Applying Manure---The Right Rate at the Right Time

Transcription

1 Applying Manure---The Right Rate at the Right Time Amber Radatz UW-Discovery Farms Program Minnesota Nutrient Efficiency & Management February 15, 2011

2 Outline So I don t get lost either! Values and costs of manure and manure application Does today s decision matter? Contributions from a single storm Considerations for application Manure and tile drainage: too wet, too dry or both? No till and P stratification

3 Important manure facts 4-letter word

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7 Why do we spread manure? What s in it? What does water quality have to do with manure spreading?

8 Important manure facts Manure is a great source of nutrients All manure is not created equal Nutrients are not all available Total nutrient content = inorganic + organic

9 What s manure worth? Based on nutrient content Book values Manure testing history Based on purchased fertilizer cost Usually based on N, P, K Based on handling and transportation cost Soil amendments? Organic matter, infiltration, structure

10 What did I forget? Cost to mix, load and haul manure to field Cost to apply manure (compared to fertilizer) Cost to incorporate (minus value of tillage) Compaction potential Public relation issues odor, traffic, etc. Regulations

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12 Winter 2004 Mid-Feb runoff 5 snow, 1 water equivalent Rain on snow Sep: 6,000 gal/acre Fall applications Nov: 7,000 gal/acre Winter applications Feb. 14: 4,300 gal/acre Feb. 13: 7,000 gal/acre

13 The Outcome Samples represent approximately the first two days of snowmelt in 2004

14 Winter 2004 Nutrient Loss P loss Winter 2004 N Loss Winter Effective Wintertime Application Rates Feb. 14: 5,200 gal/acre Feb. 14: 4,800 gal/acre Feb. 14: 1,550 gal/acre

15 P loss, in pounds/acre P Losses for Entire Total Phosphorus Loss Entire Water Year 2004 Winter Only Rest of Year A manure management decision can have a big impact to annual nutrient losses.

16 SW1, 2005 SW1, 2006 SW1, 2007 SW2, 2004 SW2, 2005 SW2, 2006 SW2, 2007 SW2, 2008 Pioneer, 2003 Pioneer, 2004 Pioneer, 2005 Pioneer, 2006 Pioneer, 2007 Pioneer, 2008 SE1, 2006 SE1, 2007 SE1, 2008 NE1, 2004 NE1, 2005 NE1, 2006 Total phosphorus yield, in pounds per acr Non-frozen ground Frozen ground Mean

17 N loss, in pounds/acre Nitrogen Speciation Nitrogen Loss Speciation Winter 2004 Nitrate Ammonium Organic N 1 2 3

18 SW1, 2005 SW1, 2006 SW1, 2007 SW2, 2004 SW2, 2005 SW2, 2006 SW2, 2007 SW2, 2008 Pioneer, 2003 Pioneer, 2004 Pioneer, 2005 Pioneer, 2006 Pioneer, 2007 Pioneer, 2008 SE1, 2006 SE1, 2007 Total nitrogen yield, in pounds per acre Non-Frozen Ground Frozen Ground Mean

19 Several rain events Ice layer Warm temps Winter 2005 Sep: 13 T/acre Fall applications Oct: 4,100 gal/acre and 13 T/acre (partial field only) Winter applications Jan 1, 28, Feb 12, 19 at 13 T/acre

20 Flow Weighted N Concentration, in mg/l Flow Weighted P Concentration, in mg/l Winter 2005 Nutrient Concentrations 14.0 Nitrogen Loss Concentrations Winter Phosphorus Loss Concentrations Winter None Wintertime Application Rates None Split Applications: 13 T/acre

21 P loss, in pounds/acre P Losses for Entire Total Phosphorus Loss Entire Water Year 2005 Winter Only Rest of Year 1 2 3

22 SW1, 2005 SW1, 2006 SW1, 2007 SW2, 2004 SW2, 2005 SW2, 2006 SW2, 2007 SW2, 2008 Pioneer, 2003 Pioneer, 2004 Pioneer, 2005 Pioneer, 2006 Pioneer, 2007 Pioneer, 2008 SE1, 2006 SE1, 2007 SE1, 2008 NE1, 2004 NE1, 2005 NE1, 2006 Total phosphorus yield, in pounds per ac Non-frozen ground Frozen ground Mean

23 Lbs/acre lost and dollars/acre to replace losses Economics of Losses N lb/acre lost P lb/acre lost Total $ to replace $7 $7 $5 $3 $3 $1 $2 $2 $1 $0 $0 $0 A-04 B-04 C-04 A-05 B-05 C-05 A-06 B-06 C-06 A-07 B-07 C-07 Site Years

24 What is the distribution of runoff for various soil conditions? Example: No-till farm in SW Wisconsin ( ) Frozen ground: 80%, Non-Frozen Ground: ~ 20% Of the frozen ground runoff, about ¾ has occurred in February and March Of the non-frozen ground runoff: 83% occurred when soils were Wet (>35%) 10% occurred when soils were Medium (25-35%) 7% occurred when soils were Dry (<25%)

25 Rainfall, inches How much rain does it take to produce runoff for a given soil condition? Example: No-till farm in SW Wisconsin ( ) <25% (low ) 25-35% (med) > 35% (high) Frozen <25% (low) 25-35% (med) > 35% (high) Frozen Soil Condition

26 Field Conditions 32% 5% 34% Frozen Days "Low" Moisture Days "Medium" Moisture Days "High" Moisture Days 29%

27 Manure and Tile Drainage

28 Soil Phosphorus levels (ppm) P Stratification in No Till inches 1-6 inches 6-12 inches B1 B2 B3 R1 R2 R3 R4 K1 K2 Sites

29 Yield (lbs/acre) Yield (lbs/acre) Basin Average Phosphorus Loss Dissolved P Particulate P S - Surface T - Tile 0.0 S T S T S T S T FY2005 FY2006 FY2007 FY Surface/Tile Basin Phosphorus Losses by Year DRP Particulate P KP2 KP3 KP2 KP3 KP2 KP3 FY2006 FY2007 FY2008

30 Manure Management through the Seasons Right rate Reduced rates (?) Right time Snowmelt Soil at or near saturation Soil dry and cracked (with tile or groundwater concerns) Frozen/snow covered ground Right location Away from surface water Relatively flat

31 Manure applications on non-frozen ground: Conclusions Soil moisture and forecasted precipitation are important considerations When soil moisture content is medium to high category, consider: Forecasted precipitation Amount of water in manure

32 Conclusions Surface water runoff was not significantly affected by the surface application of manure, suspected that the low rates of the application may influence this Both LDM and SBM significantly increased the losses of TN and TP when applied within one week of runoff Nutrient losses were less when manures were applied in the fall or early winter

33 Why not ban winter spreading? Having all livestock farms apply manure in a narrow window greatly increases the risk Spreading entire field verses portions of a field can increase risk Storage does not reduce the risk of a runoff event Management reduces risk Work with producers to limit spreading in high risk periods, offer options to storage Stacking; spreading fields with limited risk; etc The shorter the time between a manure application and a runoff event, the greater potential for nutrient losses.

34 Needed research: Impacts of manure applications to frozen/snow-covered ground in early winter compared to late winter. Distance/rate/manure type impacts. Are low recommended rates really ok? Wintertime runoff forecasting Impact via subsurface Tiles

35 Questions? Thank you! Amber Radatz SW WI Nutrient Management Specialist UW-Discovery Farms Program