Impact of Winter Weed Management and Crop …...At low weed populations, winter annual weed...
Transcript of Impact of Winter Weed Management and Crop …...At low weed populations, winter annual weed...
Impact of Winter Weed Management and Crop Rotation on Winter Annual Weeds and Soybean Cyst Nematode
Bill Johnson and Earl CreechAssociate Professor and Graduate Research Assistant
Field in Knox Co., IN, Fall 2003
Winter Annual Weed Hosts of SCNCommon Chickweed
Henbit
Shepherd’s-purse
Purple Deadnettle
Venkatesh, R., Harrison, S. K., and Riedel, R. M. 2000. Weed hosts of soybean cyst nematode (Heterodera glycines) in Ohio. Weed Technol. 14:156-160.
Winter Weed Species in Indiana Fields
---Number of fields---
10013-146310-122107-97104-6161-3
South (26)North (29)# of species/field
SCN Hosts in Indiana Fields
---Number of fields---
915-61473-43171-2040
South (26)North (29)# of SCN hosts/field*
*Confirmed hosts - henbit, deadnettle, shepherd’s-purse, field pennycress, common chickweed, smallflowered bittercress
Reproduction of SCN on Purple Deadnettle
PDN plants collected from NT soybean field at SWPAC in mid October 2004Examined roots of 10 PDN plants and found SCN cysts on 9/10
Reproduction of SCN on Purple Deadnettle
Recovered cysts from PDN and reinoculatedWilliams soybean varietyRecovered new cysts from soybean after 6 weeks1st confirmed report of SCN reproduction on PDN in the field.
Creech, J. E., Johnson, W. G., Faghihi, J., Ferris, V. R., and Westphal, A. 2005. First report of soybean cyst nematode reproduction on purple deadnettle under field conditions. Online. Crop Management doi:10.1094/CM-2005-0715-01-BR.Venkatesh, R., Harrison, S. K., Regnier, E. E., and Riedel, R. M. 2004. Purple deadnettle effects on soybean cyst nematode populations in no-till soybean. Proc. North Central Weed Sci. Soc. 59:56.4.
Soybean Cyst Nematode (SCN)
Microscopic round wormCysts contain up to 600 eggsFound in most soybean growing regions of U.S.In 2002, estimated yield losses in U.S. were $783.8 million (Wrather et al. 2003)
Wrather, J. A., S.R. Koenning, and T.R. Anderson. 2003. Effect of diseases on soybean yields in the United States and Ontario (1999-2002). Online. Plant Health Progress doi:10.1094/PHP-2003-0325-01-RV.
SCN Management Recommendations
1. Crop rotation2. SCN resistant
varieties
Role of winter annual weed
management??
Objectives
To determine the effect of various winter weed management tactics and crop rotation on:
1. SCN populations 2. Winter weed seedbank
Materials and MethodsSeptember 2003Agronomy Center for Research and Education (ACRE)
Chalmers silty clay loamLow weed, low SCN
Southwest Purdue Agricultural Center (SWPAC)
Patton silt loamHigh weed, high SCN
SWPAC
ACRE
Treatments
Split-plot design with 6 replicationsCrop Rotations
1. Soybean-Soybean2. Soybean-Corn
Winter Weed Management Tactics1. No herbicide application2. Fall + spring herbicide applications3. Spring herbicide application4. Fall herbicide application 5. Annual ryegrass cover crop6. Winter wheat cover crop
Materials and Methods
Plots measured 9.1 x 12.2 mWinter wheat border around plots to prevent soil movementGlyphosate or glufosinate for fall, spring, and in-crop applications Burndown application prior to plantingCrops planted in 76 cm rowsLong term experiment (at least 4 growing seasons)
Data CollectionHarvested center 4 (SWPAC) or 8 (ACRE) rows of plots and adjusted soybean yields to 13% moisture38 soil cores/plot at harvest and at planting
1. SCN counts by Purdue Nematology Lab2. Weed seedling emergence
technique1,500 cc soil26 x 26 cm flats
Data Analysis
RCBD with 12 replicationsSCN and seedbank data were analyzed with covariate analysis. Mean separations with t-tests.Yield data subjected to ANOVA and means separated with Fisher’s Protected LSD.
Number of Seedlings Emerged from Seedbank – SWPAC (2004)
No WeedControl
Weed Free SpringApplied
Herbicide
FallApplied
Herbicide
FallSeededWheat
FallSeeded
Ryegrass
# se
edlin
gs /
1500
cc
soil a
cc
bc
b b
62
2731
38
45 45
Number of Seedlings Emerged from Seedbank – ACRE (2004)
No WeedControl
Weed Free SpringApplied
Herbicide
FallApplied
Herbicide
FallSeededWheat
FallSeeded
Ryegrass
# se
edlin
gs /
1500
cc
soil a
cdd
bcd bcb
18
2.21.2
2.5 2.94.1
SCN Egg Density - SWPAC
0
1000
2000
3000
4000
5000
6000
Spring 2004 Fall 2004 Spring 2005
SCN
egg
s / 1
00 c
c so
il
No Weed ControlWeed FreeSpring Applied Herb.Fall Applied Herb.Fall Seeded WheatFall Seeded Ryegrass
Treatment
P = 0.7156
SCN Egg Density - ACRE
0
50100
150
200250
300
350400
450
Spring 2004 Fall 2004 Spring 2005
SCN
egg
s / 1
00 c
c so
il
No Weed ControlWeed FreeSpring Applied Herb.Fall Applied Herb.Fall Seeded WheatFall Seeded Ryegrass
Treatment
P = 0.1904
Purple Deadnettle and Henbit Density
ACRE – less than 1 plant /sq. m.SWPAC – 12 plants / sq. meter
2004 Soybean Yield - SWPACSo
ybea
n yi
eld
(kg/
ha)
No WeedControl
Weed Free SpringApplied
Herbicide
FallApplied
Herbicide
FallSeededWheat
FallSeeded
Ryegrass
aa a a
aa
35403140 3200 3110
3430 3510
2004 Soybean Yield - ACRESo
ybea
n yi
eld
(kg/
ha)
No WeedControl
Weed Free SpringApplied
Herbicide
FallApplied
Herbicide
FallSeededWheat
FallSeeded
Ryegrass
ab aba ab
bc
3910 39404160 4050
34803780
Conclusions
1. To reduce seedbank, spring herbicide application timing most effective
2. Winter wheat negatively influenced soybean yield on heavier soils
3. At low weed populations, winter annual weed management does not appear to impact SCN egg density
4. However, the story is not complete!
Future Studies
Fall weed control timing may be the most important factorFocus on fields that contain the best overall host – purple deadnettle
Thanks!Indiana Soybean BoardUSDA NCIPM Competitive Grants Program