1. Platte River – High Plains Aquifer (PR-HPA) Nebraska
ARDC, Mead (M)
Platte River – High Plains Aquifer (PR-HPA). Partnership between UNL and USDA- ARS (Agroecosyst. Manage. Res. Unit and Environ. Manage. Res. Unit )
Continental climate (MAP= 760; MAT=10°C)
Sharpsburg silty clay loam, (0- 2% slope), pH 6.6, SOM 2.8%
Elevation approximately 360 m
Irrigated and rain fed croplands and pastures
Agroecosystem Management Research Unit (AMRU); and USDA-ARS Environmental Management Research Unit (EMRU) Clay Center.

2. Proposed Treatments ‘Business as Usual’
Irrigated and rainfed maize-soybean rotation (since 2001)
Season long pasture grazing with yearling steers
‘Aspirational’ under development
Rotation grazing of paddocks with fertilized improved forage varieties.
Precision agriculture – variable rate irrigation and nutrient application based on readings from airborne and soil sensors
Integration of cover crops
PRHP Nebraska

3. Management Priorities
Crop and livestock production
Mitigation of Greenhouse gas fluxes
Nutrient and water use efficiency
Water quality and nutrients and water runoff
Biological diversity
Microbial activity and biodiversity
Economic and sustainability of cropping and livestock systems
Sustainable water and nutrient resource management (e.g. Variable Rate Irrigation)
Remote determination of agroecosystem productivity and responses to the environment
Adaptation and mitigation of climate change in agroecosystems
PRHP Nebraska

4. Unresolved Issues Design considerations Site security/integrity
Greenhouse gas flux measurements are currently possible at the microscale (chambers) and macroscale (eddy covariance). Need to determine methods for the medium scale (plot or paddock.
Site security/integrity
Land owned by UNL, and available for use for the LTAR. UNL is responsible for site security and access
Resource limitations
Ability to integrate and manage data flow and analysis (particularly image analysis), as well as assessing other ecosystem responses like NO and Methane, pollinators, insects and diseases, wildlife, biodiversity…etc.
PRHP Nebraska