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Using soil moisture to predict the risk ofrunoff on non-frozen groundWaste to Worth 2013April 3rd, 2013Tim Radatz - Resear...
Introduction• Identifying critical highrisk runoff periods canreduce environmental risk• Understanding keyparameters influ...
ObjectivesImprove the understanding of the factors that influencerunoff generation in agricultural watersheds1) Evaluate t...
Methods and Materials• Discovery FarmsProgram (DFP)– Direct plant tillage– Surface residue 50-65%– Three year croprotation...
Methods and Materials• Pioneer Farm (PF)– Conventional tillage• Fall - chisel plow• Spring - soil finisher– Surface residu...
Storm Event Data• Data include – precipitation depth andintensity, runoff depth from each basin,antecedent soil moisture (...
Runoff CharacteristicsStudy period runoff• Lower number of runoffevents and runoff depth atDFP• %Precipitation as Runoff– ...
Soil Moisture BreakpointAnalysis• Runoff coefficient(runoff/precipitation)vs. antecedent soilmoisture• Completed for eachb...
Soil Moisture BreakpointAnalysis• ASM threshold of0.39 cm3cm-3• Above Threshold– 16% of precipitation– 78% of runoff depth...
Soil Moisture BreakpointAnalysis
I30 Breakpoint Analysis• Comparing runoff coefficients and stormintensity (30 minute max)– DFP and PF storm events were av...
I30 Breakpoint Analysis0 20 40 60 80 100I30 (mm hr-1)0 20 40 60 80 1000.00.10.20.30.4RunoffCoefficient(mmmm-1)ThresholdI30...
I30 Breakpoint AnalysisAntecedent Soil Moisture 0.35 to 0.40 cm3cm-3Crop Cover ≥50% Crop Cover <50%
I30 Breakpoint AnalysisAntecedent Soil Moisture <0.35 cm3cm-3Crop Cover ≥50% Crop Cover <50%
Conclusions• The ability to identify high risk periods is vital• Soil moisture measurement can be an indicator• Thresholds...
So What Does This Mean…Important to think about moisture levels whenplanning field operations – manure/fertilizerand pesti...
Questions?Special Thanks To:•Dr. Anita Thompson, Dr. Fred Madison, and Dr. Birl Lowery•UW-Platteville Pioneer Farm•UW Disc...
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Using Soil Moisture to Predict the Risk of Runoff on Non-Frozen Ground

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For more: http://www.extension.org/67683 Identifying time periods when land application of manure is likely to contribute to surface runoff contamination is important for making proper management decisions and reducing the risk of surface water contamination. Recently, a great deal of attention has been focused on reducing nutrient and sediment losses from the winter period. However, sediment and nutrient losses during the late spring period can be significant and it is important to understand landscape and weather conditions that lead to elevated runoff risk during this time period.

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Using Soil Moisture to Predict the Risk of Runoff on Non-Frozen Ground

  1. 1. Using soil moisture to predict the risk ofrunoff on non-frozen groundWaste to Worth 2013April 3rd, 2013Tim Radatz - Research Specialist, MN and WI Discovery Farms
  2. 2. Introduction• Identifying critical highrisk runoff periods canreduce environmental risk• Understanding keyparameters influencingthe likelihood of runoffgeneration
  3. 3. ObjectivesImprove the understanding of the factors that influencerunoff generation in agricultural watersheds1) Evaluate the influence of storm and landscapecharacteristics on surface runoff generation2) Determine critical thresholds for surface runoffgeneration1) Soil moisture2) Rainfall Intensity
  4. 4. Methods and Materials• Discovery FarmsProgram (DFP)– Direct plant tillage– Surface residue 50-65%– Three year croprotation (Cg/Cs/S)– Grass waterways andbroad-based terraces– Tama soil series– Mean slopes - 5%http://uwdiscoveryfarms.org/
  5. 5. Methods and Materials• Pioneer Farm (PF)– Conventional tillage• Fall - chisel plow• Spring - soil finisher– Surface residue 15-30%– Seven crop year rotation(C/C/C/O/A/A/A)– Grass waterways and terraces– Tama and Ashdale soil series– Mean slopes – 5 to 7 %– Farmstead area (2 ha) within PF7http://www.uwplatt.edu/pioneerfarm
  6. 6. Storm Event Data• Data include – precipitation depth andintensity, runoff depth from each basin,antecedent soil moisture (ASM), and crop cover• Only storm events >2.5 mm• Non-frozen ground periods 2004-2007
  7. 7. Runoff CharacteristicsStudy period runoff• Lower number of runoffevents and runoff depth atDFP• %Precipitation as Runoff– 0.9% DFP– 2.0% PF (1.8% PF3 and PF5)• Similar precipitation andlandscape characteristicsexcept for tillage strategiesand crop rotations• Impervious surfaces locatedwithin PF7RunoffEvents0102030405060708090DF1 DF2 DF3 PF3 PF5 PF7RunoffDepth(mm)0102030405060
  8. 8. Soil Moisture BreakpointAnalysis• Runoff coefficient(runoff/precipitation)vs. antecedent soilmoisture• Completed for eachbasin• Breakpoint regressionexample
  9. 9. Soil Moisture BreakpointAnalysis• ASM threshold of0.39 cm3cm-3• Above Threshold– 16% of precipitation– 78% of runoff depth• Below Threshold– Few runoff events– Intense stormevents
  10. 10. Soil Moisture BreakpointAnalysis
  11. 11. I30 Breakpoint Analysis• Comparing runoff coefficients and stormintensity (30 minute max)– DFP and PF storm events were averaged andcombined• Antecedent soil moisture groups– ≤0.35, 0.35 to 0.40, and ≥0.40 cm3cm-3• Crop cover groups– <50% and ≥50%
  12. 12. I30 Breakpoint Analysis0 20 40 60 80 100I30 (mm hr-1)0 20 40 60 80 1000.00.10.20.30.4RunoffCoefficient(mmmm-1)ThresholdI30:9mmhr-1Slope Above Threshold: 0.007 hr mm-1ThresholdI30:6mmhr-1Slope Above Threshold: 0.006 hr mm-1Antecedent Soil Moisture ≥0.40 cm3cm-3Crop Cover ≥50% Crop Cover <50%
  13. 13. I30 Breakpoint AnalysisAntecedent Soil Moisture 0.35 to 0.40 cm3cm-3Crop Cover ≥50% Crop Cover <50%
  14. 14. I30 Breakpoint AnalysisAntecedent Soil Moisture <0.35 cm3cm-3Crop Cover ≥50% Crop Cover <50%
  15. 15. Conclusions• The ability to identify high risk periods is vital• Soil moisture measurement can be an indicator• Thresholds for runoff generation– ASM• 0.39 cm3cm-3• Above threshold: 16% of precipitation but 78% ofrunoff– I30• Strongly influenced by ASM• As ASM increased, I30 thresholds decreased
  16. 16. So What Does This Mean…Important to think about moisture levels whenplanning field operations – manure/fertilizerand pesticide application, tillageToo late! Planning for intermediatemoisture conditionsSource: http://www.tractorbynet.com
  17. 17. Questions?Special Thanks To:•Dr. Anita Thompson, Dr. Fred Madison, and Dr. Birl Lowery•UW-Platteville Pioneer Farm•UW Discovery Farms•WI USGS•Mark, Jan, and Joe Riechers

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