Brief Summary of Minutes of Annual Meeting

1. Introductions The following individuals were present and introductions were made: Robin Bellinder, NY Toni DiTommaso, NY Russ Hahn, NY Chuck Mohler, NY John Teasdale, ARS-Beltsville Dan Brainard, NY Jim Parochetti, CSREES Mark VanGessel, DE 2. Elect secretary for 2006 (to become chairperson 2007) Chuck Mohler, NY, agreed to serve as Secretary for 2006. Responsibilities of the Secretary include (A) recording Minutes of the annual meeting and (B) submission of the Minutes from the Annual Meeting to the Chairperson one month from the date of the meeting. 3. Approval of minutes of last years meeting. We neglected to do this. 4. Report from Administrative Advisor (Dr. William Vinson, WV) Dr. Vinson was unable to attend the meeting. 5. Report from CSREES Liaison Member, Dr. Jim Parochetti Jim reported that the Presidents 2007 budget includes substantial changes to Hatch funds, including regional projects. Under the proposed budget, 44.4% of Hatch funds would be distributed to states according to the formula. The remaining 55.6% of funds would be used for MultiState projects (up from the current 25% of Hatch funds). However, these MultiState funds would be distributed through a competitive grants program rather than through the experiment stations as is currently done. Projects would meet federally identified needs and would be both mult-state and multi-disciplinary. Projects already approved by the time the budget is adopted would, in theory at least, not be affected, and our new project may well be approved before the budget. Also, the change in the way Hatch funds are handled may not be approved by Congress this year, though Jim seemed to feel that some change along these lines was likely eventually. The report generated considerable discussion. 6. Meeting location and format for next year. We did not choose a meeting location for next year. Based on the poll taken last year regarding whether to meet in conjunction with WSSA or NEWSS, it seems likely that we will meet in conjunction with WSSA, but we will need to decide that. 7. Research Presentations Project Reports from the following participants were presented, reviewed, and discussed: 1. R. Bellinder, Cornell University 2. C. Mohler, Cornell University 3. D. Brainard, Cornell, University 4. R. Hahn, Cornell University 8. Future Directions Because so few people involved in the new project from outside NY were in attendance, discussion of objectives and procedures for that project was postponed. Dan Brainard and Chuck Mohler will complete revision of the proposal based on reviewers comments and circulate that within the next two weeks. Meeting concluded at 4:30 pm, Mon. Feb. 13, 2006.

Objective 2: Effects of mulch on soil moisture and weed emergence. In NY, a procedure was developed to examine effects of soil moisture on seed germination. Field soil was equilibrated to -10, -100, -300, -500 or -1000 kPa using a pressure plate. Prepared soil in Petri dishes was sown with weed seeds, covered with soil, and germination compared with seeds in PEG solutions. Petri dishes were sealed or left open and placed in a germination cabinet at 100% relative humidity. Constant weight of soil showed no moisture loss or gain in open dishes. PEG overestimated germination relative to closed dishes for Powell amaranth and common lambsquarters at intermediate soil moisture potentials, but underestimated germination for those species at -1000 kPa. Open dishes had lower germination than closed dishes at -300 or -500 kPa for Powell amaranth, velvetleaf and giant foxtail, even though moisture loss or gain was negligible in both treatments. Objective 4: Weed management in crop rotation. In NY, a manual on crop rotation planning was reviewed and revision was begun. Also in NY, a vegetable crop rotation x weed management intensity field trial was continued into the 4th of 5 years with the following crops in production this year: sweet corn, beet, cabbage and potatoes. In the spring, crop rotations involving continuous sweet corn had lower weed seed bank densities than those involving cabbage. Crop rotations involving cultivation without herbicides (0x) had almost 3 times the weed seed bank as those involving broadcast (1x) or banded herbicides (1/3X). Yields of beets were significantly reduced under 0 x treatments. Hairy galinsoga (Galinsoga ciliata) was the dominant weed species, accounting for greater than 50% of all seeds in all crop rotations. Galinsoga, pigweed, and lambsquarters densities were over three times greater in 0x treatments compared to 1/3x and 1x treatments; whereas there were no significant differences in grass species densities. In 2006, beans will be grown in all crop rotation treatments, allowing assessment of crop rotation and historic weed management intensity on crop yields. In Maine, a cropping systems study was continued, comparing no cover cropping in two year rotation of broccoli and winter squash, to fall cover cropping, a two-year red clover cover crop followed by the cash crops, and short duration cover cropping with periods of summer fallowing in alternate years with cover crops. Soil quality improved by cover cropping, as evidenced by decreases in bulk density and increases in water holding capacity, water stable aggregates, and particulate organic matter in select cover-cropping systems. Similar benefits of a preceding red clover cover crop were noted when the above ground biomass was removed prior to incorporation, indicating important contributions from the below ground biomass and opening up many questions regarding the role of roots in sustainable cropping systems. Despite an overall decline in the total weed seed bank in three of the four systems over the four years, common lambsquarters, a particularly pernicious species in most northeast cropping systems, increased in each of the systems. However, compared to a system without cover crops, common lambsquarters increased only slightly in the disturbance-intensive, alternate year cover crop system. The perennial cover crop system, despite an abundance of invertebrate seed predators, experienced no net reduction in the germinable weed seedbank over the four-year period. Abundant weed seed rain in the winter squash, as well as within select cover crops, prevented greater progress in depleting the weed seedbank in these cover cropping systems, and suggests that fall weed seed rain management should be carefully considered as part of a comprehensive weed seedbank management plan. Cover crop-based weed management systems appear to attract and retain significantly greater numbers of Maines dominant invertebrate weed seed predator, the ground beetle Harpalus rufipes. We decided to focus most of our work on H. rufipes, as it was the most abundant species throughout the duration of our research. On average, background H. rufipes populations were three times higher in fields planted with a pea-oat cover crop than in fallow fields. Pea-oat fields acted as refuges for beetles released in fallow fields. Within one week, greater than half of all beetles released in fallow fields moved into pea-oat fields. Over 90% of beetles released in pea-oat fields did not move into other fields. This finding supports the use of vegetated refuges as a way to preserve H. rufipes during periods of intense disturbance. In contrast, the presence or absence of a cover crop did not affect the abundance of H. rufipes adults emerging from pupation in the soil during June and July. This suggests that other factors are responsible for determining where immature H. rufipes develop. We also compared H. rufipes abundance in four additional cover crop-based weed management systems (buckwheat/brassica/buckwheat rotation, pea-oat/rye-vetch rotation, snap beans/rye-vetch rotation, and a clover-oat mix) to a fallow control. Significantly more beetles were found in the pea-oat/rye-vetch rotation than in the other cover crop and fallow systems. In comparison with the other systems, the pea-oat system is intermediately disturbed. In contrast, the fallow control and buckwheat/brassica/ buckwheat rotation endure greater soil disturbance while the snap beans/rye-vetch rotation and clover-oat mix receive less. This suggests that while the presence of vegetation alone encourages adult H. rufipes populations, some level of soil disturbance is needed to achieve even higher densities. We will also evaluate other differences amongst the systems (weed density, aboveground biomass, temperature, humidity, etc.) that may have also contributed to higher H. rufipes populations in the pea-oat/rye-vetch rotation. The impact of disturbance independent of cover cropping is currently under investigation at both Rogers and Aroostook Farms. Adult H. rufipes density is measured following disturbance (chisel plow, moldboard plow, or rototillage) versus an undisturbed control. No significant differences have been detected between control and disturbance treatments, though higher adult densities have been observed in the chisel plowed and rototilled plots. Furthermore, greater numbers of adults emerging from pupation have been noted in the control plots versus the three disturbances combined. This observation suggests that the softer-bodied newly emerged adults may be more sensitive to disturbance than the fully sclerotized adults. We will analyze this data further when this study concludes at the end of September 2005. New Objective 1. Reducing rates of natural product herbicides. Greenhouse trials were initiated to test the effects of acetic acid concentrations of 15, 20 (WeedWorks product), 25, and 30% on common lambsquarters (Chenopodium album L.), velvetleaf (Abutilon theophrasti Medic.), and powell amaranth (Amaranthus powellii S.) at the cotyledon, 2-, and 4-leaf stages. Applications were made at 34 and 68 gallons per acre (GPA). All treatments included yucca extract at 0.1% dilution, and each treatment was replicated 4 times. An additional trial evaluated the recommended and 2X recommended rates of three organically approved adjuvants, NaturL Oil (0.2, 0.4%), Yucca extract (0.1, 0.2%), and Humasol (2.5, 5%), when added to 20% acetic acid at 34 GPA. Velvetleaf proved least susceptible to injury compared to powell amaranth and common lambsquarters. Survival rates increased with increasing weed size for all weed species, particularly once the weeds were at the 4-leaf stage. Fifteen percent acetic acid applied at 34GPA was often not effective beyond the cotyledon stage; although 15% acetic acid applied at 68 GPA provided consistently better control. With the addition of selected adjuvants to 20% acetic acid at 34 GPA, there was some improvement in control of velvetleaf, lambsquarters, and pigweed. New Objective 2. Effects of cover crop planting date and method of incorporation on weed suppression A trial was initiated to examine the effects of (i) buckwheat cover crops on in-season weed growth, and (ii) buckwheat residue on emergence and growth of weeds in a subsequent wheat crop. In-season weed suppression by buckwheat in the field ranged from 97-99%. Freshly incorporated buckwheat residue suppressed emergence and growth of wheat as well as 7 out of 8 weed species. The most sensitive species were Powell amaranth, corn chamomile and shepherds purse. Several experiments were initiated to assess possible mechanisms of suppression. Initial results suggest that buckwheat residue interactions with nitrogen availability and fungal pathogens play a significant role in the suppression by buckwheat residue of certain weed species. New Objective 3. Effects of soil nutrients on crop-weed competition and weed management. An experiment examining effects of gypsum amendment on weeds was begun for the proposed new Multi-state project. Gypsum was applied at 480 lb/a or not to 40 by 60 plots in a randomized block design. Organically managed soybeans did not differ in yield (43 bu/a), weed density (38 /m sq), or weed biomass (20 g/sq m). The experiment will be continued on the same plots.

Brainard, D. C., A. DiTommaso and C. L. Mohler. 2005 Ecotypic variation in seedcharacteristics of Powell amaranth from habitats with contrasting crop rotation histories. Proceedings of the 59th Annual Meeting of the Northeastern Weed Science Society 59:142. Gallandt, E. R. 2005. Experimental substrate affects rate of seed removal in assays of invertebrate seed predation. Weed Technology 19:481-485. Gallandt, E. R., T. Molloy, R. P. Lynch, and F. A. Drummond. 2005. Effect of cover cropping systems on invertebrate seed predation. Weed Science 53:69-76. Haramoto, E. R., and E. R. Gallandt. 2005. Brassica cover cropping: I. Effects on weed and crop establishment. Weed Science 53:695-701. Haramoto, E. R., and E. R. Gallandt. 2005. Brassica cover cropping: II. Effects on growth and interference of green bean and redroot pigweed. Weed Science 53:702-708. Mohler, C. L., J. C. Frisch and C. E. McCulloch. 2006. Vertical movement of weed seed surrogates by tillage implements and natural processes. Soil and Tillage Research, in press. Mohler, C. L. 2005, Weeds and weed management on eleven northeastern organic farms. Proceedings of the 59th Annual Meeting of the Northeastern Weed Science Society 59:141. Shearin, A. and S.C. Reberg-Horton. 2005. Cover crop management impacts on the weed seed predator Harpalus rufipes. Proceedings of the Annual Meeting  Northeastern Weed Science Society 59: 77. Shearin, A. F., S.C. Reberg-Horton, E.R. Gallandt, and F.A. Drummond. 2005. Cover crop and cultivation impacts on the weed seed predator Harpalus rufipes. Programs and Abstracts of the Annual Meeting  American Society for Horticultural Science. Hortscience 40(1): 1102.