Phosphorus Management to protect water quality

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Phosphorus Managementto protect water quality
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P essential element

• Plant growth
• Photosynthesis
• Respiration
• Seed production
• Root growth

• Animal growth
• Bone and muscle growth
• Metabolism
• Reproduction
• Animal performance

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P potential pollutant
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What are the P sources

• Point (31)
• Industrial process water
• Human waste products
• Garbage disposal waste

• Non-point (69)
• Agricultural runoff
• Atmospheric deposition
• Other runoff
• Others

2004 Minnesota data average flow water year
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Non-point sources
2004 Minnesota data average flow water year
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Source University of Wisconsin-Extension
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Phosphorus ( P2O5) fertilizers

• 10-34-0
• 18-46-0
• 11-48-0
• 0-46-0
• Animal manures
• Bio solids

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Use P fertilizers when

• Provides an economic response
• Use P fertilizers efficiently
• Maximize crop response
• Minimize water contamination

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Crop Response to P
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Critical levels
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Critical Level
Maintenance Limit
Buildup Range
Drawdown Range
Maintenance Range
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Maintenance limits
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Maintenance application rate

• 140 bushel corn yield goal
• Utilization rate 0.37 lbs P2O5/bu
• 140 x .37 51.8 lbs P2O5/A

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P recommendation for corn
Numbers highlighted are maintenance amounts
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P recommendation for alfalfa
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Right to Farm GuidelinesGAAMPs

• Nutrient Management
• Manure Management
• gt75 ppm P application limited to crop use
• gt150 ppm P application discontinued.

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Induced Zinc deficiency

• High P soil tests marginal Zn test
• Zinc deficiency
• In Zn responsive crops
• Dry beans
• Corn
• Sorghum-sudangrass

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1966
2006
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Soil Test, Dont Guess

• Every 2-4 years
• Same time of the year
• Corn/soybean rotation 2 year
• Corn/corn/soys/wheat 4 year
• Representative sample
• 20 sub samples

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Realistic yield goals

• Achieve yield 50 of the time
• Overly optimistic
• Lose farm income
• Water quality risk

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Realistic yield goals
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Nutrient P credits

• Manure
• Dairy solid 4 lb/ton
• Hog liquid 2-27 lb/1000 gal
• Poultry 45-64 lb/ton
• Bio solids
• .01-22.3 P205
• 300 lb/1000 gal (medium)

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Fertilizer P placement

• Generally immobile in soil
• Banded application
• more efficient (near seedlings)
• 2to the side x 2 below the seed
• Reduced runoff
• Broadcast application
• less efficient
• Do not broadcast on frozen or snow covered ground

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Source University of Wisconsin-Extension
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Adjust application equipment

• Proper application rate
• Proper fertilizer placement

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Soil conservation practices
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P management areas
Source University of Wisconsin-Extension
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Buffer strips
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Atmospheric Deposition

• Control wind erosion
• Wind breaks
• No-till conservation systems
• Cover crops

Source USDA NRCS
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Record keepingnutrient management

• Soil tests / plant tissue analysis
• Previous crops and yields
• Dates of nutrient application
• Nutrient compositions fertilizers or other
  materials
• Amounts applied per acre
• Method of application and placement
• Vegetative growth and cropping history of
  perennial crops.
• 3 years, or 5 years with livestock

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http//www.agry.purdue.edu/mmp/
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Paper recordkeeping system
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Tiled field management

• Keep P tests levels lt optimum range
• Conservation tillage
• () reduced erosion P losses
• (-) Increased tile P losses

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Tile discharge into surface water
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Irrigation management

• Prevent soil erosion
• Irrigation GAAMPs
• System uniformity (water application)
• Delivery rate matched to soil infiltration rate

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Do the right thing!