Weed Management in Irrigated and Dryland Cropping Systems

WEED MANAGEMENT IN IRRIGATED AND DRYLAND CROPPING SYSTEMS

Sponsoring Institution

National Institute of Food and Agriculture

Project Status

TERMINATED

Funding Source

HATCH

Reporting Frequency

Annual

Accession No.

0189868

Grant No.

(N/A)

Project No.

MONB00657

Proposal No.

(N/A)

Multistate No.

(N/A)

Program Code

(N/A)

Project Start Date

Oct 1, 2001

Project End Date

Oct 1, 2006

Grant Year

(N/A)

Project Director
Mickelson, J. A.

Recipient Organization
MONTANA STATE UNIVERSITY
(N/A)
BOZEMAN,MT 59717

Performing Department
SOUTHERN AGRI RES CENTER

Non Technical Summary
In irrigated and dryland crops of Montana, high populations of many weeds are present. If allowed to compete, weeds cause substantial crop yield loss, contaminate grain, and cause problems with irrigation and harvest practices. This research seeks to improve weed management practices in irrigated and dryland cropping systems of Montana by developing efficient and environmentally sound weed management practices.

Animal Health Component

(N/A)

Research Effort Categories

Basic

10%

Applied

90%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
213	2300	1140	10%
213	4020	1140	10%
213	1410	1140	10%
213	1541	1140	10%
213	2010	1140	20%
213	1640	1140	10%
213	1510	1140	10%
213	1550	1140	20%

Knowledge Area
213 - Weeds Affecting Plants;

Subject Of Investigation
1640 - Alfalfa; 1550 - Barley; 2010 - Sugar beet; 4020 - Fungi; 1541 - Hard red spring wheat; 1510 - Corn; 2300 - Weeds; 1410 - Beans (dry);

Field Of Science
1140 - Weed science;

Goals / Objectives
1. Evaluate registered and experimental herbicides for use in integrated weed management strategies for irrigated and dryland cropping systems of south-central Montana. 2. Quantify the effects of showy milkweed competition on irrigated malt barley and sugar beet yield and quality. Determine if seed production and/or vegetative reproduction significantly contribute to the survival and proliferation of showy milkweed populations in irrigated barley and sugar beet fields. Identify possible management strategies for showy milkweed in sugar beet - barley rotations. 3. Determine the effects of soil moisture potential on wild oat seed mortality and fungi associated with wild oat seeds collected from the soil seedbank. Determine if exposure to Penicillium spp. can cause mortality in wild oat seeds.

Project Methods
Objective 1. Field experiments will be conducted on-station at the Southern Agricultural Research Center and at off-station locations with farmer-cooperators. Experiments will be conducted to evaluate registered and experimental herbicides and factors that affect herbicide performance in sugar beet, barley, wheat, corn, dry beans, and alfalfa. Weed control will be evaluated visually and by sampling weed biomass. Crop tolerance will be evaluated visually and by collecting crop yield data. Objective 2. Experiments will be conducted in irrigated barley and sugar beet fields with a history of milkweed infestation. At each site, plots will be established in areas of the field so that a range of low to high milkweed density areas are represented. Soil samples will be collected in the spring to determine the milkweed seedbank density. A sample of milkweed shoots will be exhumed to determine the proportion of shoots that originated from seed versus root buds. For shoots that originated from root buds, the depth of the root bud will be determined. Samples of milkweed seed from each field will be collected to determine seed viability. At crop maturity, weed and crop biomass and yield parameters will be collected. Objective 3. Field experiments will be conducted to determine the effects of soil moisture potential on weed seed mortality and fungi associated with weed seeds. Wild oat will be used as a model weed species. The experiments will be conducted at the Montana State University Southern Agricultural Research Center. The experiment consists of four supplemental irrigation treatments (0, 2.5, 5.0, and 10 cm of water applied per 4 week period) in a randomized complete block design with three replicates. The experiment will be conducted and evaluated over a two year period. Wild oat seedbanks will be established in the center of each plot in the fall. Plot area surrounding the seedbank will be tilled in the spring and fall and wheat will be planted in rows spaced 30 cm apart at a seeding rate of 27 kg/ha. Seedbank areas of plots will be sampled by removing 3.8-cm dia by 15-cm deep soil cores to estimate the viable seedbank population and to isolate fungi from wild oat seeds. Soil will be sampled each fall and spring, beginning in the fall of the seedbank establishment year. Seeds retrieved from a portion of the soil samples will be tested for viability. Seeds retrieved from the remaining soil samples will be plated on growth media to identify fungi associated with wild oat seeds. Lab experiments will be conducted using a model fungus species to demonstrate the potential ability of microorganisms to cause mortality of weed seeds. The experimental design is a randomized complete block with six replicates and each experiment will be repeated. Treatments consists of two species of seeds (wild oat and wheat) applied with or without an imazalil seed protectant, placed in two soils (silt loam and clay loam), and inoculated with or without Penicillium. Fifty seeds will be added to soil in petri dishes. The seeds will be incubated at 17 C for 8 weeks. Seeds will then be tested for viability or incubated to determine percent of seeds colonized by Penicillium.

Progress 10/01/01 to 10/01/06

Outputs
1) Research was conducted to evaluate and optimize the use of herbicides as a component of integrated weed management strategies for irrigated and dryland cropping systems of south-central Montana. Eighty five field experiments have been conducted from 2001 to 2003 to optimize the use of herbicides in sugar beet, barley, spring and winter wheat, corn, dry bean, soybean, dry peas, alfalfa, and in fallow. 2) Research conducted on showy milkweed indicates that milkweed population increases within a field are likely due to vegetative reproduction, however, seeds may be partly responsible for establishment of new populations at uninfested sites. Observations indicate that showy milkweed shoots can emerge from pieces of rootstock located below the plow layer, thus moldboard plowing may not be an effective management tool. The 2001 barley and sugar beet yield data confirm the results of the 2000 data and suggest that within milkweed patches, milkweed is very competitive and can greatly reduce crop yields. However, in 2001 yield loss due to milkweed intereference was not as great as yield loss in 2000. Crop yield loss on a field scale is dependent on how much of a field is infested with milkweed patches. If estimates of crop yield loss are accurate, costly herbicide applications may be justified if they can be applied to the patches only. Broadcast applications of herbicides to fields are probably not justified unless a large portion of the field is infested with milkweed. Alternative methods of control may need to be identified in the future. 3) Field experiments were conducted near Huntley, MT to determine the effects of soil water content on wild oat seed mortality and seedling emergence. Seedbanks were sampled each fall and spring (beginning in the fall of the establishment year) by removing 3.8-cm dia by 15-cm deep soil cores to estimate the viable seedbank. Wild oat seedling emergence was determined during the growing season by counting and removing newly emerged seedlings at 7 to 10 day intervals. Soil water content in the top 15 cm of soil was measured twice per week using a time domain reflectometry based sensor unit. Regression analysis was used to relate mean soil water content (% volumetric basis from June through September) to mortality and emergence parameters. Mean soil water content ranged from 6 to 24% in 2000 and 8 to 22% in 2001. As mean soil water content increased, total seed bank decline over a 1 year period increased linearly ranging from 81 to 88% during the first year for seed banks established in 1999, 63 to 91% during the first year for seed banks established in 2000, and 66 to 99% during the second year for seed banks established in fall of 1999. Differences in slopes of the linear relationships occurred between years. Differences in wild oat seedling emergence pattern occurred among treatments and emergence occurring during the fall was affected by mean soil water content. However, total seedling emergence (% of the seed bank) was not related to mean soil water content.

Impacts
This research will result in improved management strategies for irrigated and dryland cropping systems in Montana including sugar beet, barley, spring and winter wheat, forage and seed alfalfa, corn, dry bean, and soybean. Improved management strategies will likely result in more profitable cropping systems that utilize herbicides more efficiently, safely, and with less risk of negative impacts on the environment.

Publications

Mickelson, J.A., and Stougaard, R.N. 2003. Assessment of soil sampling methods to estimate wild oat seed bank populations. Weed Sci. 51:226-230.
Mickelson, J.A., Bussan,A.J., Davis E.S., Hulting A., and Dyer, W.E. 2004. Post harvest kochia (Kochia scoparia) management with herbicides in small grains. Weed Technol. Vol. 18, Issue 2.

Progress 01/01/02 to 12/31/02

Outputs
1) Research was conducted to evaluate and optimize the use of herbicides as a component of integrated weed management strategies for irrigated and dryland cropping systems of south-central Montana. Thirty field experiments were conducted in 2002 in sugar beet, barley, spring and winter wheat, forage and seed alfalfa, corn, dry bean, and soybean. 2) Field research trials were conducted to evaluate the effectiveness of post harvest herbicide applications in barley for controlling showy milkweed. Glyphosate at 1.125 lb ae/A provided 95% control of showy milkweed 1 year after treatment. Other treatments containing higher rates of glyphosate or tank mixtures with glyphosate provided similar control of showy milkweed but are more costly. 2,4-D alone provided less than 50% control of milkweed 1 year after treatment. Dicamb + diflufenzopyr treatments provided 75 and 96% control at low and high rates, respectively, 1 year after treatment. 3) Field experiments were conducted near Huntley, MT to determine the effects of soil water content on wild oat seed mortality and seedling emergence. Mean soil water content ranged from 6 to 24% in 2000 and 8 to 22% in 2001. As mean soil water content increased, total seed bank decline over a 1 year period increased linearly ranging from 81 to 88% during the first year for seed banks established in 1999, 63 to 91% during the first year for seed banks established in 2000, and 66 to 99% during the second year for seed banks established in fall of 1999. Differences in slopes of the linear relationships occurred between years. Differences in wild oat seedling emergence pattern occurred among treatments and emergence occurring during the fall was affected by mean soil water content. However, total seedling emergence (% of the seed bank) was not related to mean soil water content.

Impacts
This research will result in improved management strategies for irrigated and dryland crops including sugar beet, barley, spring and winter wheat, forage and seed alfalfa, corn, dry bean, and soybean. Improved management strategies will likely result in more profitable cropping systems that utilize herbicides more efficiently, safely, and with less risk of negative impacts on the environment.

Publications

Mickelson, J. A., M. G. Particka, and N. D. Flowers. 2002. Influence of soil water content on wild oat seed mortality and seedling emergence. Proc. West. Soc. Weed Sci. 55:28.
Particka, M. G., J. A. Mickelson, and N. D. Flowers. 2002. ALS resistant kochia management in a barley - sugar beet rotation. Proc. West. Soc. Weed Sci. 55:32.

Progress 01/01/01 to 12/31/01

Outputs
1) Research was conducted to evaluate and optimize the use of herbicides as a component of integrated weed management strategies for irrigated and dryland cropping systems of south-central Montana. Thirty-one field experiments were conducted in 2001 in sugar beet, barley, spring and winter wheat, forage and seed alfalfa, corn, dry bean, and soybean. 2) Research on showy milkweed indicates that milkweed population increases within a field are likely due to vegetative reproduction, however, seeds may be partly responsible for establishment of new populations at uninfested sites. Observations indicate that showy milkweed shoots can emerge from pieces of rootstock located below the plow layer, thus moldboard plowing may not be an effective management tool. The 2001 barley and sugar beet yield data confirm the results of the 2000 data and suggest that within milkweed patches, milkweed is very competitive and can greatly reduce crop yields. However, in 2001 yield loss due to milkweed intereference was not as great as yield loss in 2000. Crop yield loss on a field scale is dependent on how much of a field is infested with milkweed patches. If estimates of crop yield loss are accurate, costly herbicide applications may be justified if they can be applied to the patches only. Broadcast applications of herbicides to fields are probably not justified unless a large portion of the field is infested with milkweed. Alternative methods of control may need to be identified in the future. 3) Field experiments were conducted near Huntley, MT to determine the effects of soil water content on wild oat seed mortality and seedling emergence. Seedbanks were sampled each fall and spring (beginning in the fall of the establishment year) by removing 3.8-cm dia by 15-cm deep soil cores to estimate the viable seedbank. Wild oat seedling emergence was determined during the growing season by counting and removing newly emerged seedlings at 7 to 10 day intervals. Soil water content in the top 15 cm of soil was measured twice per week using a time domain reflectometry based sensor unit. Regression analysis was used to relate mean soil water content (% volumetric basis from June through September) to mortality and emergence parameters. Mean soil water content ranged from 6 to 24% in 2000 and 8 to 22% in 2001. As mean soil water content increased, total seed bank decline over a 1 year period increased linearly ranging from 81 to 88% during the first year for seed banks established in 1999, 63 to 91% during the first year for seed banks established in 2000, and 66 to 99% during the second year for seed banks established in fall of 1999. Differences in slopes of the linear relationships occurred between years. Differences in wild oat seedling emergence pattern occurred among treatments and emergence occurring during the fall was affected by mean soil water content. However, total seedling emergence (% of the seed bank) was not related to mean soil water content.

Impacts
This research will result in improved management strategies for irrigated and dryland crops including sugar beet, barley, spring and winter wheat, forage and seed alfalfa, corn, dry bean, and soybean. Improved management strategies will likely result in more profitable cropping systems that utilize herbicides more efficiently, safely, and with less risk of negative impacts on the environment.

Publications

No publications reported this period