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Articles 511 - 540 of 698

Full-Text Articles in Physical Sciences and Mathematics

The Influence Of Nutrients And Physical Habitat In Regulating Algal Biomass In Agricultural Streams, Mark D. Munn, Jeffrey Frey, Anthony Tesoriero Jan 2010

The Influence Of Nutrients And Physical Habitat In Regulating Algal Biomass In Agricultural Streams, Mark D. Munn, Jeffrey Frey, Anthony Tesoriero

United States Geological Survey: Water Reports and Publications

This study examined the relative influence of nutrients (nitrogen and phosphorus) and habitat on algal biomass in five agricultural regions of the United States. Sites were selected to capture a range of nutrient conditions, with 136 sites distributed over five study areas. Samples were collected in either 2003 or 2004, and analyzed for nutrients (nitrogen and phosphorous) and algal biomass (chlorophyll a). Chlorophyll a was measured in three types of samples, fine-grained benthic material (CHLFG), coarse-grained stable substrate as in rock or wood (CHLCG), and water column (CHLS). Stream and riparian habitat were characterized at each site. TP ranged from …


Can R&D Investment Offset The Negative Impact Of Climate Change On Agricultural Productivity?, Nazrul Islam, Ruhul A. Salim Nov 2009

Can R&D Investment Offset The Negative Impact Of Climate Change On Agricultural Productivity?, Nazrul Islam, Ruhul A. Salim

Climate Science Published Reports

Productivity growth in agriculture helps maintain the nation's economic prosperity. However, long-run productivity growth in agriculture faces several challenges such as the potential worsening of climate due to global warming and the loss of productive land due to land use competition, salinity, wind erosion and soil acidity. Strategic policy making and appropriate funding for sustained productivity growth in agriculture is therefore crucial.

Research and development (R&D) to drive innovation is an acknowledged main source of productivity growth. The development and application of technologies generated through R&D boosts agriculture's productivity. Agricultural R&D activities in Australia and in most other developed economies …


Crop Yield Gaps: Their Importance, Magnitudes, And Causes, David B. Lobell, Kenneth G. Cassman, Christopher B. Field Oct 2009

Crop Yield Gaps: Their Importance, Magnitudes, And Causes, David B. Lobell, Kenneth G. Cassman, Christopher B. Field

Nebraska Center for Energy Sciences Research: Publications

Future trajectories of food prices, food security, and cropland expansion are closely linked to future average crop yields in the major agricultural regions of the world. Because the maximum possible yields achieved in farmers’ fields might level off or even decline in many regions over the next few decades, reducing the gap between average and potential yields is critical. In most major irrigated wheat, rice, and maize systems, yields appear to be at or near 80% of yield potential, with no evidence for yields having exceeded this threshold to date. A fundamental constraint in these systems appears to be uncertainty …


Applications And Potentials For Biogenic Methane Recovery Operations In Nebraska Agriculture, Industry, And Economic Development, David Micheal Dingman Jul 2009

Applications And Potentials For Biogenic Methane Recovery Operations In Nebraska Agriculture, Industry, And Economic Development, David Micheal Dingman

Department of Environmental Studies: Undergraduate Student Theses

ABSTRACT: This thesis report illustrates the applications and potentials of biogenic methane recovery in Nebraska’s agricultural and industrial sectors and as a means for increasing sustainable economic development in the state’s rural communities. As the nation moves toward a new green economy, biogenic methane recovery as a waste management strategy and renewable energy resource presents significant opportunities for Nebraska to be a national and world leader in agricultural and industrial innovation, advanced research and development of renewable energy technology, and generation of new product markets. Nebraska’s agricultural economy provides a distinct advantage to the state for supporting methane recovery operations …


Slides: Indian Water Rights, Robert T. Anderson Jun 2009

Slides: Indian Water Rights, Robert T. Anderson

Western Water Law, Policy and Management: Ripples, Currents, and New Channels for Inquiry (Martz Summer Conference, June 3-5)

Presenter: Robert T. Anderson, Native American Law Center, University of Washington Law School

19 slides


Slides: Status Of Southern Nevada Water Authority (Snwa): Third Intake Into Lake Mead And Groundwater Project, Kay Brothers Jun 2009

Slides: Status Of Southern Nevada Water Authority (Snwa): Third Intake Into Lake Mead And Groundwater Project, Kay Brothers

Western Water Law, Policy and Management: Ripples, Currents, and New Channels for Inquiry (Martz Summer Conference, June 3-5)

Presenter: Kay Brothers, Southern Nevada Water Authority (SNWA), Las Vegas, NV

37 slides


Slides: Northern Integrated Supply Project, Northern Front Range--Colorado, Don Carlson Jun 2009

Slides: Northern Integrated Supply Project, Northern Front Range--Colorado, Don Carlson

Western Water Law, Policy and Management: Ripples, Currents, and New Channels for Inquiry (Martz Summer Conference, June 3-5)

Presenter: Don Carlson, Northern Colorado Water Conservancy District

20 slides


Slides: Water Leasing In The Lower Arkansas Valley: The "Super Ditch Company", Peter Nichols Jun 2009

Slides: Water Leasing In The Lower Arkansas Valley: The "Super Ditch Company", Peter Nichols

Western Water Law, Policy and Management: Ripples, Currents, and New Channels for Inquiry (Martz Summer Conference, June 3-5)

Presenter: Peter NIchols, Trout, Raley, Montano, Witwer & Freeman, Denver, CO

28 slides


Slides: Finding Flows: Fish Still Need Water Everyday, Melinda Kassen Jun 2009

Slides: Finding Flows: Fish Still Need Water Everyday, Melinda Kassen

Western Water Law, Policy and Management: Ripples, Currents, and New Channels for Inquiry (Martz Summer Conference, June 3-5)

Presenter: Melinda Kassen, Director of the Western Water Project, Trout Unlimited

12 slides


Slides: Agricultural Resilience And Urban Growth: A Closer Look, William R. Travis Jun 2009

Slides: Agricultural Resilience And Urban Growth: A Closer Look, William R. Travis

Western Water Law, Policy and Management: Ripples, Currents, and New Channels for Inquiry (Martz Summer Conference, June 3-5)

Presenter: William R. Travis, Department of Geography, Center for Science & Technology Policy Research, CIRES, University of Colorado at Boulder

30 slides


The Use Of Soil Enzyme Activities And Active Carbon As Indicators Of Soil Quality In Response To Management Practices, Tracy Marie Woodruff May 2009

The Use Of Soil Enzyme Activities And Active Carbon As Indicators Of Soil Quality In Response To Management Practices, Tracy Marie Woodruff

Student Theses and Dissertations

In order to meet the increasing needs of food, fiber, and fuel, management practices that enhance the soil health must be sought out. The two studies conducted examined the effects of management practices on soil enzyme activities and active carbon concentration. A forested ecosystem in Oregon was examined following nutrient treatments on forest plots. The effects of tillage, residue management and time on soil enzyme activities and active C were measured in a greenhouse study from the University of Arkansas in Fayetteville, AR, USA. In both studies, β-glucosidase, arylsulfatase, acid phosphatase, and active carbon were analyzed in soil samples. Results …


Soil Organic Carbon And Site Characteristics In Aspen And Evaluation Of The Potential Effects Of Conifer Encroachment On Soil Properties In Northern Utah, Mical K. Woldeselassie May 2009

Soil Organic Carbon And Site Characteristics In Aspen And Evaluation Of The Potential Effects Of Conifer Encroachment On Soil Properties In Northern Utah, Mical K. Woldeselassie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In the Intermountain West, aspen (Populus tremuloides) has declined mainly due to a combination of successional processes, fire suppression and long-term use of ungulates which has led to replacement by conifers, sagebrush or other shrub communities. Conifer encroachment is believed to cause critical changes in the ecosystem properties. In order to understand the impacts of conifer encroachment on soil properties such as soil organic carbon (SOC) storage, soil morphology, and soil chemical properties, and the implications of such changes, it is very important to assess the soil properties under the two vegetation types. The objectives of this study …


Changes In Producer Attitudes Towards Windbreaks In Eastern Nebraska, 1983 To 2009, Kim Tomczak Apr 2009

Changes In Producer Attitudes Towards Windbreaks In Eastern Nebraska, 1983 To 2009, Kim Tomczak

Department of Environmental Studies: Undergraduate Student Theses

Abstract Windbreaks are rows of trees or shrubs arranged on the landscape to reduce wind speed. In agricultural landscapes we find them as farmstead windbreaks, livestock windbreaks and field windbreaks. While farmstead and livestock windbreaks are well accepted by the agricultural community, field windbreaks are often viewed differently. A 1982 study of the attitudes of farmers in Eastern Nebraska indicated that many of the producers were around the age of 50 and that they used different types of windbreaks. This study repeated that survey in the same. When compared to data from 1982, farmers today are not educated about the …


Historical Review Of Elk–Agriculture Conflicts In And Around Riding Mountain National Park, Manitoba, Canada, Ryan K. Brook Apr 2009

Historical Review Of Elk–Agriculture Conflicts In And Around Riding Mountain National Park, Manitoba, Canada, Ryan K. Brook

Human–Wildlife Interactions

Conflicts between elk (Cervus elaphus) and farmers have been occurring since the 1880s when agriculture began around what is now Riding Mountain National Park (RMNP). Initially, the conflicts were related to low elk numbers caused primarily by unregulated harvest of elk. The creation of RMNP in 1930 and the associated ban on hunting allowed elk numbers to reach critically high levels. Since farming began, elk have been associated with considerable damage to fences and crops around RMNP, with annual damage often >$240,000. Hunting on agricultural lands has been the most common approach to mitigating elk impacts, despite its limited success. …


Long-Term Agricultural Land-Use Trends In Nebraska, 1866–2007, Tim L. Hiller, Larkin A. Powell, Tim D. Mccoy, Jeffrey J. Lusk Jan 2009

Long-Term Agricultural Land-Use Trends In Nebraska, 1866–2007, Tim L. Hiller, Larkin A. Powell, Tim D. Mccoy, Jeffrey J. Lusk

School of Natural Resources: Faculty Publications

Although landscape changes from anthropogenic causes occur at much faster rates than those from natural processes (e.g., geological, vegetation succession), human perception of such changes is often subjective, inaccurate, or nonexistent. Given the large-scale land-use changes that have occurred throughout the Great Plains, the potential impacts of land-use changes on ecological systems, and the insight gained from knowledge of land-use trends (e.g., to compare to wildlife population trends), we synthesized information related to land-use trends in Nebraska during 1866–2007. We discussed and interpreted known and potential causes of short- and long-term land-use trends based on agricultural and weather data; farm …


Land Resources Series No 21 - Tambellup-Borden Area Land Resources Survey, Angela Stuart-Street, Rohan Marold Jan 2009

Land Resources Series No 21 - Tambellup-Borden Area Land Resources Survey, Angela Stuart-Street, Rohan Marold

Natural resources published reports

AGDEX 526

Land Resources Series No. 21

This report presents results from soil-landscape mapping at a scale of 1: 100,000 in the Tambellup- Borden area of Western Australia. It is accompanied by a soil-landscape map covering almost 511,000 hectares.

Most of the survey occurs within the upper Frankland-Gordon, Kent, North Stirlings Basin and upper reaches of the Pallinup and Kalgan River catchments. The survey falls within the Katanning and Albany Department of Agriculture and Food advisory districts.

Seventeen soil-landscape systems have been identified and are represented on the map on the accompanying CD-ROM. These systems have been further divided into …


Slides: Lower Arkansas Valley Super Ditch Company, Inc.: Water Leasing Program, Peter Nichols Dec 2008

Slides: Lower Arkansas Valley Super Ditch Company, Inc.: Water Leasing Program, Peter Nichols

Evolving Regional Frameworks for Ag-to-Urban Water Transfers (December 11)

Presenter: Peter Nichols, General Counsel of the Lower Arkansas Valley “Super Ditch” Company, Trout, Raley, Montano, Witwer & Freeman PC, Colorado

33 slides


Slides: Idaho Rental Pool: Rules And Procedures, Idaho Water Resource Board, Jerry R. Rigby Dec 2008

Slides: Idaho Rental Pool: Rules And Procedures, Idaho Water Resource Board, Jerry R. Rigby

Evolving Regional Frameworks for Ag-to-Urban Water Transfers (December 11)

Presenter: Jerry Rigby, Counsel for Fremont‐Madison Irrigation District, Rigby, Thatcher, Andrus, Rigby & Moeller, Idaho

25 slides


Agenda: Evolving Regional Frameworks For Ag-To-Urban Water Transfers, University Of Colorado Boulder. Natural Resources Law Center, Western Water Policy Program, Western Water Assessment (Program), Red Lodge Clearinghouse Dec 2008

Agenda: Evolving Regional Frameworks For Ag-To-Urban Water Transfers, University Of Colorado Boulder. Natural Resources Law Center, Western Water Policy Program, Western Water Assessment (Program), Red Lodge Clearinghouse

Evolving Regional Frameworks for Ag-to-Urban Water Transfers (December 11)

The permanent transfer of water from agricultural users to municipalities has become a common feature of water management in several western states. In many cases, these voluntary market‐based transfers provide significant benefits to both the buyers and sellers, but many third parties—including remaining irrigators, rural businesses and communities dependent upon agricultural economies—have been negatively impacted. While some impacts of these so‐called “buy and dry” transfers are largely unavoidable, many can be lessened by temporary arrangements that only shift water to cities in years when municipal supplies are inadequate, such as drought and post‐drought storage recovery, and by consolidating individual farm‐to‐city …


Slides: Pvid/Mwd Land Management, Crop Rotation And Water Supply Program, Ed Smith Dec 2008

Slides: Pvid/Mwd Land Management, Crop Rotation And Water Supply Program, Ed Smith

Evolving Regional Frameworks for Ag-to-Urban Water Transfers (December 11)

Presenter: Ed Smith, General Manager, Palo Verde Irrigation District, Southern California

25 slides


Hydrological Characterization Of A Riparian Vegetation Zone Using High Resolution Multi-Spectral Airborne Imagery, Osama Zaki Akasheh Dec 2008

Hydrological Characterization Of A Riparian Vegetation Zone Using High Resolution Multi-Spectral Airborne Imagery, Osama Zaki Akasheh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Middle Rio Grande River (MRGR) is the main source of fresh water for the state of New Mexico. Located in an arid area with scarce local water resources, this has led to extensive diversions of river water to supply the high demand from municipalities and irrigated agricultural activities. The extensive water diversions over the last few decades have affected the composition of the native riparian vegetation by decreasing the area of cottonwood and coyote willow and increasing the spread of invasive species such as Tamarisk and Russian Olives, harmful to the river system, due to their high transpiration rates, …


Optimal Irrigation Management For Sloping, Blocked-End Borders, Jorge Jose Escurra Dec 2008

Optimal Irrigation Management For Sloping, Blocked-End Borders, Jorge Jose Escurra

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A robust mathematical model of one-dimensional flow for sloping, blocked-end border irrigation was developed using the four-point implicit method to solve the Saint-Venant equations, the volume-balance solution method, and the implementation of new algorithms to avoid numerical instability and solution divergence. The model has the capability of successfully simulating all surface irrigation phases in blocked-end borders for a range of inflow rates (0.01 - 0.05 m3/s per m), longitudinal slopes (up to 1.00%), and border lengths (100 - 500 m).

To achieve numerical stability over the specified parameter ranges, the model was divided into three parts: (1) advance-phase …


Non-Blackbird Avian Occurrence And Abundance In North Dakota Sunflower Fields, Dionn A. Schaaf, George M. Linz, Curt Doetkott, Mark W. Lutman, William J. Bleier Sep 2008

Non-Blackbird Avian Occurrence And Abundance In North Dakota Sunflower Fields, Dionn A. Schaaf, George M. Linz, Curt Doetkott, Mark W. Lutman, William J. Bleier

The Prairie Naturalist

Sunflower fields are well-documented as foraging habitat for fallmigrating blackbirds (Family Icteridae). There is, however, a paucity of information on the use of sunflower fields by non-blackbirds. We assessed non-blackbird use of 12 ripening sunflower fields in the Prairie Pothole Region of central North Dakota. From mid-August to mid-October 2000, we counted 4,129 individual birds, consisting of 22 families and 61 species, in the sample fields and within 5 m of the field edges. We saw the largest number of birds from 18 September to 27 September. The Family Emberizidae (sparrows) accounted for 26% of the species and 20% of …


Effects Of Global Irrigation On The Near-Surface Climate, William J. Sacks, Benjamin I. Cook, Nikolaus Buenning, Samuel Levis, Joseph H. Helkowski Jul 2008

Effects Of Global Irrigation On The Near-Surface Climate, William J. Sacks, Benjamin I. Cook, Nikolaus Buenning, Samuel Levis, Joseph H. Helkowski

United States National Aeronautics and Space Administration: Publications

Irrigation delivers about 2,600 km3 of water to the land surface each year, or about 2% of annual precipitation over land. We investigated how this redistribution of water affects the global climate, focusing on its effects on near-surface temperatures. Using the Community Atmosphere Model (CAM) coupled to the Community Land Model (CLM), we compared global simulations with and without irrigation. To approximate actual irrigation amounts and locations as closely as possible, we used national-level census data of agricultural water withdrawals, disaggregated with maps of croplands, areas equipped for irrigation, and climatic water deficits. We further investigated the sensitivity of …


Traditional Natural Resource Use And Development In Northeast Thailand, Christie Moulton May 2008

Traditional Natural Resource Use And Development In Northeast Thailand, Christie Moulton

Senior Honors Projects

This paper explores the effects of development projects on traditional natural resource use in three communities in Northeast Thailand, a region known as Isan. I interviewed villagers in each community and asked them to describe their environmental perceptions, management practices and livelihood strategies. Participants described several subsistence livelihoods that have traditionally been present in Isan. These include rice farming, fishing, community forestry, and wetland use. Residents from the three communities all described various cultural activities, knowledge systems, and religious ceremonies that are closely tied to their local resources. Raising silk worms, making clay pots, and performing rituals for a spirit …


A New Methodology To Map Irrigated Areas Using Multi-Temporal Modis And Ancillary Data: An Application Example In The Continental Us, Mutlu Ozdogan, Garik Gutman Apr 2008

A New Methodology To Map Irrigated Areas Using Multi-Temporal Modis And Ancillary Data: An Application Example In The Continental Us, Mutlu Ozdogan, Garik Gutman

United States National Aeronautics and Space Administration: Publications

We present a dryland irrigation mapping methodology that relies on remotely sensed inputs from the MODerate Resolution Imaging Spectroradiometer (MODIS) instrument, globally extensive ancillary sources of gridded climate and agricultural data and on an advanced image classification algorithm. The methodology involves four steps. First, we use climate-based indices of surface moisture status and a map of cultivated areas to generate a potential irrigation index. Next, we identify remotely-sensed temporal and spectral signatures that are associated with presence of irrigation defined as full or partial artificial application of water to agricultural areas under dryland conditions excluding irrigated pastures, paddy rice fields, …


Sustainability In A Time Of Climate Change: Developing An Intensive Research Framework For The Platte River Basin And The High Plains Proceedings From The 2008 Climate Change Workshop, Monica Norby, Ashley Washburn Jan 2008

Sustainability In A Time Of Climate Change: Developing An Intensive Research Framework For The Platte River Basin And The High Plains Proceedings From The 2008 Climate Change Workshop, Monica Norby, Ashley Washburn

Office of Research and Economic Development: Publications

Proceedings from the 2008 Climate change Workshop, Nebraska Sandhills, May 19-22, 2008. Hosted by the University of Nebraska–Lincoln and the U.S. Geological Survey


Wheat Invest. A Compelling Business Case For Investment In The Western Australian Wheat Industry, Department Of Agriculture And Food, Western Australia Jan 2008

Wheat Invest. A Compelling Business Case For Investment In The Western Australian Wheat Industry, Department Of Agriculture And Food, Western Australia

Farm Systems and Economics published reports

Western Australia (WA) is an ideal location for wheat production. It has competitive advantages including:

• A proven track record in wheat production accounting for approximately 50 per cent of Australia's production. Based on a five year average from 2003/04 to 2007/08*, WA produces around 7.7 million tonnes of wheat per year.

• Over the past five years, the top 25 per cent of farmers averaged 10 per cent return on capital excluding changes in land value.

• Export focussed due to WA's small population. 90 per cent of WA's wheat is exported

• Abundant land at competitive prices and …


A Century Of Land Use And Water Quality In Watersheds Of The Continental U.S., Whitney P. Broussard Iii Jan 2008

A Century Of Land Use And Water Quality In Watersheds Of The Continental U.S., Whitney P. Broussard Iii

LSU Doctoral Dissertations

Human endeavors, particularly the agricultural and industrial activities of the last half century, now produce more biologically available nitrogen (N) than all other natural sources combined. The increased N availability can have consequences for the health of aquatic biota on the local, regional, and global scales. One manifestation of this problem is the formation of coastal hypoxic zones where terrestrial N loading creates eutrophic conditions in coastal waters. This dissertation examines a century of changes in land use and water quality to quantify the relationships between agricultural land use practices and riverine N yields in the Mississippi River Basin and …


Hydrogeochemistry And Water Quality Of Echo Hills, Joel M. Kimball Jan 2008

Hydrogeochemistry And Water Quality Of Echo Hills, Joel M. Kimball

Browse all Theses and Dissertations

Ground water of the Echo Hills area in Clark County, Ohio was investigated for common water contaminants such as nitrate and coliform bacteria. Thirty-four water samples were collected from locations including private wells, streams and a spring. Nine of those samples were selected for nitrogen isotope analysis. Three locations were chosen for a tracer test. Additionally, well log data, historical water quality data, and GIS data were obtained from the Clark County Health Department in Springfield, Ohio. Results show that local agriculture likely has the greatest impact on ground water quality in Echo Hills especially the north-eastern portion, with local …