PHOSPHORUS LOSS
FROM TILE DRAINS:
SHOULD WE BE
CONCERNED?
Matt Ruark
Allison Madison
Fred Madison
Eric Cooley
Dennis Frame
Fred Madison
Todd Stuntebeck
Matt Komiskey
QUICK REVIEW
General consensus is that tile drainage will
reduce erosion and surface P losses, but
increase N leaching losses.
Discovery Farms has intensely monitored
four farm sites that have tile drainage and
extremely high soil test phosphorus values.
The question is – how much P are losing,
what is causing it, and what are our options
for mitigation?
COWS & TILE DRAINAGE IN WI
U.S. Census of Agriculture, 2007
U.S. Census of Agriculture, 1992
STUDY OBJECTIVES
Quantify P losses from tile drained fields
Evaluate factors that influence P loss
FOUR DISCOVERY FARMS SITES
CP1: Chisel plowed, continuous corn
Kewaunee Co., STP=80 ppm , slope 2-6%
CP2: Chisel plowed field, continuous corn
Kewaunee Co., STP=56 ppm, slope 2-6%
NT: No-till field, corn-soybean rotation
Waukesha Co., STP=85 ppm, slope 1-3%
GP: Grazed pasture
Manitowoc Co., STP=108 ppm, slope 2-6%
CP1 & CP2
NT
GP
LOCATIONS – IN OR CLOSE TO LAKE
MICHIGAN WATERSHED
CP1
CP2
GP
NT
F. Hole, 1976
http://techalive.mtu.edu/meec/module01/images/MichiganWatershedAtlas.gif
USGS MONITORING
Methods of Data Collection, Sample
Processing, and Data Analysis for Edge-ofField, Streamgaging, Subsurface-Tile, and
Meteorological Stations at
Discovery Farms and Pioneer Farm in
Wisconsin, 2001–7
http://pubs.usgs.gov/of/2008/1015/
DATA
Dissolved P = P in water
Particulate P = P in sediment (in water)
Total P = DP + TP
Flux = lb/ac/yr
Concentration = mg/L or ppm
Flow-weighted concentration
 Averaging concentrations over time
 e.g.: 1,000 L with 1 ppm and 100 L with 50 ppm
 Flow weighted = 5.5 ppm
TOTAL P LOSSES
2005
Site
Tile
2006
Surface
Tile
Surface
2007
Tile
Surface
2008
Tile
Surface
2009
Tile
Surface
-------------------------------------------- lb/ac--------------------------------------------
CP1 1.43
1.67
1.47
2.51
0.46
0.60
1.41
2.24
CP2 0.24
1.17
1.47
4.55
0.39
2.10
1.53
1.42
0.49
2.27
0.53
1.05
2.73
6.93
1.25
4.14
2.63
9.73
NT
GP
0.27
4.33
PERCENT OF ANNUAL P LOSS
Surface DRP
Surface PP+DUP
Tile DRP
Tile PP+DUP
Percentage of Annual TP Load
ANNUAL TP LOADS
100
80
60
40
20
0
2006
2007
NT
2008
2005
2006
2007
CP1
2008
2005
2006
2007
CP2
Site & Water Year
2008
2007
2008
GP
2009
IS THIS A LOT?
Bray P1 equiv.
Tile FW-TP
Tile TP
mg kg-1
mg L-1
lb ac-1 yr-1
CP1
54
0.70
0.9
CP2
57
0.50
0.9
NT
85
0.22
1.3
GP
108
1.31
1.4
IL1
NA
0.15
0.2
Quebec2
29
0.30
1.6
Quebec2
58
0.08
0.4
Denmark3
NA
0.10
0.4
MN4
NA
>0.02
0.1
UK5
42
1.11
1.9
Location
WHEN DO WE LOSE P IN TILES?
25
2005
2006
2007
2008
Drainage (cm)
20
15
10
5
2.0
-1
Tile TP (kg ha )
0
1.5
1.0
0.5
0.0
Oct
Nov
Dec
Jan
Feb March April May June July
Month
Aug Sept
DRAINFLOW VS P LOSS
1.6
1.4
y=0.03x-0.02
y=0.07x
RR2=0.16
2=0.69
Site
TP
DRP
1.0
CP1
0.69
0.80
0.8
CP2
0.67
0.80
0.6
NT
0.16
0.17
0.4
GP
0.78
0.80
1.2
-1
TP (kg ha )
R2 Table
NT
CP1
0.2
0.0
0
2
2
4
6
4
8
6
Drainage (cm)
10
12
8
14
10
0
20
5
15
Manure
Application
Surface DRP
Tile DRP
Precip
Manure
Application
10
15
10
20
5
25
0
10/1/05
30
4/1/06
10/1/06
4/1/07
10/1/07
Date
The application on 4/1/08 was the only
“clear” evidence of manure having a large
impact on tile losses across all sites
4/1/08
10/1/08
Precipitation (cm)
25
-1
DRP (mg L )
MANURE APPLICATIONS
EVENT P CONCENTRATIONS:
ALL SITES
16
14
-1
Tile FW-DRP (mg L )
1:1
y=0.29x+0.28
R2=0.66
12
10
8
6
4
2
0
0
2
4
6
8
10
Surface FW-DRP (mg L-1)
12
14
16
CONCLUSIONS
Tile drainage can represent between 17 and
52% of the total P loss from a field.
Total flow explains most of the variation in P
loss.
Manure applications were not found to
consistently affect P loss from drains.
Since there is a significant relationship
between overland flow and tile flow, a simple
model may be effective in accounting for
these losses.
SO..SHOULD WE BE CONCERNED?
We need to exploring both management
options (e.g. different manure applications)
and engineering options (e.g. controlled
drainage, tile filters) to determine if any
reductions can be obtained.
The best management option is to apply
manure at appropriate times, not when tiles
are flowing.
BEST THING TO DO IS CHECK TILE
DRAINS
http://www.nocafos.org/news.htm
“Frothy-ness” is evidence of organic carbon
loss – most likely from manure