NC202: Characterizing Weed Population Variability for Improved Weed Management Decision Support Systems to Reduce Herbicide Use

(Multistate Research Project)

Status: Inactive/Terminating

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SAES-422 Reports

Annual/Termination Reports:

[08/22/2002] [07/25/2003] [10/25/2004] [10/06/2005]

Date of Annual Report: 08/22/2002

Report Information

Annual Meeting Dates: 07/16/2002 - 07/17/2002
Period the Report Covers: 07/01/2001 - 07/01/2002

Participants

John Lindquist, Stevan Knezevic, Shawn Hock, and Brescia Terra Nebraska, Jim Kells, Karen Renner, and Corey Guza Michigan, Ed Luschei Wisconsin, Christy Sprague Illinois, Sharon Clay South Dakota, Gregg Johnson Minnesota, Kathrin Schirmacher and Konanani Liphadzi Kansas, George Kegode North Dakota, Joel Felix Ohio, Frank Forcella USDA Minnesota, Jack Dekker Iowa, Susan Ratcliffe CSREES Regional IPM facilitator, Illinois, Randy Woodson Administrative Advisor, Indiana

Brief Summary of Minutes

The meeting was started at 8:00 a.m. July 16, 2002 with a welcome from UNL representatives, introductions, an update from our Administrative Advisor, and an introduction to the Regional IPM coordinator followed by a discussion about our role in implementing IPM. We then spent nearly 3 hours discussing the status of and future plans on our efforts to accomplish Objective 1 Understand the basis and relative importance of variability in weed/crop competition. After lunch, we spent 2 _ hours discussing our progress and future plans for accomplishing Objective 2 Understand the variability of weed seed in the soil seedbank and its impact on weed/crop competition. We concluded the afternoon with a discussion of where we are with objective 3 Develop DSS modules to incorporate risk into weed management recommendations. On Wednesday morning, July 17, 2002, we concluded unfinished business from the day before and made several administrative decisions.

Minutes Attachment:

Attachment

Accomplishments

Objective 1 - Understand the basis and relative importance of variability in weed/crop competition Protocol studies had been designed to determine the relative competitive indices of selected annual weeds in corn and soybeans (1a) and the effect of relative time of emergence on relative competitive indices (1b) using the biomass of individual weed plants as surrogates for competitiveness. An expanded protocol (1e and 1f) designed to obtain the same information using corn and soybean yield loss was optional. Objectives 1 c and d were not discussed because they are to be completed during years 3-5. Participants are listed in Appendix 3. Shawn Hock (NE) described results of research into Objective (1a) and (1b). The Nebraska group planted 12 weed species (8 broadleaf and 4 grass) at two soybean row spacings and two locations. Shawn outlined some problems with weed establishment, particularly with Pennsylvania smartweed and late-planted cohorts (due to drought). Frank Forcella (USDA/ARS, MN) noted that smartweed germination could be improved with prolonged cold-water soaking treatments (1 month at 4 deg C). Kathrin Schirmacher (KSU) presented more results from Objective 1a and b. KSU examined four broadleaf (ABUTH, AMAPA, CHEAL, HELAN) and four grass (DIGSA, PANDI, SETFA and SORVU) weeds in corn and soybean. They found the relative competitive indices on a per-individual basis to be 6/6/4/10 for the broadleaves and 0.1/0.2/0.3/3.0 for grasses. The KSU crew also implemented the objective 1e and f protocol and found that the biomass ranks differed from the competitive impact ranks. It was noted that the yields at that site/year were very low. Corey Guza (MI) summarized his work on two studies designed to complete objectives 1a and 1b (study 1) and 1e and 1f (study 2) in corn. Study 1 involved 8 weed species at 4 planting times. In study 2, good populations and uniformity were achieved using 3 species and an untreated area. Approximately 5% of the study was lost due to soil water problems. Some irrigation was used to save plots that might have otherwise perished. Due to problems with survival of late emerging seedlings, the group discussed the pros and cons of adopting an emergency irrigation treatment. Sharon suggested that we should water fields to their historical averages. There was no firm consensus on the best course of action, though most agreed that irrigation was preferable to losing a treatment altogether. Sharon Clay then presented a re-analysis of the corn-foxtail interference data. She plotted estimates of the i and a parameters of the conventional yield-loss function against number of growing degrees days from emergence to physiological maturity and found a strong negative correlation, indicating that a shorter season brought on by stress resulted in greater yield reduction from weeds. Sharon also presented data on the rate of nitrogen uptake in weedy and weed-free plots. They found the rate (on a per-plant basis as a function of nitrogen levels) to be the same. Therefore, it might be feasible to predict weed size from nitrogen level. Objective 2 Understand the variability of weed seed in the soil seedbank and its impact on weed/crop competition. Protocol studies had been designed to assess (2a) the fates of weed seed in the soil seed bank, (2b) weed seed decay due to depth, field site, and cropping system, and (2c) the predictability of seedling emergence from the weed seedbank. Most of our discussions were on objective 2b, as it was the most widely implemented protocol. Objective 2c will be addressed during years 3-5. Participants are listed in Appendix 3. The discussion of Objective 2b began with Karen Renner (MI) stepping forward as moderator. The group began by providing current updates of the activities of all states. Iowa State (Dekker) had extensive measurements of the fate of giant foxtail seed in soil using a seeded core method of study (Objective 2a). Minnesota (Forcella) examined fall chisel, no-till and moldboard plow systems and the fate of velvetleaf, giant foxtail and lambsquarters at 0, 2 and 10 cm depth. They divide the year into two segments (Oct April Oct) and harvested/planted bags at the beginning and end of the cycles. Gregg Johnson (MN) was also investigating objective 2b. Wisconsin (Luschei) examined five species, those used by MN + wild proso millet and yellow foxtail. Depths and evaluation times were the same as MN. WI used three systems: a conventional continuous corn system using pre- and post-emergence herbicides as well as row cultivation, no-till and no-chem system that used cultivation and rotary-hoeing for weed control. Illinois used the three core species plus giant ragweed, common water hemp and woolly cupgrass. They used the same depths and systems as MN but had three different types of evaluation timings (Oct Oct, Oct April Oct, Oct April July Oct). Sprague (IL) also mentioned enlisting the cooperation of a soil microbiologist to investigate the microbial community biomass on the surface of the seeds in various treatments. Ohio State (Joel Felix) examined velvetleaf only, but had several different types of treatments that involved moving bags between different soil depths at certain times (the method was designed to mimic the position in the profile that one would likely find weeds after agronomic operations). Luschei (WI) suggested performing reciprocal transplant studies to eliminate some of the potential biases in selecting seed for study and enhancing the ability to investigate the influence of environmental effects on seed fate. Several states noted interest. An involved discussion began as to what methods were appropriate and economical to assess the final state of seeds after burial treatments. Among the methods used were: tetrazolium test to assess viability, germination tests to assess viability or germinability, forceps or pressure tests to assess viability. Many states noted that predation occurred on bags located on the soil surface, particularly of the large seeded weeds. Objective 3 Develop DSS modules to incorporate risk into weed management recommendations. Lynn Bills (UNL) explained the algorithms involved in the decision support tool WeedSoft (WS). WS is a heuristic management tool based on expert opinion and small-scale experimentation. The WS development group uses user-input cropping system data and a prediction of the economic value of weed impact to help select the most economical weed control measures for a given field. The strength of WS was in the yield-loss estimation, which included adjustments for crop health, row spacing and relative emergence time. From its inception, the first objective of NC202 was designed to evaluate whether the yield loss estimates would be stable across the region. Bills noted that the decision support system (DSS) is being locally adapted to many states throughout the region. The current objective 1 is designed to provide data that will be used to adjust these yield loss estimates within the local versions of WeedSoft. While WS incorporates a rough categorization of potential weed population effects of particular management strategies, the estimates are based on product efficacy data and not studies of realized population growth rates. It was noted that there is a natural fit between the activities of the NC202 group and the WS development team. There was strong support from the entire group for encouraging further collaboration between the WS team and the NC202 group. It was suggested that group activities at the 2002 North Central Weed Science Society meeting (NCWSS) be made to overlap in order to facilitate the communication between these two groups. Members of NC202 also will attend the regional WS meeting in September, 2002. In order to realize the full potential usefulness of the research being conducted within the NC202 group, it was emphasized that a formal economic analysis incorporating risk into the decision making process is needed. By using stochastic life-cycle models in combination with economic models, the NC202 group will be able to couch forecasts of the weed population consequences of management tactics considered in the WS DSS in probabilistic terms. This would be an important step in the evolution of WS from a heuristic-based expert system to scientific forecasting tools. A formal plan for moving the risk-based bioeconomic analysis forward was drawn up that included delivery of data to one and possibly several agricultural economists and the issuance of a preliminary report at the December NCWSS meeting. John Lindquist and Jack Dekker both said they would contact ag economist Paul Mitchell (TX), who was unable to attend the 2002 meeting due to scheduling. Frank Forcella (USDA-ARS) stated that he would approach Dave Archer (USDA MN) about possibly assisting with the economic and risk analysis. George Kegode (NDSU) also will contact an agricultural economist he worked with at NDSU. Bruce Maxwell (MT) remains interested in NC202 and is becoming more involved in risk analysis research. Participants in the planning stage for this objective are listed in Appendix 3. Jim Kells passed out a recently completed paper comparing the economic performance of three postemergence weed control decision aids (Swinton et al. 2002). Action Plans and Administrative Decisions There was unanimous support for drawing together a regional extension publication of competitive impact and weed seed population dynamics. Such a publication would provide valuable information to both growers and the research community. This publication could potentially impact tens of thousands of acres of corn and soybean production across the region. Jim Kells raised the question of how many site-years were necessary to answers the questions implicit in objective 1. For corn, there was a current tally of 12 site-years of data and there would be 18 by the end of 2003. For soybean, there were 11 site-years currently with another 8 possible next year. For corn and soybean, there were currently 6 site-years with another 8 possible. Jim suggested that we compile data before the NCWSS meeting in order to answer the question of whether current data was sufficient to meet objectives. Kathryn Schirmacher from KSU agreed to collate data sets for objectives 1a and 1b in corn. She will solicit data from MN, IL, MI and ND. Shawn Hock (NE) will collect the soybean data for objectives 1a and b, obtaining data from MN, SD, ND, and KS. Corey Guza (MI) will work on collecting and processing the corn and soybean data for objective 1e, obtaining data from NE, WI, ND, and KS. Karen Renner (MI) agreed to collate and summarize the objective 2 data. These individuals will also be in charge of data analysis and manuscript preparation. Ed Luschei agreed to send out a request for multi-species competitive impact data (from the previous five year project), analyze those data, and write up the manuscript. The 2003 NC202 annual meeting will be held July 15 & 16 (tentative), 2003 in Champaign/Urbana Illinois. Christy Sprague has agreed to serve as local host and vice chair. John

Publications

Publications in 2002: Buhler, D. D. 2002. Challenges and opportunities for integrated weed management. Weed Science 50:273-280. Cardina, J., C. P. Herms, and D. J. Doohan. 2002. Crop rotation and tillage system effects on weed seedbanks. Weed Science 50:448-460. Conley, S. P., L. K. Binning, C. M. Boerboom, and D. E. Stoltenberg. 2002. Estimating giant foxtail cohort productivity in soybean based on weed density, leaf area, or volume. Weed Science 50:72-78. Dekker J., M. Hargrove. 2002. Weedy adaptation in Setaria spp.: V. Effects of gaseous environment on giant foxtail (Setaria faberii R. Hermm.) (Poaceae) seed germination. American Journal of Botany 89(3):410-416. Dekker, J., J. Lathrop, B. Atchison, and D. Todey. 2001. The weedy Setaria spp. phenotype: How environment and seeds interact from embryogenesis through germination. Proceedings of the Brighton Crop Protection Conference-Weeds 2001:65-74. Fischer D. W. and R. G. Harvey. 2002. Yellow nutsedge (Cyperus esculentus) and annual weed control in glyphosate-resistant field corn (Zea mays). Weed Technology 16:482-487. Gower, S. A., M. M. Loux, J. Cardina, and S. K. Harrison. 2002. Effect of planting date, residual herbicide, and postemergence application timing on weed control and grain yield in glyphosate-tolerant corn (Zea mays). Weed Technology 16:488-494. Hoffman, M. L. and D. D. Buhler. 2002. Utilizing Sorghum as a functional model of crop-weed competition. I. Establishing a competitive hierarchy. Weed Science 50:466-472. Hoffman, M. L., D. D. Buhler, and E. E. Regnier. 2002. Utilizing Sorghum as a functional model of crop-weed competition. II. Effects of manipulating emergence time or rate. Weed Science 50:473-478. Johnson, G. A. and T. R. Hoverstad. 2002. Effect of row spacing and herbicide application timing on weed control and grain yield in corn (Zea mays). Weed Technology 16:548-553. Knezevic, S. Z. S. P. Evans, E. Blankenship, R. C. Van Acker, and J. Lindquist. 2002. Critical period for weed control: The concept and data analysis. Weed Science (in press). Moechnig, M. J., D. E. Stoltenberg, C. M. Boerboom, and J. M. Norman. 2002. Canopy development, biomass accumulation, and corn-yield loss as influenced by time of weed emergence. Weed Sci. Soc. Am. Abstr. 42:45. Murphy, C. and J. L. Lindquist. 2002. Growth response of velvetleaf to three post emergence herbicides. Weed Science 50:364-369. Nelson, K. A., K. A. Renner, and D. Penner. 2002. Yellow nutsedge (Cyperus esculentus) control and tuber yield with glyphosate and glufosinate. Weed Technology 16:360-365. Nelson, K. A. and K. A. Renner. 2002. Yellow nutsedge (Cyperus esculentus) control and tuber production with glyphosate and ALS-inhibiting herbicides. Weed Technology 16:512-519. Retrum, J. and F. Forcella. 2002. Giant foxtail (Setaria faberi) seedling assay for resistance to sethoxydim. Weed Technology 16:464-466. Shrestha, A., S. Z. Knezevic, R. C. Roy, B. R. Ball-Coelho, and C. J. Swanton. 2002. Effect of tillage, cover crop and crop rotation on the composition of weed flora in a sandy soil. Weed Research 42:72. Swinton, S. M., K. A. Renner and J. J. Kells. 2002. On-Farm Comparison of Three Postemergence Weed Management Decision Aids in Michigan. Weed Technology 16(3): 691-698. Tharp, B. E. and J. J. Kells. 2002. Residual herbicides used in combination with glyphosate and glufosinate in corn (Zea mays). Weed Technology 16:274-281. Traore, S., J. L. Lindquist, A. R. Martin, D. A. Mortensen, and S. C. Mason. 2002. Comparative ecophysiology of grain sorghum and Abutilon theophrasti in monoculture and in mixture. Weed Research 42:65-75. Tranel, D., J. Dekker. 2002. Differential seed germinability in triazine-resistant and -susceptible giant foxtail (Setaria faberii). Asian Journal of Plant Sciences 1(4):334-336. Van Wychen, L. R., E. C. Luschei, A. J. Bussan, and B. D. Maxwell. 2002. Accuracy and cost effectiveness of GPS-assisted wild oat mapping in spring cereal crops. Weed Science 50:120-129. Wiles, L. and E. Schweizer. 2002. Spatial dependence of weed seedbanks and strategies for sampling. Weed Science 50:595-606. Williams, B. J. and R. G. Harvey. 2002. Influence of simulated seed rain on the seed bank of wild-proso millet. Weed Science 50:340-343. Williams, M. M., D. A. Mortensen, W. J. Waltman, and A. R. Martin. 2002. Spatial inference of herbicide bioavailability using a geographic information system. Weed Technology. 16:603-611. Wyse-Pester, D. Y., L. J. Wiles, and P. Westra. 2002. Infestation and spatial dependence of weed seedling and mature weed populations in corn. Weed Science 50:54-63.

Impact Statements

Date of Annual Report: 07/25/2003

Report Information

Annual Meeting Dates: 07/15/2003 - 07/16/2003
Period the Report Covers: 07/01/2002 - 07/01/2003

Participants

Anita Dille, Kathrin Schirmacher -KS, Adam Davis, Jim Kells, Corey Guza MI, Don Wyse, Gregg Johnson MN, John Cardina OH, Bill Simmons, Pat Tranel, Aaron Hager, Christy Sprague, Joanne Chee-Sanford IL, John Lindquist NE, Jack Dekker, IA, David Stoltenberg,- WI, Kevin Gibson, IN, Jim Parochetti - CSREES, Marty Williams USDA, Susan Ratcliffe NCIPM.

Participants Attachment:

Attachment

Brief Summary of Minutes

John Lindquist (chair) welcomed the group and asked Christy Sprague (local host) to provide a general overview of activities for the next two days. Dr. Steve Pueppke (Associate Dean of Research, College of ACES at the University of Illinois) attended as administrative advisor on behalf of Dr. Randy Woodson. Dr. Jim Parochetti (CSREES representative) reiterated the importance of adhering to deadlines and the need to remain focused on a multidisciplinary project. Susan Ratcliffe (NCIPM facilitator) spoke in detail about the NCIPM program.

Election of officers for 2003-04

Chair: Christy Sprague

Secretary: Gregg Johnson

Location of 2004 Summer Annual meeting, Madison, Wisconsin University of Wisconsin. The meeting date was tentatively set for Monday and Tuesday, July 19-20, 2001.

Minutes Attachment:

Attachment

Accomplishments

Objective 1. Understand the basis and relative importance of spatial, temporal, and biological variability in weed/crop competition. </dir> </dir> </dir> Kathrin Schirmacher (KS) discussed results of field research specifically targeted at objective 1a and 1b. Overall, corn and soybean yield data was variable from year to year. In corn, all four cohorts were established but had problems with lambsquarters and fall panicum establishment. In soybeans, cohort 1 was established but they had problems with cohort 2 and 3. She also talked about their use of dose-response models for analyzing weed competitiveness. Dave Stoltenberg (WI) talked about their results addressing objective 1e. Overall, the range in yield varied between years. However, some general relationships were evident over both years. Lower yield was associated with giant ragweed and velvetleaf. Conversely, higher yield was associated with wild proso millet and large crabgrass. The other four species tested were intermediate, but the order of these species changed from 2001 to 2002. The group talked about ways of integrating this data with WeedSoft. Do we pool data over years and use single indices? This is a concern with very competitive weeds. However, the rank of highly competitive weeds did not change over years. More discussion is needed on this topic. Corey Guza (MI) discussed results from field research in support of sub-objective 1a, 1b, 1e, and 1f. All experiments are in the 3rd year and are focused on 4 cohort timings across 8 weed species. Corey also reviewed a recent survey of NC-202 members to determine if we had enough data as well as to determine the quality of data. Those involved in research supporting objective 1e and 1f are Michigan, South Dakota, and Wisconsin. Overall, data quality was excellent and there appeared to be enough data to move forward. Most states are following through with their commitments as indicated in the 2002 minutes. Discussion moved to data analysis. Kathrin Shirmacher (KS) and Corey Guza (MI) agreed to analyze the corn data from objective 1a and 1b. Shawn Hock (NE) will be asked to analyze soybean data from objective 1a, 1b, and 1e. Objective 1c and 1d standard regional protocol (years 3-5): Michigan, Minnesota, Kansas, Nebraska, and Illinois committed to the protocol outlined in objective 1d for both corn and soybeans in 2004. Wisconsin agreed to establish field studies in support of objective 1c and possibly 1d. John Lindquist will send an e-mail asking for commitments from each state along with protocol information. It was suggested that this group write a paper demonstrating how NC202 data was used to support the development and enhancement of a bioeconomic model, i.e. WeedSoft. Status of lambsquarters competition paper: David Stoltenberg contacted David Fischer two years ago regarding the status of this paper but has not heard any word to date regarding progress. Dave Stoltenberg will contact David Fischer to follow up on the status of this paper. We do not want this paper to slip through the cracks. Objective 2. Understand spatial, temporal, and biological variability of weed seed in the soil seedbank and it‘s impact on weed/crop competition. Adam Davis (MI) presented results on weed seed fate in the soil seedbank (objective 2b) based on 2001 and 2002 data. Illinois, Michigan, Minnesota (two sites), Nebraska, Ohio, Washington, and Wisconsin provided data for this study. Overall, weed seed decay was highly variable between sites and years. The group discussed whether to explore the genetic by environment interaction as it relates to these findings. Adam also argued the need to think more about the methodology. The group discussed several ideas related to placement and extraction of weed seed from the soil. The group also discussed the need to consider invasiveness as a function of cropping system as it relates to seed germination and establishment. Michigan and Ohio will continue with the experiment beginning in the fall of 2003. Wisconsin may also participate. Adam Davis (MI) and John Cardina (OH) will discuss protocol and share information with others. Anybody interested can choose to participate at that time. Adam will also take charge of data analysis. Jack Dekker (IA) presented information on FoxPatch, a new model he has developed to forecast weedy foxtail seed behavior in soil seed banks. Drivers in this model are oxygen, water, and temperature. The protocol involves obtaining information on foxtail dormancy state, weather data from time of introduction to emergence, and time of emergence. Jack plans to submit a regional proposal this fall. Anyone interested in participating in this project should contact Jack. Objective 3. Develop DSS modules to incorporate risk into weed management recommendations. The WeedSoft bioeconomic model group met with representatives from NC202 this past year. There is strong interest to incorporate NC202 data into WeedSoft. One example is to look at developing a teaching component based on NC202 data. This would allow users to learn concepts using regional data collected by this NC202 group. It was also proposed to incorporate fecundity information based on data collected by Kathrin Schirmacher (KS). The economist involved in the project (Paul Mitchell, TX) has indicated that he is too busy with other things to be of much help to the NC202 group. It was suggested that we contact David Archer (USDA, Morris MN) as a replacement. Don Wyse (MN) will contact David Archer to determine his level of interest and if he is indeed the right person to work on the project. If we are unsuccessful in this regard, we need to reconsider how we address the risk component of this project. Some members questioned the need to study economic risk and suggested that we focus on biological risk. Discussion of Future Project Direction and Rewrite Discussions centered on how best to frame our research questions. It was suggested that bioeconomic models (e.g, WeedSoft) should be the basis for development of appropriate research questions. Some group members felt that we should focus on diverse cropping systems while others suggested the field of invasion biology be incorporated into the development of a new proposal. A number of ideas were talked about during this period. Jim Parochetti (CSREES representative) was asked to provide some guidance regarding new directions and choice of research topic. Jim indicated that the topics discussed thus far are timely and address national issues. Moreover, a change in direction may be viewed favorably. Overall, the group felt strongly that we need to insure that the researchable questions can be addressed using a multi-state approach. John Cardina suggested that we might want to look at a trait-based approach rather than a species-based approach. Measuring traits rather than specific species allow you to get at the reason the system behaves that way it does. The challenge is to decide what traits are important. Phenotypic plasticity is one such trait that was discussed because it oftentimes drives the observed differences in plant growth rate, form, etc However, genotypic traits resulting from outcrossing results in populations with a unique set of traits. For example, what are the determinants in species shifts resulting from changes in tillage, i.e. it is it genotypic variability or phenotypic variability? At this point in the discussion, it was becoming clear that a trait based approach appears to be something we can all get excited about. Continued talks focused on possible traits that we would deem important. Those include:<DIR> <DIR> l Emergence patterns. For example, what is the variability of this trait and how does this influence the ability of weed species to adapt to different systems? What drives the expression of variability? l Characteristics associated with seed rain. l GxE interaction in emergence. An example of this would be to establish a common nursery in all states where we could be determine the influence of starting state of seeds vs. the environmental signal at different locations.</dir> </dir> It was suggested that we consider organizing objectives of the new project by the life history stage. A second objective would focus on trait assessment beginning at emergence (phase II of life history). Another idea was to establish a wide variety of weeds in different cropping systems. This approach will allow us to determine what traits might be driving the observed differences in population dynamics, e.g. is it changes in planting time, light, etc What gives rise to variability? That is, how does environment (cropping system, terrain) affect dormancy? It may just be an inherent property modified by environment. Clearly, we need to consider recruiting someone with a genetic background to join our group. It was agreed upon that we would make an invitation to anyone interested in participating.

Publications

Impact Statements

Date of Annual Report: 10/25/2004

Report Information

Annual Meeting Dates: 07/13/2004 - 07/14/2004
Period the Report Covers: 07/01/2003 - 07/01/2004

Participants

Cardina, John (cardina.2@osu.edu) - Ohio State University; Clay, Sharon (sharon.clay@sdstate.edu) - South Dakota State University; Davis, Adam (davisad7@msu.edu) - Michigan State University; Dille, J. Anita (dieleman@ksu.edu) - Kansas State University; Eyherabide***, Juan (jeyherabide@balcarce.inta.gov.ar) - National University Mar del Plata; Forcella, Frank (forcella@morris.ars.usda.gov) - USDA-ARS, Minnesota; Hock**, Shawn (shock2@bigred.unl.edu) - University of Nebraska-Lincoln; Johnson, Gregg (johns510@umn.edu) - University of Minnesota; Knezevic, Stevan (sknezevic2@unl.edu) - University of Nebraska-Lincoln; Lindquist, John (jlindquist1@unl.edu) - University of Nebraska-Lincoln; Luschei, Ed (ecluschei@wisc.edu) - University of Wisconsin-Madison; Maxwell, Bruce (bmax@montana.edu) - Montana State University; Parochetti*, James (jparochetti@csrees.usda.gov) - USDA-CSREES; Sprague, Christy (sprague1@msu.edu) - Michigan State University; Stoltenberg, Dave (destolte@wisc.edu) - University of Wisconsin-Madison; Woodson*, Randy (woodson@purdue.edu) - Purdue University;

* Attendee was present in an advisory capacity and not included in Attendance tally on page 1.
** Graduate student
*** International visitor

Brief Summary of Minutes

David Stoltenberg (WI, Local Host) and Christy Sprague (MI, Chair) welcomed us to Madison, WI and to the NC-202 summer annual meeting at 8:00 am on Tuesday morning. Randy Woodson commented on the fact that this next year was critical for the NC-202 group because of our project re-write. Jim Parochetti shared that the House budget was looking good and that formula $$ (Hatch, Smith-Lever) were available to continue support of agricultural research projects.

The location and date for next years summer annual meeting were determined: Minneapolis-St. Paul, Minnesota on Tuesday and Wednesday, July 26-27, 2005. Local host will be the Minnesota group (Frank Forcella and Gregg Johnson). Gregg Johnson is Chair for 2005 and Adam Davis was elected Chair for 2006.

Minutes Attachment:

Attachment

Accomplishments

<ol type=A><li>Objective 1: Understand the basis and relative importance of spatial, temporal, and biological variability in weed-crop competition. <ol type=a><li>Standard Regional Protocol (years 1-3) <ol type=i><li>Subobjective 1A: Determine the relative competitive indices of selected annual grass and broadleaf weed species in corn and soybean cropping systems. <li>Subobjective 1B: Determine the effect of time of emergence (i.e., cohort) on the relative competitive ability of these species.</ol> <li>Optional Expanded Protocol (years 1-3) <ol type=i><li>Subobjective 1E: Determine the relative competitive indices of selected annual grass and broadleaf weed species based on corn and soybean yield loss. <li>Subobjective 1F: Determine the effect of time of emergence (i.e., cohort) of these weed species on corn and soybean yield loss.</ol> <li>Standard Regional Protocol (years 3-5) <ol type=i><li>Subobjective 1C: Incorporate weed competitive indices and time of emergence (i.e., cohort) effects into a weed management DSS <li>Subobjective 1D: Determine corn and soybean grain yield loss associated with four cohorts of a multi-species weed community to use as validation data sets for the weed management DSS</ol></ol> Accomplishments: Field studies have been completed for Objective 1: subobjectives 1A,B and 1E, F during 2000 - 2003 at many locations across the North Central region. Data have been presented at North Central Weed Science Society annual meetings each year by individual state representatives, some presenting state-specific data, other presenting a regional summary of data. Manuscripts are currently being prepared to bring regional data and results together. Impacts: One major impact of this project has been the greater understanding of weed/crop interactions throughout the North Central Region. This is particularly important as current trends have dictated the use of glyphosate applications at various weed stages in Roundup Ready crops. This project has shown that the time of weed emergence as well as weed species type has a major impact on weed/crop interactions and is important when devising weed management strategies. One example how this data can impact weed management efforts is that information collected from this research has been incorporated into WeedSOFT, a computer-based decision support system. WeedSOFT is commercially available in the following states: Nebraska, Missouri, Kansas, Wisconsin, Illinois, Indiana, and Michigan. <li>Objective 2: Understand spatial, temporal and biological variability of weed seed in the soil seedbank and impact on weed-crop competition. <ol type=a><li>Subobjective 2A: conduct a regional protocol to assess the fates (primarily predation) of weed seed in the soil seedbank. <li>Subobjective 2B: conduct a regional protocol to assess weed seed decay due to depth, field site, and cropping system. <li>Subobjective 2C: conduct a regional protocol assessing the predictability of seedling emergence from the weed seedbank.</ol> Accomplishments: This second objective has fostered close collaboration with other states and researchers regarding the three primary weed species of the north central states. Researchers have determined robust estimates of seed persistence for velvetleaf, common lambsquarters, and giant foxtail. When the seed persistence data are pooled over sites within burial periods, persistence rates for each burial period are the same across years for each of the species (ABUTH: Oct Mar, 75%, Mar-Oct, 59%; CHEAL: Oct-Mar, 70%, Mar-Oct, 67%; SETFA: Oct-Mar, 73%, Mar-Oct, 32%). This has led to considerably heightened understanding and insights into how these species survive in soil seedbanks. As a consequence, our ability to forecast the population dynamics of these species under differing soil management scenarios has increased significantly. Impacts: An impact of this project has been a greater understanding on the management of weed seed banks. Weed management strategies have typically focused on the seedling to mature stage of the plants life-cycle. One focus of this project has been to evaluate how management strategies influence weed seed bank degradation. Results have shown that seed depth and environmental factors such as moisture and temperature have a significant impact on weed seed dynamics. This is just the beginning of understanding what factors affect weed seed bank degradation. This information could potentially be important in constructing models to manage weed populations. Additionally, working groups have been constructed in Michigan to work with growers to discuss and implement different practices to help manage the weed seed bank. <li>Objective 3: Develop DSS modules to incorporate risk into weed management recommendations. <ol type=a><li>Subobjective 3A: develop a DSS module based on stochastic weed-crop competition to incorporate yield loss risk into weed management recommendations. <li>Subobjective 3B: develop a DSS module based on stochastic seedbank dynamics to incorporate time of emergence risk into weed management recommendations.</ol> Accomplishments: There is an overlap of participants in both the multi-state research project with the regional development of the decision support system, WeedSOFT. Knowledge generated from research projects is directly input into annual updates of WeedSOFT for each state. Members of NC202 have met with the WeedSOFT group on numerous occasions to discuss opportunities and plans for integrating information. Impacts: NC202 derived data is input into a widely available decision support tool across the North Central region. As of 2004, 620 new, updated, or complementary copies of WeedSOFT were in the hands of crop consultants, agronomists, county agents, and producers across 7 states in the Midwest. The success of NC202 could serve as a model for regional research efforts. The participating scientists developed research protocols that were conducted in multiple environments, leading to a database much more powerful than would have been possible working independently. The result is the generation of valuable biological and environmental data in a very efficient manner. </ol></ol>

Publications

Andersen, S., S.A. Clay, L.J. Wrage, and D. Matthees. 2004. Soybean foliage residues of dicamba and 2,4-D and correlation to application rates and yield. Agron. J. 96:750-760. Banken, K. 2000. Influence of yellow foxtail on corn growth and western corn rootworm development. M.S. Thesis, Brookings, SD 128 p. Blinka, E.L. 2004. Growth analysis of shattercane (Sorghum bicolor), common sunflower (Helianthus annuus), Palmer amaranth (Amaranthus palmeri), and corn (Zea mays). MS Thesis, Kansas State University, Manhattan. Burton, M.G., D.A. Mortensen, and J.L. Lindquist. 2004. Effect of cultivation and soil heterogeneity on survival, growth and fecundity of Helianthus annuus in maize. Soil Tillage Research (in press). Burton, M.G., D.A. Mortensen, D.B. Marx, and J.L. Lindquist. 2004. Factors affecting the realized niche of common sunflower (Helianthus annuus L.) in ridge tillage corn. Weed Science 52:779-787. Chang, J., D.E. Clay, K. Dalsted, S.A. Clay, and M. ONeill. 2004. Corn (Zea mays L.) yield prediction using multispectral and multidate reflectance. Agronomy J. 95:1447-1453. Chang, J., S.A. Clay, D.E. Clay, and K. Dalsted. 2004. Detecting weed-free and weed-infested areas of a soybean (Glycine max) field using near-infrared spectral data. Weed Sci. 52:642-648. Clay, D.E., S.A. Clay, J. Jackson, K. Dalsted, C. Reese, Z. Liu, D.D. Malo, and C.G. Carlson. 2003. C13 discrimination can be used to evaluate soybean yield variability. Agron. J. 95:430-435. Clay, S., J. Kleinjan, D.E. Clay, F. Forcella, and W. Batchelor. 2005. Growth and fecundity of several weed species in corn and soybean. Agronomy Journal 97: in press (accepted 10 September 2004). Clay, S.A. 2000. Herbicide management to maintain environmental quality: Lessons to be learned from North American herbicide management practice. P. 167-176. In: Wilson, M.J. and B. Maliszewska-Kordybach. Soil Quality, Sustainable agriculture and environmental security in Central and Eastern Europe. Series 2. Environmental Security. Vol. 69. Klewer Academic Publishers. Boston, MA. Clay, S.A. and G. Johnson. 2002. Scouting for weeds. Crop Manage. Doi:10.1094/cm-2002-1206-01-MA Published Dec. 2002. Clay, S.A., J. Chang, D.E. Clay, C.L. Reese, and K. Dalsted. 2004. Using remote sensing to develop weed management zones in soybeans. Site Specific Management Guidelines. SSMG-42. April 2004. Online at www.ppi-far.org/ssmg. Conley, S. P., D. E. Stoltenberg, C. M. Boerboom, and L. K. Binning. 2003. Predicting soybean yield loss in giant foxtail (Setaria faberi) and common lambsquarters (Chenopodium album) communities. Weed Sci. 51:402-407. Conley, S. P., L. K. Binning, C. M. Boerboom, and D. E. Stoltenberg. 2003. Parameters for predicting giant foxtail cohort effect on soybean yield loss. Agron. J. 95:1226-1232. Conley, S. P., L. K. Binning, C. M. Boerboom, and D. E. Stoltenberg. 2002. Estimating giant foxtail cohort productivity and fecundity in soybean based on weed density, leaf area, or volume. Weed Sci. 50:72-78. Deines, S.R. 2002. Shattercane (Sorghum bicolor (L.) Moench) and common sunflower (Helianthus annuus L.) interference in corn (Zea mays L.) and light level influence on their relative competitiveness. MS Thesis, Kansas State University, Manhattan. Deines, S.R., J.A. Dille, E.L. Blinka, D.L. Regehr, and S.A. Staggenborg. 2005. Common sunflower (Helianthus annuus) and shattercane (Sorghum bicolor) interference in corn. Weed Science (accepted 7/14/04). Dekker J. and M. Hargrove. 2002. Weedy adaptation in Setaria spp.: V. Effects of gaseous environment on giant foxtail (Setaria faberii R. Hermm.) (Poaceae) seed germination. American Journal of Botany 89(3):410-416. Dekker, J, B. Atchison, and K. Jovaag. 2003. Setaria spp. seed pool formation and initial assembly in agro-communities. Aspects of Applied Biology 69:247-259. Dekker, J. 2000. Emergent weedy foxtail (Setaria spp.) seed germinability behavior. Pages 411-423 In: Seed Biology: Advances and Applications (M. Black, K.J. Bradford, and J. Vasquez-Ramos, Eds). CAB International, Wallingford, UK. Dekker, J. 2003. The foxtail (Setaria) species-group. Weed Science 51:641-646. Dekker, J. 2004a. The evolutionary biology of the foxtail (Setaria) species-group. Pages 65-113 In: Weed Biology and Management; Inderjit (Ed.). Kluwer Academic Publishers, The Netherlands. Dekker, J. 2004b. Invasive plant life history determinants of yield in disturbed agro-ecosystems. XIIth International Conference on Weed Biology, Dijon, France. Association Française pour la Protection des Plantes Annales: 5-14. Dekker, J., J. Lathrop, B. Atchison, and D. Todey. 2001. The weedy Setaria spp. phenotype: How environment and seeds interact from embryogenesis through germination. Proceedings of the Brighton Crop Protection Conference-Weeds 2001:65-74. Ekeleme, F., F. Forcella, D. W. Archer D, I. O. Akobundu, and D. Chikoye. 2005. Seedling emergence model for tropic ageratum (Ageratum conyzoides). Weed Science 52: (Accepted 31 August 2004). Ekeleme, F., F. Forcella, D. W. Archer, D. Chikoye, and I. O. Akobundu. 2004. Emergence model for cogongrass (Imperata cylindrica) in the humid tropics. Weed Science 51: (Accepted 6 July 2004). Ellsbury, M. M., Clay, S. A., Fleischer, S. J., Chandler, L. D., and Schneider, S. M. 2000. Use of GIS/GPS Systems in IPM: Progress and Reality. Pages 419-438 in: Emerging Technologies for Integrated Pest Management: Concepts, Research, and Implementation. G. C. Kennedy and T. B. Sutton, eds. American Phytopathological Society, St. Paul, MN. Ellsbury, M., S.A. Clay, K.H. Banken, and F. Forcella. 2004. Interactions among western corn rootworm (Coleoptera: Chrysomelidae), yellow foxtail, and corn. Environmental Entomology (in press). Ellsbury, M.M., S.A. Clay, and K. Banken. 2004. Interactions Among Western Corn Rootworm (Coleoptera: Chrysomelidae),Yellow Foxtail, and Corn. Econ. Entom. (accepted) Evans, S.P., S.Z. Knezevic, J.L. Lindquist, and C.A. Shapiro. 2003. Influence of nitrogen and duration of weed interference on corn growth and development. Weed Science 51:546-556. Evans, S.P., S.Z. Knezevic, J.L. Lindquist, C.A. Shapiro, and E.E. Blankenship. 2003. Nitrogen application influences the critical period for weed control in corn. Weed Science 51:408-417. Fischer, D.W., R.G. Harvey, T.T. Bauman, S. Phillips, S.E. Hart, G.A. Johnson, J.J. Kells, J.L. Lindquist, and P. Westra. 2004. Chenopodium album interference with Zea mays across the north central USA. Weed Science (in press). Forcella, F. and G.A. Amundson. 2004. Methods in weed ecology: Glue retains seeds in shatter-prone seedheads. Weed Technology 18: 183-185. Forcella, F., T. Webster, and J. Cardina. 2003. Protocols for weed seed bank determination in agro-ecosystems. In: Weed management for developing countries, Addendum I. R. Labrada (Ed.). FAO-Rome Plant Production and Protection Paper 120, pp. 3-18. Guza, C. J. and J. J. Kells. 2003. Weed growth and corn yield as affected by time of weed emergence. Proc. North Cent. Weed Sci. Soc. 58 Hock, S.M., S.Z. Knezevic, A.R. Martin, and J.L. Lindquist. 2005. Competitive indices of major weed species in soybean. Weed Science (in review). Hock, S.M., S.Z. Knezevic, A.R. Martin, and J.L. Lindquist. 2005. Influence of soybean row spacing and emergence time on velvetleaf (Abutilon theophrasti). Weed Science (in press). Kegode, G. O. and M. J. Christoffers. 2003. Intriguing World of Weeds: Biennial wormwood (Artemisia biennis Willd.). Weed Technology 17:646-649. Kegode, G. O., F. Forcella, and B. R. Durgan. 2003. Effect of common wheat management alternatives on weed seed production. Weed Technology. 17:764-769. Knezevic, S.Z., S.P. Evans, E. Blankenship, R. Van Acker, and J.L. Lindquist. 2002. Critical period of weed control: The concept and data analysis. Weed Science 50:773-786. Lindquist, J.L. 2001. Light-saturated CO2 assimilation rates of corn and velvetleaf in response to leaf nitrogen and development stage. Weed Science 49:706-710. Lindquist, J.L. 2001. Performance of INTERCOM for predicting Zea mays - Abutilon theophrasti interference across the north central USA. Weed Science 49:195-201. Liphadzi, K.B. 2004. Weed competitiveness and soil health response to weed management practices. PhD Dissertation, Kansas State University, Manhattan. Mahoney, K. J. and G. O. Kegode. 2004. Biennial wormwood (Artemisia biennis) biomass allocation and seed production. Weed Science 52:246-254. Mengistu, L. W., M. J. Christoffers, and G. O. Kegode. 2004. Genetic diversity of biennial wormwood. Weed Science 52:53-60. Moechnig, M.J., C.M. Boerboom, D.E. Stoltenberg, and L.K. Binning. 2003. Growth interactions in communities of common lambsquarters (Chenopodium album), giant foxtail (Setaria faberi), and corn. Weed Sci. 51:363-370. Moechnig, M.J., D.E. Stoltenberg, C.M. Boerboom, and L.K. Binning. 2003. Empirical corn-yield loss estimation from common lambsquarters (Chenopodium album) and giant foxtail (Setaria faberi) in mixed communities. Weed Sci. 51:386-393. Murphy, C. and J. L. Lindquist. 2002. Growth response of velvetleaf to three post emergence herbicides. Weed Science 50:364-369. Paz, J.O., W.D. Batchelor, D.E. Clay, S.A. Clay, and C. Reese. 2003. Characterization of Soybean Yield Variability Using Crop Growth Models and 13C Discrimination. Trans. ASAE. ASAE meeting presentation # 033044. Schirmacher, K. 2004. Interference of eight annual weeds in corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) in Kansas. MS Thesis, Kansas State University, Manhattan. Smeltekop, H., D.E. Clay, and S.A. Clay. 2002. The impact of sava snail medic cover crop on corn production, stable isotope discrimination, and soil quality. Agron Journal 94:917-924. Tranel, D. and J. Dekker. 2002. Differential seed germinability in triazine-resistant and -susceptible giant foxtail (Setaria faberii). Asian Journal of Plant Sciences 1(4):334-336. Traore, S., J.L. Lindquist, A.R. Martin, D.A. Mortensen, and S.C. Mason. 2002. Comparative ecophysiology of grain sorghum and Abutilon theophrasti in monoculture and in mixture. Weed Research 42:65-75. Waltz, A.L., A.R. Martin, F.W. Roeth, and J.L. Lindquist. 2004. Glyphosate efficacy varies with application time of day. Weed Technology (in press). Wolf, R., S.A. Clay, and L.J. Wrage. 2000. Herbicide strategies for managing kochia (Kochia scoparia) resistant to ALS-inhibiting herbicides in wheat (Triticum aestivum) and soybean (Glycine max). Weed Tech. 14:268-273.

Impact Statements

Refer to Accomplishments Section.

Date of Annual Report: 10/06/2005

Report Information

Annual Meeting Dates: 07/26/2005 - 07/27/2005
Period the Report Covers: 07/01/2005 - 07/01/2005

Participants

Dave Archer - USDA-ARS Morris, MN; Sharon Clay - South Dakota State Univ.; Adam Davis - USDA-ARS Urbana, IL; Jack Dekker - Iowa State Univ.; Joel Felix - Ohio State Univ.; Frank Forcella - USDA-ARS Morris, MN; Matt Harbur - Univ. of Minnesota; Mark Jeschke - Univ. Wisconsin; Gregg Johnson - Univ. of Minnesota; John Lindquist - Univ. Nebraska; Ed Luschei - Univ. of Wisconsin; Fabian Menalled - Montana State University; Katherine Schirmacher - Michigan State Univ.; Lynn Sosnoskie - Univ. Wisconsin; Dave Stoltenberg - Univ. of Wisconsin; Don Wyse - Univ. of Minnesota.

Brief Summary of Minutes

Minutes Attachment:

Attachment

Accomplishments

Accomplishments and Impacts NC202 ( Objective 1: Understand the basis and relative importance of spatial, temporal, and biological variability in weed-crop competition. Accomplishments: Field studies have been completed for Objective 1 at many locations across the North Central region. Data have been presented at North Central Weed Science Society annual meetings each year by individual state representatives, some presenting state-specific data, other presenting a regional summary of data. Manuscripts are currently being prepared to bring regional data and results together. Objective 1D was summarized at annual meeting. Results indicated that modeling over-predicts potential crop yield loss, particularly at the second cohort (VE in soybean, V2 in corn). Consensus is that WeedSoft is a good tool to make herbicide recommendations, but it has several problems in its competitive component. B) Objective 2: Understand spatial, temporal and biological variability of weed seed in the soil seedbank and impact on weed-crop competition. Accomplishments: This second objective has fostered close collaboration with other states and researchers regarding the three primary weed species of the north central states. Researchers have determined robust estimates of seed persistence for velvetleaf, common lambsquarters, and giant foxtail. When the seed persistence data are pooled over sites within burial periods, persistence rates for each burial period are the same across years for each of the species (Velvet Leaf: Oct-Mar, 75%, Mar-Oct, 59%; Common Lambsquarters: Oct-Mar, 70%, Mar-Oct, 67%; Giant Foxtail: Oct-Mar, 73%, Mar-Oct, 32%). This has led to considerably heightened understanding and insights into how these species survive in soil seedbanks. As a consequence, our ability to forecast the population dynamics of these species under differing soil management scenarios has increased significantly. C) Objective 3: Develop DSS modules to incorporate risk into weed management recommendations. Accomplishments: There is an overlap of participants in both the multi-state research project with the regional development of the decision support system, WeedSOFT. Knowledge generated from research projects is directly input into annual updates of WeedSOFT for each state. Members of NC202 have met with the WeedSOFT group on numerous occasions to discuss opportunities and plans for integrating information.

Publications

Bonifas, K. D., D. T. Walters, K. G. Cassman and J. L. Lindquist. 2005. The effects of nitrogen supply on root:shoot ratio in corn and velvetleaf. Weed Science 53:670-675. Burton, M. G., D. A. Mortensen, D. B. Marx, and J. L. Lindquist. 2004. Factors affecting the realized niche of common sunflower (Helianthus annuus L.) in ridge tillage corn. Weed Science 52:779-787. Davis, A. S., J. Cardina, F. Forcella, G. A. Johnson, G. Kegode, J. L. Lindquist, E. C. Luschei, K. A. Renner, C. L. Sprague, and M. M. Williams II. 2005. Environmental factors affecting seed persistence of 13 annual weeds. Weed Science 53: in press. Fischer, D. W., R. G. Harvey, T. T. Bauman, S. Phillips, S. E. Hart, G. A. Johnson, J. J. Kells, J. Lindquist, P. Westra. 2004. Chenopodium album interference with Zea maysacross the north central USA. Weed Science 52:1034-1038. Gramig, G. G. and D. E. Stoltenberg. 2004. Progress on predicting crop yield loss from weeds. Proc. Fert. Aglime and Pest Management Conf. Coop. Ext. Ser. Univ. Wisc.-Ext. and Coll. Agric. Life Sci., Univ. Wisc.-Madison. 43:372-375. Hock, S. M., S. Z. Knezevic, A. R. Martin and J. L. Lindquist. 2005. Influence of soybean row width and velvetleaf emergence time on velvetleaf (Abutilon theophrasti). Weed Science 53:160-165. Jeschke, M. R. and D. E. Stoltenberg. 2005. Giant ragweed response to tillage and management. Proc. Fert. Aglime and Pest Management Conf. Coop. Ext. Ser. Univ. Wisc.-Ext. and Coll. Agric. Life Sci., Univ. Wisc.-Madison. 44:155-160. Jeschke, M. R. and D. E. Stoltenberg. 2004. Giant ragweed population dynamics in glyphosate-resistant corn and soybean cropping systems. North Central Weed Sci. Soc. Abstr. [CD-ROM Computer File]. North Central Weed Sci. Soc., Champaign, IL. (Dec. 2004). Swinton, S.M. 2005. "Economics of Site-specific Weed Management." Weed Science. 53(2): 259-263. Waltz, A. L., A. R. Martin, F. W. Roeth, and J. L. Lindquist. 2004. Glyphosate efficacy on velvetleaf varies with application time of day. Weed Technology 18:931-939.

Impact Statements

Greater understanding of weed/crop interactions throughout the North Central Region. This project has shown that the time of weed emergence as well as weed species type has a major impact on weed/crop interactions and is important when devising weed management strategies. One example how this data can impact weed management efforts is that information collected from this research has been incorporated into WeedSOFT, a computer-based decision support system.