Cover Crops for Pest Management and Weed Suppression - Plumer

Cover Crop Benefitsin

Agriculture Production

Michael Plumer

Cover Cropsmanaging for benefits

• Radish weed control, nematode reduction

• Cereal rye weed control, nematode reduction

• Hairy vetch weed control by mulch• Annual ryegrass nematode reduction, mulch

effect• Crimson clover mulch effect• Rapeseed disease reduction, nematode

reduction• Spring oats fall weed control

Disease Reduction by Cereal rye and rapeseed

3 year study at 8 locations in Illinois

• Septoria brown spot- significant reduction behind cover crop, especially following cereal rye

• Bacterial blight –no infection found behind cover crop

Bond, SIU—Eastburn, U of Il.

Disease Reduction

• Rhizoctonia – significantly reduced with cereal rye and rapeseed

– Increased soybean stand behind cereal rye and rapeseed

– Reduction in Rhizoctonia lesions

– Soybean yield significantly higher following cereal rye vs no cover crop

Bond, SIU—Eastburn, U of Il

Rapeseed in late April controlling winter annuals

Soybean after green manure of rapeseedSoybean – No winter cover cropSDS showing

Disease suppression by crops

Treatment SCN

eggs/100cc

Changes in

Egg count

SDS Foliar

Disease

DX 8/26

Foliar

Disease

AUDPC

Yield

(bu/A)

Fallow (No winter crop) +589 a 25.2 a 157.7 a 65.4 b

Cover crop (rapeseed) -313 b 16.8 b 103.9 a 67.5 ab

Green manure (rapeseed) -691 b 5.5 c 37.1 b 69.6 a

P > F .002 .0001 .001 0.07

Means followed by the same letter are not significant (P=0.05), according to Fisher’s LSD test.

J. Bond, SIU

Soybean cyst nematodes

• Significant reductions following cereal rye and rapeseed at all 8 locations all 3 years

3 year 8 location summary

• Cereal rye and rapeseed showed that they provided increased protection of soybeans against the effects of:

– SDS

– Rhizoctonia

– Soybean cyst nematodes

– Brown stem rot ----cereal rye

Bond, SIU --Eastburn, U of Il.

Soybean

Cyst

nematode

suppression

by annual

ryegrass

Treatment NW Plot yield SW Plot yield

Bare soil 48.9 48.2

Cereal rye 53.8 52.3

Annual ryegrass 55.7 60.6

Plumer, U of Il

Soybean Cyst Nematodes

Egg Count

Bare Cereal Rye Annual Ryegrass

NW 7533 717* 117**

SW 3650 320* 0**

LF 1559 722* 386*

JA 1202 390* 279*

Dense stand of crimson clover controlling winter annuals and early spring weeds

Annual ryegrass winter annual control

Ryegrass suppression of Palmers amaranth

U of Florida

Ryegrass cover crop

Hairy Vetch, mulch controlling most winter annuals

Hairy vetch mulch with only 2,4-D, atrazineWeed control variable due to speed of vetch decomposition

difference in vetch varieties

Understanding what a good stand really is for weed control

Annual ryegrass with vetch and crimson clover 5 days after herbicide application--2,4-D and 1.25# ae glyphosateControls winter annuals

Understanding cereal rye and weed control

• Good allelophathy when young

• Requires uniform stand seeded on time– Same time as wheat for best control

• Seeding rate for weed control 70-90#/a– Depends on planting date

• For good weed control must grow till anthesis– Earlier kill, reduces level of weed control -- only

winter annuals

• There are significant differences in varieties

Weed Control

• Controlling resistant weeds with cereal rye

– Glyphosate resistant marestail (horseweed)

• Herbicide program: $40/a + not always effective

• Cereal rye $16-24/a

– Mulch and allelopathy effect from high residue cereal rye cover crop

Aerial seed with cereal rye, radishHad sunlight on the ground at seeding

Serious mares tail population, 3 year study

Cereal rye70#/a

WEED CONTROL

Plumer2012

Replicated trial, rye residue removed mid May 2013

% Resistant Marestail Controlwith cereal rye cover crop

0

20

40

60

80

100

120

14 day rating 30 day rating

no rye-- 2 glyphosateapplications

rye removed

rye cover

3 year study; 8 replications

Glyphosate sprayed mid May and 2 weeks later at 1.5#/a ae

Uniform solid stand is critical for weed control

Rye at pollination, only time to get good controlby crimping– ave. 95+%

Crimped and drilled soybeans

This is the level of rye cover that is neededfor good weed control

Stage of

growth when

cereal rye can

damage corn

the most

Allelopathy issues

Corn must be planted 2” deep and slot tightly closedto reduce problem, or wait 2 weeks after killing rye to plant

Mature cereal rye mulch with only glyphosate

burndown- June planting

Corn into high residue issues

• Cover crop removes all the nitrogen in top 12” of soil- soil tests show < 3#/a at cover termination

• Requires in furrow nitrogen, and/or 50-70#/a surface applied at planting- issue of tie up surface applied as well—or 30+ #/a starter

• Early research shows cover crop nitrogen takes temperature, moisture and time to become available

Oats and radish controlling winter annuals

New radish developments

• 2014 there were 34 different varieties

• Many have totally different qualities

– Kill different nematodes or propagates nematodes

– Michigan State University doing extensive work

• Work starting on evaluation for soybean cyst nematode, root knot nematode, sugar beet nematode, corn nematodes

Radish- which one do you want

Consider cover crop strip till

• Requires precision planting

• Requires good GPS autosteer/RTK

• Needs to be timely– Getting it planted on time is important

• Reduce seeding rate in strip– Radishes 1—1.5#/a

– Rapeseed 3-4#/a

• Controls winter and early weeds while providing “bare, tilled” row for early planting

How to plant one cover crop in 30” rows

Bio-strip till with radish and rapeseed

Bio strip till 30” cover crops

1.5#/a radish Rapeseed 2#/a

Feb. 15

Planting on bio-till row of dead Radish

Seeding on the Radish winter killed row—notice low residue in row

Establishment –early or perennial cover crops

• Annual ryegrass/legumes establishment at V-6 to7

• Seeding middles onlyimproves establishment andplanting crop next spring in strips

• Use less seed• Increased fall growth• Better winter hardiness• Increased fall grazing• Improve weed control

Dr. W Curran, Penn State U.

Weeds

If Tillage and Herbicides controlled weeds---

Why are we still doing it every year??

Dr. D. Beck

Questions??