Brief Summary of Minutes of Annual Meeting

Election of Chair for 2013  Kevin Gibson is Chair for next year. Karen Renner is taking minutes today. Report from Administrative Advisor (Fred Servello): Fred thanked Bill for all of his efforts in organizing the meeting. The registration system took care of minimal expenses of the meeting. The communication system will be reviewed. Power points were submitted ahead of time that spurs the annual report getting completed. These power point presentations were sent to all NE participants to keep in a folder as a reference. The annual report for 2012 must include: 1) minutes from the 2013 meeting  Karen will send to Bill 2) accomplishments of the 2012 fiscal year (narrative of accomplishments given by each state). Send your states narrative to Bill Curran in the next 30 days so he can compile and send our report in. Selection of 2014 meeting date and location; Discussion of Philadelphia NE meeting next year the first week of January (dates not known by the group) or WSSA at Vancouver February 3-6. Chuck would like a longer meeting after the WSSA meeting ends. Meeting will be in Vancouver. Presentations of 2012 Results and Discussion: Objective 1: Determine how soil conditions affect efficacy and selectivity of cultivation implements for the control of various weed species. Two states are participating in this objective: Maine and Pennsylvania. The soil conditions variable differs between the two studies. Gallandt  Univ. of Maine. They are trying to determine why there is a high level of variability in mechanical weed control efficacy in farm fields. Is the variability in efficacy a function of environmental factors? Example: as you increase soil moisture do you decrease cultivation efficacy (slide 2). They seeded a surrogate weed and had 70 sample locations. They had two quadrants (wheel track side and non-wheel track side) per sample site. Soil moisture, texture, density, roughness, wheel track were the variables. Most disappointing data set Eric has ever collected. None of the statistics produced any significance in the data set. The explanatory variables had a lot of variability (moisture from 6  32%, texture from sand to clay loam). Average control by cultivation was 67%. Chuck commented that most of the data is in the middle of the histogram so not enough data in the tails. Next year suggestions: two cultivation tools and make a comparison. Two speeds and make a comparison. Two types of tines on a tine weeder would be interesting or a tine weeder and a rotary hoe. The goal is 67% across the whole field. The tail with poor control is of interest. Why do you have this tail? Maybe next year keep the in-row weed data separate (divide the quadrat into 3 sections). Maybe the tails are poor soil flow into the rows so the weeds are not being buried. Maybe next year not measure outside the row  just focus in the row since it appears that wheel tracks didnt make a difference. Maybe you should grid sample to develop variable zones and then cultivate across the system and see the variability based on EC, pH, SOM (use Veris MPX), N, P, K. Weed populations and safe sites are based on management practices that overrun inherent natural features of the field (slope, soil type). Grid sampling and developing VR zones will allow us to measure weed emergence and cultivation efficacy based on VR (KAR comment) Bill Curran/Clair  Penn State. High residue cultivator w/ 20 sweeps: John Deere 886. Two experiments: Rye (soybean) and hairy vetch (corn). Measured inter-row weed density. Had various cultivated treatments including one, two, or three cultivations w/ various timings. In 2011 soybean yields were greater in plots that had multiple cultivations. Rye mulch increased soybean yield (there was dry weather in 2011 so rye mulch improved soil moisture). Surrogate weed Ida gold mustard didnt work in no-till (poor emergence). In 2012 there was a benefit of three cultivations compared to two. There were more weeds in the rye in 2012 possibly because these plots had moisture so more weed emergence. There was poorer crop emergence in the rye mulched areas. Corn/vetch plots in 2012: needed more than one cultivation for weed control and mulch increased yield by 13 bushel. Soil moisture was also measured in soybean in 2012. Rye did not interfere with cultivation. PA will repeat the experiments in 2013. Pigweed is very sensitive to mulches so would not suggest seeding only this species. Residue stays fairly intact for treatments that are cultivated once. Corn data is analogous to Jane Mt. Pleasants work in a tilled system in the 1990s. Objective 2. Determine the reproductive growth stage at which summer annual weeds can be terminated and still produce viable seeds and quantify the effect of method of life-termination on seed production. Combined Locations: presented by Erin Taylor: 5 sites across states. Univ. of Ill will repeat the flowering timing in 2013. In 2012 they had no viable seeds produced when terminated at flowering time. Cornell had 3 species and all three kill methods. Cornell did a detailed greenhouse study and then did the summer study. Farnaz did this research and is presenting a talk at WSSA. Their work included 4 different stages of development based on appearance of capsule color on velvetleaf (yellow, yellow/green, dark green, black); Lambsquarters: 3  43 days after flowering and had 5 stages of development that were harvested; giant foxtail: 5 stages also 0  20 days after flowering. For velvetleaf when seeds are fresh they are viable; the faster rate of drying decreased viability for velvetleaf. For lambsquarters, plants that were cut and left (if inflorescence or whole plant cut) seeds were produced by13 days; this is in contrast w/ velvetleaf. Lambsquarters still produce viable seed when cut and laid in the field. They have data on black and brown seeds also that are not presented. The brown seeds have an undeveloped embryo and are not viable. The data presented is only the black seeds. For giant foxtail: the foxtail seeds lose viability when they dry (similar to velvetleaf). So a farmer should remove giant foxtail and common lambsquarters at the time of flowering by either kill method. Chopping velvetleaf reduced seed viability and velvetleaf has a longer time after first flowers are produced to remove from the field. Cornell also completed common ragweed and wild proso millet. Maine researched hairy galinsoga, crabgrass, and redroot pigweed. At the time of flowering, either cut or chop had a few seeds produced (none w/ glyphosate). Galinsoga is indeterminate so maybe at flowering there might have been a few formed seeds at flowering. Delaware had three kill methods, 3 timings, and 3 weed species. Jimsonweed  10 to 14 days between flowering and brown seed stage. Jimsonweed did not produce seed at the flowering stage. By brown seed set, viable seed was produced (10- 14 days after flowering). There were fewer viable seeds produced with glyphosate compared to the chop or cut method. For foxtail, at flowering data was similar to Farnezs data that viable seed was produced. Lambsquarters was difficult to differentiate flowering from immature seed. Michigan  2nd year of data. MI is the only site with seeds out overwintering for the second year. There was 2-3 weeks from flowering until maturity with jimsonweed. Foxtail seed flowering was still in the whorl, immature was still only green seed, mature was when 50% of the seeds were brown (this may differ by university on classifying immature and mature). Jimsonweed and velvetleaf: 90% more seed produced in mature capsules, compared to immature capsules. Ideas: Determinate plants flowering based on day length so could we use this. Could GDD since emergence be used, or biomass or other variables be used as guidelines? We would like to give growers additional guidelines for removing weeds. Objective 3 results - Determine the extent to which soil amendments such as green manures and compost affect seed mortality of various weed species. Chuck Mohler  there was no difference in seed survival over winter because of the cover crop species. They had over 50% overwinter survival of the seed. Alan Taylor and Sarah Pollicove  seed germination and viability testing developed for four weed species to have optimum percent germination without using PGRs or other chemicals to break dormancy. Then use TZ for tetrazolium test for small species and larger seed break physical dormancy. Velvetleaf: 35C 16/8 light/dark = 85% and then pierce seed by hilum to break physical dormancy; giant foxtail 20/30 and 16/8 light dark = 60% germ and then TZ test but staining should be throughout the embryo (see images from A. Taylor); lambsquarters same as giant foxtail = 64% and then TZ test and watch for lack of uniform staining (also the green and turgid embryo even though it doesnt stain is considered viable); Powell amaranth 20/35 with 10/14 dark/light 76% germination. Thomas Bjorkman buried seed bags 4 deep. There is no sand in their bags. They were buried in late June and pulled out in August. A cover crop was incorporated and then a new set of seed bags were placed into the soil. Sudangrass and buckwheat were the two cover crops. They are seeing a high level of fatal germination (sprouting) in their studies with giant foxtail. Powell amaranth had only a few sprouted seeds, and fewer sprouting after buckwheat. Erin Haramoto (Dan Brainard) Michigan the experiment is in SW MI on sandy soil with Powell amaranth and large crabgrass are the two species and the covers are rye, rye + vetch, and no cover. Dry residues are added to the bags and not green covers like other researchers. Seed bags are buried into growing cover crops in November and are removed in June. Some of the bags were mixed with dry cover crop residues and returned to the soil and reburied until August. Seeds are not analyzed for dormancy but just for viability. All seed that was TZ tested was dead. Powell amaranth 70% viable after being buried for 6 months; large crabgrass had only 19% viability. There was a trend for greater seed viability where there were cover crops. There was not a moisture difference, not a moderating temperature difference with cover/no cover. Microbial community in the seed bags are changing the microbial community in the bag. Mark Shankle  Mississippi has a burial study also. Kevin Gibson  Purdue buried bags this year (following Chucks protocol). Erin Taylor (Karen Renner) have the experiment ongoing in the field also with three species and clover, rye, and no cover. They will have viability data only. Other business 5:30 PM - Adjourn

Outcomes: This was the first official year of the project, so outcomes are yet to be determined. Outputs: Penn State - In 2011, control was similar and 90% or better for treatments cultivated either 2 or 3 times. The single cultivation treatments had the lowest level of weed control and especially 4 weeks after planting providing less than 50% control. There was no difference in cultivation efficacy between the cover crop and no cover crop plots. There was no evidence of soybean stand reduction with cultivation timing or frequency. Soybean yield did differ with cultivation treatment and cover crop residue. In general, soybean no-tilled into a rye cover crop yielded more than the no cover crop treatments. Although not always significant, plots cultivated twice or three times tended to have higher yields than plots with single or no cultivation. In the future, closer monitoring of soybean stand, soil moisture, and weed-free controls will be included in these experiments. Michigan State (Renner et al.) - Multiple weed management strategies directed at seeds and weed seedlings improve weed control in organic and sustainable systems as compared to a single tactic, thereby improving food production, quality and net return to farmers. There are three objectives in this new multi-state project and we are involved with two of these objectives (2 and 3). They are: Objective 2) to determine the reproductive growth stage at which summer annual weeds can be terminated and still produce viable seeds and quantify the effect of method of life-termination on seed production, and 3) to determine the extent to which soil amendments such as green manures and compost affect seed mortality of various weed species. Understanding how production of viable seeds relates to the point in the life-cycle at which a weed is killed and the method by which it is killed will improve preventive weed management. Improved understanding of how organic matter amendments, including green manures and compost, affect seed survival following initial seed rain will allow growers to implement cropping systems that reduce weed seed banks and thus weed pressure in subsequent crops. For Objective 2, weeds were terminated at the early floral stages, when immature seed was present, and again at 50% maturity by pulling, chopping, or herbicide application. Plants were stored in bags in the field between crop rows until early November at which time the bags were retrieved and the weed seed tested for viability and dormancy. Our site has collected 2 years of data for our 5 weed species (common lambsquarters, giant foxtail, jimsonweed, velvetleaf, and Canada thistle). For all species, termination at the time of the first open flower did not result in viable seed production for any termination method. Terminating weeds with immature seeds reduced seed bank inputs compared to allowing seeds to mature. The best termination method to use appears to be species dependent. For Objective 3, 200 weed seeds (velvetleaf, common lambsquarters, and giant foxtail) were overwintered in mesh bags filled with 100 g of sand, buried to 15 cm. Bags were buried in cover crop plots with actively growing rye Wheeler, medium red clover Marathon, or no cover. There were 4 replications. Bags were exhumed prior to cover crop incorporation with a chisel plow. One set of bags was set aside to access overwinter survival. The other 5 sets of bags were re-bagged with a fixed amount of cover crop added from the respective plot. Due to the mechanical preparation of the field prior to organic dry bean planting, the new bags were stored buried 15cm deep in a no cover area of the field for a couple of weeks and placed back into the cover crop plots (again 15 cm deep) after dry bean planting. Pull times for our study were more frequent than those of the regional group. We pulled bags at 1, 2, 4, and 6 months after cover crop incorporation and have a final set ready to be pulled at 12 months after incorporation (next June). The seed bags retrieved thus far have been sieveds, counted, and tested for germination. We are currently conducting the final viability tests using tetrazolium chloride. (Brainard et al.) As expected, over-winter survival did not differ among treatments for any species, although high variability limited our ability to detect small differences. Overall, 70% of A. powellii seeds survived overwinter, and 19% of D. sanguinalis seeds survived. Cornell (Mohler et al.) - For objective 2, Results of greenhouse study Velvetleaf seeds began becoming viable during the second development stage stage (7-13 DAF), and reached 100% viability during the third stage (14-16 DAF). The rate at which full viability was approached differed significantly among treatments. In common lambsquarters, black-colored seeds were viable and poorly developed brown-colored seeds were not viable. This species did not produce seed at 3 DAF and seeds from 13 DAF had lower viability than later stages of development. For objective 3, As expected, over-winter survival did not differ among treatments for any species. For all species sufficient seeds remained in the spring to provide an adequate test of whether the incorporation of cover crop material affects seed survival. Maine - For objective 1, efficacy ranged from 6.7 to 100%, with mean and median values of 67 and 68%, respectively. Contrary to expectations, soil conditions failed to explain any portion of the considerable variation in efficacy. Mustard mortality was similar with or without tractor wheel traffic (P = 0.6708). Likewise, bivariate fits of mustard mortality with percent sand, bulk density, soil moisture, or surface roughness failed to detect any relationships between our dependent and explanatory variables. It was surprising that the large amount of variability in efficacy was not related to measured soil conditions, despite relatively large ranges in these explanatory variables. Sand, for example, ranged from 2 to 90%; bulk density ranged from 0.64 to 1.27 g cc-1; soil moisture ranged from 10 to 32%; and surface roughness from 62 to 90 on a relative scale. For objective 2, seed was not recovered from the glyphosate treated plants; often the plants as decomposed and were not recognizable, presumably due to the small size at the time of application, and the duration they remained in the field (Table 1). Cutting and chopping prevented viable seed production in both A. retroflexus, and D. sanguinalis. Two cut and two chopped H. galinsoga plants produced viable seeds (9 viable seeds for each treatment). Although we attempted to impose our treatments at the first appearance of an open flower, it is possible that our study plants had flowers that were more mature than this. H. galinsoga is day-neutral with regard to flowering, with each lateral branch terminating in a flower head (Warwick and Sweet, 1983). Viable seeds are formed as early as two weeks after flowering (Ivany and Sweet, 1973). Activities: Penn State - We are participating in the first objective of a three objective regional project (NE-1047). This objective is to determine how soil conditions affect efficacy and selectivity of cultivation implements for the control of various weed species. In PA, we are specifically evaluating the effectiveness of shallow high residue cultivation in no-till soybean and corn. In 2011, we conducted an experiment in central Pennsylvania in soybean and in both soybean and corn in 2012. Cash crops were no-till planted in 76-cm rows with banded herbicide application at planting. The main plot was cultivation treatment and a split plot was cover crop residue (cereal rye) vs. no cover crop residue. Data collection included crop stand count, weed density, late summer weed biomass, and crop grain yield. Cultivation treatments included once at 4, 5, or 6 weeks after planting, cultivation twice at 4 and 5, 4 and 6, or 5 and 6 weeks, and cultivation three times at 4, 5, and 6 weeks after soybean planting. Data for 2012 is still being processed. Michigan (Renner et al.) - Objective 2: We will choose one weed from each of group A (small seeded broadleaves), B (velvetleaf), C (Canada thistle) and D (grasses). Plants from each species will be terminated at the early floral stage for Groups A, B, and C or at the first appearance of the green seed head for Group D. Additional plants will be terminated when immature seed is present and again at 50% seed maturity. Collection times are based on the most advanced stage on a given plant. Three methods of termination will allow us to determine how method and timing of termination influence viable seed production. The termination methods are: pulling the plant (simulating hand pulling or hoeing), clipping/chopping (simulating mowing), applying the herbicide glyphosate. Each plant or collection of reproductive structures from a plant will be stored separately in a nylon-mesh residue bags or baskets. In early November of each year, the baskets and residue bags will be retrieved from the field, and seed production determined for each sample. Some seeds will be immediately tested for viability, while other seeds will be returned to the field surface and tested for viability in the spring. For each weed species, viability and germination will be analyzed using ANOVA in SAS to determine if termination methods and timings differ. Objective 3: Seeds of two or more weed species collected from local populations will be buried in fine mesh packets in each plot late in the fall of year 0 while cover crops are growing, but before any cover crop residue or other amendment has been incorporated. Each packet will contain several hundred seeds mixed with 100 g of fine sand and initially no amendment. Amendments will include a control treatment that receives no amendment, at least one legume cover crop, and at least one small grain cover crop. Cover crops will be planted at the appropriate time for each location. Packets will be buried at 15 cm, and enough packets buried to allow removal of one packet from each replication in each of the following two or more springs. Each spring before incorporation of cover crops and other amendments, all packets will be removed from the soil. One set will be set aside for analysis of surviving seeds. The other packets will be weighed, the sand and seeds mixed with amendment at a rate corresponding to the rate incorporated in the field plots, and the sand and seeds will then be returned to a packet, and reburied in the plot from which they came. The same crop or summer cover crop will be grown on all plots during the summer. To assess the number of seeds remaining in a packet, the sand-seed-residue mix will be spread shallowly in a dish, and partially decomposed seeds and empty seed coats will be destroyed when screening out the sand. The seeds will be counted and viability assessed by light pressure. Differences in seed survival between amendment treatments, burial periods and species will be assessed initially at the state level by time-series ANOVA of arcsine square root transformed seed survival proportions. Michigan (Brainard et al.) - Overwinter survival of buried weed seeds (Amaranthus powellii and Digitaria sanguinalis) was evaluated in a long-term trial examining the effects of cover crops (none, rye or rye-vetch) and tillage (moldboard plow vs strip-till) on weeds in a three-year vegetable crop rotation (sweet corn: snap beans: winter squash). Cover crop and tillage treatments have been imposed in the same plots since 2009. Seeds were buried following winter squash harvest in fall 2011, exhumed in spring 2012, and tested for viability. Sufficient additional bags have been buried to examine survival for 3 additional years. Initial Burial. Mesh bags (approx. 8 x 10 cm) were constructed from no see-um mesh (Outdoor Wilderness Fabrics) using nylon thread. Bags were filled with 100 g of sand that had been sieved through a 500 µ sieve (smaller fraction kept) mixed with 100 seeds of A. powellii or 200 seeds of D. sanguinalis. Bags were buried 15 cm deep in all 6 cover crop x tillage combinations, on 9 November 2011. Cover crops had already been established (10 September 2011)rye was seeded at 112 lbs/acre in rye only plots and at 56 lbs/acre in the rye/vetch plots with vetch at 20 lbs/acre. The field was disked prior to cover crop planting; no other weed management was used in the fall. Exhumation and viability testing. One bag of each species from each plot was exhumed on 4 June and stored until viability testing. Seeds were removed from bags by sieving through a 500 µ sieve. Seeds of A. powellii were then germinated at 30°C with 2 µM GA. Seeds of D. sanguinalis were germinated in deionized water at 30°C. Ungerminated seeds were assessed for viability by a combination of squeeze testing and TZ testing. Reburial. In moldboard plow treatments, all remaining bags were pulled prior to spring tillage, filled with a fixed amount of cover crop residue, and re-buried following tillage and planting the next day. Bags were filled with rye and vetch residue that had been collected prior to termination (9 May 2012), dried down, and coarsely ground in a Wiley mill. Pieces of ground residues were approximately 5-10 mm long. Experiment-wide, dry rye biomass averaged 6350 kg/ha in rye only plots and 6460 kg/ha with 1100 kg/ha vetch biomass in rye/vetch plots. For rye plots, we added 0.3 g of dry rye residue per bag; for rye and vetch plots we added 0.3 g dry rye and 0.05 g dry vetch residue. Cornell - For objective 2, three common summer annual weed species: velvetleaf, common lambsquarters, and giant foxtail were grown in a greenhouse greenhouse. The flowering phenology of each plant was recorded throughout the experiment, and individual capsules of velvetleaf tagged with flowering date. The experiment had three treatments: (a) plant cut at base and left to dry for 4 wk on the greenhouse bench, (b) individual capsules (velvetleaf), terminal infolorescence (common lambsquarters) or first seed head (giant foxtail) were cut from the plant and left to dry in the greenhouse for 4 wk, and (c) reproductive material removed from the plant and seeds evaluated immediately. Velvetleaf plants were harvested when two or more capsules were fully mature and capsule were classified into four developmental stages based on color.. Common lambsquarters and giant foxtail were harvested at 5 developmental stages based on days after flowering (DAF). Seeds were tested for germination and viability of non-germinable seeds assessed by piercing velvetleaf and staining giant foxtail and common lambsquarters with tetrazolium chloride. . This experiment was repeated in the field during the 2012 growing season but results are not yet available. Additional experiments were conducted on velvetleaf, common lambsquarters, giant foxtail, wild proso millet and common ragweed during the 2012 growing season following the standard Obj. 2 protocols. Treatments were (1) plants pulled, (2) plants chopped, and (3) plants painted with glyphosate. Plants were harvested (1) shortly after flowering, (2) at milk stage and (3)when mature seeds first appeared. Plants weere left in the field in mesh bags until November. For objective 3, Cover crop treatments of grain rye, hairy vetch and bare control were planted 11 Sep 2011 ina replicated block design with five replications. Plots were 20 x 45. Seeds of velvetleaf (200), common lambsquarters (200), Powell amaranth (200) and giant foxtail (250) were placed in 83 g of sand in 3 x 4 organza mesh bags and individually buried at the bottom of a 7 hole made with a bulb planter. This put the center of the bag at about 6 depth. On 17 May bags were dug up, brushed off, opened and material dumped into a pan. One set of samples were retained for analysis. These were placed in 6 pie pans and dried at 40 C in a forced draft oven for 24 hr to prevent seed germination. If originating from a cover crop plot, chopped cover crop material was mixed with the sand and seds of the remaining samples. Cover crop material was added at a rate equivalent to 600 g/m2 (calculation assumed a 2,000,00 lb/A furrow slice of 6depth). The sand mix was replaced into new mesh bags and double baged to avoid rupturing bags during recovery. Plots were mowed, disked and then rototilled the same day. Samples destined for reburial were held in ice chests before and after opening. Bags were tied to three washers for 1 bolts and bags plus washers were reburied as before on 18 May 2012. Maine - For objective 1, the University of Maine research group conducted a single field experiment related to Objective 1 in 2012. Cultivation efficacy and soil conditions were measured at 70 locations, randomly selected along five corn row transects in a 2 ha field of silage corn. The cultivator was a common, older model, 3-point-hitch-mounted, 4-row Case International Model 183 with Danish s-tines and 10 cm sweeps and gage wheels. Condiment mustard, Idagold, (Sinapis alba) was used as a surrogate weed. On June 20, 2012 (corn 10 cm tall, 2-leaf stage), Idagold was sown over the top of the corn at 5.5 kg ha-1 using an air seeder with 15 cm row spacing. Due to wheel tracks in this four-row system, our study rows were not in a uniform soil environment: wheel-tracked sides of the rows were more compact than areas lacking wheel traffic. Thus, paired samples were taken at each of 70 locations for a total of 140 samples. Soil surface roughness was measured on July 1; samples to measure bulk density and texture were collected on July 1-2. Soil moisture was measured, and pre-cultivation censuses performed on July 3, and the field was cultivated (mustard at 1-leaf stage); post-cultivation censuses were performed on July 5. For objective 2, the University of Maine research group tested cutting, chopping and glyphosate application effects on seed maturation in Galinsoga cilata, Amaranthus retroflexus, and Digitaria sanguinalis. Treatments were imposed on August 28-30, 2012; plants were collected from the field on November 7, 2012. Milestones: (year 1) Objective 1. Plant cover crops in fall. Till ground or roller-crimp cover crops and plant crops. Measure soil properties, count weeds in quadrats, assess crop stand; cultivate; count weeds in quadrats and assess crop stand after cultivation. Repeat for additional cultivations. Objective 2. Determine which labs will study which species. Plant crops and weeds in spring. Terminate sample plants at various phenological stages and confine plants in mesh to capture seeds as they mature. Objective 3. Plant cover crops, gather seeds, and bury seed packets in the fall. Run tests of initial seed viability. Recover seed packets in the spring, till plots, mix amendments into packets, rebury most packets. Assess seed viability in spring sample packets. Plant and maintain crops or cover crops over the summer and remove crops in the fall in time for cover crop planting. Collect and analyze Study B rapid assessment packet at 3 month intervals.

Keene, C.L. and W.S. Curran. 2012. Effectiveness of shallow high residue cultivation in no-till soybean. Proc. Northeast Weed Sci. Soc. 66. Taylor, E., K. Renner, and C. Sprague. 2012. Reproductive potential of summer annual weeds based on termination method and timing. North Central Weed Science Society annual meeting. 71. St. Louis, MO. Poster.