Can Multiple Benefits Make Cover Cropping Profitable? An update

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Can Multiple Benefits Make Cover Cropping
Profitable?An update

• Ray Weil
• with Sandra Sardanelli, Lisa Stocking, Amy
  Kremen, Jill Dean, Guihua Chen, Dechassa Duressa,
  Cheryl Edge, Yvonne Lawley
• University of Maryland
• and
• John Teasdale, USDA/ARS Beltsville

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Cover crops great for the Bay, but can they pay
for themselves?

• Research on environment or long term soil
  quality.
• Little on benefits to the farmer.
• Our Brassica cover crops project attempts to fill
  this gap.

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March 2002 after mild winter
The main actors
Wheeler Rye
Adagio Oilseed radish
Essex Rapeseed (Canola)
Daikon Forage radish
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Some seeding rates. Best by late August.
Possibly in late march?
Cover Crop Species Seeding Rate (lbs/acre)
Mustard mixture (Sinapis alba and Brassica juncea) 8
Rapeseed (Brassica napus Dwarf Essex and Humus) 8
Oilseed Radish (Raphanus sativus Adagio) 13
Forage Radish (Raphanus sativus Daikon) 13
Forage radish Rye mixture 13 75
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Brassicas are sensitive to water logging
Rape
Forage radish
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Frost damage after a week of December nights in
the low 20s
Oilseed Radish
Rape over-winters, but the radishes and mustard
winter kill.
Forage Radish
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Environmental Benefits of Cover Crops

• Soil conservation
• Raindrop splash
• Erosion
• Organic matter
• Habitat/food
• beneficial insects
• earthworms
• wildlife
• Water conservation
• Reduced runoff
• Reduced evaporation

Plasticuture- no cover crop
No-till with cover crop
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NUTRIENT CYCLING
Additional Benefits to Make Brassica Cover Crops
Pay
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Nutrient cycling

• Capture residual N before it leaches
• Release N in spring for main crop
• Enhance availability of other nutrients (K, P, S
  etc.)

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Fall growth and N uptake may be even faster than
rye. Planted August 29, shown October 17, 2004.
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Oilseed radish in October running out of N
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Collecting deep soil cores
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Ability of Radishes to Soil Capture N in Fall,
2003
2003 nitrogen
2002 nitrogen?
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Radish Growth N Capture in Fall
Dry matter Dry matter Nitrogen (kg/ha) Nitrogen (kg/ha) Nitrogen (kg/ha)
root shoot root shoot total
Forage radish 1618 5213 31 112 143
Oilseed radish 1670 5874 26 118 140
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Nitrogen capture in fall2003 at Wye
- The taproot accounts for a major part of
radish biomass and N uptake
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How about those roots?
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Forage radish after frost damage
Fleshy taproot accounts for about ½ of total dry
matter. Sometimes half the root is above ground
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Difference in the roots
Soil surface
Forage radish
mustard
Oilseed radish
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Intervale CSA Multipurpose cover crop?
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Spring 2004 Nitrogen release in upper foot of
soil
Still less than 10 lbs N/A Where has all the
nitrogen gone? maybe still in organic form?
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Radish root C/N in December (not shown) was
similar to 25/1 shown for Rape shoot in April.
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Brassicas appear to be particularly adept at
solubilizing P
Nutrient cycling Phosphorus
Soil Test P Silt loam at Wye, fall 2003 Means for
top 18 inches
Biological pumping organic acid root exudates
Third year of cover crop treatments in a
corn-soybean rotation
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More Potential Benefits to Make Cover Crops Pay
Weed suppression

• Compete for light, nutrients during cover crop
  growth
• Smother under mulch by cover crop residue
• Allelopathic compounds exuded or from
  decomposition.

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Fall covers by late October 03
Forage radish
No cover planted
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Weed groundcover in November after cover crops
planted 08/19 or 09/10
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Weed suppression in fall
Forage radish planted Aug. 26
Forage radish planted Sept. 10
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Weed growth without cover crop
Control plot tilled for Aug. 26 planting
Control plot tilled for Sept. 10 planting
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Radish grew much better than rape, mustard or rye
when interseeded into lodged, narrow row soybeans.
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Some glucosinolates inhibit weed seed germination
at lower concentrations
BIOFUMIGATION
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Biofumigation or smoothering?
Forage Radish plot in early April
Weeds outside the radish plot
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Winterkilled radish plots in spring-very little
residue, almost no weeds
Potential for organic no-till planting?
Spring after forage radish Little residue or
weeds
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PEST SUPPRESSION
Potential Benefits to Make Brassica Cover Crops
Pay
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Potential for Pest Suppression

• Disease suppression
• Insect management
• Nematode suppression
• lack of host
• repellent or toxic chemicals

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How Cover Crops May Suppress Nematodes

• Trap Crop
• Non-Host Plant
• Direct Toxicity (bio-fumigation)
• Cultivars Vary in Effectiveness
• High Plant Biomass Needed (plant early)
• Nematode Species Differ in Their Response

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Bioassay to test toxicity of cover crop tissues
to root-knot nematodes
1 leaf tissue in sand
5 leaf tissue in sand
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Soybean cyst nematode damage can Brassica cover
crops help?
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Soybean cyst nematode
Mixed results so... Possibly some suppression
from Humus Rape.
Nematodes / g dry soil
Soybean Cyst Nematode in soil sampled June 2004
as influences by winter 2003-2004 cover crops at
LESREC. Means for each Brassica are for the
average of the Brassica alone and with rye and
clover.
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Nematode research on strawberry farm
Mustard mix
rapeseed
No cover
rye
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Fall 2003 Oilseed Radish cover crop greatly
increased non-parasite nematodes in June 2004
soybean field.
Note Forage Radish plots were not analyzed for
nematodes.
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Compaction alleviation
Potential Benefits to Make Brassica Cover Crops
Pay
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Which answer to compaction?
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Brassica cover crops and their roots
Mustard
Oilseed radish
Forage radish
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Rye roots in a compacted soil
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Rye
Crimson clover
Rapeseed
Different roots for different effects
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Biodrilling
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Biodrilling to alleviate subsoil compaction
Rapeseed root
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Effect of Rye and Forage Radish cover crops on
soybean yield
Compacted silt loam in drought year, 2002
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Hayden 2004
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7 bushel soybean yield advantage following forage
radish cover crop
Hayden 2004
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Hayden Farm 2004 Soybean growing season
Subsoil, after Forage Radish
Wet
Topsoil, after Forage Radish
Dry
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practicing infiltration measurements ands
collecting runoff samples ... Preliminary
results showed extremely high infiltration on
plots after radish winter killed.
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How to fit Brassicas into common rotations?
Possible planting options.

• Direct drilling into crop residue in Aug/Sept
• Drill in early spring (end of March)
• Over seed into standing crop at senescence
• Frost-seed
• Relay crop
• Intercrop with other covers

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Broadcasting Techniques
Broadcasting by hand into soybeans at leaf
yellowing. Stand 1month after broadcasting forage
radish rye into soybeans.
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Broadcasting Techniques
Broadcasting by hand into soybeans at leaf
yellowing. Stand 1month after broadcasting forage
radish rye planted into soybeans.
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• Tyler Johnson
• Kings Grant Farm, Chestertown
• Forage Radish
• Seeded by airplane into standing corn

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Normal practice Barley cover crop drilled after
corn harvest
Forage Radish
Forage Radish, aerial seeded
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Forage Radish aerial seeded into soybeans
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Mid November Dry Matter
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Shade stunts interseeded root growth more than
shoot growth.
Rye roots not collected
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Farmer Research
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Drew Normans Brassica Trial in Harford County, MD
Oats/Peas
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Steve Groffs Brassica Cover Crop Trial in PA

• Flag Color, Cover Crop Treatments
• 1 Pink, For. Rad SpO Vtch
• 2 Green, Rapeseed SpO Vtch
• 3 Orange, Mustard SpO Vtch
• 4 Yellow, SpO Vtch only
• 5 Yellow Orange, Sun Hemp

Barns
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100
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Combined cover crop dry matter Vetch/Oats ,-
Brassica at Cedar Meadow Farm, Fall 03
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Steves Corn yields the following year (2004)
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Farmer research Steve wanted enough oats to
leave good residue cover in spring. So he and
Lisa drilled oats and radish in separate rows.
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There are still more questions than answers

• Soil compaction?
• Nematode problems?
• Weed suppression?
• Nitrogen losses?
• Spring planting?

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