Brief Summary of Minutes of Annual Meeting

The annual meeting was held at the Kellogg Biological Station, Hickory Corners, MI on July 28-29, 2009. The Administrator Advisor opened the meeting with a reminder that our current NC1026 project will expire as of September 2010 and that the rewriting process needs to begin to meet immediate deadlines (revised proposal submitted by December 2009). Based on discussion with ideas of a new direction for this project, a request for a 1-year project extension will be submitted. Researchers present at the meeting presented reports on research results from on-going and near completion studies that meet the project objectives. Data for the demographic study (Objective 1A) and the soil feedback study (Objective1B) have been compiled and reviewed. All sites have submitted soil samples for microbial analysis. Several different approaches to data analyses and summarization were discussed to guide manuscript preparation. Many ideas for the future direction of NC1026 project were discussed in preparation for the rewrite along with selection of a writing committee. Communication among the writing committee will continue through e-mail and conference calls. The next annual group meeting will be held in Champaign, IL area from July 26-28, 2010.

The overarching goal of the NC1026 project and its multi-state group of collaborators is to use a more unified framework to incorporate risk in the development of weed management recommendations and decision support systems. Over the past year, researchers have conducted a fourth year of common field and greenhouse studies as part of understanding the population dynamics of two important weed species: common sunflower and giant ragweed, that differ in their distribution and competitiveness across the region. Five collaborators have conducted the demography study of common sunflower and giant ragweed in the field (Objective 1A) over the past three years. All data has been collected and summarized within a common format. The overall growth rates of populations of these two species appears to be very high in our experiments. The rich database of demographic parameters, including seedbank dynamics (germination, viability, and death of seed in the soil over different seasons) and seedling emergence, survival, mature plants, and seed production estimates allow for valuable comparison among site-years. These comparisons will allow for improved understanding of why these species occur with different distributions and competitiveness across the study region. Five sites also conducted the soil feedback study in the greenhouse using common accessions of the two weed species. Feedback scores, that is, plants grow well when grown and conditioned in their own soil, rather than soil of the other species, tended to follow local abundance and weediness characteristics. That is, common sunflower from Kansas had positive feedback scores in Kansas soil and conditions compared to giant ragweed grown in Kansas. Soil samples from each greenhouse pot have been collected and microbial analyses are being done to determine what influence they have on the feedback scores observed. Results from these two studies are providing valuable information about weed biology, competitiveness, and extent of variability across the region to assist in improvements of weed management decision support systems to provide greater reality and risk measures. This regional project continues to generate useful information to move beyond decision tools for herbicide selection only.

Bonifas, K. D. and J. L. Lindquist. 2009. Effects of nitrogen supply on the root morphology of corn and velvetleaf. Journal of Plant Nutrition 32:1371-1382. Ramirez, A.H.M., A.M. Ndou, and J. A. Dille. 2008. Survey of common sunflower and giant ragweed populations in Kansas. North Central Weed Sci. Soc. Abstract 63:67. (Poster) Sieh, H., G. Reicks, and S.A. Clay. 2009. Influence of Corn on Seed Production of Giant Ragweed and Common Sunflower. South Dakota Academy of Science, April, 2009.