Submitted to: Annual Water Resources Conference
Publication Type: Abstract Only
Publication Acceptance Date: 3/8/2020
Publication Date: N/A
Interpretive Summary: Abstract only
Technical Abstract: Land management and water quality are inherently linked to soil health, which is broadly defined as the productivity of agricultural systems and their impact on the environment. Due to spatial variability, edge of field (EoF) studies are limited because of the large number of water and soil measurements required to characterize the field. New approaches are needed to reduce laboratory preparation and analysis, reduce chemical waste, and to increase timeliness. Our work addresses the design, technical measurements, and statistical methodologies that can be used to link soil point measurements with summary measures of water quality. Specifically, this research employs radiometry to measure reflectance (across the 350 to 1200 nm region of the electromagnetic spectrum) of soil and water samples representing the spatial variability captured in our current parameterization experiment. The reflectance data are then used to develop predictive equations to provide measures of selected soil and water quality constituents from new samples. The experiment was conducted on the Water Resources and Erosion watersheds experiment (WRE) located at the USDA-ARS Grazinglands Research Laboratory El Reno, OK. The WRE contains 1.6 ha watershed treatments, representing paddocks in native warm season grasslands or winter wheat (Triticum aestivum) in highly disturbed or minimal tillage management. This research builds upon earlier efforts to measure and link environmental quality to specific land management practices. During the first 23 yr (1977-99), surface water quality data (runoff amount, suspended sediment, nitrogen and phosphorus) verified that reductions in disturbance coupled with retention of plant biomass significantly reduced soil and nutrient losses. In 2018, uniform zones of management representing variable characteristics affecting production within the larger watersheds were established to codify the collection of soil and water quality baseline data at variable scales within watersheds, managed as diversified adaptive crop livestock system. The use of radiometry enabled us to reduce the number of soil and water samples taken such that soil and water quality can simultaneously be monitored on the WRE with the aim of to determining the impact of conservation and land management practices on soil and water quality. Establishing this baseline will enable us to participate in NRCS EoF programming.