Location: Global Change and Photosynthesis Research
2017 Annual Report
Objectives
Objective 1: Determine how crop management practices (such as cultivar selection) and abiotic factors affect weed ecology in the upper Midwest, especially in vegetable and bioenergy crops.
Sub-objective 1a: Identify cover crop residues that favor edamame over the weed.
Sub-objective 1b: Quantify the impact of Miscanthus invasion and removal on plant community composition.
Sub-objective 1c: Quantify the role of soil environmental parameters (e.g., C, C:N and NO3-:NO2- ratios, pH, diurnal temperature variations, soil moisture) in controlling nitrification along with N-loss (denitrification) vs. N-retention (DNRA), and evaluate the link between measured N-cycle processes to weed seed germination and seedling development.
Objective 2: Improve the feasibility of using multi-tactic integrated weed management approaches for regaining control of weeds with resistances to multiple herbicides, and for preventing or slowing the evolution of herbicide resistance in susceptible weed populations.
Sub-objective 2a: Evaluate the impact of harvest weed seed control (HWSC) on population dynamics and management of multiple-herbicide-resistant weed genotypes in field crops.
Sub-objective 2b: Develop and compare weed management systems in edamame, utilizing cover crops, herbicides, and physical weeding.
Approach
Multi-tactic integrated weed management (IWM) offers one potential approach to address the problem of multiple herbicide resistant (MHR) weeds. In IWM systems, suites of multiple complementary tactics are deployed throughout weed life cycles to increase efficacy of weed suppression, prevent survival of weeds that escape earlier management, and reduce weed populations over the long-term. In this project, we evaluate the utility of chemical, cultural, biological, and physical tactics in IWM systems for weed suppression and crop yield protection in fields with MHR weed populations. Edamame (vegetable soybean) cultivars tolerant to cover crop residues will be combined with cover crops, recently registered herbicides, and physical weeding to examine the potential of IWM in legume vegetable production systems. The contribution of improved knowledge of soil N cycling to aid better prediction of weed seedling emergence and community composition also will be evaluated in this production system. In field crops, interactions among weed seed destruction at crop harvest, cover crops, and tank mixtures of herbicides will be quantified for their impact on MHR weeds in corn and soybean. Finally, in a continuation of previous research, the impact of escaped invasive bioenergy crops on weeds of arable areas will be measured.
Progress Report
n FY17, substantial progress was made in initiating investigations of weed ecology and management, with special emphasis on understanding and responding to multiple herbicide resistance. In combination with variable herbicide programs and tillage treatments, a device for mechanical destruction of weed seeds was tested in a field study. This study is quantifying the impact of Harvest Weed Seed Control with the mechanical device on the population dynamics of multiple herbicide resistant weeds in central Illinois.
Following a five-year study of the impact of controlled Miscanthus invasions in native plant communities in central Illinois floodplain forests and old fields, we began the process of eradicating Miscanthus in summer of 2015. We have an ongoing monitoring and eradication program in place to detect and control re-sprouting plants. A small number of re-sprouts were found and treated in November 2016, meaning that the monitoring and eradication effort will need to continue for at least one more year.
Research to improve the feasibility of using multi-tactic integrated weed management systems continues, with particular emphasis on Midwest vegetable crops. Data from recently concluded experiments on edamame, an emerging nutraceutical soybean food crop, are being analyzed to determine the role of seed size, planting depth, and use of cover crop mulches on crop emergence and seedling competitiveness. Initial research on edamame has been expanded to include lima bean and snap bean. Current field experiments are comparing the agronomics and economics of weed management systems that integrate cover crops, herbicides, and physical weeding in these vegetable processing legumes. Research in sweet corn, one of America’s favorite vegetables, has focused on improving crop competiveness by examining underlying genetic, environmental, and management drivers to crowding stress tolerance. On-farm experiments have been completed on 25 site-years throughout the Midwest, with additional field experiments in 2017.
N2O-reducing microorganisms are dominated by metabolically diverse bacteria that are not the conventional denitrifiers previously thought to control gaseous N-losses in soils. We are finding specific groups of these mainly non-denitrifying bacteria are responsive to temperature change and urea ammonium nitrate (UAN) fertilizer in the top 0-5 cm of soil. The lack of cultivated representatives of these Type II N2O reducers from agricultural soils limits much needed physiological studies. A new task to isolate novel strains for study has been identified, adding to ongoing research that tests dynamical changes of identified taxa, including both consumers and producers of N2O in response to diurnal temperature, flooding and drainage, and 15N-fertilizer to ultimately aid in the predictive strength of greenhouse gas models.
Accomplishments
1. Cooperation aids fight against herbicide resistance. Widespread multiple herbicide resistance in agricultural weeds, yet no new herbicide modes of action have been released in over 30 years, create an urgent need for integrated weed management in support of herbicide stewardship. ARS researchers in Urbana, Illinois found in a simulation model that when farmers coordinated their weed management decisions to implement best management practices at landscape scales, evolution of herbicide resistance occurred more slowly than when weed management was uncoordinated. Cooperation at the largest landscape scales bought more than an extra decade of time before resistance evolution was observed in the model, potentially providing time for the development of new tactics. This research demonstrates the importance of cooperative weed management areas as the foundation for an integrated weed management approach to combat herbicide resistance.
2. Alternatives to atrazine in sweet corn. Increased restrictions in recent years have reduced or eliminated atrazine use in certain sweet corn production areas that have relied heavily on the herbicide for weed control. From 12 site-years throughout Illinois, Minnesota, and Oregon, an ARS researcher in Urbana, Illinois and collaborators developed, tested, and identified economically viable atrazine-free weed management systems. The impact of this work is that the processing sweet corn industry is now adopting weed management systems that utilize control tactics other than atrazine in areas where the herbicide is no longer suitable for use.
3. Developed molecular probes that now allow specific detection and quantification of at least five NosZ (N2O reductase) groups of numerically significant but overlooked N2O reducers. The probes were validated for use in a multiplex PCR array platform followed by high-throughput sequencing of gene fragments in DNA and cDNA samples generated from a completed soil microcosm study that tested field diurnal temperature effects on N2O and CO2 emissions. The probes were made available for public use through the NCBI (National Center for Biotechnology Information) database. This research now allows identification of the populations of N2O reducers that are most responsive to actual field temperature conditions and other factors, along with determining their spatial differentiation across soil depths and field locations.
Review Publications
Mattia, C., Lovell, S.T., Davis, A.S. 2016. Identifying barriers and gateways for agroforestry adoption by landowners in the Upper Sangamon River Watershed, Illinois. Agroforestry Systems. doi: 10.1007/s10457-016-0053-6.
Williams, A., Davis, A.S., Jilling, A., Grandy, A., Koide, R.T., Smith, R.G., Snapp, S.S., Spokas, K.A., Yannarell, A.C., Jordan, N.R. 2017. Reconciling opposing soil processes in row-crop agroecosystems via soil functional zone management. Journal of Applied Ecology. 236:99-107.
Shaffer, J., Sarmiento, C., Zalamea, P., Gallery, R., Davis, A.S., Baltrus, D.A., Arnold, E.A. 2016. Diversity, specificity and phylogenetic relationships of endohyphal bacteria in fungi that inhabit tropical seeds and leaves. Frontiers in Ecology and Evolution. doi.org/10.3389/fevo.2016.00116.
Davis, A.S., Fu, X., Schutte, B.J., Berhow, M.A., Dalling, J.W. 2016. Interspecific variation in persistence of buried weed seeds follows trade-offs among physiological, chemical and physical seed defenses. Ecology and Evolution. 6(19):6836-6845.
Tomasek, B.J., Williams, M., Davis, A.S. 2015. Optimization of agricultural field workability predictions for improved risk management. Agronomy Journal. 107(2):627-633.
Ferero, R., Lima, M., Davis, A.S., Gonzalez-Andujar, J.L. 2017. Disentangling diversity and climatic impacts on crop production. Frontiers in Plant Science. 8:236.
Tomasek, B.J., Williams, M., Davis, A.S. 2017. Changes in field workability and drought risk from projected climate change drive spatially variable risks in Illinois cropping systems. Environmental Research Letters. 12(2):e0172301.
Evans, J.A., Lankau, R.A., Davis, A.S., Raghu, S., Landis, D. 2016. Evolutionary feedbacks on the ecology of the invasive plant Alliaria petiolata. Functional Ecology. 30:1053-1061.
Jordan, N.R., Schut, M., Graham, S., Barney, J., Childs, D., Christensen, S., Cousens, R., Davis, A.S., Eisenberg, H., Ervin, D., Mirsky, S.B. 2016. Transdisciplinary weed research: new leverage on challenging weed problems? Weed Research. 56:345-358.
Li, M., Jordan, N.R., Koide, R.T., Yannarell, A.C., Davis, A.S. 2016. Meta-analysis of crop and weed growth responses to arbuscular-mycorrhizal fungi. Weed Science. 64:642-652.
Dozier, I.A., Behnke, G.D., Davis, A.S., Nafziger, E.D., Villamil, M.B. 2017. Tillage and cover cropping effects on soil properties and crop production in Illinois. Soil and Tillage Research. 109(4):1-10.
West, N.M., Matlaga, D.P., Muthukrishnanan, R., Spyreas, G.R., Forester, J.D., Jordan, N.R., Davis, A.S. 2017. Short term impacts provide a management window for minimizing invasions from bioenergy crops. Frontiers in Plant Science. 8:767.
Duke, S.O., Rimando, A.M., Reddy, K.N., Cizdziel, J.V., Bellaloui, N., Shaw, D.R., Williams, M., Maul, J.E. 2017. Lack of transgene and glyphosate effects on yield, and mineral and amino acid content of glyphosate-resistant soybean. Pest Management Science. 74:1166-1173. https://doi.10.1002/ps.4625.
Boydston, R.A., Williams, M. 2016. No-till snap bean performance and weed response following rye and vetch cover crops. Renewable Agriculture and Food Systems. doi: 10.1017/S1742170516000405.
