Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Retrospective Theses and Dissertations

Environmental Sciences

Agricultural and biosystems engineering

Articles 1 - 13 of 13

Full-Text Articles in Life Sciences

Integration Of Remote Sensing And Crop Growth Modeling For Nitrogen Management Decision Support In Corn , Kelly Robert Thorp Jan 2006

Integration Of Remote Sensing And Crop Growth Modeling For Nitrogen Management Decision Support In Corn , Kelly Robert Thorp

Retrospective Theses and Dissertations

This dissertation describes efforts to move toward a completely integrated remote sensing and crop growth modeling tool for developing precision nitrogen management recommendations for corn. Aerial hyperspectral remote sensing imagery collected throughout the 2004 growing season was used to estimate corn plant stand density, and a machine vision system was used to map corn population on the ground. Multiple linear regression analysis was used to assess the ability of all combinations of three reflectance bands to estimate corn plant population at resolutions of 2 m, 6 m, and 10 m. Coefficients of multiple determination of up to 0.82 were ...


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 ...


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 ...


Herbicide And Conservative Tracer Movement Through The Soil Profile And To Subsurface Drains Under No-Till And Chisel Plow Systems , Syed Imran Ahmed Jan 1999

Herbicide And Conservative Tracer Movement Through The Soil Profile And To Subsurface Drains Under No-Till And Chisel Plow Systems , Syed Imran Ahmed

Retrospective Theses and Dissertations

Adoption of conservation tillage has increased the role of macropore flow on the transport of agricultural chemicals to groundwater. Therefore, it is important to understand the role of macropore flow in the transport of water through the vadose zone and to the shallow groundwater. Two field studies were conducted at Iowa State University's Agricultural Research Center near Boone, Iowa, to determine the effect of two tillage practices (chisel plow and no-till) on the transport of herbicides and tracers, with applied water, through the soil profile and to the shallow groundwater. Two herbicides, atrazine [(6-chloro-N-ethyl-N-(1-methylethyl-1,3,5 triazine)-2-4-diamine ...


Use Of Site Specific Farming Systems And Computer Simulation Models For Agricultural Productivity And Environmental Quality , Allah Bakhsh Jan 1999

Use Of Site Specific Farming Systems And Computer Simulation Models For Agricultural Productivity And Environmental Quality , Allah Bakhsh

Retrospective Theses and Dissertations

Site specific farming systems have the potential to increase farmers' net income by reducing the use of agro-chemicals and applying variable rate technology for areas showing stable yield patterns. This study was designed to: (1) study yield patterns in given fields using variography; (2) seek correlation among soil attributes and yield data using GIS; and (3) simulate the effects of N-fertilizer and swine manure application rates on NO 3-N losses with subsurface drainage water and crop yields. The results of this study showed that the spatial correlation lengths were found to vary from 40 m for corn to about 90 ...


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 ...


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 ...


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 ...


A Spatial Decision Support System For The Analysis Of Environmental Impacts Of Integrated Crop-Livestock Production System , Dharmesh Kumar Jain Jan 1995

A Spatial Decision Support System For The Analysis Of Environmental Impacts Of Integrated Crop-Livestock Production System , Dharmesh Kumar Jain

Retrospective Theses and Dissertations

Recent shifts toward intensive and large confined livestock production units to enhance economic growth coupled with increased concerns for air, soil, and water quality have necessitated the development of computer-based management decision support systems for selecting environmentally sound production sites and for planning sustainable production systems. This dissertation describes the development and application of an interactive spatial decision support system that integrates a geographic information system, spatial and biophysical modeling, and a knowledge-based system into an interactive tool to facilitate planning and management of environmentally-sound livestock production. The spatial decision support can be used to select suitable watershed land areas ...


Modelling And Evaluation Of A Cistern-Based Ground-Coupled Heat Pump: Its Implications In Reducing Energy In A Commercial Swine Operation , James D. Leary Jan 1994

Modelling And Evaluation Of A Cistern-Based Ground-Coupled Heat Pump: Its Implications In Reducing Energy In A Commercial Swine Operation , James D. Leary

Retrospective Theses and Dissertations

This research details the analysis of a ground-coupled heat pump system which utilizes a 20,000 gallon well-water storage tank as a source of heating and cooling. It addresses the feasibility of such a system and discusses the system in terms of energy efficiency--first law conservation analysis. The potential use of this type of system for the control of sensitive thermal environments involving swine is also evaluated;The goal of this research was to investigate ISU's SNMRC heat pump system. Specific objectives were: (1) To evaluate the system in terms of heat exchanger and heat pump efficiencies. (2) To ...


Measurement And Simulation Of Water Table Management Effects On Groundwater Quality , Prasanta Kumar Kalita Jan 1992

Measurement And Simulation Of Water Table Management Effects On Groundwater Quality , Prasanta Kumar Kalita

Retrospective Theses and Dissertations

The goal of this study was to investigate the effect of various water-table management (WTM) practices on corn growth and yield and agricultural chemical concentrations in shallow groundwater. Field experiments were conducted for three years (1989-91) at the research sites near Ames and Ankeny. Water-table depths of 0.3, 0.6, and 0.9 m were maintained in field lysimeters at the Ames site, and variable water-table depths were maintained in a subirrigation field at the Ankeny site;Photosynthesis measurements were made regularly during the growing season, and yield data were collected at harvest. In 1989, a relatively dry year ...


Modeling Spatial Variability And Transport Processes In A Glacial Till Soil , Binayak Prasad Mohanty Jan 1992

Modeling Spatial Variability And Transport Processes In A Glacial Till Soil , Binayak Prasad Mohanty

Retrospective Theses and Dissertations

The objective of this study was to investigate the spatial variability of different physical and chemical properties of soils, and their role on transport processes of chemicals to groundwater sources in a glacial till soil of central Iowa;Measurements were made to determine the in-situ saturated hydraulic conductivity (K[subscript] sat) of a glacial till soil at sixty six sites in a tillage established plot. One hundred thirty-two data points on K[subscript] sat collected at two soil depths along two bisecting perpendicular transects, were used to develop semivariogram models, in conjunction with split-window median polish approach. Nested structure with ...


Efficient Herbicide Application To Reduce Environmental Losses , Steven Kent Mickelson Jan 1991

Efficient Herbicide Application To Reduce Environmental Losses , Steven Kent Mickelson

Retrospective Theses and Dissertations

A point-injection system has successfully been designed to inject and incorporate herbicides applied with water into the soil profile in a band. This point-injection cylinder (PIC) can incorporate herbicides in a single pass through the field while leaving the soil surface virtually undisturbed. The PIC functions effectively on both bare soil surfaces and soil surface covered with crop residue;The relative persistence of banded herbicides (alachlor, atrazine, and propachlor) using the PIC and a band sprayer was compared in a field study. A bare soil surface and a soil covered with an average of 79 percent corn residue were used ...