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Low-disturbance Manure Application Methods in a Corn Silage-Rye Cover Crop System
Bill Jokela, Jason Cavadini, and Mike BertramUSDA-ARS, Marshfield, WI, and Univ. WI Agric. Research Station,
Marshfield and Arlington, WI
Technical Support: Jess Sherman, Tony Sternweis, Ashley Braun, and Matt Volenec
Partial Financial Support: USDA-NIFA and WI Fertilizer Research Program
Wisconsin Crop Management ConferenceMadison, WI, Jan. 14, 2015
Situation• Manure a good source of nutrients for
crops• Large ammonia-N (NH3-N) losses from
surface-applied manure reduce N available to crop and contribute to environmental problems
• Quick tillage or injection minimizes NH3-N losses, but reduces crop residue cover, which may increase erosion potential.
Objective• Evaluate methods for applying liquid
manure that minimize NH3-N and nutrient runoff losses, conserve N for crop, while maintaining crop residue cover.
Field Site• Marshfield Ag Research Station, Marshfield,
WI (central WI)• Withee silt loam (Aquic Glossudalf)– Somewhat poorly drained, 0-2% slope
Broadcast –Disk Incorporation
Manure and Fertilizer Application• Late fall manure application (late Oct-early Nov) into corn silage
stubble-rye cover crop• Target application rate 8000 gal/acre (aim 80% of crop N need)
• Supplied 190 total N, 90 NH4-N, 80 P2O5, 200 K2O lb/acre/yr (average; nutrient content and rate variable)
• Fertilizer N: 0, 60, 120, 180 lb N/acre pre-plant (no manure)• Starter (9-11-30-6S) applied to all plots
Broadcast – Surface
Low-disturbance sweep injection (DSI/Dietrich)
Strip-till/sweep injection (DSI with paired disks – “Clozr”)
Low-disturbance Manure Application Methods
Coulter injection (Yetter Avenger)
Aerator-band applicator
All plots except strip-till injection field cultivated in spring
Planting strip-till injection plotPlanting field cultivated plot
Measurements• Soil sampling
– Routine, PSNT, deep NO3
• Plant sampling (N, P, K…)– Early growth, earleaf at silk
• Surface residue cover– Photos and image analysis
• Ammonia volatilization– Dynamic chamber technique
• Runoff (P, N, sediment)– Rainfall simulator
• Silage yields and nutrient uptake– Silage wagon with weigh cells
How does manure application method affect…?
• Manure ammonia-N volatilization/loss• Manure N availability to crop– Pre-sidedress Soil Nitrate Test (PSNT)– Earleaf N content at silking– Silage N content and uptake
• Silage yield• Surface residue cover• Sediment and phosphorus loss in runoff
Ammonia EmissionNovember 2013
Early NovemberLow temperatures: 25 to 43 FRain: 0.6 inch following manure application
• Greatest loss from broadcast-surface
• Least from injection (strip-till, coulter)
• Broadcast-disk and aerator-band intermediate
• Low NH3 losses due to low temperatures and rain, but probably more in following days
Ammonia EmissionManure N Timing Study, Marshfield, 2009-2011
• Greatest loss from pre-plant-surface
• Large reduction from disk incorporation
• Least loss from injection
• Relative losses similar to current study, but different pattern and greater NH3 emissions– Higher
temperatures– Little/no rain
Mid-late May 2009-2011
Indicators of Crop N Availability
bcdcde
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Nit
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Pre-sidedress Soil Nitrate Test 2013
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0.5
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% N
Ear Leaf N Content 2013
2013
Pre-sidedress Soil Nitrate Test (PSNT)• Most treatments <
threshold for adequate N• Manure
– Injection and disk highest– Surface lowest = Control
• Fertilizer N (spring) > Manure (fall)
Earleaf N Content at Silking• Similar trends to PSNT, but
less pronounced
Indicators of Crop N Availability
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b
a
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10
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60
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Nit
rate
-N (p
pm)
Pre-sidedress Soil Nitrate Test 2014
ab
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c c c
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b
a
0.0
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1.0
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2.0
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3.0
% N
Ear Leaf N Content 2014
2014
Pre-sidedress Soil Nitrate Test (PSNT)• All but No N Control >
threshold for adequate N
• Fertilizer N and Sweep Injection highest
Earleaf N Content at Silking• Similar trends to PSNT
Silage Yield and N Uptake
a
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N U
ptak
e (lb
/a)
2014 N Uptake
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Yiel
d (D
M T
/a)
2014 Yield
• Injected and disk incorporated manure = Fertilizer N
• Broadcast-surface manure and No N Control lowest (not significantly different)
Surface Residue Cover Pre-Manure, November 2013
0
5
10
15
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25
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45
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Sweep Inject Strip-Till Inject Coulter Inject Aerator/Band Bdcst-Disk Bdcst-Surf No Manure
% R
esid
ue C
over
Surface Residue CoverNovember 2013 and May/June 2014
Pre-manure
Post-Manure
2014 Pre-till
2014 Post-plant
• Residue = corn stubble, rye, weeds (no manure)
• Minimal rye growth in fall
• Greatest residue decrease from broadcast-disk, least from injection of manure
0
5
10
15
20
25
30
35
40
45
50
Sweep Inject Strip-Till Inject Coulter Inject Aerator/Band Bdcst-Disk Bdcst-Surf No Manure
% R
esid
ue C
over
Surface Residue CoverNovember 2013 and May/June 2014
Pre-manure
Post-Manure
2014 Pre-till
2014 Post-plant
Broadcast-Disk Strip-till Inject
Surface Residue Cover Post-Manure, November 2013
• Greatest residue decrease from broadcast-disk, least from injection of manure
• Spring residue cover increased to pre-manure levels, except disk
0
5
10
15
20
25
30
35
40
45
50
Sweep Inject Strip-Till Inject Coulter Inject Aerator/Band Bdcst-Disk Bdcst-Surf No Manure
% R
esid
ue C
over
Surface Residue CoverNovember 2013 and May/June 2014
Pre-manure
Post-Manure
2014 Pre-till
2014 Post-plant
Broadcast-Disk Sweep Inject
Surface Residue Cover Pre-tillage Spring 2014
• Greatest residue decrease from broadcast-disk, least from injection of manure
• Spring residue cover increased to pre-manure levels except disk
• Large residue decrease from spring tillage, except strip-till injection
0
5
10
15
20
25
30
35
40
45
50
Sweep Inject Strip-Till Inject Coulter Inject Aerator/Band Broadcast-Disk Broadcast-Surf No Manure
% R
esid
ue C
over
Surface Residue CoverNovember 2013 and May/June 2014
Pre-Manure
Post-Manure
2014 Pre-till
2014 Post-plant
Spring field cultivated Strip-till Inject
Surface Residue Cover Post-Planting Spring 2014
Nutrient Runoff Losses• No significant effect
on runoff quantity• No significant effect
on sediment loss• Big effect on P losses
– Total P – Dissolved P (DRP)
• Decreased P losses vs. Bdcst-Surface– Aerator-Band 35%– Bdcst-Disk 70%– Strip-till Inject 90% =
No Manure
Preliminary Conclusions• Low-disturbance manure application methods:– Reduced ammonia loss (especially injection, >90%)
compared to broadcast surface application– Increased manure N availability to the crop compared to
surface application• PSNT, ear leaf N content, silage N content
– Maintained residue cover better than disk incorporation of manure
– Reduced runoff P losses (35-90%) compared to surface application
• In summary, low-disturbance methods provide a viable option to reduce environmental impact of manure application and improve manure N availability to the crop.