastes, J. P. Martin, Ronald C. Sims, J. Matthews

Biological Engineering Faculty Publications

Land treatment is categorized in the Resource Conservation and Recovery Act of 1976 (RCRA) as one of the land disposal options for managing hazardous wastes. Land treatment relies on detoxification, degradation, and immobilization of hazardous waste constituents within the defined treatment zone to ensure protection of surface water, groundwater, and air. Under the authority of Subtitle C of RCRA, the U.S. Environmental Protection Agency has promulgated regulations governing the treatment of hazardous wastes in land treatment units (40 CRF, Part 264, Subpart M, July, 1982).

This paper describes the land treatment practices used by petroleum waste land treatment facilities in …

Hydraulics Of Perforated Irrigation Trail Tube, John E. Gilley, Jan Feyen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The author presented a methodology for calculating the hydraulics of trail tubes for center-pivot irrigation systems. While he mentioned several possible difficulties with trail tube irrigation, and stated that they have potential benefits in energy saving and improvements in water-use efficiency, additional clarification and analysis are required before the procedures he presented can be used for the rational design of such systems.
First and most importantly, a potential error in the analysis should be mentioned and discussed. The author used the two-term infiltration model of Philip to describe the water intake beneath a center-pivot irrigation system. The assumption of one-dimensional …

Interril Soil Erosion, Part I. Development Of Model Equations, John E. Gilley, D. A. Woolheiser, D, B. Mcwhorter

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Equations describing overland flow depth, rainfall induced soil detachment and sediment transport capacity on interrill areas were identified. The Darcy-Weisbach equation which included a parameter for predicting flow resistance caused by rainfall was used to calculate depth of overland flow. Soil detachment was determined from an equation incorporating raindrop induced, impact pressure estimates. The product of a soil transport factor, bottom shear stress and flow velocity was used to calculate sediment transport capacity. Nondimensional forms of the model equations were evaluated using existing experimental data.

Interril Soil Erosion, Part Ii. Testing And Use Of Model Equations, John E. Gilley, D. A. Woolhiser, D. B. Mcwhorter

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Laboratory measurements were made of interrill erosion as affected by varying overland flow discharge and slope slope steepness. Soil detachment and sediment transport capacity relations were then evaluated using experimentally obtained information.

The model equations were utilized to further characterize interrill soil erosion. The overland flow region over which the model equations are applicable for a disturbed Nunn clay loam soil was determined from laboratory tests and critical shear stress analyses. The influence of slope length on interrill erosion was also examined.

Soil Erosion From Tillage Systems Used In Soybean And Corn Residues, Elbert C. Dickey, David P. Shelton, Paul J. Jasa, Thomas Peterson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Rainfall simulation techniques were used to compare soil losses from various tillage systems used on plots where corn and soybeans had been grown the previous season. The two year study was conducted on a silty clay loam soil with a 5% slope and on a silt loam soil with a 10% slope. Five tillage treatments, ranging from a moldboard plow system to no-till, were evaluated for each residue at each site. Tillage and planting operations were conducted up-and-down hill on replicated plots. Total soil loss following 63.5 mm of rainfall applied during a 60 min period averaged more than 40% …

Estimating Crop Residue- Using Residue To Help Control Wind And Water Erosion, Elbert C. Dickey, John Havlin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The Importance of Conservation Tillage

Conservation tillage has been practiced for many years and is becoming increasingly popular with Nebraska farmers. Recent surveys show, about 8 of 19 million cropland acres in Nebraska were farmed with conservation tillage systems. Conservation tillage includes a variety of tillage and planting systems that leave at least 30 percent of the previous crop's residue on the soil surface after planting.

Knowing how to measure or estimate residue cover is an important facet of conservation tillage. A minimum requirement of cover on the soil surface is often specified for U.S. Department of Agriculture programs and …

Soil Compaction I Where, How Bad, A Problem, Elbert C. Dickey, Thomas Peterson, Dean E. Eisenhauer, Paul J. Jasa

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Soil compaction is a more common problem now than it was 15 years ago, regardless of the tillage system used. Producers now use heavier tractors, larger implements, bigger combines, earlier spring tillage, reduced tillage, and no-till planting systems.

While all of these have a potential to increase compaction, the major cause of the problem is conducting field operations when the soil is too wet. Most think about tilling wet soils in the spring as being the major problem, but harvesting a too-wet field in the fall can cause just as much compaction. Large combines and auger wagons can have loads …

Model And Production Function For Irrigation Management, Derrel L. Martin, Darrell G. Watts, James R. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A simulation model was developed to estimate the effect of deficit irrigation upon crop yield. The model was designed to provide relative yield estimates for numerous combinations of irrigation system, crop growth and irrigation management parameters. A daily soil moisture balance was used to predict evaporation and transpiration from which crop yields were estimated. Gross irrigation water requirements were estimated from net irrigation requirements, irrigation efficiencies, irrigation system limitations, and effective rainfall. Crop production functions that use physically defined parameters were also developed to relate crop yields to gross irrigation requirements. The production functions worked well on a limited test …

Suitability Of Reduced Pressure Center-Pivots, John E. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Selection criteria for reduced pressure center-pivot irrigation systems are developed. An analysis of the combined effects of the application rate characteristics or center-pivot irrigation systems and the Soil Conservation Service (SCS) soil intake family curves is used to determine the maximum depth of water which could be applied per irrigation for various types of soils and sprinkler packages. These irrigation depths are used to determine guidelines for proper selection of reduced pressure center-pivot systems. The results can be used as a general guide to determine if a particular system may have a runoff problem under a given situation.

Fuel Ethanol From Raw Corn, Curtis Weller, M. P. Steinberg, E. D. Rodda

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Crude amylase preparations were produced by growing Aspergillus awamori and A. niger on raw, ground, whole corn. These Koji preparations were used to hydrolyze the starch of raw, ground whole corn to sugars during simultaneous fermentation of the sugars to ethanol by distillers active dry yeast. Ethanol concentrations of the fermentation beers were determined with gas-chromatography. These fermentations yielded an average of 89.6% theoretical ethanol compared to control, conventional, fermentations that had an average of 89.9%. Carbon dioxide evolutions were determined with use of Alwood valves. The initial fermentation rate was greater for the conventional fermentation than the Koji fermentation. …