Swine manure on alfalfa

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Swine manure on alfalfa and soybeans
Charles Shapiro and Bill Kranz University of
Nebraska Haskell Agricultural Laboratory Concord,
NE
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How much N can we apply to Alfalfa and Soybeans?
Without damage?
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Results from two in-season swine manure
application experiments

• Lagoon effluent rate affect on alfalfa
• Below barn pit foliar application to soybeans

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Nitrogen harvest greater for alfalfa
than corn
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Water applied here
Manure applied here
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Analysis of Swine Effluent

• 3 yr ave --- lbs/ acre in ---
• Total N 79
• NH4-N 74
• K2O 94
• P2O5 12
• EC 3.4 mmhos/cm

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Swine effluent increased alfalfa yields
(tons/acre)
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Harvest frequency affected alfalfa production
Tons/acre
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Alfalfa nitrogen input/harvest

• Averaged over three years
• No effluent Hi rate
• effluent
• ---- lbs N/acre -------
• Nitrogen harvest 430 564
• Nitrogen applied 0 250

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Manure N on alfalfa

• Schedule irrigation based on ET.
• N, P, K contents low
• Low irrigation requirement
• Reduce leaching potential
• Apply manure so that available N is less than
  half removal.
• P, K needs to be monitored
• Application when crop can use it.
• Manage crop for maximum yield

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Salt Thresholds for Liquid Manure Applications
Through Center Pivots

• Bill Kranz, Irrigation Engineer
• Charles Shapiro, Soil Fertility
• Charles Wortmann, Manure Management

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Swine facilities are set on pivot corners to take
advantage of the irrigation system
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What do we mean by salt?

• Salt is measured by electrical conductivity
• Two units mmhos/cm or dS/m
• Soluble salts
• Sum of the cations and anions
• Ca, Mg, Na, K, Cl

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Salt effects on crop focus on long term effects
on soil-crop interface

• Irrigation water salt content and yield reduction
  by crop

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Objectives

• Determine damage from various salt concentrations
  in swine manure on corn and soybeans
• Evaluate the impact of effluent application at
  different crop stages

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Liquid Swine Manure Treatments

• Four EC (salt) levels
• 0, 6, 12, 20 dS/m
• Two stages of growth
• Corn V8 V14
• Soybeans V3 R1

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Swine Slurry Nutrients

• Chemical Concentration lbs/in
• Organic N 179
• Ammonium-N 366
• Phosphorus (P2O5) 301
• Potassium(K2O) 281
• Soluble salts 1303
• EC (dS/m) 20.3
• pH 6.2

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Plots were 4 rows wide by 20 foot long
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V3 Application Most Plants Died After Full
Concentration
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Soybean _at_ R1
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Soybean Plant Leaf Area Index
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Soybean Grain Yield
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V8 0, 6 gt 12, 24 V14 0 lt 6, 12,24
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• Soybean yields reduced at V3 and R1
• 6 loss with 6 and 12 EC
• 89 loss with 20 EC at V3
• 45 loss with 20 EC at R1
• Corn yields reduced at V8
• 12 loss with 12 EC
• 15 loss with 20 EC
• Corn yields increased at V14
• 14 increase with 6 EC
• 10 increase with 12 EC
• 13 increase with 20 EC

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Recommendations

• Keep swine manure off soybeans until after V3
• EC levels less than 6 dS/m are probably okay
  anytime of the season
• EC levels greater than 12 dS/m decreases LAI
  and may decrease soybean yield
• Very little research has been conducted so
  proceed with caution

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Soybean _at_ V3