effects of conservation tillage systems on dissolved phosphorus dr. david baker
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Building Science Assessments for State-Level Nutrient Reduction Stategies. Effects of Conservation Tillage Systems on Dissolved Phosphorus Dr. David Baker Heidelberg University Tiffin, Ohio 44883 November 15, 2012 Davenport, IA. This talk -- . - PowerPoint PPT PresentationTRANSCRIPT
Effects of Conservation Tillage Systems on Dissolved Phosphorus
Dr. David BakerHeidelberg University
Tiffin, Ohio 44883
November 15, 2012
Davenport, IA
Building Science Assessments for State-Level Nutrient Reduction
Stategies
This talk -- Lessons learned from agricultural
phosphorus control programs in the Lake Erie BasinThe teacher has been:
1. Detailed, long-term monitoring data for several major watersheds draining into Lake Erie.
2. Information on changing crop production practices in those watersheds.This research was supported by state and federal agencies, foundations ,
agribusinesses and the fertilizer industry . Special thanks to the EPA’s Great Lakes National Program Office and the Great Lakes Protection Fund for recent support for bioavailability studies and phosphorus stratification studies.
15 stations
All at USGS Stream Gages
Today’s data from three rivers:
Maumee – 6,330 sq.mileSandusky – 1,250 sq. mileCuyahoga - 708 sq. mile
1. Suspended solids2. Total phosphorus3. Dissolved reactive phosphorus4. Nitrate5. Nitrite6. Ammonia7. Total Kjeldahl Nitrogen8. Chloride9. Sulfate10. Silica11. Fluoride12. Conductivity
Seasonally pesticidesSelected metals
Bioavailable Phosphorus
Analytical Program at the NCWQR
• Program started in 1975
• ~ 500 samples analyzed per station per year
• Annual loads calculated by integration with corrections for final USGS daily discharge
• Data available at Heidelberg’s web site: http://www.heidelberg.edu/academiclife/distinctive/ncwqr/data
Program Characteristics:
Total Phosphorus
Load
Total Particulate
PhosphorusLoad
Total Dissolved
PhosphorusLoad
+=
TotalBioavailablePhosphorus
Load+=
BioavailableParticulate
PhosphorusLoad
BioavailableDissolved
PhosphorusLoad
Management Options for Phosphorus Load Reduction
Focus of reduction programs
Nonpoint phosphorus control programs were planned in the 1980s and initiated in the 1990s.
ParticulatePhosphorus
82%
Dissolved Phosphorus
18%Forms of
phosphorus transported in northwestern Ohio rivers, 1975-1987.
Phosphorus reduction programs focused on reducing erosion and particulate phosphorus loading through fostering adoption
of no-till and reduced till crop protection methods.
Particulate phosphorus during storm
runoff is attached to soil
particles.
1. What does the water quality monitoring data look like?
2. What changes in agricultural practices could explain the loading changes?
3.What changes in hydrology could help explain the loading changes?
Trends in annual loads and flow weighted mean concentrations of particulate phosphorus in the Maumee and Sandusky rivers
• Note the close relationship between variations in annual discharge and variations in TP load.
• Discharge increased by 41% while TP load increased by 31%.
• Weather and hydrology drive nonpoint pollution from cropland.
Trends in annual loads and flow weighted mean concentrations of dissolved reactive phosphorus in the Maumee and Sandusky rivers
Dissolved Reactive Phosphorus
50% decrease from 1982-2011
Total Phosphorus
24% decrease from 1982-2011
Internet Explorer.lnk
From here
To here
With some very good years in
between!
Phosphorus reduction programs in the Lake Erie Basin have been driven by the lake’s eutrophication problems.
Point source control problems were initiated first and quickly resulted in substantial reductions in phosphorus loading.
Total Phosphorus Tributary Loads to Lake Erie, 2005
MaumeeSanduskyCuyahogaThamesCattaraugus CreekGrand (Ont)ChagrinHuron (OH)VermilionGrand (OH)BlackDetroit R Canada
Maumee and Sandusky• 26% of land area• 51% of total phos. load• Export rate 3x higher than
average for rest of drainage area
How does nutrient export from the Northwestern Ohio rivers compare with the export from other areas?
Land use in study watersheds, as percent
Watershed Agricul-ture Forest
Grass_Hay_
Pasture
Open Water Urban Wetland Other
Maumee 73.3 6.5 6.3 0.7 10.6 2.3 0.2Sandusky 77.6 8.8 4.3 0.5 8.1 0.3 0.3Cuyahoga 9.0 33.6 11.8 2.6 39.5 3.1 0.4
Average annual nutrient export rates, 1996-2011
River SS TP, DRP, Nitrate-N TKN,
lbs/acre lbs/acre lbs/acre lbs/acre lbs/acreMaumee 504 1.21 0.25 21% 17.08 5.23Sandusky 642 1.46 0.29 20% 18.73 5.76Cuyahoga 1,175 1.26 0.18 14% 7.59 4.86
DRP as % TP
Data for 2004-2008 Water Years
WatershedPoint source Phosphorus
Non-Point Phosphorus
Maumee 5% 95%
Sandusky 3% 97%
Trends in tillage practices in northwestern Ohio: 1989-2004
Tillage Practices Corn,(1142 fields)
Soybeans (1147 fields)
Wheat (945
fields)
Hay(52 fields)
1 Moldboard plow, < 5% cover
5% 1% 1% 4%
2 Reduced tillage, soil heavily mixed, < 30% cover
72% 9% 3% 48%
3 Mulch tillage, soil lightly mixed, > 30% cover
15% 17% 12% 13%
4 No till, strip till 8% 73% 84% 35%
Tillage Practices in the Sandusky Watershed: 2009-2010
“Rotational no till”
Phosphorus fertilizer sales in Ohio, 1955-2007
Heidelberg Monitoring started
Start of Heidelberg monitoring
Long-term trend in average phosphorus soil tests in Northwest Ohio
Fertilizer application method # of fields
% of fields
1 Broadcast and unincorporated 211 20%
2 Broadcast and incorporated within one week
212 21%
3 Broadcast and incorporated after one week or more
115 11%
4 Banded with corn planter 496 46%
5 Banded more than 2 inches deep with a coulter/knife injection tool
23 2%
Total number of reported fields 1,030 100%
How will the majority of phosphorus fertilizer be applied to this field?
Sandusky Watershed Soil Stratification Studies
Timing of fertilizer application # of fields
% of fields
1 In spring (April to June), prior to planting
86 8.4 %
2 In spring (April to June), at planting 513 50.0 %
3 In late summer or fall (August – November) after wheat or hay harvest.
92 9.0 %
4 In fall (September – November) after soybean harvest
283 27.6 %
5 In fall, (September – November) after corn harvest
47 4.6 %
6 In winter (December – March) 4 0.4%
7 In winter (December – March) on snow covered or frozen soils.
1 0.1 %
Total Responses 1,026
When will the majority of phosphorus fertilizer be applied?
Total Phosphorus Loading
Total Bioavailable Phosphorus Loading
A bottom line …
1. After 20+ years of efforts to reduce phosphorus loading to Lake Erie from cropland, we now have more bioavailable phosphorus entering Lake Erie from cropland than ever.
2. The increases in bioavailable phosphorus loading are due to increases in dissolved phosphorus runoff.
3. The increases in dissolved phosphorus loading appear to be contributing increased harmful algal blooms in Lake Erie.
Characteristics of average annual export of phosphorus from the Sandusky River, 2002-2011
Total Phosphorus (594 metric tons/year)
73% particulate phosphorus27% dissolved phosphorus
Bioavailable Phosphorus (275 metric tons/year)46% particulate phosphorus54% dissolved phosphorus
Management choice impacts--• Trading• TMDLs• BMP selection
93% bioavailable
29% bioavailable
Why has the dissolved phosphorus loading from the Sandusky and Maumee rivers dropped and
then increased so much?Potential causes of the increasing dissolved phosphorus export
1. increasing fall and winter broadcasting of phosphorus fertilizers, often without timely incorporation.
5. changes in rainfall patterns that have resulted in increases in winter rainstorms and resulting stream flows, especially in December and January.
2. phosphorus stratification in the soil associated with widespread adoption of no-till and reduced-till production and the accompanying lack of inversion tillage.
3. increased tile drainage coupled with macropore flow that carries surface water to tile drains and increases total discharge.
4. increasing trends in flashiness of northwestern Ohio streams.
Phosphorus stratification in cropland of the Sandusky Watershed
Analysis of dilute aqueous soil suspensions
Analysis of dilute aqueous soil suspensions
Questions?
NCWQRPhosphorus
Analyses
Sample PretreatmentPortion
Analyzed acidadded
oxidant added
auto-clave
Dissolved Phosphorus (DP) (filter sample through 0.45 micron filter)
Total Phosphorus (TP) whole sample x xx
NaOH Extractable PP (extract residue on filter with NaOHand analyze as DRP)
Particulate Phosphorus (PP) calculated as TP - TDP
Dissolved Organic P (DOP) calculated as TDP - DHP
Total Dissolved P (TDP) xxxfiltrate
Dissolved Hydrolyzable P (DHP) x xfiltrate ---
Dissolved Reactive P (DRP) filtrate --- ------
all samples extra analyses for bioavailability studies
BioavailableForms