What We Monitor For and What We Learn at Different Monitoring Scales

Kevin KingUSDA-ARS

Soil Drainage Research UnitColumbus, OH

Nutrient Management and Edge of Field Monitoring; Memphis, TN; Dec 3, 2015

Plots and Lysimeters

(processes)Edge-of-field

(MRBI & GL EOF & 4R)

Watershed

(SWPI, CEAP and 4R)

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

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.

• 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

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

Edge-of-fieldMonitoring

Edge-of-field

In-stream

Watershed outlet

In-streamWatershed outlet

4R Research FundUSDA-ARS: USDA-Agriculture Research ServiceCEAP: Conservation Effects Assessment ProjectEPA: DW-12-92342501-0Ohio Agri-BusinessesOhio Corn and Wheat Growers

Funding Sources: CIG: 69-3A75-12-231 (OSU)CIG: 69-3A75-13-216 (Heidelberg University)MRBI: Mississippi River Basin InitiativeThe Nature ConservancyBecks Hybrids/Ohio State UniversityOhio Soybean Association

Recommendations based on collected data

• Soil testing

• Subsurface placement of nutrients

• Application timing in late summer after wheat harvest

• Disconnection of hydrologic pathways

http://www.toledoblade.com/local/2014/08/02/City-of-Toledo-issues-do-no-drink-water-advisery.html

(Photo : Tom Archer/University of Michigan)

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)

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

Upland/In-field Edge-of-field Downstream%

Re

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n in

Po

lluta

nt

Tran

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rt4-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?

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

Data Interpretation