Nutrient Management and Edge of Field Monitoring Conference December 1-3, 2015 Memphis, TN

1. Andrew Sharpley
What we learnt from
monitoring across scales

2. • Some drivers of water quality monitoring
• Scaling up
• Defining clear goals & outcomes
• Coordinated & adaptive monitoring
• Stakeholder involvement & participation
• Lessons learnt

3. • Maryland implements restrictive STP
threshold for P mgt.
• Pull back from ag. community led to
one of the first focused “research &
monitoring” initiatives
1998

4. 1999
Joint US EPA & USDA Initiative requires
P loss assessment prior to applying P
 Site specific assessment using a P index,
 Soil-specific P threshold level, or
 Soil test P recommendations

5. Pedon
…. to runoff box
… to small
runoff plot

6. …. to larger plots
2 m2 plot
30 m2 plot

7. 0
0.2
0.4
0.6
0.8
1
0 100 200 300 400 500
Mehlich-3 extractable soil P, mg/kg
Dissolved P
in runoff,
mg/L
Relationship between soil P & runoff P not affected by scale
30 m2 plot
R2 = 0.88
2 m2 plot
R2 = 0.92

8. from landscape …

9. … to watershed scale

10. High
source
High
transport
Critical Source Area
Led to the 80/20 rule:
80% of P comes from
20% of land area

12. Federal
Land Grant

13. Outreach

14. 2009
• Often, not leading to a decline in STP nor
improvement in water quality
 Legacy effects
• Indices seen as “farmer friendly”
• The P Index was never meant to be the
solution to P management issues!!

15. 2014
• Maryland implements a revised &
restrictive P Management Tool – PMT

16. 2015
• 12:01, Jan. 1 - New MD Governor Hogan
retracts PMT
• Jan. 29 - P Summit held at Wye College, MD
• June 8 – New PMT regulations went into
effect

17. • In-field monitoring essential for farmer buy in
• But we can’t monitor every field
• Attempts to validate Indices identified a lack
of edge-of-field monitoring & models used to
fill gaps
• Nonpoint sources models tended to lack
sufficient accuracy & can’t supplant
monitoring

18. • EOF monitoring has moved to private lands
• Creates difficulty in conducting “cause & effect”
research & demonstration
• Support program must be flexible enough to
accommodate day-to-day farm decisions
• Essential to assess CP effectiveness
• Essential for model calibration & validation
• But, beware of liberties taken with freely
available data