1.
What We Monitor For and What We Learn
at Different Monitoring Scales
Kevin King
USDA-ARS
Soil Drainage Research Unit
Columbus, OH
Nutrient Management and Edge of Field Monitoring; Memphis, TN; Dec 3, 2015

2.
Plots and Lysimeters
(processes)
Edge-of-field
(MRBI & GL EOF & 4R)
Watershed
(SWPI, CEAP and 4R)

3.
Sample
collection Suction cup
lysimeter
Tile
Pan lysimeter
Suction cup lysimeters
sample slowly moving water
in soil pores and the bulk
soil matrix
Pan lysimeters
sample fast, free draining
water (preferential flow paths)
Using lysimeters to quantify P transport
to tile drains

4.
What have we learned thus far:
20-80% of tile flow can be attributed to preferential flow
Phosphorus concentrations measured from pan and suction cup lysimeters were not
significantly different. DRP range: 0.01 to 0.18 mg/L; TP 0.02 to 0.52 mg/L.
Median DRP concentrations were not significantly different between pan lysimeters and
suction cup lysimeters, but median TP concentrations were significantly greater in the pan
lysimeters compared to the suction cup lysimeters.
DRP concentrations measured in the pan and suction cup lysimeters were similar to
concentrations measured at the tile outlet. TP concentrations measured at the tile outlet
were similar to TP concentrations measured in the pan lysimeters, but were greater than
TP concentrations measured in the suction cup lysimeters.
DRP concentrations are not related to macropore flow paths for the majority of the year
except after P application. Macropore flow paths were, however, important for TP
delivery to tile drains. Further data collection is required as data collection during storms
and around P application are lacking.

5.
• Increasing frequency and extent
of HABs linked to dissolved
phosphorus
Edge of Field and
Watershed
http://www.toledoblade.com/local/2014/08/02/City-of-Toledo-
issues-do-no-drink-water-advisery.html
• Greater water treatment costs,
reductions in fish populations,
and poor water quality that has
negatively impacted drinking
water supplies, fishing, and
tourism industries
• Educational programs directed at
growers and nutrient service
providers emphasize principles of
the 4Rs (Right Source, Rate, Time,
and Placement of fertilizer) and the
4R Nutrient Stewardship
Certification program

6.
Goal
• Evaluate the 3Ps (Triple Bottom Line) of adoption of the 4Rs and
the 4R Nutrient Stewardship Certification Program
Objectives
• Monitoring of 4R Impacts
• Modeling of Sustainable
Environmental Benefits
• Determining the Behavioral Impact
of 4R Education and Certification
Efforts
• Outreach & Education

7.
Edge-of-field
Monitoring
Edge-of-field
In-stream
Watershed outlet
In-stream
Watershed outlet

8.
4R Research Fund
USDA-ARS: USDA-Agriculture Research Service
CEAP: Conservation Effects Assessment Project
EPA: DW-12-92342501-0
Ohio Agri-Businesses
Ohio Corn and Wheat Growers
Funding Sources: CIG: 69-3A75-12-231 (OSU)
CIG: 69-3A75-13-216 (Heidelberg University)
MRBI: Mississippi River Basin Initiative
The Nature Conservancy
Becks Hybrids/Ohio State University
Ohio Soybean Association

9.
Recommendations based on collected data
• Soil testing
• Subsurface placement of nutrients
• Application timing in late summer after wheat harvest
• Disconnection of hydrologic pathways

10.
http://www.toledoblade.com/local/2014/08/02/City-of-Toledo-issues-
do-no-drink-water-advisery.html
(Photo : Tom Archer/University of Michigan)

11.
DRP
(kg P/ha)
TP
(kg P/ha)
Maumee 0.273 1.12
Sandusky 0.311 1.41
Honey Cr. 0.369 1.29
Rock Cr. 0.250 1.38
Low phosphorus loads
< 2 kg/ha (3 to 5% of application rates)

12.
SWPI and CEAP: Watershed Scale
Most effective practices will be those
that lead to improvements in instream
habitat quality
Practices that reduce nutrient and
pesticide loading without altering
physical habitat not likely to improve
fish biodiversity
Ecology
Water chemistry (atrazine)
Demonstrated the effectiveness of
different NRCS cost-share programs on
reducing atrazine loading to Columbus
drinking water supply

13.
Upland/In-field Edge-of-field Downstream%ReductioninPollutantTransport
4-R approach
Scale
What is the most effective scale to address water quality?
How do we avoid tradeoffs among pollutants? How does it depend on the
ecoregion? How do we convince landowners to look at their individual fields
in a larger environmental context?

14.
“No one trusts the model except the model
developer; yet, everyone trusts the field data
except the person who collected it.” (anonymous)
Data Interpretation