NU Water-Related Research in Clay 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 21 records found for Clay 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 Bernards, Mark
Unit Agronomy and Horticulture
Email mbernards2@unl.edu
Phone 402-472-1534
Web Page http://agronomy.unl.edu/bernards
Project Information
Title Water Use of Winter Annual Weeds
Other(s) Suat Irmak, Biological Systems Engineering, sirmak2@unl.edu 
Description

This study examines the water use of winter annual weeds. More winter annual weeds grow now than 20 years ago because of the adoption of reduced tillage systems, where the soil is not disturbed between harvest and planting. Winter annuals typically germinate in the fall, overwinter as small plants, and grow rapidly as temperatures warm in the spring; these weeds are especially well adapted to limited summer rainfall. Common winter annuals in Nebraska are downy brome, henbit, field pennycress, wild mustard, marestail (horseweed), foxtail barley, shepherdspurse, speedwell, and prickly lettuce. This project is investigating whether allowing winter annual weeds to grow too long in the spring depletes the soil of moisture that would benefit the crop later in the summer.

Estimated potential nitrogen immobilization by winter annual weeds may be calculated as:

  • 500 lbs/ac of winter annual biomass growth at planting time (this would be a relatively dense, uniform stand of weeds).
  • As a general statement, nitrogen composes approximately 3% of plant biomass.
  • $0.58/lb of nitrogen fertilizer (based on $950/ton of anhydrous ammonia)

Based on these assumptions, a dense, uniform stand of winter annuals could tie up approximately 15 lb of nitrogen per acre (500 x 0.03), or $8.70 per acre (15 x 0.58) of nitrogen intended for a corn crop.

Estimating the irrigation cost to replace water used by the same 500 lbs/A of winter annual biomass by assuming:

  • 500 lbs/A of winter annual weed biomass at planting time,
  • 800 lbs of water is required to produce 1 lb of winter annual weed biomass.
  • At $2.50 diesel fuel, applying 1 inch of irrigation water per acre would cost $9.66.

The 500 lbs of winter annual biomass would use 400,000 lbs of water per acre (500 x 800), or 47,920 gallons of water (400,000 lb x 0.1198 gal/lb). This equals 1.75 acre inches of soil water (47,920 gal /{27,158 gal/acre in}) used by these weeds. Based on a cost of $9.66 to apply 1 inch of irrigation water, it would cost approximately $17.00 per acre to replenish the water used by winter annual weeds in this scenario.

Project Support n/a
Project Website http://weedscience.unl.edu/
Report
Current Status Completed
Topic Crop Water Use
Project's Primary Contact Information
Name Hubbard, Kenneth
Unit High Plains Regional Climate Center
Email khubbard1@unl.edu
Phone 402-472-8294
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=55
Project Information
Title Data for Estimating Crop Water Use
Other(s) Ayse Kilic, School of Natural Resources, akilic@unl.edu 
Description

The University's High Plains Regional Climate Center (HPRCC) operates automated weather monitoring stations that take the essential information for calculating the Penman and Penman-Montieth reference evapotranspiration estimates. The estimates serve as the basis for estimating crop water use and as such are an essential element of the water budget for the hydrological cycle. These stations also monitor the soil moisture at four levels (10, 25, 50, and 100 cms) in the soil profile. The HPRCC is collecting hourly data from stations in Clay Center, Curtis, Holdrege, Imperial, McCook, Red Cloud, and Smithfield.

Project Support National Climatic Data Center
Project Website http://hprcc.unl.edu
Report
Current Status Continuing
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 Extension
Project's Primary Contact Information
Name Irmak, Suat
Unit Biological Systems Engineering
Email sirmak2@unl.edu
Phone 402-472-4865
Web Page http://bse.unl.edu/sirmak2
Project Information
Title South Central Agricultural Laboratory - Crop Water Use Research
Description

The South Central Agricultural Laboratory is a University of Nebraska research farm located about 15 miles east of Hastings immediately south of Highway 6. The primary focus of this farm is the development and refinement of irrigated crop production practices for Nebraska agriculture and beyond. A number of research projects are currently underway on site and in conjunction with producers in the region.

  1. Crop water use efficiency, nitrogen use efficiency, and best irrigation and fertigation management practices for subsurface-irrigated corn and soybeans.
  2. Measurement of soil evaporation under no-till, conventional (disk) till, and ridge till practices for corn using frequency-domain reflectometers under three irrigation frequencies and five irrigation levels for corn.
  3. Development of best deficit irrigation management strategies for soybeans.
  4. Center pivot irrigation engineering and evapotranspiration research: measurement of crop coefficients, evapotranspiration, and yield of corn under deficit irrigation settings.
  5. Measurement of crop water use and crop water use efficiency of eight corn hybrids under full and deficit irrigation and dryland settings.
  6. Measurement of maximum allowable crop water stress that can be imposed on corn, stress versus crop growth-yield- and available soil water relationships.
  7. Crop canopy temperature measurements to quantify crop water stress index for corn and soybeans.
  8. Measurements of hydraulics and uniformity coefficients, crop water use efficiency of a new low pressure irrigation system for soybeans.
  9. Measurement of energy fluxes and crop coefficients using high frequency techniques such as Bowen ratio energy balance system and Eddy covariance system to provide improved evapotranspiration data for corn, soybeans, and natural grassland.
  10. Measurement of non-growing (dormant season) evaporative losses to quantify annual evaporation and other water balance components.
  11. Operational characteristics of atmometers (ETgage) to measure reference evapotranspiration and Watermark granular matrix sensors to monitor soil water status and their practical applications and demonstrations for effective irrigation management.
  12. Rootworm pressure effect on crop water uptake under center pivot irrigation.
  13. On-farm demonstration of limited irrigation strategies for making maximum use of water resources. The project is being conducted in partnership with the NRCS and Nebraska Corn Board in Hordville, Geneva, York, Edgar, Ord, West Point, Schuyler, and Mead in grower fields.
Project Support Varies according to program and project
Project Website http://scal.unl.edu/
Report
Current Status Continuous
Topic Extension
Project's Primary Contact Information
Name Skipton, Sharon
Unit Southeast Research and Extension Center
Email sskipton1@unl.edu
Phone 402-472-3662
Web Page http://www.southeast.unl.edu/staffdir/Skipton_Sharon
Project Information
Title Southeast Research and Extension Center
Other(s) Gary Zoubek, York County Extension, gzoubek@unl.edu 
Description Each day University of Nebraska Extension makes a difference in the lives of adults and youth. The faculty and staff in the Southeast Research and Extension Center and the 28 County Offices work to bring relevant researched based information to people in communities, towns and urban centers. Our efforts rely increasingly on partnerships with government agencies, business, industry, schools and community organizations. Working together with our partners Extension strives to strengthen the social, economic and environmental base of Nebraska's communities. Our programs must be ever-changing as Extension listens and responds to issues as they evolve. The Southeast Research and Extension District is unique because it serves both urban and rural communities Nebraska. The faculty and staff are committed to bringing the resources of the University and its research based information to the individuals and communities of Southeast Nebraska.
Project Support Varies according to program and project - for more information see http://www.southeast.unl.edu/
Project Website http://www.southeast.unl.edu/
Report
Current Status Continuous
Topic Hydrology
Project's Primary Contact Information
Name Chen, Xun-Hong
Unit School of Natural Resources
Email xchen2@unl.edu
Phone 402-472-0772
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=19
Project Information
Title Investigation of Stream-Aquifer Hydrologic Relationship for Clear Creek in Polk and Butler Counties
Other(s) Weihong Dong, Jilin University; Zhaowei Wang, School of Natural Resources; Gengxin Ou, School of Natural Resources; Can Liu, School of Natural Resources, can.liu1989@huskers.unl.edu 
Description

Vertical hydraulic conductivities (Kv) of both streambed and point bars can influence water and solute exchange between streams and surrounding groundwater systems. The sediments in point bars are relatively young compared to the older sediments in the adjacent aquifers but slightly older compared to submerged streambeds. Thus, the permeability in point bar sediments can be different not only from regional aquifer but also from modern streambed. However, there is a lack of detailed studies that document spatial variability of vertical hydraulic conductivity in point bars of meandering streams. In this study, the authors proposed an in situ permeameter test method to measure vertical hydraulic conductivity of the two point bars in Clear Creek, Nebraska, USA. We compared the Kv values in streambed and adjacent point bars through 45 test locations in the two point bars and 51 test locations in the streambed.

The Kv values in the point bars were lower than those in the streambed. Kruskal–Wallis test confirmed that the Kv values from the point bars and from the channel came from two statistically different populations. Within a point bar, the Kv values were higher along the point bar edges than those from inner point bars. Grain size analysis indicated that slightly more silt and clay particles existed in sediments from inner point bars, compared to that from streambed and from locations near the point bar edges. While point bars are the deposits of the adjacent channel, the comparison of two groups of Kv values suggests that post-depositional processes had an effect on the evolution of Kv from channel to point bars in fluvial deposits.

We believed that the transport of fine particles and the gas ebullition in this gaining stream had significant effects on the distribution of Kv values in a streambed-point bar system. With the ageing of deposition in a floodplain, the permeability of point bar sediments can likely decrease due to reduced effects of the upward flow and gas ebullition.

Project Support Upper Big Blue Natural Resources District, Chinese Ministry of Education, National Natural Science Foundation of China
Project Website
Report Chen_Hydraulic_Conductivity.pdf
Current Status Completed
Pic 1 Project Image
Pic Caption 1 Map showing the study site in Clear Creek, Nebraska 
Pic 2 Project Image 2
Pic Caption 2 Schematic for the in situ permeameter test in the point bars 
Topic Hydrology
Project's Primary Contact Information
Name Chen, Xun-Hong
Unit School of Natural Resources
Email xchen2@unl.edu
Phone 402-472-0772
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=19
Project Information
Title Hydrologic Connections in the Big and Little Blue River Basins
Other(s) Cheng Cheng, School of Natural Resources, ccheng2@unl.edu 
Description Over extraction of groundwater near a stream can lower stream stage and induce streamflow depletion when the stream and aquifer are hydrologically connected. The Little Blue River Basin is an area of intensive groundwater development for irrigation, and the streamflow depletion in this basin was determined by an analog model (Emery, 1966). However, the post audit of the model (Alley and Emery, 1986) suggested that the decline of water-levels was overestimated and streamflow depletion was underestimated. Therefore, it is necessary to re-evaluate stream-aquifer interactions in the basin. In this study, an area is chosen for this analysis from the basin and three main streams -- the Little Blue River, Big Sandy Creek, and Spring Creek are included. Channel sediments and structures play an important role in determining stream-aquifer interactions. Firstly, field and laboratory methods including geoprobe logging and permeameter tests are utilized to investigate the channel deposits in the three main streams in the Little Blue River Basin. Results show that channels have low hydraulic-permeable layers which reduce their hydraulic connections to the adjacent aquifers. Secondly, a groundwater flow model is constructed to identify the hydraulic properties of the aquifer and evaluate streamflow depletion under groundwater withdrawals in the study area. Modeling results indicate that streamflow depletion is very low and aquifer storage loss is the main source of groundwater pumpage.
Project Support Upper Big Blue Natural Resources Distrect, Lower Big Blue Natural Resources District, Little Blue Natural Resources District
Project Website
Report
Current Status Completed
Topic Hydrology
Project's Primary Contact Information
Name Chen, Xun-Hong
Unit School of Natural Resources
Email xchen2@unl.edu
Phone 402-472-0772
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=19
Project Information
Title Groundwater Flow Model for Franklin County
Description

Dr. Chen conducted a pumping test in the alluvial aquifer near Bloomington and streambed tests in the Republican River channel. This data was used to develop a groundwater flow model in Franklin County to simulate the impact of groundwater pumping on stream flow.

Project Support n/a
Project Website
Report
Current Status Completed
Topic Hydrology
Project's Primary Contact Information
Name Eisenhauer, Dean
Unit Biological Systems Engineering
Email deisenhauer1@unl.edu
Phone 402-472-1637
Web Page http://bse.unl.edu/eisenhauer1
Project Information
Title Impacts of Land Terracing and Small Ponds on Basin Water Supplies
Other(s) Jim Koelliker, Biological and Agricultural Engineering, Kansas State University, koellik@ksu.edu; Derrel Martin, Biological Systems Engineering, dmartin2@unl.edu; Phil Barnes, Biological and Agricultural Engineering, Kansas State University, lbarnes@ksu.edu; Ayse Kilic, School of Natural Resources, akilic@unl.edu 
Description

Terraces in the Republican River Basin total about 2 million acres; about 15% of the basin above Hardy, Nebraska is terraced. The goal of this project is to better understand how on-farm conservation practices, specifically terraces and small ponds, affect the basin's water supplies. Data has been collected at five dryland fields near Culbertson, Curtis, and Stamford, Nebraska and Colby and Norton, Kansas. The Kansas sites are in areas where three main tributaries of the Republican River - Beaver, Sappa, and Prairie Dog creeks - flow toward Harlan County Reservoir. The field data collected will be used to determine if computer models created for the Republican River Basin accurately measure the impact of conservation terraces and small reservoirs on the basin.

Initial research results show:

  • About 16% of land in the Republican Basin is protected by terraces, and an equal number by small reservoirs
  • About 45% of runoff into a terrace channel goes to evapotranspiration (ET), 45% goes to groundwater recharge, and 10% overtops the terraces
  • Small reservoirs retain about 90% of inflow, most of which goes to groundwater recharge - little evaporation
  • Much overland flow is loss in transmission as recharge or ET from plants in the creek

Integrated values for the basin be completed by the end of 2010. For more information, see the following slides presented at the 2010 Greater Platte Basins Symposium:

Project Support U.S. Bureau of Reclamation
Project Website http://watercenter.unl.edu/PRS/PRS2010/Presentations/Eisenhauer%20Dean.pdf
Report
Current Status Continuing
Topic Hydrology
Project's Primary Contact Information
Name Harvey, F. Edwin
Unit School of Natural Resources
Email feharvey1@unl.edu
Phone 402-472-8237
Web Page http://eas.unl.edu/people/faculty_page.php?lastname=Harvey&firstname=Ed&type=ADJ
Project Information
Title Hydrologic Research in the Rainwater Basin Wetlands of South-Central Nebraska
Description

As part of this project, Harvey and his students are conducting research to unravel the hydrology of central Nebraska's Rainwater Basin wetlands. These wetlands are of international importance as habitat for millions of migratory water birds. In addition, these playa wetlands may contribute to groundwater recharge and water quality improvement. However, many of the wetlands have been drained, and those remaining suffer functional impairment due to sedimentation and pesticide and fertilizer runoff.

Most of the remaining Rainwater Basin wetlands are geographically isolated. Currently research is underway to investigate the role of these wetlands in providing groundwater recharge and water quality improvement. This is a significant environmental issue of concern because groundwater in this region is of vital importance, providing drinking and irrigation water. Moreover, groundwater levels are declining throughout much of the region. Levels of nitrate and atrazine exceed drinking water standards in some parts of the basin. Most of the remaining playa wetlands are impaired by sediment and there is an active program to restore the wetlands by removing this sediment. Study sites are located in Phelps, Kearney, Clay, Fillmore, and York counties (see map below).

Three components need to be measured when establishing a hydrologic budget for these closed basin wetlands which are surface storage, evapotranspiration (ET), and groundwater recharge. ET is calculated by the Bowen-Ratio Energy Budget (BREB) Method with the aid of a Bower Tower. Surface storage and recharge data will be aided by stilling wells and drive-point wells, respectively. Hydroperiods and plant community diversity are being determined before and after sediment removal to evaluate the impact of in-washed sediments on recharge and underlying groundwater quality. Chloride concentrations obtained from upland runoff collectors will be incorporated into the Chloride Mass-Balance Method along with precipitation and sediment chloride concentrations to obtain recharge fluxes for a wetland site.

Two Master's theses and one Bachelor's thesis have been completed as part of this project:

  • Wilson, Richard D. (2010), Evaluating Hydroperiod Response in the Rainwater Basin Wetlands of South-Central Nebraska, MS Thesis, UNL School of Natural Resources, 163 p.
  • Foster, Sarah E., (2010), Temporal and Spatial Variations of Ions, Isotopes and Agricultural Contaminants in Surface Waters and Groundwater of Nebraska’s Rainwater Basin Wetland Region, MS Thesis, UNL Department of Earth and Atmospheric Sciences, 185 p.
Project Support U.S. Environmental Protection Agency
Project Website http://snr.unl.edu/harvey/projectrainwater.htm
Report
Current Status Continuing
Pic 1 Project Image
Pic Caption 1 The Rainwater Basin area of Nebraska. 
Topic Hydrology
Project's Primary Contact Information
Name Woldt, Wayne
Unit Southeast Research and Extension Center
Email wwoldt1@unl.edu
Phone 402-472-8656
Web Page http://bse.unl.edu/wwoldt1
Project Information
Title Watershed Modeling System
Description Due to the highly connected nature of the water resources in the Republican River region, the significant increase in groundwater utilization for irrigation is suspected of inducing changes to the surface water system. These changes are exacerbated by drought conditions. Therefore, a greater understanding of the complex surface-groundwater system is very important for better management of water resources in the area. This project involves developing a watershed modeling system capable of simulating subsurface, overland, and stream flow in a fully integrated manner. This model considers various hydrogeological properties and therefore provides a more real picture of groundwater and surface water flow patterns and connections in the region. (This modeling system is different than traditional models such as ModFlow.) The objective of the research is to study the interaction processes of groundwater and surface water flow. The second objective is to progress toward simulating large-scale watersheds and significant amounts of data with increased time efficiency.
Project Support n/a
Project Website
Report
Current Status Underway
Topic Invasive Species
Project's Primary Contact Information
Name Huddle, Julie
Unit School of Natural Resources
Email jhuddle2@unl.edu
Phone 402-472-8556
Web Page http://snr.unl.edu/vitae/faculty/2011/huddle-julie-cv-11012010.pdf
Project Information
Title Effects of eastern redcedar on the hydrology of cottonwood stands in the Republican River Basin
Other(s) Tala Awada, School of Natural Resources, tawada2@unl.edu, Derrel Martin, Biological Systems Engineering, dmartin1@unl.edu, Xinhua Zhou, School of Natural Resources, xzhou3@kumc.edu, Sue Ellen Pegg, School of Natural Resources, spegg2@unl.edu, Scott Josiah, Nebraska Forest Service, sjosiah2@unl.edu 
Description

This study examines how much water trees use in different forests. In riparian forests, invasive plants affect the quantity of water infiltrating and running off land by intercepting water and transpiring water. Sap flow sensors are being used to monitor how removal of invasive tree species affects tree-level and stand-level evapotranspiration. In addition, vegetation transects will reveal how understory plants respond to invasive tree removal. Researchers are gathering data using eddy covariance towers and satellite images. Study results will be used to test whether removing eastern Red Cedar and Russian Olive Trees can significantly improve water yields.

In regards to the understory response following the removal of invasive woody species from a cottonwood riparian forest, this research shows that:

  • Removing invasive species increased the frequency of invasive form and warm season grasses.
  • Species diversity increased when invasive tree species were removed.
  • Changes in understory species following thinning were most pronounced where eastern redcedars were removed.
  • Light level differences observed under different canopy types likely explain differences in understory species response to thinning. This will be examined in future studies.
Project Support Burlington Northern Endowment, Nebraska Department of Natural Resources, Nebraska Natural Resources Districts in the Republican River Valley, Southwest Nebraska Resource Conservation and Development (RCandD) Council Inc., Nebraska Southwest Weed Management Area
Project Website
Report Photographs of Understory.pdf
Current Status Published in the Great Plains Research 2011 21: 49-71
Topic Production Agriculture
Project's Primary Contact Information
Name Ferguson, Richard
Unit Agronomy and Horticulture
Email rferguson1@unl.edu
Phone 402-472-1144
Web Page http://agronomy.unl.edu/ferguson
Project Information
Title Interactions of Water and Nitrogen Supply for Irrigated Corn across Field Landscapes
Other(s) Tim Shaver, West Central Research & Extension Center, tim.shaver@unl.edu; Nicholas Ward, Agronomy & Horticulture, ward.nick.c@gmail.com; Suat Irmak, Biological Systems Engineering, sirmak2@unl.edu; Simon van Donk, West Central Research & Extension Center, simon.vandonk@unl.edu; Daran Rudnick, Agronomy & Horticulture, daran.rudnick@huskers.unl.edu; Brian Wienhold, Agronomy & Horticulture, bwienhold1@unl.edu 
Description

Water and nitrogen (N) supply to a crop can interact throughout the growing season to influence yield potential. The increasing availability of variable rate irrigation systems to growers in irrigated regions, along with existing capacity for variable rate fertilization, provides the opportunity for temporal and spatial management of inputs of water and nitrogen. This study was initiated in 2011 to explore interactions of landscape and soil features with water and N inputs on grain yield and water and N use efficiency. Five field locations were used across Nebraska to evaluate the effects of landscape variation, climate, and capacity for temporal and spatial management of water and N. Preliminary results in 2011 showed that at sites with significant topographic variation these features influenced grain yield as much as the rate of irrigation water or nitrogen fertilizer, indicating the importance of considering spatial variation in landscape features when optimizing rates and timing of water and nitrogen.

Five field locations were used for the study in 2011. Two sites were at University of Nebraska-Lincoln (UNL) research laboratories the South Central Agricultural Laboratory (SCAL) and the Brule Water Resources Laboratory (BWL). Three sites were located on cooperating producer’s fields one in Morrill County, and two in Hamilton County. The UNL research sites included more detailed measurements, and inclusion of treatments that were more yield-limiting than those on producer fields. Locations were situated across a rainfall and soils gradient in Nebraska, allowing evaluation of site-specific water/N management interactions over a range of annual rainfall and soil types. Three of the sites included the use of variable rate irrigation systems and two of the sites implemented canopy sensor-based in-season N treatments.

Project Support John Deere
Project Website
Report Ferguson_Landscape.pdf
Current Status Completed
Pic 1 Project Image
Pic Caption 1 Study locations in 2011, with precipitation gradient across Nebraska 
Topic Riparian Vegetation Water Use
Project's Primary Contact Information
Name Lenters, John
Unit School of Natural Resources
Email jlenters2@unl.edu
Phone 402-472-9044
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=743
Project Information
Title Riparian Vegetation Impacts on Water Quantity, Quality, and Stream Ecology
Other(s) Kyle Herrman, University of Wisconsin - Stevens Point, Kyle.Herrman@uwsp.edu; Erkan Istanbulluoglu, University of Washington, erkani@u.washington.edu; Durelle Scott, Virginia Tech, dscott@vt.edu; Tiejun Wang, University of Washington-Seattle, tjwang@u.washington.edu 
Description

The State of Nebraska is attempting to aggressively manage invasive species along the riparian corridors of the Platte River and the Republican River. Although the impetus for the removal is different, in both basins state agencies and weed management districts are using herbicides and mechanical removal to control a combination of invasive species led by Phragmites australis (common reed), Tamarix ramosissima Ledeb. (saltcedar), and Elaeagnus angustifolia L. (Russian olive).

Along the central stretch of the Platte River, invasive species have overtaken sandbars and side channels which are invaluable wildlife habitat. In an attempt to reclaim this habitat for bird species such as the Piping Plover and Whooping Crane, the state is removing large stretches of common reed. Along the Republican River, the state is removing all invasive species to reduce riparian evapotranspiration. By reducing evapotranspiration the hope is to increase stream flow along the Republican River. Since 2007 invasive species along the mainstem of the river and along the banks of the Harlan Reservoir have been sprayed with herbicide or mechanically removed.

In order to understand the impacts of removing invasive species along riparian corridors researchers at the University of Nebraska-Lincoln and collaborators at other universities have developed a multi-faceted research project.

On the Republican River basin researchers are directly measuring evapotranspiration rates from native and invasive plants. Researchers are also using a regional water balance model to estimate the water savings that could be achieved by removing all invasive species within the basin.

On the Platte River researchers are monitoring water quality changes associated with a controlled herbicide treatment of common reed. Using a combination of in situ instruments and grab samplers researchers are determining the impacts of species removal. Other experiments are being conducted to measure how invasive species alter biogeochemical processes and sediment characterization.

Visit the project website for more information, including real-time meteorological data from a riparian wetland near the Republican River, real-time water quality data at a stream site on the Platte River, and quarterly project reports.

Project Support Nebraska Environmental Trust, University of Nebraska Rural Initiative, University of Nebraska Institute of Agriculture and Natural Resources
Project Website http://www.geosciences.unl.edu/riparian/
Report
Current Status

Final Report on Riparian Vegetation Impacts on Water Quantity, Quality, and Stream Ecology

Topic Riparian Vegetation Water Use
Project's Primary Contact Information
Name Martin, Derrel
Unit Biological Systems Engineering
Email dmartin2@unl.edu
Phone 402-472-1586
Web Page http://bse.unl.edu/faculty/Martin.shtml
Project Information
Title Estimation of Evapotranspiration from Riparian and Invasive Species Using Remote Sensing and in Situ Measurements in the Republican River Basin
Other(s) Ayse Kilic, School of Natural Resources, akilic@unl.edu; Suat Irmak, Biological Systems Engineering, sirmak2@unl.edu; Shashi Verma, School of Natural Resources, sverma1@unl.edu; Tala Awada, School of Natural Resources, tawada2@unl.edu 
Description

This study is using a combination of techniques including remote sensing, to develop reliable estimates of evapotranspiration from riparian zones and determine varying water use rates for typical and invasive species in the Republican River Basin. The project will provide datasets of evapotranspiration and the annual water balance for a range of conditions in the riparian areas along the Republican River. Specific deliverables of the project include:

  • Map of surface energy fluxes, including evapotranspiration, across three watersheds in the Lower, Middle and Upper Republican Natural Resources Districts for different spatial and temporal (i.e. daily, seasonal and annual) scales.
  • Map of riparian vegetation classification across three watersheds using high resolution remote-sensing and ground truth observations.
  • Comparison of water use and water availability on riparian vegetation and adjacent treated research area by measuring evapotranspiration rates, using various methods.
  • Data for planners and decision-makers to develop water management policies.
  • Extension and education materials to inform and communicate results to stakeholders.
Project Support Nebraska Department of Natural Resources
Project Website
Report
Current Status Underway
Topic Water Quality
Project's Primary Contact Information
Name Riens, John
Unit Wisconsin Ecological Services Field Office, U.S. Fish & Wildlife Service
Email John_Riens@fws.gov
Phone 541-885-2503
Web Page http://www.fws.gov/
Project Information
Title Macroinvertebrate Response to Buffer Zone Quality in the Rainwater Basin Wetlands of Nebraska
Other(s) W. Wyatt Hoback, Biology UNK, hobackww@unk.edu; Matt Schwarz, U.S. Fish & Wildlife Service 
Description

The Rainwater Basin is one of the most endangered wetland ecosystems in North America. This ecosystem is critical to many species including migratory waterfowl. Land use and runnoff from agriculture and cattle confinement operations are likely to be reducing the basin's health and diversity, however little information exists concerning macroinvertebrates. Twenty-two locations were assessed for water quality parameters, vegetation composition, and macroinvertebrates identified to genus. Samples were collected biweekly starting in April through July for three years. Macroinvertebrate diversity was impacted in areas with little buffer although the effects were not pronounced. Institution of a more effective vegetative buffers strip may reverse this trend to improve ecosystem quality and provide for invertebrate resources for migratory birds.

Click here to see a poster about this research

Project Support n/a
Project Website
Report
Current Status Completed
Topic Water Quality
Project's Primary Contact Information
Name Tang, Zhenghong
Unit Architecture
Email ztang2@unl.edu
Phone 402-472-9281
Web Page http://architecture.unl.edu/people/bios/tang_zhenghong.shtml
Project Information
Title Assessment of Sedimentation and Water Quality Conditions in the Rainwater Basin's Playa Wetlands
Other(s) Mark Kuzila, School of Natural Resources, mkuzila1@unl.edu; Xu Li, Department of Civil Engineering, xuli@unl.edu; Amy Burgin, School of Natural Resources, aburgin2@unl.edu 
Description

The overall goal of this project is to prioritize watershed restoration/acquisition programs in the Rainwater Basin (RWB) by examining playa wetlands’ sedimentation and water quality conditions using the Revised Universal Soil Loss Equation 2 (RUSLE2) and the fly ash technology.

Three specific tasks are included in this project:

  1. Calculate and map the sedimentation rates and the age of deposition for all playa wetlands in RWB
  2. Consolidate existing water quality data of the RWB playa wetlands and evaluate the key factors influencing playa wetland water quality
  3. Assess the effects of sedimentation control practices and prioritize future watershed restoration/acquisition programs

The final products of this project include:

  1. An atlas of wetland sedimentation maps and a risk report highlighting the areas in watersheds with the highest sedimentation rates
  2. A geodatabase and an evaluation report on the water quality conditions of the playa wetlands in the RWB
  3. A written assessment report for sedimentation control practices and a watershed index to prioritize future conservation/acquisition programs
Project Support U.S. Environmental Protection Agency
Project Website http://www.unl.edu/playawetlands/
Report
Current Status Underway
Topic Watershed Management
Project's Primary Contact Information
Name Knutson, Cody (advisor)
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 Stakeholder Perceptions of Water Supply Management and Sustainability in the Republican River Basin in Nebraska
Other(s) Ryan Bjerke, ryan.bjerke@huskers.unl.edu 
Description Due to a variety of human-induced and natural factors, water resources throughout the world will continue to face mounting challenges to their longevity and extent, and those within the Republican River Basin in Nebraska are no exception. Understanding the perspectives of water users is essential for developing informed and effective water resource policies and management plans. This study utilized a key informant sampling strategy in conjunction with in-depth telephone interviews to ascertain the perceptions of 32 key stakeholders in the Republican River Basin in Nebraska on concepts pertaining to water supply management and sustainability. The interview questionnaire was designed using a mixed methods approach that relied on qualitative and quantitative measures. Specifically, stakeholders were asked a series of questions to understand their perspectives on: the causes of water supply stress in the basin; what sustainable water management meant to them; the sustainability of water resources in the basin; and solutions that could be implemented to reduce water supply stress in the basin (e.g., financial, regulatory, infrastructure development, and water conservation and technical options). The study found a majority of individuals attributed ground water level declines to increased ground water use, more ground water users, and changing climate, while most believed surface water flow reductions were due to these factors in addition to soil and water conservation measures and increased near- and in-channel plant growth. Because of the need to maintain economic viability and protect water for future generations, water resource sustainability was very important to participants. Stakeholders thought solutions to water resources issues could be best achieved by employing a combination of: regulatory measures, like irrigated acreage and pumping limits; water conservation options, such as crop rotations and conservation tillage; and technological advancements, like more water-efficient irrigation systems and improved hybrids. Overall, eliciting stakeholder's perceptions on issues related to water supply stress and sustainability, along with potential solutions, may help inform policy and management decisions aimed at promoting water resource sustainability in the basin.
Project Support
Project Website
Report
Current Status Graduate thesis project completed December 2009 - thesis available at UNL CY Thompson Library (Call # LD3656 2009 .B547)
Topic Wetlands
Project's Primary Contact Information
Name Tang, Zhenghong
Unit Architecture
Email ztang2@unl.edu
Phone 402-472-9281
Web Page http://architecture.unl.edu/people/bios/tang_zhenghong.shtml
Project Information
Title Developing LiDAR-Derived Wetland Maps To Assess Conservation Design Practices For Playa Wetlands In Rainwater Basin
Other(s) Ed Harvey, School of Natural Resources, feharvey1@unl.edu; Xu Li, Department of Civil Engineering 
Description The overall goal of this project is to provide wetland managers with topographically-correct 3-D wetland maps to prioritize wetland conservation efforts and assess wetland conservation design practices. This project addresses three specific tasks for the playa wetlands: 1) Establish accurate, topographically-correct, 3-D wetland maps to relate weather conditions and wetland functions; 2) Develop a measurable Restorable Wetland Index to prioritize playa wetland and drainages conservation; 3) Assess wetland conservation design practices for watershed-based wetland conservation. This research will use high-resolution Light Detections And Ranging (LiDAR) data to create next-generation wetland maps for playa wetlands. The research provides the missing link in conservation design as these data will provide accurate elevation measures to delineate watershed extent and determine the impact of individual hydrologic modifications. This project will be one of the first to integrate LiDAR data and a hydrologic modifications datasets to find the relations of current weather conditions and wetland functions. This project provides reliable, accurate wetland spatial parameters to prioritize playa wetland conservation and assess the effectiveness of existing wetland conservation design practices. The wetland conservation design tools and protocols will be examined in two pilot counties in Nebraska. The intellectual merit of the research is based on advancing knowledge linkage of wetland mapping technologies and wetland function modifications, and showing how to adapt wetland conservation designs. The outputs from this project provide practical protocols for state/regional/local wetland managers and thus ensure "no net loss" in quality and quantity of wetlands.
Project Support US EPA
Project Website
Report
Current Status Completed