Source: PENNSYLVANIA STATE UNIVERSITY submitted to NRP
INTEGRATED WEED MANAGEMENT AT A CROSSROADS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
1001605
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Oct 1, 2013
Project End Date
Sep 30, 2018
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
PENNSYLVANIA STATE UNIVERSITY
208 MUELLER LABORATORY
UNIVERSITY PARK,PA 16802
Performing Department
Plant Science
Non Technical Summary
Crops bred to be resistant to multiple herbicide modes of action hold the promise to reduce the glyphosate resistance problem that plagues some 60 million acres of US corn, soybean and cotton. However, these new crops have been bred to be resistant to 2,4-D and dicamba, both plant growth regulator herbicides. While these herbicides are highly effective, they have a long history of drifting to adjacent fields and field edges and are equally or more active on many non-target broadleaf plants. This projects sets out to quantify the impact of such drift events on floristic diversity and the cascading effects on the insect community. We will also study the weed suppressive effects of cover crop cocktails in an attempt to identify mixtures of cover crops that would help take the weed suppressive pressure off herbicides. Finally, we know that practices like cover crops are likely to require additional management time and cost. In order to better understand the factors that hold such practices back we will analyze the true constraints to adoption of such alternative methods like cover cropping.
Animal Health Component
70%
Research Effort Categories
Basic
30%
Applied
70%
Developmental
0%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
21315991140100%
Knowledge Area
213 - Weeds Affecting Plants;

Subject Of Investigation
1599 - Grain crops, general/other;

Field Of Science
1140 - Weed science;
Goals / Objectives
The overarching goal for this body of work is to develop data and insights that will inform the development of more ecologically-based weed management systems. Specifically, the project is guided by the following three objectives: Objective 1: Determine the impacts of drift-level PGR herbicide exposures to non-crop plant and associated arthropod communities Objective 2: Assess the weed suppressive role of cover crops as part of an integrated weed suppressive crop production practice Objective 3: Identify the constraints to adoption of more sustainable methods of pest management and summarize them in a high profile synthetic paper
Project Methods
Objective 1: Determine the impacts of drift-level PGR herbicide exposures to non-crop plant and associated arthropod communities. Study System: Non-crop plant communities and associated arthropod communities including beneficial species may be altered by particle and vapor drift of PGR herbicides. Here we will build on several experiments we have conducted assessing the influence of drift level doses of dicamba on the fitness of weedy and other field edge plant species (Egan et al. 2013b, c). Unfortunately, there is very little data available to determine the response of non-crop plant communities to drift level concentrations of PGR herbicides and there is no data at all on the influence of these compounds in mixture (which is the way they will be used if the crops are deregulated). Further, while we have just begun to assess the food-web implications of altering or reducing floristic diversity on the beneficial insect provisioning capacity of these plant communities (Russo et al. 2013 and Bohnenblust et al. 2013) much more work is needed. Using a set of experiments on both created and naturally occurring plant communities, we will determine how combinations of 2,4-D, dicamba and glyphosate drift affects non-crop plants and whether changes in plant community composition cascade through food webs and influence arthropod communities. Taken together, the paired experiments will allow us to assess community change in both a created community where initial plant composition is more uniform and controlled and in natural communities where initial plant composition will be more variable. While these experiments will mainly assess indirect changes in the arthropod community caused by changes in plant community composition, herbicides could also have direct toxic effects on arthropods. It is not our intent to screen for these direct effects, but they could certainly play a role structuring insect communities (Brooks et al. 2005) and may warrant further investigation. Research on created plant communities will utilize a conservation mixture that is currently being promoted by the National Resource Conservation Service to enhance floristic diversity to support beneficial insects, including pollinators and natural enemies. The mixture comprises 18 plant species (see Russo et al. 2013) that are attractive to beneficial insects. In Pennsylvania, this conservation mixture is being marketed to fruit and vegetable growers to improve pollination services as well as field crop growers to improve biocontrol services. If PGR resistant soybeans become widely adopted, there is a high probability that some of these conservation plantings will encounter PGR drift. Experiments on naturally occurring plant communities will examine woodlot edges, which are an important type of non-crop habitat in both the mid West and mid Atlantic regions. Woodlots can contain high plant species richness, including native plants, and provide crucial resources for beneficial insects such as pollinators and natural enemies (Winfree et al. 2008, Landis et al, 2008, Egan and Mortensen 2012). Woodlots frequently border crops fields, making them at large risk of exposure to herbicide drift (Gove et al. 2007, Boutin and Jobin 1998). In each woodlot, the ten plots will be randomly assigned to dicamba, 2,4-D and glyphosate mixtures at 1/1000, 1/100, 1/10 X of the labeled rate of the mixtures plus a water control. Two plots per treatment per woodlot will provide greater statistical power to detect community change when initial plant composition may vary from plot to plot. PGR herbicide mixtures will be repeated on these same plots in late June 2015 and 2016, and plant community and insect community data will be collected as in 2014. We will actively sample arthropods communities using vacuums fitted with nylon mesh bags. To further characterize the arthropod communities in the conservation mixture and woodlot edge communities, we will also use passive trapping techniques including pitfall traps (for epigeal arthropods) and yellow pan traps (for flying insects, mostly wasps and flies). We will install two traps of each type per plot and collect traps after 24hr. All arthropod samples will be carefully labeled in the field and returned to the laboratory for sorting and identification. Arthropods will be identified at least to the family level, but to genus and species when possible. For those that we cannot identify to genus or species with certainty, we will group them into morphospecies within each family. Help will be sought from taxonomists when necessary. The statistical methods for quantifying the effects of herbicide mixtures on the plant community composition and the cascading effects on the insect community used in our recent papers (Egan et al., 2013a, b, c and Bohnenblust et al. 2013) will be applied to this data. Objective 2: Assess the weed suppressive role of cover crops as part of an integrated weed suppressive crop production practice. The mid-Atlantic region has seen an upsurge in adoption of cover crops as a result of initiatives to improve water quality in the Chesapeake watershed. To identify cover crops species and agronomic production practices that will fit farming systems in the region, several studies have recently been funded (for example, Multifunctional cover crop cocktails for organic systems funded by the USDA Organic Research and Extension Initiative competitive grants program). While none of those studies expressly addresses glyphosate resistance management, they do take a broad, ecosystems services approach to identifying such practices. In this objective, we propose to add value to several of those studies by testing the weed suppressive effects of several candidate cover crops that could be easily adapted to conventionally produced soybean and corn. Objective 3: Identify the constraints to adoption of more sustainable methods of pest management and summarize them in a high profile synthetic paper. For this objective, I will lead a series of workshop/writing sessions with a group of agroecologists seeking to understand and reveal the true constraints to adoption of more ecologically-based sustainable agricultural practices. Members of two USDA-NIFA funded projects (Precision Zonal Management: A Climate Change Mitigating Crop Management Strategy and Multifunctional Cover Crop Cocktails for Organic Systems) have recognized the critical need for a robust assessment of the true constraints to adoption of more sustainable agricultural practices. This group of scientists (David Mortensen, Penn State University; Richard Smith, University of New Hampshire; Nick Jordan, University of Minnesota; Adam Davis, USDA-ARS Champaign-Urbana, Jason Kaye and Meagan Schipanski, Penn State University) are concerned that until we fully understand the constraints hold back adoption of sustainable agricultural practices, the potential impact of our research and outreach programs will not be realized. Additionally, knowing the constraints could direct a research program that is more likely to provide solutions that will work for farmers within their current set of constraints. Finally, such insights could and should help guide policy that encourages adoption of such practices.

Progress 10/01/13 to 09/30/18

Outputs
Target Audience:The target audience for this research is diverse and with a very wide reach spanning a broad continuum of farm to fork (farmers to consumers). This research work provided important outputs and information relevant to federal scientists (USDA APHIS), federal regulators (EPA), policy makers (USDA and EPA), natural resource managers, farmers (in the region and nationally), input providers, agroecological research scientists, pest management consultants, journalists, environmentalists, university undergraduate and graduate students, and consumers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Over the course of this project, the results of the research were used to refresh course content in applicable courses. This approach has allowed for providing training for both undergraduate and graduate students through case studies, mock Congressional panels, and through living laboratory experiments and demonstrations. The project and associated research and outreach work hasinformedFederal agencies, farmers and those engaged in farm management toshape federal policy throughUSDA APHIS and EPA reviews of the herbicide resistant crop deregulation applications while at the same time providing concrete recommendations for changes in agricultural practices on the ground. This project has enabled ongoing interaction between Penn State researchersand USDA APHIS and EPA on pesticides and GM deregulation policy. How have the results been disseminated to communities of interest?Results of this research have been disseminated through peer-reviewed papers, book chapters, talks and professional presentations (local, regional, national, and international), radio and press articles and interviews (national and local), magazine articles, webinars, and results have been used to update and enrich engaged scholarship-oriented courses. What do you plan to do during the next reporting period to accomplish the goals?PI has left Penn State and research project has been terminated.

Impacts
What was accomplished under these goals? Objective 1 Several studies were conducted in the greenhouse and field to determine the impacts of drift-level PGR herbicide exposures to non-crop plant and associated arthropod communities. We found that drift-level doses of auxinic herbicides reduce the abundance of broadleaf plants in the field edge from approximately 60 to 25%. These studies were conducted in in-tact field edge plant communities where simulated doses of herbicide drift were deliberately applied to the field edges. While we consistently observed a reduction in broadleaf plants, the impact on insect communities in these field studies was less clear. In a more controlled experiment in which select field edge plants were exposed to drift-level doses of auxinic herbicides during flowering, floral area was significantly reduced and as was pollinator abundance. Over a range of drift level doses, flowering was eliminated at the higher drift level doses and bee visitation too dropped to zero. This work provided clear evidence that abundance of broadleaf plants is reduced when subjected toauxinic herbicide drift and that the reduction in broadleaf plants had measurable adverseeffectson theabundance of pollinators. We found that while drift level doses of dicamba and 2,4-D herbicides damaged the vegetative growth of these plants, the effect was more pronounced on flowering and therefore the pollinatorprovisioning capacity of the plants. This disproportionate effect on floral provisioning underscores the need to understand field-level effects of herbicide drift on non-target plant communities. A national level spatial analysis of agricultural fields to quantify the amount of edge habitat in close proximity to agricultural fields was alsoinitiated. Objective 2 Several studies were conducted to assess the weed suppressive role of cover crops as part of an integrated weed suppressive crop production practice. Through ourresearchwequantifiedtheextent to whichcover crop monocultures and mixtures suppress weeds. Importantly, this work was done in a multi-functional way which is to say, that while we were measuring the effects of cover crops on weeds, we were also measuring the impact of cover crops on nitrogen retention and provisioning, soil organic matter accumulation and insect biodiversity.In general, we saw significant suppression of winter annual weeds along with suppression of late germinating summer annual weeds. Additionally, the process of cover crop planting stimulates the germination of late season summer annuals which are then suppressed by the rapidly growing cover crops. Place-based research studies at the Penn State Research farm coupled with a rapid ecosystem assessment conducted on 47 farms across 109 fieldsprovided our research team with a unique data set documenting how farmers are using such mixtures on their farms. We found that cover crop functional trait diversity is important in cover crop mixtures and that greater functional diversity (as opposed to species diversity) results in greater weed suppression. Our on-farm research taught us that the conservation goal of individual farms should guide the design and execution of cover crop mixtures in order to match local context with needed ecosystem services. Objective 3 Much effort has been spent to identify the constraints to adoption of more sustainable methods of pest management and summarize them in a high profile synthetic paper. Research has been conducted to quantify the benefits of a range of sustainable agriculture practices however the adoption of many of those practices has fallen short of expectations. A manuscript was written detailingthe need to focus our attention on theenvironmental challenges facing grain crop production. While food demand will increase with a growing global human population, we have conducted a broad and deep analysis of the environmental challenges that must be addressed as we design sustainably intensified cropping systems.

Publications


    Progress 10/01/16 to 09/30/17

    Outputs
    Target Audience:The target audience is broad and diverse. During the reporting period I published 14 peer-review papers out of this project. Those papers reached policy makers, scientists, and agency (EPA, USDA-ARS, National Forest Service) scientists. I presented at a number of regional and national workshops where the audience was farmers and pest management consultants. I taught during the reporting period reaching undergraduate and graduate students here and at the University of New Hampshire and at Boston College. Changes/Problems:I don't plan any major changes in the course of my work. As discussed in the previous section, I am working to finish a number of projects and to write a number of broad synthetic pieces. What opportunities for training and professional development has the project provided?A good number of professional development opportunities have arisen out of our work. First, I have spoken widely about the benefits of cover crop mixtures and have also reminded scientists that we need to improve the process by which we contribute our insights to shape and form pesticide and GM deregulation policy. I have trained four graduate students, two undergraduate students and a post-doctoral scientist over the past year as well as working closely with two technical support people in my lab. I have also served on another 7 graduate committees other than my own. How have the results been disseminated to communities of interest?Peer-reviewed papers, a book chapter, I've spoken at numerous workshops and field days and through the two courses I teach. What do you plan to do during the next reporting period to accomplish the goals?I am in the process of finish a number of projects. So one major thrust will be to focus on providing the support needed to have my people finish strong. For me, finishing strong means publishing our work and positioning ourselves to move on to the work we aspire to do. I am also at a point where writing more synthesis pieces interests me a great deal. The title of my project, Integrated Weed Managmenet at a Crossroads begs writing about how we transcend the crossroads in the face of increasing private sector influence shaping the future of sustainable food systems in the US. I believe writing such pieces will help the next generation of scientists see their way clear to the kind of science we need to be doing and how to fund it.

    Impacts
    What was accomplished under these goals? Work tied to this project dates back to our initial findings demonstrating that stacked trait herbicide resistant crops were likely to select for multiple resistance in common weedy species and strongly cautioning against the use of traits confering for resistance in crop plants to 2,4-D and dicamba. Our 20 plus publications not demonstrated that there was a high looklihood of drift by both herbicides we also conducted in-situ studies documenting the downside effects of drift on wild flowering plants and the knock-on effects of plant injury on their capacity to provision wild and commercial polinators. This summer widespread drift of dicamba herbicide resulted in widespread adjacent crop plant injury and resulted in widespread damage to the flowering plant flora in the field edges, much the same way that we predicted. Our meta-analysis documenting the susceptibility of crop plants to 2,4-D and dicamba received a national award and also quanitified the sort of damage that we saw this summer, that paper was published three years ago. The cover crop work has yielded more hopeful results as we're seeing farmers adopting the practice of cover crop mixtures as documented in our recent Soil and Water Conservation paper. Our work has helped provide additional insight into the benefits of cover crop mixtures.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Hunter, M, RG Smith, ME Schipanski, LW Atwood, DA Mortensen. 2017. Agriculture in 2050: Recalibrating targets for sustainable intensification. BioScience, 67, 386-391.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Smith, RG, and DA Mortensen. 2017. A disturbance-based framework for understanding weed community assembly in agroecosystems: challenges and opportunities for agroecological weed management. Pg. 127-154. In: Wezel, A. (Ed.) Agroecological Practices for Sustainable Agriculture: Principles, Applications, and Making the Transition. World Scientific Publishing, London.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Harker, KN, C Mallory-Smith, BD Maxwell, DA Mortensen, RG Smith. 2017. Another View. Weed Science, 65, 203-205.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Schipanski, ME, ME Barbercheck, EG Murrell, J Harper, DM Finney, JP Kaye, DA Mortensen, RG Smith. 2017. Balancing multiple objectives in organic feed and forage cropping systems. Agriculture, Ecosystems & Environment, 239, 219-227.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Murrell, EG, ME Schipanski, DM Finney, MC Hunter, M Burgess, JC LaChance, B Baraibar, CM White, DA Mortensen, and JP Kaye. 2017. Achieving diverse cover crop mixtures: Effects of planting date and seeding rate. Agronomy Journal 109, 259-271.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Williams, A, AS Davis, A Jilling, AS Grandy, RT Koide, DA Mortensen, RG Smith, SS Snapp, KA Spokas, AC Yannarell. 2017. Reconciling opposing soil processes in row-crop agroecosystems via soil functional zone management. Agriculture, Ecosystems & Environment 236, 99-107.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Rauschert, SJ and DA Mortensen. 2017. Human-mediated dispersal via rural road maintenance can move invasive propagules. Biological Invasions, 7, 2047-2058.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Hamilton, AV, DA Mortensen, and M Kammerer Allen. 2017. The state of cover crop nation and how to set realistic future goals for the popular conservation practice. Journal of Soil and Water Conservation 72, 111-115.
    • Type: Journal Articles Status: Awaiting Publication Year Published: 2017 Citation: Baraibar, B, M Hunter, M Schipanski, A Hamilton, DA Mortensen. 2017. How do cover crop monocultures and mixtures deal with weeds? The importance of planting window and cover crop species. Weed Science, in press.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Bohnenblust, EW, AD Vaudo, JF Egan, DA Mortensen, and J Tooker. 2016. Effects of the herbicide dicamba on non-target plants and pollinator visitation. Environmental Toxicology and Chemistry, Journal of Pest Science, 35, 144-151.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Vaudo, AD, D Stabler, HM Patch, DA Mortensen, GA Wright, CM Grozinger, and JF Tooker. 2016. Macronutrient ratios in pollen shape bumble bee (Bombus impatiens) foraging strategies and floral preferences. PNAS, 113, E4035-42. doi: 10.1073/pnas.1606101113.


    Progress 10/01/15 to 09/30/16

    Outputs
    Target Audience:There are several important audiences for my work. First, as a basic and applied researcher, my work seeks to expand our understanding of ecologically-based approaches to integrated pest and weed management. Through our work, we seek to grow our understanding for the dynamics that regulate pest populations and use our understanding of those dynamics to improve methods of pest management. Here, we publish the results of our work in peer-reviewed journals and regularly attend regional, national and international meetings to report on our findings. A second audience is farmers and state and federal agency scientists and natural resource managers. Here, we regularly organize and participate in applied workshops, field-days, webinars and report our work in various newsletters and on-line outlets. A third audience is policy makers, an audience our work is increasingly relevant to. Those policy and regulatory agencies include EPA, USDA APHIS, as well as those engaged in legislating those agencies. A fourth audience is undergraduate and graduate students who benefit directly from our research by either engaging in the research directly or through enriched curricula. Finally, the consumer is an audience to our work. Here again, we regularly participate in local and regional workshops and conferences to share results of our work. Changes/Problems:I don't anticipate major changes to the proposed plan of work. What opportunities for training and professional development has the project provided?There is an ongoing interaction betweenUSDA APHIS and EPA who continue to carry out reviews of herbicide resistant crop deregulation applications. Our paper entitled Egan, JF, KB Barlow, and DA Mortensen. 2014. A meta-analysis on the effects of 2,4-D and dicamba on soybean and cotton. Weed Science 62: 193-206 has helped to shape language in two reregulation applications currently under review by these two federal regulatory agencies. Our lab is one of a handful that works in this area and the meta-analysis was centrally important in informing our understanding of the on-the-ground risk of crop injury in the event the auxinic engineered soybean and corn crops are deregulated. The paper was also awarded the Outstanding Paper in Weed Sciencein 2015. I have also been actively involved in Dutch funded project assessing the impacts of such herbicide use on so-called tipping points in agriculture. Just last month I was invited to present in a European symposium on the subject. Finally, I routinely use the research we conduct to refresh the courses I teach. In this way, over the past year I have reached some 135 undergraduate students and 20 graduate students through case studies, mock Congressional panels, and through living laboratory experiments and demonstrations. I mentor 5 graduate students and a post-doctoral scientist all of who are directly or indirectly benefiting from the work underway in this project How have the results been disseminated to communities of interest?The results have been diseminated through peer-reviewed journals, through radio and press interviews, through regional, national and international talks given by me and those in my lab group. I also serve on the Board of Directors of the nation's largest state-led sustainable agriculture education-oriented association and results have been presented at their conference over the past two winters. Finally, the results are used to update and enrich my engaged scholarship oriented courses. What do you plan to do during the next reporting period to accomplish the goals?I will continue to focus on getting our papers out. I am currently co-author on nine papers that have been accepted or are in press. I will steward those papers through the publication process. I also have two book chapters that are at stages of development with one in press and another that I am currently writing that will be submitted in the spring of 2017. Both chapters address ecologically-oriented pest and weed management and are direct outcomes of the work outline in the first two objectives of this work plan. Finally, I have one foundational program proposal in review that would support the first and second objective of this project and will be submitting an additional two proposals in the coming year.

    Impacts
    What was accomplished under these goals? Objective I. I just returned from Wageningen University where I am collaborating with two spatial modelers who are working with us on quantifying the landscape effects of auxinic herbicide drift on floristic diversity in agricultural fields and field edges and the knock-on effects on ecosystem services. Specifically, the ecosystem service we are focusing on is pollination and we're doing that using a spatially explicit, landscape-scale pollinator resource model. Over the past year, we published a paper on adapting the model to better estimate the field edge flora in the paper: Kammerer, MA, DJ Biddinger, NK Joshi, EG Rajotte, DA Mortensen. 2016. Modeling local spatial patterns of wild bee diversity in Pennsylvania apple orchards. Landscape Ecology, doi:10.1007/s10980-016-0416-4. In addition, we have revamped several detailed literature reviews and have a paper in review in Environmental Entomology that addresses the potential effects of further losses of floristic diversity in fields and field-edges. I worked to pull this interdisciplinary group together to address this important topic, the paper was invited by the Editor of Environmental Entomology after hearing a seminar I presented on the subject:Mortensen, DA, RG Smith, MA Kammerer, J Tooker, BD Maxwell, J LaChance, JF Egan, M Schipanski. 2015. It's time to rethink the edge. Environmental Entomology, invited and inreview. Objective 2. An important paper is currently in-press that summarizes the results of our place-based research studies at the Penn State Research farm assessing the likelihood that cover crop mixtures are realized from known proportions of cover crop seed mixes. We found that site context strongly shapes the biomass of the resulting plant mixture and that the resulting biomass was much more sensitive context than to the proportion of seed planted. That is to say, that soils rich in N result in low expression of legumes and greater expression of Brassicaceous and grass cover crops. Those findings were reported in Murrell, EG, ME Schipanksi, DM Finney, MC Hunter, JC LaChance,BM Bradley, B Baraibar, M Burgess, CM White, DA Mortensen, and JP Kaye. 2016. For success, express without excess: Cover crop species' performances over time are affected by planting date and community composition. Agronomy Journal, in press. Objective 3.Just this week we learned that the synthetic paper addressing constraints to food production systems was accepted in BioScience. That paper entitled:Hunter, M, Smith, RG, Schipanski, ME, Atwood, LW , Mortensen, DA. Agriculture in 2050: How intensified? How sustainable? BioScience, accepted. should be out, in-print by the first quarter of 2017. This is a very important paper and the subject of a symposium at the coming Agronomy Society meetings.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Jongejans, E, O Skarpaas, MJ Ferrari, ES Long, JT Dauer, CM Schwarz, ESJ Rauschert, R Jabbour, DA Mortensen, SA Isard, DA Lieb, Z Sezen, AG Hulting, K Shea. 2015. A unifying gravity framework for dispersal. Theoretical Ecology, 8:207-223.
    • Type: Journal Articles Status: Published Year Published: 2015 Citation: Giller, KE, JA Anderson, M Corbeels, J Kirkegaard, D Mortensen, O Erenstein, B Vanlauwe. 2015. Beyond conservation agriculture. Frontiers in Plant Science, 6: 870.
    • Type: Journal Articles Status: Published Year Published: 2015 Citation: Williams, A, AS Davis, P Ewing, F Forcella, S Grandy, DA Kane, RT Koide, DA Mortensen, RG Smith, SS Snapp, KA Spokas, AC Yannarell, NR Jordan. 2015. A comparison of soil hydrothermal properties in zonal and uniform tillage systems across the northern US Corn Belt. Geoderma, 273: 12-19.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Williams, A, MC Hunter, M Kammerer, DA Kane, NR Jordan, DA Mortensen, RG Smith, S Snapp, and M Davis. 2016. Soil water holding capacity mitigates downside risk and volatility in US rainfed maize: time to invest in soil organic matter? PLOS ONE. 1-11, DOI:10.1371/journal.pone.0160974.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Kammerer, MA, DJ Biddinger, EG Rajotte, and DA Mortensen. 2016. Local plant diversity across multiple habitats supports a diverse apple pollinator community. Environmental Entomology, 45:32-48.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Smith, RG, LW Atwood, MB Morris, DA Mortensen, RT Koide. 2016. Evidence for indirect effects of pesticide seed treatments on weed seed banks in maize and soybean. Agriculture, Ecosystems & Environment, 21: 269-273.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Williams, A, DA Kane, PM Ewing, LW Atwood, A Jilling, M Li, Y Lou, AS Davis, AS Grandy, SC Huerd, MC Hunter, RT Koide, DA Mortensen, RG Smith, SS Snapp, K.A. Spokas, AC Yannarell, NR Jordan. 2016. Soil functional zone management: a vehicle for sustainable temporal intensification of agriculture. Frontiers in Plant Science. 7:65.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Averill, KM, DA Mortensen, EAH Smithwick, E Post. 2016. Deer feeding selectivity for invasive plants. Biological Invasions, 18: 1247-1263.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Nettles, R., Watkins, J., Ricks, K., Boyer, M., Licht, M., Atwood, L.W., Peoples, M., Smith, R.G., Mortensen, D.A., Koide, R.T. 2016. Pesticide seed treatments influence rhizosphere fungal and bacterial communities in maize and soybean. Applied Soil Ecology, 102: 61-69.


    Progress 10/01/14 to 09/30/15

    Outputs
    Target Audience:The target audiences included: farmers (in the region and nationally); input providers; USDA and EPA policy makers; agroecological research scientists; journalists; environmentalists;university undergraduate and graduate students. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project and associated research and outreach work informs my ability to help shape USDA APHIS and EPA reviews of herbicide resistant crop deregulation applications. For example, the Bohenblust et al 2015 papers listed herein along with the Egan, Barlow, and Mortensen 2014 paper have provided important information on the extent and implications of drift of auxinic herbicides. During the course of this past year, I have presented on work out of this project to some 16 national audiences as well as scientists and policy makers engaged in EU policy at an international workshop in Paris in December 2014 and The Hague in March 2014. Finally, I routinely use the research we conduct to refresh the courses I teach. In this way, over the past year I have reasched some 135 undergraduate students and 20 graduate stduents through case studies, mock Congressional panels, and through living laboratory experiments and demonstrations. I mentor 5 graduate students and a post-doctoral scientist all of who are directly or indirectly benefiting from the work underway in this project. How have the results been disseminated to communities of interest?The results have been disseminated through peer-reviewed papers, through the above mentioned presenations, and through lay magazine and newspaper articles about our work and featured on National Public Radio. What do you plan to do during the next reporting period to accomplish the goals?Much of the work I had planned to conduct addressing the first objective is now complete with one important exception. Our landscape analysis of field edge extent and quality is underway and should result in the publication of two important peer-reviewed papers in the coming year. In addition, I will follow through to see that our paper (currently in review) entitledIt's time to rethink the edgeis published. I am currently working with one graduate student who is writing up her thesis work on the intentions, perceptions and actual ecosystem services arising from cover cropping. That work will be submitted for publication in the coming year and resuts of that work will be presented at a number of regional and national workshops and conferences on the subject of building soil health and climate resilient cropping systems (one of those is coming up in December 2015 in Grand Rapids, Michigan). Finally, our paper on constraints to adoption of sustainable agricultural practices will be submitted within the next month.

    Impacts
    What was accomplished under these goals? Objective 1 - Followed through and completed several field studies that resulted in the publication of several important papers documenting the impact of sub-lethal herbicide dose levels on field-edge plant fitness and the knock-on effects on natural enemies and pollinators. Specifically, we found that while drift level doses of dicamba and 2,4-D herbicides damaged the vegetative growth of these plants, the effect was more pronounced on flowering and therefore the provisioning capacity of the plants. This disproportionate effect on floral provisioning underscores the need to understand field-level effects of herbicide drift on non-target plant communities. We also initiated a national level spatial analysis of agricultural fields to quantify the amount of edge habitat in close proximity to agricultural fields. This work is being conducted in concert with colleagues at Wageningen University. Objective 2 - Place-based research studies a the Penn State Research farm coupled with a rapid ecosystem assessment conducted on 47 farms across 109 fields has provided our research team with a unique data set. We found that cover crop functional trait diversity is important in cover crop mixtures and that greater functional diversity (as opposed to species diversity) results in greater weed suppression. Our on-farm research has taught us that the conservation goal of individual farms should guide the design and execution of cover crop mixes in order to match local context with needed ecosystem services. Objective 3 - We have a manuscript that is about ready to be submitted to Science detailing the need to accelerate our attention to environmental challenges facing grain crop production. While food demand will increase with a growing global human population, we have conducted a broad and deep analysis of the environmental challenges that must be addressed as we design sustainably intensified cropping systems.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2014 Citation: Schipanski, ME, ME Barbercheck, MR Douglas, DM Finney, K Haider, JP Kaye, AR Kemanian, DA Mortensen, MR Ryan, J Tooker and CM White. 2014. A framework for evaluating ecosystem services provided by cover crops in agroecosystems. Agricultural Ecosystems and the Environment, 125:12-22.
    • Type: Journal Articles Status: Published Year Published: 2014 Citation: Vaudo, AD, HM Patch, DA Mortensen, CM Grozinger, and JF Tooker. 2014. Bumble bees exhibit daily behavioral patterns in pollen foraging. Arthropod-Plant Interactions 8: 273-283.
    • Type: Journal Articles Status: Accepted Year Published: 2015 Citation: Bohnenblust, EW, AD Vaudo, JF Egan, DA Mortensen, and J Tooker. 2015. Effects of the herbicide dicamba on non-target plants and pollinator visitation. Environmental Toxicology and Chemistry, Journal of Pest Science, in press.
    • Type: Journal Articles Status: Submitted Year Published: 2015 Citation: Mortensen, DA, RG Smith, MA Kammerer, J Tooker, BD Maxwell, J LaChance, JF Egan, M Schipanski. 2015. Its time to rethink the edge: My View. Weed Science, in review.


    Progress 10/01/13 to 09/30/14

    Outputs
    Target Audience: The project work provided important outputs relevant to Federal scientists (USDA APHIS), Federal regulators (EPA), farmers, input providers, students and consumers. Work conducted under this project had a very broad reach spanning a broad continuum of farm to fork (farmers to consumers). Efforts conducted under this project included classroom instruction, involvement in Congressional briefings, public presentations to such programs as The Pennsylvania State University Rock Ethics GMO Ethics Panel, metanalyses used by EPA to guide deregulation labeling for GMO herbicide resistant crops, assessments of pesticide use that were useful in guiding USDA APHIS' assessment of several GMO herbicide resistant crop deregulatioin requests. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Many to report here. First, I routinely use the research we conduct to refresh the courses I teach. In this way, over the past year I have reached some 120 undergraduate students and 25 graduate students through case studies, mock Congressional panels, and through living laboratory experiments and demonstrations. I mentor 4 graduate students and serve on the committees of an additional 12 students. The project and associated research informs my ability to provide current, thoughtful, meaningful input in this important process. The results of our research has directly shaped the USDA APHIS and EPA reviews of the herbicide resistant crop deregulation applications. I have presented no fewer than 20 presentations to sustainable agriculture conferences, national science organizations and international research and policy groups (France and The Netherlands) over the past year reaching an estimated 3,000 attendees. How have the results been disseminated to communities of interest? The results have been disseminated through peer-reviewed papers, through the above mentioned presentations, through our meta-analysis synthesis, through a webinar, and through my teaching. In addition, I have been interviewed with public press articles appearing in the New York Times, National Public Radio and numerous national and local newspapers and blogs. What do you plan to do during the next reporting period to accomplish the goals? We continue to expand our work in the first objective. We have a series of spatially explicit simulation studies underway where we're parameterizing spatially explicit models with results from our empirical field-based studies. That modeling will enable us to assess a range of ways of limiting the downside effects of herbicide drift. Our work on cover cropping outlined in the second objective will be expanded to include organic and conventional (herbicide-based) systems for complementary weed suppression. Finally, the constraints work in the third objective is an active work in progress. We hope to publish an additional 4-6 papers in the coming year in each of these three areas.

    Impacts
    What was accomplished under these goals? Objective 1 - Several studies were conducted in the greenhouse and field to address this objective. We found that drift-level doses of auxinic herbicides reduce the abundance of broadleaf plants in the field edge from approximately 60 to 25%. These studies were conducted in in-tact field edge plant communities where simulated doses of herbicide drift were deliberately applied to the field edges. While we consistently observed a reduction in broadleaf plants, the impact on insect communities in these field studies was less clear. In a more controlled experiment in which select field edge plants were exposed to drift-level doses of auxinic herbicides during flowering, floral area was significantly reduced and as was pollinator abundance. Over a range of drift level doses, flowering was eliminated at the higher drift level doses and bee visitation too dropped to zero. This work provides clear evidence that the abundance of broadleaf plants is reduced in the face of auxinic herbicide drift and as is the abundance of pollinators. Objective 2 - Several studies are underway to assess the weed suppressive role of cover crops. We are currently in the process of summarizing the results of 3 years of research quantifying how and to what extent cover crop monocultures and mixtures suppress weeds. In general, we are seeing significant suppression of winter annual weeds along with suppression of late germinating summer annual weeds. In addition, the process of cover crop planting stimulates the germination of late season summer annuals which are then suppressed by the rapidly growing cover crops. Objective 3 - Much research has been conducted to quantify the benefits of a range of sustainable agriculture practices however the adoption of many of those practices has fallen short of expectations. At least it has fallen short of the expectations of many of the researchers conducting the research. Here we have been asking what are the constraints to adoption of these practices and ask what prevents their implementation. Conversely, we have been studying the features of agricultural innovations that have been widely adopted over the past 2-3 decades. This is a work in progress however it is our interest to publish several papers revealing our findings over the next 1-2 years with the goal of guiding a more realistic research agenda and informing policy.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2013 Citation: Russo, L, N DeBarros, S Yang, K Shea, and D Mortensen. 2013. Supporting crop pollinators with floral resources: network-based phonological matching. Ecology and Evolution, 1-16.
    • Type: Journal Articles Status: Published Year Published: 2013 Citation: Bohnenblust, E, JE Franklin, DA Mortensen and J Tooker. 2013. Direct and indirect effects of the synthetic-auxin herbicide dicamba on two lepidopteran species. Environmental Entomology, 42: 586-594.
    • Type: Journal Articles Status: Published Year Published: 2013 Citation: Egan, JF, I Graham DA Mortensen. 2013. A comparison of the herbicide tolerances of rare and common plants in an agricultural landscape. Environmental Toxicology and Chemistry, 33: 696-702.
    • Type: Journal Articles Status: Published Year Published: 2013 Citation: Egan, J.F., E. Bohnenblust , S. Goslee, D.A. Mortensen, and J. Tooker. 2014. Herbicide drift can affect plant and arthropod communities. Agriculture, Ecosystems, and Environment 185: 77-87.
    • Type: Journal Articles Status: Published Year Published: 2013 Citation: Egan, J.F., K.B. Barlow, and D.A. Mortensen. 2014. A meta-analysis on the effects of 2,4-D and dicamba on soybean and cotton. Weed Science 62(1): 193-206.