NU Water-Related Research in Lincoln County

The list below shows water-related research being conducted within your district or that affects your district. They are sorted by water topic, then by primary contact's last name.

Displaying 16 records found for Lincoln County


Topic Crop Nutrient Use
Project's Primary Contact Information
Name Wortmann, Charles
Unit Agronomy and Horticulture
Email cwortmann2@unl.edu
Phone 402-472-2909
Web Page http://agronomy.unl.edu/wortmann
Project Information
Title Nitrogen Use Efficiency of Irrigated Corn for Three Cropping Systems in Nebraska
Other(s) Charles Shapiro, Agronomy & Horticulture, cshapiro@unl.edu; Richard Ferguson, Agronomy & Horticulture, rferguson1@unl.edu; Gary Hergert, Panhandle Research & Extension Center, ghergert1@unl.edu 
Description

Overview Nitrogen fertilizer will continue to be indispensible for meeting global food, feed, and fiber needs. Voroneyand Derry (2008) estimated that 340 million Mg yr-1 N is fixed by natural means, including lightning and biological N fixation, and 105 million Mg yr-1 is fixed by human activities, including burning of fossil fuels and N fertilizer production, with N fixation by human activities expected to continue to increase. Townsend and Howarth (2010) estimated the amount of N fixed by human activities to be about 180 million Mg yr-1, with most used as mineral fertilizer. Fertilizer N production has important environmental implications with an average of ~2.55 kg CO2 emitted per kg fertilizer N fixed and transported (Liska et al., 2009). Th e amount of N applied is associated with emission of N2O (IPCC–OECD, 1997) and N accumulation in sensitive aquatic, marine, and terrestrial ecosystems (Groffman, 2008; Malakoff , 1998). Th e challenge is to produce more grain to meet growing global needs with high NUE.

Conclusions Across diverse production environments, high corn yields can be achieved with efficient use of soil and applied N and without high risk of NO3 -N leaching to groundwater. With excellent farm management, recovery of applied fertilizer-N in high-yielding corn fields of Nebraska was well above 60 to 70% at the economically optimal nitrogen rate (EONR), resulting in low residual soil nitrate nitrogen (RSN) levels. Agronomic efficiency and crop partial factor productivity (PFP), the Nitrogen use efficiency (NUE) components most closely related to profitability of production, can also be high at EONR. Less preplant and more in-season N application may be especially important for drybean (CD) which had low recovery efficiency (RE) and much postharvest RSN compared with corn (CC) and soybean (CS). The levels of NUE achieved in our study for CC and CS far exceed current national or regional means, demonstrating the potential for high NUE with high yield corn production. Further NUE efficiency may be gained through more accurate in-season N application such as with use of the presidedress NO3 test (Andraski and Bundy, 2002) and spatial variation in N rate in response to variation in crop need, such as through use of reflectance sensors (Scharf and Lory, 2009; Barker and Sawyer, 2010; Roberts et al., 2010).

Project Support Nebraska State Legislature, Nebraska Agricultural Business Association
Project Website
Report Wortmann_NUE.pdf
Current Status Completed
Topic Crop Water Use
Project's Primary Contact Information
Name van Donk, Simon
Unit West Central Research and Extension Center
Email svandonk2@unl.edu
Phone 308-696-6709
Web Page http://westcentral.unl.edu/web/westcentral/svandonk
Project Information
Title Determining the effect of the amount and timing of irrigation on corn production, using subsurface drip irrigation (SDI)
Description

It is important to learn how to grow crops with limited amounts of water and to determine crop water use with SDI. In 2007 a field study with corn was initiated that will be continued in 2008 and 2009. The treatments are:

  • Rainfed (no irrigation)
  • 0.50 ET (meet 50% of evapotranspiration requirements) throughout the season
  • 0.75 ET throughout the season
  • 1.00 ET throughout the season
  • no irrigation at first, 1.00 ET during 2 weeks around tasseling, then no more irrigation after that
  • 0.50 ET at first, 1.00 ET during 2 weeks around tasseling, then 0.50 ET after that
  • 0.50 ET at first, 1.00 ET during 3 weeks around tasseling, then 0.50 ET after that
  • 0.50 ET at first, 1.00 ET during 4 weeks around tasseling, then 0.50 ET after that
  • 0.75 ET at first, 1.00 ET during 4 weeks around tasseling, then 0.75 ET after that

Using SDI may not only increase water use efficiency, but also nutrient use efficiency when applying nutrients through the SDI system. This study was conducted at WCREC to assess the effect of different in-season nitrogen (N) application (via SDI) timings on corn production and residual soil nitrate-nitrogen (NO3-N). We evaluated the effect of three N application timing methods at two N application rates (UNL recommended rate and the UNL rate minus 20%) on corn grain, biomass yield, and end-of-study distribution of residual soil NO3-N.

In 2006, there were no significant differences in corn grain yields between the two N application rates. In 2007, the grain yield under the UNL recommended N rate was significantly higher (3.0 bu/ac) than under the UNL-minus-20% N rate. In both years, grain yield and biomass production for the N application timing treatments were not significantly different. The lack of response to different N application timing treatments indicates that there is flexibility in N application timing for corn production under SDI. This two-year field study was published in Soil Science.

Impact: This study helps us better understand the most appropriate times to apply N with SDI (underground fertigation). If applied at inappropriate times, nitrates are not used by the crop and may leach into groundwater. If N use is minimized, the producer's cost can be minimized.

Project Support n/a
Project Website
Report SDI_Corn_Yield.pdf
Current Status Completed
Topic Crop Water Use
Project's Primary Contact Information
Name van Donk, Simon
Unit West Central Research and Extension Center
Email svandonk2@unl.edu
Phone 308-696-6709
Web Page http://westcentral.unl.edu/web/westcentral/svandonk
Project Information
Title Effect of Crop Residue on Soil Water Content and Yield of Sprinkler-irrigated Corn
Other(s) Derrel Martin, Biological Systems Engineering, dmartin1@unl.edu; Suat Irmak, Biological Systems Engineering, sirmak2@unl.edu; Steve Melvin, Extension, smelvin1@unl.edu 
Description

The magnitude of soil water savings from reduced tillage with increased crop residue is unclear. This study was initiated in 2007 at North Platte to learn more about the effect of residue on soil water content and crop yield. Preliminary results show that soil water content was not much different under residue-covered soil as compared to bare soil; however, corn yield was significantly greater in the residue covered plots. Other research shows this greater amount of corn usually needs 2-4 inches of water to grow. This amount may be considered the water "savings" due to the residue.

This study will continue and focus on "real world" tillage systems where lower amounts of residue are associated with more tillage. A tillage pass will often result in loss of water by evaporation, since typically it brings moist soil to the soil surface. In addition, long-term no-till would increase infiltration and decrease run-off; reduced overwinter evaporation and increased snow trapping would also contribute to water conservation.

Project Support Anna H. Elliott Fund, administered by the University of Nebraska Foundation
Project Website
Report Crop_Residue_Cover_Effects.pdf
Current Status Completed
Topic Crop Water Use and Water Use Efficiency
Project's Primary Contact Information
Name Abunyewa, Akwasi
Unit Agronomy and Horticulture
Email akwasi_abunyewa@yahoo.com
Phone
Web Page
Project Information
Title Skip-Row and Plant Population Effects on Sorghum Grain Yield
Other(s) Richard Ferguson, Agronomy and Horticulture, rferguson@unl.edu; Charles Wortmann. Agronomy and Horticulture, cwortmann2@unl.edu; Drew Lyon, Panhandle Research and Extension Center, dlyon1@unl.edu; Stephen Mason, Agronomy and Horticulture, smason1@unl.edu; Robert Klein, West Central Research and Extension Center, rklein1@unl.edu 
Description This research conducted in Clay, Gosper, Frontier, Hayes, Center, Lincoln, Red Willow, and Cheyenne Counties from 2005 to 2007 evaluated the effect of skip-row configuration and planting population on sorghum grain yield and yield stability in nonirrigated, no-till fields. Results were not consistent or significant across the sites. Skip-row planting is expected to produce higher yields when growing season water is less than 26-27 inches, with conventional planting producing higher yields in wetter areas.
Project Support U.S. Agency for International Development to the International Sorghum and Millet Collaborative Research Support Program, Scholarship Secretariat, Government of Republic of Ghana
Project Website
Report Wortmann_Sorghum.pdf
Current Status Published Agron.J. 2010 102:296-302
Topic Drought
Project's Primary Contact Information
Name Knutson, Cody
Unit National Drought Mitigation Center
Email cknutson1@unl.edu
Phone 402-472-6718
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=430
Project Information
Title Republican River Basin Water and Drought Portal
Other(s) Mark Svoboda, NDMC, msvoboda2@unl.edu; Donna Woudenberg, NDMC, dwoudenberg2@unl.edu; Jae Ryu, jryu@uidaho.edu 
Description The National Drought Mitigation Center (NDMC) is developing a decision-support web portal for the Republican River Basin in Nebraska, Colorado and Kansas, with support from the managers and staff of the Lower, Middle and Upper Republican Natural Resources Districts (NRDs) in Nebraska. Under the terms of the two-year grant, the NDMC will collaborate with the NRDs to identify and compile local drought monitoring and planning information needed by resource managers in the basin, including government agencies, local community planners, and agricultural producers, and package it into a web portal. The portal will eventually be housed on the websites of the NRDs and can serve as a model for developing local applications of the National Integrated Drought Information System.
Project Support National Oceanic and Atmospheric Administration - Sectoral Applications Research Program
Project Website http://www.rrbdp.org
Report
Current Status Underway
Topic Economics
Project's Primary Contact Information
Name Schoengold, Karina
Unit Department of Agricultural Economics
Email kschoengold2@unl.edu
Phone 402-472-2304
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=731
Project Information
Title Analysis of Potential Groundwater Trading Programs for Nebraska
Description

The goals of a recently funded project to measure the potential benefits of developing a groundwater trading market in Nebraska is discussed in this Cornhusker Economics article. Groundwater is a major component of agricultural water use. In extensive regions of the Western United States, rural agricultural economies rely entirely on groundwater. At the same time as providing water for human needs, groundwater is also an input to streams, wetlands and riparian areas that provide important ecosystem services. Ongoing groundwater pumping will deplete flows in adjacent streams, leading to potential conflict between human and environmental uses of water. In the last decades, many conflicts over transboundary allocations of water, endangered species and instream and riparian habitat have been driven by surface water-groundwater interaction. For example, claims have been filed with the United States Supreme Court over the impacts of groundwater use on flows of transboundary rivers for the Pecos River (Texas vs. New Mexico), the Arkansas River (Kansas vs. Colorado) and the Republican River (Kansas vs. Nebraska and Colorado). Groundwater has typically been viewed as private property, and its use in agriculture is generally neither regulated nor quantified precisely. However, there is growing interest in moving to systems that regulate groundwater use. The ability to trade groundwater allocations is often a part of such conversations.

Project Support National Science Foundation; USDA
Project Website
Report Groundwater_Trading_Nebraska.pdf
Current Status Underway
Topic Extension
Project's Primary Contact Information
Name Melvin, Steve
Unit West Central Research and Extension Center
Email smelvin1@unl.edu
Phone 308-367-4424
Web Page http://www.frontier.unl.edu/
Project Information
Title Irrigation Strategies Field Tour Series
Other(s) Bill Kranz, Northeast Research and Extension Center, wkranz1@unl.edu; Charles Shapiro, Northeast Research and Extension Center, cshapiro1@unl.edu; Simon Van Donk, West Central Research and Extension Center, svandonk2@unl.edu; Derrel Martin, Biological Systems Engineering, dmartin1@unl.edu 
Description

The 2009 Irrigation Strategies Field Tour Series will focus on showing farmers and crop consultants management strategies to conserve water.

The tour topics, which vary by location, include: Water Resource Update; Comparing Irrigation Energy Sources: Costs and Emissions Requirements; Monitoring Crop Water Use and Soil Moisture Status - Simple, Durable, Accurate, and Economical Tools; Water Savings with Crop Residue Management; How the Amount of Water and Nitrogen Applied with a Center Pivot Affects Crop Yield; How to Get the Most from Your Nitrogen Dollar; Where Slow Release Nitrogen Fertilization Fits into Corn Production; Variable Rate Irrigation Equipment for Center Pivots; Predicting the Last Irrigation; and How Time of Application and Amount of Water Applied Affects Crop Yield.

In 2008 eleven field demonstrations, with thirteen field tours at the sites, were conducted around the state to teach irrigation options specifically adapted for Nebraska crops, soils, and irrigation issues. No-till water savings were shown at the Curtis site and at the Ainsworth site, and a demonstration showed producers how nitrogen losses due to drainage taking soluble nitrogen below the root zone can be prevented with correct water application.

The farmers participating in 2008 reported managing an average of 1,067 acres of irrigated cropland per farm. The average reported value of the knowledge gained by the producers completing the survey was $22,215 per operation. If this average was extended to all of the 160 producers attending, the value of the education gained would be more than $3.55 million per year. The reported potential water savings of 2.2 acre-inches/acre by the farmers would be a 15-20% savings from the typical irrigation water usage and if extended to the average farm size, would be more than 31,300 acre-feet/year. The other 40 people attending the tours also reported substantial knowledge gains that will help save water and increase returns per acre. Their occupations ranged from crop consultants, agri-business representatives, government agency personnel, etc. The acre influence/manage ranged from none to over 100,000 acres. This variation makes it difficult to determine the impact of their involvement, but it is very significant as well. For example, just the eight people that listed the acres they manage/influence (38,875 acres on average) and the value of the knowledge gained ($18.78/acre on average) would result in over $5.84 million per year.

Nine of the eleven irrigation demonstration sites were in farmer fields in 2008, and two were located on the NCTA farm. The plot locations included sites near Alma, Gothenburg, Axtell, Edison, Loomis, Ainsworth, Imperial, Benkelman, Upland, and Curtis (two sites). Two sites (Curtis and Loomis) had line-source sprinkler systems installed to demonstrate irrigation strategies for corn. All sites had soil-moisture-monitoring equipment and ET gauges installed for use at the field tours and to allow the producers and crop consultants to work with the equipment. The Ainsworth site demonstrated the relationship between varying amounts of nitrogen on irrigated corn. The data generated from the sites will also be used for Extension programs in the future.

Project Support U.S. Department of Interior - Bureau of Reclamation
Project Website http://water.unl.edu/irrigationtournews
Report
Current Status Continuing
Topic Extension
Project's Primary Contact Information
Name van Donk, Simon
Unit West Central Research and Extension Center
Email svandonk2@unl.edu
Phone 308-696-6709
Web Page http://westcentral.unl.edu/web/westcentral/svandonk
Project Information
Title West Central Research and Extension Center - Gudmundsen Sandhills Laboratory
Other(s) Jim Goeke, West Central Research and Extension Center, jgoeke1@unl.edu 
Description

The University of Nebraska West Central Research and Extension Center is a research and extension facility of the University of Nebraska Institute of Agriculture and Natural Resources (IANR). It serves as the site for field-based research and extension involving faculty and graduate students in eight IANR departments. West Central consists of approximately 1,800 acres of which 1,100 acres are in pasture with the remaining in dryland and irrigated cropping systems. West Central delivers research-based education and information to citizens throughout the state. Extension specialists and educators are committed to excellence, conducting educational programs customized to meet the needs of Nebraskans. These educational programs, delivered via a variety of methods, are offered through federal, state and county partnership arrangements and provide research-based information and other educational resources to the 20-county West Central district and beyond.

The Gudmundsen Sandhills Laboratory (GSL), a 13,000 acre working ranch in the Nebraska Sandhills, is also part of West Central. GSL is situated over a relatively small portion of the High Plains Aquifer where saturated thickness exceeds 1000 feet. GSL also features a valley with a live stream, a drained valley with wet meadows, an adjacent lake, dry valleys, and many dune types so that literally all the surface and groundwater locales in the Sandhills are represented and available for research. In 2004 a U.S. Climate Reference Network station was established at GSL to provide future long-term observations of temperature and precipitation accurate enough to detect present and future climate change.

Project Support Varies according to program and project - for more information see http://www.westcentral.unl.edu
Project Website http://westcentral.unl.edu/web/gudmundsen/
Report
Current Status Continuous
Topic Hydraulics
Project's Primary Contact Information
Name Szilagyi, Joe
Unit School of Natural Resources
Email jszilagyi1@unl.edu
Phone 402-472-9667
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=119
Project Information
Title Identifying Cause of Declining Flows in the Republican River
Description

The Republican River, shared by three states, Colorado, Nebraska, and Kansas, has yielded depleted streamflow at the Nebraska-Kansas border for about 20 years when compared to values preceding 1970. Based on model results estimating the average annual water balance of the basin, it is concluded that the observed decline in runoff cannot be explained by changes in climatic variables over the area; rather, it is the result of the combined effects of the following human activities: crop irrigation, change in vegetative cover, water conservation practices, and construction of reservoirs and artificial ponds in the basin. These human-induced changes have one property in common: they all increase the amount of water being evaporated over the basin, thereby reducing the amount of water available to runoff.

More about this research in the Journal of Water Resources Planning and Management

Project Support UNL School of Natural Resources
Project Website n/a
Report
Current Status Completed
Topic Hydrology
Project's Primary Contact Information
Name Admiraal, David
Unit Civil Engineering
Email dadmiraal2@unl.edu
Phone 402-472-8568
Web Page http://www.engineering.unl.edu/civil/faculty/DavidAdmiraal.shtml
Project Information
Title Flow Measurement of Power Plant Water Sources and Discharge Using Thermal Imaging
Description

Water flow measurements are necessary for a wide variety of environmental and energy related applications, such as thermal cooling water and irrigation flow measurements. Current water velocity and discharge measurement methods are generally costly since specially designed structures, placement of expensive equipment in non-secure locations or deployment of personnel are required. Remote sensing is a potentially viable alternative to collect accurate and reliable data of surface water properties at a relatively low cost; however, accurate methods to remotely measure velocity and discharge currently do not exist.

In order to find a relatively low cost and more effective alternative to current methods, a remote thermal imaging process was developed for this project. The remote system tracked the motion of thermal plumes and temperature variations on the surfaces of water bodies at power generation facilities. The tracked motions of the thermal structures were converted to surface velocity fields and ultimately to flow discharges. This project showed that it is feasible to accurately measure surface velocity in seeded flows, and it appears to be feasible to accurately measure surface velocity in unseeded flows, but a more robust algorithm will be important to reduce the effects of noise. The project research also showed that the coice of image interrogation algorithms and filtering can improve velo The results of this research have been valuable to power generation facilities because they allow the simultaneous measurement of water temperature and flow rates, two parameters that are monitored closely by environmental and regulatory agencies. A portion of this research was done in the Sutherland Reservoir and the Gerald Gentleman Station cooling pond.

Project Support Nebraska Public Power District through the Nebraska Center for Energy Sciences Research
Project Website http://www.ncesr.unl.edu/grants/energyresearch/7-02-21_9.pdf
Report
Current Status n/a
Topic Invasive Species
Project's Primary Contact Information
Name Narumalani, Sunil
Unit School of Natural Resources
Email snarumalani1@unl.edu
Phone 402-472-9842
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=85
Project Information
Title Detecting and Mapping Four Invasive Species along the Floodplain of North Platte River, Nebraska
Other(s) Deepak R. Mishra, University of New Orleans, dmishra@uno.edu; Robert G. Wilson, Panhandle Research and Extension Center, rwilson1@unl.edu; Patrick Reece, Panhandle Research and Extension Center, preece1@unl.edu; Ann Kohler 
Description

This research focused on the dominant invasive plant species in Nebraska, including saltcedar, Russian olive, Canada thistle, and musk thistle. Once established, these invasive species can have several harmful effects, such as increasing (1) soil salinity, which reduces productivity of native plants and results in the loss of natural habitat (Pimentel et al. 2000); (2) soil water consumption to such an extent that it can dry up streams and reduce water levels of rivers and lakes (Friederici 1995); (3) risk of wildfires during summer (Brooks et al. 2004); and (4) chances of flooding during high-intensity rainfall by impeding stream flow (Zavaleta 2000).

The study area was a corridor approximately 1.6 km wide and 257 km long located along the North Platte River starting at the Wyoming/Nebraska border and ending at Kingsley Dam on Lake McConaughy. The elevation ranges from 1,244 m above sea level at the Wyoming/Nebraska state line to 943 m, in an area below Kingsley Dam. The Platte River is generally considered to be a braided river with a network of small channels separated by large and small islands and sandbars. It has been noted that historically the banks of the Platte River were rarely covered with trees but instead with grasses and sedges (Farrar 1983; Kuzelka et al. 1993). Some of the islands were wooded, and willows (Salix exigua) and cottonwood (Populus deltoids) trees were observed. In the 1930s, Russian olive was introduced into the region for conservation plantings. It has rapidly spread along the Platte River, replacing willows and cottonwoods. More recently, saltcedar has also invaded the study area from the west and, along with Russian olive, occupies riverbanks, sandbars, and islands. Saltcedar seedlings are tolerant of shade and thrive in a variety of soil and moisture conditions, but especially saline soils.

When examined from a comprehensive perspective for the entire study area (22 flight lines) from the Nebraska/Wyoming Border to Kingsley Dam, invasive plants covered an area of 139,632 ha, of which 1,965 hectares (2% of the total area) were identified as saltcedar and 1,478 hectares (1.1% of the total area) as Russian olive. The three mixed classes occupied approximately 5% of the total area. These numbers indicate the severity of invasion of nonnative species along the North Platte River. Nonnative species such as saltcedar have been known to consume large quantities of water, and because western Nebraska is frequently affected by drought, mapping and monitoring their spread along the river corridor can aid in the implementation of biological, mechanical, chemical, or some combination of these control mechanisms to minimize the effects on water resources.

Effective control and management of an invasive species begins with its detection and inventory. The ability to detect invasive plants with the use of remotely sensed data has improved with new sensors, enhanced technology (e.g., hyperspectral), and innovative image processing techniques. However, datasets that have the highest likelihood of detecting invasive plants come with high fiscal and technical considerations. When compared with low-resolution multispectral data, airborne hyperspectral data is most appropriate for detecting subtle changes in the reflectance properties of various vegetation species present in the landscape (Narumalani et al. 2006).

Project Support n/a
Project Website http://snr.unl.edu/invasives/file/northplatte_sunil_deepak.ppt
Report Narumalani_Platte.pdf
Current Status Published in Weed Technology 2009 23:99-107
Topic Invasive Species
Project's Primary Contact Information
Name Narumalani, Sunil
Unit School of Natural Resources
Email snarumalani1@unl.edu
Phone 402-472-9842
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=85
Project Information
Title Predicting Potential Occurrence and Spread of Invasive Plant Species along the North Platte River, Nebraska
Other(s) Justin D. Hoffman; Deepak R. Mishra, University of New Orleans, dmishra@uno.edu; Paul Merani; Robert G. Wilson, Panhandle Research and Extension Center, rwilson1@unl.edu 
Description

Riparian habitats are important components of an ecosystem; however, their hydrology combined with anthropogenic effects facilitates the establishment and spread of invasive plant species. Researchers used a maximum-entropy predictive habitat model, MAXENT, to predict the distributions of five invasive plant species (Canada thistle, musk thistle, Russian olive, phragmites, and saltcedar) along the North Platte River in Nebraska. Projections for each species were highly accurate. Researchers studied a 1-mile wide buffer on either side of the North Platte River channel from the Wyoming-Nebraska state line to approximately 3.2 km west of North Platte. Field work was conducted in September 2005, March 2006, and May 2007.

Researchers found different distribution patterns among the species. Russian olive and thistles closely resembled each other in extent and variable contribution. While conducting field work, researchers repeatedly documented thistles below Russian olives or in close proximity. In addition, both species were commonly documented at varying distances from the river. Conversely, researchers found phragmites and saltcedar to have a more restricted potential distribution. Saltcedar was common throughout most of the study area except in the extreme eastern parts. The eastern edge of the study area approaches the distribution limit of saltcedar in Nebraska (Kaul et al. 2006; Wilson and Knezevic 2006). Phragmites was common in the eastern parts of the study area; however, there was low to no probability of phragmites occurrence in the west. Potential suitable habitat diminished just west of Lake MaConaughy, suggesting researchers have identified the western distributional limit of phragmites on the North Platte River and in Nebraska.

Variable contribution among all species was similar, with elevation and distance from river as the two most important variables for all species. The most probable underlying variable explaining the significance of distance from river is soil moisture. In most cases soil moisture will decrease as distance from river increases. Although soil moisture may be more directly responsible for the observed plant distributions, this variable is not easily estimated over large areas, unlike distance from river. There was a large disparity of elevation in the study area. The importance of elevation may be the result of the locations of the survey sites, underlying mechanistic variables, or both. Collection sites occurred at the elevational extremes. For Russian olive, thistle, and saltcedar, the lack of presence data at median elevations most likely caused MAXENT to weight that variable higher than others. The predictive model of phragmites also determined elevation to be the most important variable. Unlike the other species, no phragmites was documented at the western site. It is possible that phragmites can not survive at higher elevations because of colder temperatures found at these sites. However, Saltonstall (2002) found invasive haplotypes of phragmites occurring at high elevations in Wyoming and Utah, which does not support the previous hypothesis. A more likely explanation is that phragmities is in the process of expanding its range westward on the North Platte River and has not had enough time to disperse to the western parts of the river.

The results of this study have management implications for these species along the North Platte River, as well as other river ecosystems. For example, the variables used in this study resulted in excellent predictions of the distributions of invasive plants. As mentioned above, some of these variables (i.e., elevation and distance from river) may have underlying mechanistic factors that are more accurate measures of plant distributions. However, one of the utilities of the current approach is that these variables are easy to access and generate in a geographic information systems environment and useful predictions can be derived, which is not the case for some of their potential underlying factors. Also, predictive modeling shows limited areas of suitable habitat in the western parts of the North Platte River, primarily along the river channel. Researchers suggest that extensive monitoring be conducted in these areas to identify any populations that may occur there. Identification and control of these populations will significantly slow or stop the westward spread of phragmites. Also, any populations of phragmites that occur in the west should be relatively small and isolated making control of these populations more feasible. Similarly, abundances of saltcedar decreased in the eastern parts of the North Platte River. As with phragmites in the west, a control strategy should be used for saltcedar while populations are small and manageable. In addition, both species were found to occur close to the river bed, thus by monitoring the riverbanks and sandbars, the majority of populations could be identified within a very limited search area. Russian olive and thistles occur throughout the study area. Researchers suggest that control of these species should take place in areas with high probability of occurrence to prevent establishment of monotypic stands of each species.

Project Support U.S. Department of Agriculture - Animal and Plant Health Inspection Service
Project Website
Report Narumalani_Invasive.pdf
Current Status Published in Invasive Plant Science and Management 2008 1:359-367
Topic Production Agriculture
Project's Primary Contact Information
Name Supalla, Raymond
Unit Agricultural Economics
Email rsupalla1@unl.edu
Phone 402-472-1792
Web Page http://agecon.unl.edu/supalla
Project Information
Title Economic and State Budget Cost of Reducing the Consumptive Use of Irrigation Water in the Platte and the Republican Basins
Other(s) Brian McMullen, Agricultural Economics, bmcmullen2@unl.edu 
Description

The terms of the Cooperative Agreement for the Platte Basin and the Supreme Court settlement decision for the Republican Basin both require that Nebraska reduce its consumptive use of irrigation water. This analysis evaluated the economic and the budgetary costs of meeting these requirements. Both the on-farm and off-farm costs were evaluated for both land retirement and water allocation programs, implemented in several different ways, over three alternative time periods, 10, 25 and 50 years.

The on-farm economic costs were defined as the change in net farm income associated with less irrigation. Off-farm economic costs were defined as the statewide change in household income resulting from changes in irrigation, as the effects ripple through the Nebraska economy. Budgetary costs were defined as the cost to the state budget (taxpayers) of policies which compensate irrigators for reducing consumptive use are implemented. Statewide economic costs were found to be lower for land retirement than for allocation programs, assuming the same total change in consumptive use. Total budgetary costs depended primarily on: where the irrigation reductions occurred (proximity to river); on how long the program was continued (number of years), and on whether irrigation was reduced voluntarily with incentives, or by regulation, or by some combination of regulation and incentives. It was found that policy makers could minimize the cost of reducing consumptive use from irrigation and augmenting stream flow by purchasing rather than leasing irrigation rights, by using a regulatory rather than a willing seller incentive approach, and by reducing irrigation at locations close to the river.

More on this research in a UNL Agricultural Economics working paper

Project Support n/a
Project Website
Report
Current Status Completed
Topic Property Values
Project's Primary Contact Information
Name Shultz, Steve
Unit UNO Real Estate Research Center
Email sshultz@mail.unomaha.edu
Phone 402-554-2810
Web Page http://cba.unomaha.edu/dir/HomePageBio.cfm?id=347
Project Information
Title Ongoing UNO/UNL Research on the Determinants of Agricultural Land Values: How Irrigation Contributes to Land Values in Western and Central Nebraska
Other(s) Nick Schmitz, UNO Real Estate Research Center 
Description

Hedonic (mass appraisal) land valuation models were estimated in the Republican and Platte watersheds of Central and Western Nebraska. These models are based on assumption that the buyers and sellers of agricultural land are able to accurately assess the value of irrigation when negotiating sale contract prices, and that irrigation equipment can be distinguished from land and irrigation values. Alternative models were estimated using various combinations of explanatory variables (all measured at the parcel level of analysis). These include: soil productivity measures, topography precipitation, parcel size, cropping patterns, topography, aquifer thickness, well pumping capacity, distances to elevators and towns, and irrigation systems.

The location of all agricultural land sales statewide (2000-2007) and estimated irrigation values in the Platte and Republican Watersheds were identified. Preliminary mass appraisal model results were summarized in tables and the locations of retired irrigation parcels in the Republican Watershed (as part of a 2006 NE DNR and USDA Pilot Program) were identified. The value of irrigated cropland is on average $615/acre (this is the value of irrigated cropland only and does not include the value dryland corners within pivot systems). As well, there are numerous areas and site-specific parcels within the watershed with both lower and higher irrigation values. In fact, we have calculated irrigation values for all of the natural resource districts in the Republican watershed: they range from $488/acre to $948/acre. These estimates are still considered 'preliminary' and may be subject to revision. These irrigation values also do not account for premiums above and beyond marginal market values that farmers and landowners will likely require to willingly participate in future irrigation retirement programs.

More on this research in a journal of the Western Agricultural Economics Association

Project Support U.S. Department of Agriculture Water and Watershed Program
Project Website
Report
Current Status Complete (up to 2007)
Topic Water Quality
Project's Primary Contact Information
Name van Donk, Simon
Unit West Central Research and Extension Center
Email svandonk2@unl.edu
Phone 308-696-6709
Web Page http://westcentral.unl.edu/web/westcentral/svandonk
Project Information
Title Quantify the extent of vertical hormone movement through vadose zone soils
Description

The extent of exogenous hormone use in beef cattle production, in addition to endogenous hormones, increases the risk of hormone residues entering the environment when manure is applied to soil. This research will provide key information on the environmental fate of hormones commonly found in feedlot cattle manure. This information is critical in developing management practices for concentrated animal feeding operations and farms that will reduce environmental risks associated with land application of manure.

This research will be conducted using the specialized percolation lysimeters research site at the West Central Research and Extension Center during 2008 and 2009. The site contains fourteen percolation lysimeters installed at the center of each of fourteen field plots. Each plot is 40 ft m by 40 ft. Each lysimeter contains an undisturbed soil core with a diameter of 3 ft and a depth of 8 ft and has porous extractors at the bottom, which allows the extraction of leachate from unsaturated soil using a vacuum pump. These lysimeters have been used successfully for several nitrate-leaching experiments. Water samples, which represent the water that is leached from the crop root zone, can be collected at the bottom of these lysimeters and will be used to determine the amounts and types of hormones leaching below the crop root zone. Treatments will consist of treated stockpiled manure, treated compost manure, and a check (no manure application). The manures will be applied to the lysimeters and field areas adjacent to the lysimeters in the spring of 2008 at application rates to satisfy the nitrogen needs of corn based on University of Nebraska recommendations. The check plots will receive commercial nitrogen fertilizer to match the manure N availability. Three treatments and three replications (nine lysimeters in nine plots) will be used for this study.

Wheat will be planted in the lysimeters and adjacent plots during both years. Soil moisture from each plot will be measured weekly at 1 ft depth increments to a depth of 7 ft, using the neutron probe method. Water samples will be collected every three weeks from the lysimeters from April to November in both years. Soil samples will be collected at six depth increments down to a depth of 8 ft, four times between application and October in 2008, and three times from April to August in 2009. To reduce sampling errors created by spatial variability within each plot, five sub-samples will be taken from each depth. The sub-samples will then be mixed to create one composite sample. Background soil profile samples will be taken before the manure is applied. Sampling depths will be increased as needed, based on the confirmed movement of hormones of interest through the soil profile. Soil and leachate samples will only be taken during the periods when the ground is not frozen (April to November), when movement of water is expected.

Project Support n/a
Project Website
Report
Current Status Continuing
Topic Watershed Management
Project's Primary Contact Information
Name Jenkins, Allan
Unit Economics
Email
Phone
Web Page
Project Information
Title Middle Platte Socioeconomic Overview
Description This report was published in February 1999 and designed to provide a common body of knowledge to all groups engaged in decisions regarding the Platte River. Recognizing that different decision-makers have different levels of prior knowledge concerning the Platte River, the author attempted to create a document suitable for a range of audiences that also facilitated discussion.
Project Support U.S. Environmental Protection Agency
Project Website http://watercenter.unl.edu/PRS/PlatteRiverReports/The%20Platte%20Watershed%20Program.pdf
Report
Current Status Completed