Nitrogen Research

CPNRD/UNL Demonstration Project

Practices that impede nitrogen fertilizer from leaching into the aquifer have been successfully demonstrated throughout the District.  Farmers from throughout the District with varying soils and conditions were recruited to work with the NRD in using the best management practices to demonstrate that nitrates can be managed efficiently and effectively while maintaining crop yields. As farmers began using the new tools, word of mouth spread the story of their effectiveness.

As new technology develops to help farmers practice better management, the District’s board modifies cost-share programs to accommodate new tools.  Initially, the emphasis was given to reducing the commercial fertilizer input by counting the contribution from residual sources. However, the leaching problem has two components: fertilizer and water.  Reductions in the amounts of applied water normally produce less leaching than just reduction of fertilizer inputs.  The Board decided to make the practice of monitoring well outputs mandatory in Phase II and Phase III.  Because research indicated that most farmers didn’t know how much water they were using during irrigation.

The Nitrogen and Irrigation Management Demonstration Project has been one of the longest existing demonstration projects in Nebraska and possibly the nation.  Other state and national demonstration projects have been modeled after this educational effort that has been conducted in cooperation with the NRD. The Project was initiated in 1984 following the Hall County Water Quality Special Project.  The primary financial supporter for the project has been the NRD with grants exceeding $1.3 million since its initiation.

The Platte Valley Project includes parts of 11 counties in the central Platte Valley which includes the entire area of the CPNRD.  Within these boundaries, there are areas with groundwater nitrate-N concentrations in excess of 40 ppm, which are among the highest in Nebraska.  Due to a combination of coarse-textured soil, shallow groundwater, intense irrigation and over application of nitrogen on acres in corn production; nitrate contamination exists in a large portion of the NRD. With areas of the NRD exceeding the 10 ppm set by the EPA, the NRD was required to develop a groundwater management plan to address groundwater quality. In 1988, State of Nebraska requirements forced the NRD to develop regulations involving nitrogen application. This plan has addressed the contamination problem using a phased system based on the average nitrate-N found within the NRD.

Over 350 demo sites have been located on producers’ cornfields in the project area. Randomized replicated levels of nitrogen application have been placed on most of these locations, usually in increments of 50 lbs. above and 50 lbs. below the calculated nitrogen recommendation, based on the University of Nebraska’s algorithm. These plot locations have provided a point of focus for over 290 field days and winter meetings.  Results from these field length, producer applied, and producer harvested plots have been instrumental in the adoption of water quality practices by the producers of the CPNRD.  Producer survey results taken in 1997 showed that 54% of producers responding tested irrigation water for nitrates, 34% used a nitrification inhibitor and 70% attended a tour or meeting on best management practices to protect water quality.

The project emphasis has changed over the years, as new technology becomes available to the agricultural sector. Evaluation and demonstration of these technologies are incorporated into the activities of the project.  Some of these technologies include use of ET Gage, watermark sensors for scheduling irrigation, soil moisture capacitance probes, application of a polymer material to an irrigated field to evaluate its effects on leaching of nitrate-nitrogen, evaluation and demonstration of slow-release or controlled release nitrogen fertilizer products, and nitrogen fixation using cover crops in seed corn. Extension and demonstration efforts in areas of irrigation management have also been a part of the project.  Such things as a demonstration surge trailer have been influential in the adoption of more efficient ways of irrigation.  The project coordinator, Dean Krull, has been working with the NRD since 1984 and has an office in the NRD headquarters. Krull also contributes articles in the NRD’s In Perspective newsletter to educate producers on results of the demonstrations and on best management practices.

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Crop & Irrigation Demand Network

Started in 2013, this program receives data collected with the Adcon Telemetry program which provides a vast amount of real-time data. Duane Woodward, hydrologist, and Dean Krull, UNL-CPNRD demo coordinator, contact producers who may be interested in the areas targeted in the pilot program.  The Program allows the NRD to view information such as water usage and soil moisture from fields where producers have installed telemetry meters.  The program also allows landowners the opportunity to check their own readings such as gallons per minute used, inches applied each day and throughout the season, and soil moisture readings through a website called McCrometer Connect. This advanced program was initiated through the NRD in 2013 with $60,000 budgeted for the project.

The NRD is planning the same level of funding and data collection the next 4 years with the goal to enhance and expand the program.  The District applied for but did not receive a Nebraska Environmental Trust grant in the amount of $427,000 that would be used to fund an expanded program over a 3-year period.  There were11 meters installed in 7 of the GMAs during the 2013 irrigation season.  To date, there are 30 data collection sites established in 10 of the 24 GMAs collecting daily water pumped, rainfall, system pressure, and at some of the locations soil moisture.  Partners include DNR, UNL Extension, Seim Ag Technology, CPNRD, and McCrometer.

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Airborne Electromagnetic Results

Jim Cannia, AquaGeo Frameworks, gave a final report on the Airborne Electromagnetic (AEM) survey saying the study provides the NRD with improved water table data and geological data. The Study will help the NRD to make determinations such as where additional wells may be drilled, where vadose zone and recharge monitoring may be needed, and where water table boundaries are located.

Airborne surveys are conducted with a helicopter and cover large areas quickly with minimal impacts to local activities and the environment. 3-D maps, produced by integrating airborne geophysics with other information, provide powerful tools for locating local features of the aquifer system important to water managers. These maps can be combined with a water table elevation map to provide the geometry of the aquifer including, locations of the most saturated thickness, heterogeneity of aquifer materials, recharge zones, lithologic barriers to groundwater flow, and connections to the surface water system.

Cannia said the survey team flew two to three flights per day at 100-150 feet above ground. The data was collected every 100 feet, providing better detail than current test-holes that provide data every six miles.

The maps also indicate where preferential flow paths may exist, which is particularly important for understanding base flow to streams and interpreting water quality samples in relation to the various stresses in the system. Ultimately, this information will be used to site wells, focused-recharge areas, facility construction, and many other areas of interest when considering the impact to the aquifer. This data will be used for the NRD’s groundwater models to do predictive analysis of management scenarios.

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PROJECT SENSE

Project SENSE (Sensors for Efficient Nitrogen Use and Stewardship of the Environment) is a collaborative effort between the University of Nebraska-Lincoln, the Nebraska Corn Board, five Natural Resources Districts (NRDs) in Nebraska, and producers participating in the Nebraska On-Farm Research Network. After three years in the field, Project SENSE  participants are seeing reduced nitrogen per acre and increased net return. Project SENSE focuses on improving the efficiency of nitrogen fertilizer use.  2018 Project SENSE Update

Contact Dean Krull, UNL/CPNRD project coordinator, for more information regarding Project SENSE at (402) 469-0155.

Project SENSE (Sensors for Efficient Nitrogen Use and Stewardship of the Environment) is a project focused on improving the efficiency of nitrogen fertilizer use.  It will implement 20 on-farm research sites each year, over the next 3 years.  Richard Ferguson, UNL Extension Soil Specialist, is leading the project which will focus on crop canopy sensors to direct variable-rate, in-season nitrogen application in corn.

Since 1988, the nitrate concentration in groundwater in Nebraska’s Central Platte River Valley has been steadily declining, largely due to the conversion from furrow to center-pivot irrigation.  However, over the last 25 years, fertilizer nitrogen use efficiency has remained static.  This trend points to the need for adoption of available technologies such as crop canopy sensors for further improvement in nitrogen use efficiency.  Strategies which direct crop nitrogen status at early growth stages are promising as a way to improve nitrogen fertilizer efficiency.

For more information please visit http://cropwatch.unl.edu/farmresearch/articlearchives/introducing-project-sense.