Location: Forage Seed and Cereal Research Unit
2023 Annual Report
Objectives
The long-term aim of this project is to address strategic, high priority needs of grass seed growers in the Pacific Northwest (PNW) by assessing and developing management practices that simultaneously improve crop productivity and advance soil health. This aim will be met by interrogating research questions that fall into two broad objectives. The first objective is primarily focused on improving crop production by lessening the overall impact of pests, weeds, and pathogens, improving the arability of marginal lands with novel soil amendments, and assessing the impacts of management practices on soil health and fertility. Objective 2 also aims to improve crop productivity by identifying key interactions between genetics, environment, and management (G x E x M). Within this objective, tradeoffs between intensifying production and advancing ecosystem services are quantified and better understood to help farms reach and sustain their potential, including the impact of crop rotation and other management practices on increasing populations of beneficial microbes and improving soil health. Collectively, Objectives 1 and 2 advance our understanding of how G x E x M interactions impact agroecosystem productivity and resilience. For Objective 3, these data will be synthesized and developed into decision-support tools and models to provide growers with concrete strategies for improved land management and cultivation of grass seed cropping systems.
Objective 1: Identify and evaluate management practices that improve crop productivity and crop health or that enhance environmental quality.
- Sub-objective 1A: Identify technologies to reduce priority pests, diseases, and weeds that limit the profitability and sustainability of the cropping system.
- Sub-objective 1B: Assess the environmental and production outcomes from the application of biochar on marginal soils.
- Sub-objective 1C: Determine the effectiveness of crop rotation in reducing populations of weeds, diseases, and invertebrate pests.
Objective 2: Identify and assess key interactions between cropping system, environmental conditions and management practices that influence cropping outcomes and agroecosystem productivity.
- Sub-objective 2A: Evaluate the impact of management practices, including crop rotation, on soil health parameters.
- Sub-objective 2B: Assess the impact of cruciferous crop rotations on plant growth and microbiomes.
Objective 3: Develop knowledge and decision support tools that enable growers to optimize production.
- Sub-objective 3A: Develop and expand decision support tools that provide information about biochar to growers.
- Sub-objective 3B: Develop models and decision aids that improve soil health and improve system productivity by decreasing the yield gap.
- Sub-objective 3C: Develop strategies to reduce priority pests, diseases, and weeds and improve soil health.
Approach
The overall hypothesis of the project is that improved cropping practices in grass seed cropping systems provides simultaneous benefits to soil health and crop productivity. This hypothesis is tested within three objectives and their related subobjectives. In Objective One, we explore methods to reduce the populations of weeds and pests that limit productivity. This research is conducted in laboratory, greenhouse, and field experiments that determine if practices that promote soil health and lessen environmental impacts (application of soil amendments, selective herbicide application, and precision weed management) are detrimental or beneficial to crop yield. In Objective Two, the research aims to determine if conservation practices (cover cropping and reduced tillage) improve soil health, and if soil health can be attributed to improvements in crop yield. These objectives are met with laboratory, greenhouse, and field experiments that assess soil health and identify allelopathic responses mitigated by cover crops. The aim of Objective Three is to synthesize the information gathered in Objectives One and Two, and to create decision support tools that enable growers to optimize production. These tools will be provided to growers as web-based tool kits, models, or agronomic measures used to control pests, pathogens, and weeds, and to apply soil amendments. In general, these approaches aim to identify key interactions between genetics, environment, and management that simultaneously reduce farm inputs and improve ecosystem services by identifying and quantifying tradeoffs.
Progress Report
This is the final report for project 2072-12620-001-000D.
Seed crops in the Willamette Valley (WV), Oregon, supply seeds for turf, forage, and cover crop (CC) applications. Ryegrasses are a cornerstone of the CC market; however, concerns regarding herbicide resistant weeds have emerged. In response, an herbicide resistant bioassay is being developed to detect the presence of glyphosate resistant weeds in support of Sub-objective 1.A. Twelve varieties of ryegrass were obtained from different seed certification levels. Different glyphosate doses and seed testing methods were evaluated, and progress has been made on the identification of an herbicide dose that discriminates between susceptible crops and resistant weeds. Optimization and expansion of the assay to test more varieties and chemistries is ongoing.
Aphid-transmitted viruses are widespread in grass seed production systems (GSPS) and are associated with reduced yield. In support of Sub-objectives 1.A and 3.C, the composition and spatiotemporal distribution of the aphid-yellow dwarf virus (YDV) complex were investigated to inform predictive models. In addition, a field trial evaluating management factors indicated that reducing nitrogen inputs and insecticide application reduces YDV incidence and maintains yield, providing growers with cost-effective, integrated management strategies for this complex.
Economically damaging noctuid (armyworm/cutworm) pest outbreaks in GSPS is a critical issue. In support of Sub-objectives 1.A and 3.C, monitoring efforts determined the spatiotemporal distribution and ecology of these important pests. Environmental risk factors are being investigated using GIS and geospatial predictive modeling to understand drivers of noctuid pests. Automated moth traps are being developed to provide real-time data to stakeholders. These traps are economical, easy to use, and will be an excellent monitoring tool for researchers and grass seed producers.
Carbon banding is a weed management practice that allows producers to establish crops by applying a narrow band of activated carbon (AC) directly over the seed furrow, followed by treatment with a broadcast preemergent herbicide. The AC provides crop safety by absorbing the herbicide, essentially deactivating it within the planting row. While this method is effective, the combined cost of the AC and the herbicide limits its feasibility. In support of Sub-objective 1.A, the efficacy of biochar as a replacement for AC was investigated. Greenhouse experiments suggested that the ability of biochar to bind herbicides is driven by feedstock origin, production conditions, and the chemical properties of the herbicide. Field trials to validate these results are ongoing.
Biochar has received growing attention as a soil amendment that can improve soil structure, increase crop production, and sequester carbon. These impacts are especially evident on degraded soils. Research in support of Sub-objective 1.B developed methods to screen biochar for metal absorption capacity. These methods were used to design and implement greenhouse and field experiments at the Formosa mine site. These trials identified amendment blends that facilitate the growth of plants in highly degraded mine soils and that outperform business-as-usual practices involving lime applications. These methods are now being used at other mine sites to design reclamation protocols.
The use of biochar is gaining attention for promoting carbon sequestration and developing circular economies. Research in support of Sub-objective 1.B examined the use of biochar in diverse forest, crop, and rangeland ecosystems. In general, this research determined that the effect of biochar on crop yield and soil chemistry depended both on inherent properties of the biochar and the soil and on crop nutrient requirements. Although yield increases were only observed in wheat and blueberry, no deleterious impacts of biochar on yield in other crops were observed. This research indicated that biochar has the potential to help sequester carbon in soils without negatively impacting yield.
Pyroligneous acid (PA) is a byproduct of biochar production that has the potential to control soil-borne phytopathogenic fungi. Progress under Sub-objective 1.B confirmed that PA is fungicidal towards Verticillium dahliae at very low concentrations. Researchers also determined that PA significantly increases the growth of mint. Ongoing experiments are assessing PA-based amendments to determine if they can control disease symptoms or promote plant growth in other crops.
Grass seed production in the WV has traditionally employed practices that are known to degrade soil quality, including annual tillage and removal of crop residues. As regulations on carbon (C) emissions loom, there is a need to quantify the amount of C stored in GSPS and to understand how conservation practices (CP) influence soil organic C (SOC) and C stocks. Research under Sub-objective 2.A informed our understanding of how CPs impact soil health and yield. This research suggests that reduced tillage increases SOC and C stocks; however, increased residue return does not. This research also indicated that the relationship between CPs and soil health and yield outcomes were influenced by soil texture. For example, CPs significantly improved aboveground biomass in silty clay loams. Furthermore, CPs improved C cycling-related soil health metrics in silt loam soils. The influence of soil texture on soil health and yield responses suggests that growers should consider inherent soil properties when implementing management decisions.
Soils in the WV are poorly drained and rely on tile drainage systems to provide access to fields, extend the growing season, and maximize yields. Despite its widespread use, little is known about the consequences of tile drainage on SOC. Research under Sub-objective 2.B aims to address this knowledge gap. The preliminary results of this study suggest that tile drainage may cause a decline in SOC; however, more research is needed to confirm these results.
Brassica species produce glucosinolates and isothiocyanates (ITC), allelopathic compounds that alter the soil microbiome. The ability of ITCs to positively select for beneficial microbes, including plant growth promoting rhizobacteria, is not well understood. In support of Sub-objective 2.B, a biosensor that detects the presence of ITCs was developed to sense ITC concentrations in the soil. Dose response curves indicated that the biosensor responds to biologically relevant concentrations of ITCs in soils. Thus, the biosensor is being deployed in greenhouse experiments to determine if ITCs are produced in the rhizosphere and if allelopathic impacts promote plant growth. A patent describing the biosensor is currently under review.
In support of Sub-objective 3.A, researchers significantly expanded the Pacific Northwest Biochar Atlas, an online biochar decision support toolkit. In addition to expanded biochar and case study libraries, recent funding will support the geographical and functional expansion of this decision support tool to provide guidance to farmers, biochar producers, conservation planners, and technical service providers across the globe.
In support of Sub-objective 3.B, the Carbon Reduction Potential Evaluation (CaRPE) Tool was developed. This tool was designed for high level planning and evaluation of CP selection and prioritization for climate goals. This tool, based on outputs from publicly available data sets and modeled scenarios, was recently launched on the Northwest Climate Hub Tools Webpage
Annual bluegrass (ABG) is a major weed in grass seed production systems and herbicides are frequently used to suppress this weed. In support of Sub-objective 3.C, a growing degree day model is being developed to provide growers with a decision support tool to improve herbicide application timing and efficacy.
In support of Sub-objectives 1.A and 3.C, a regional survey was initiated to optimize detection of Anguina seed gall nematodes in GSPS. Early detection of these nematodes assesses the risk of export rejection. A molecular protocol was developed and validated for Anguina spp. identification. Comparisons of this protocol to manual nematode extraction indicate increased identification capacity. Accurate and timely identification of these nematodes will allow growers to make informed decisions on exporting seed from infested fields.
Timely monitoring, reporting, and forecasting of pest outbreaks is an integral part of effective integrated pest management (IPM) programs to provide information on the spatial distribution and phenology of pests to support management decisions. In support of Sub-objectives 1.A and 3.B, we developed the Oregon Pest Monitoring Network, an online GIS hub to share real-time data on insect pest populations in GSPS. The project aims to connect researchers, crop advisors, and growers, facilitating the rapid dissemination of pest data for multiple seed crop production regions. In addition to interactive visualizations of observational data, the site will provide regular pest updates, historical data, and pest forecasts.
In support of Sub-objectives 1.A and 3.C, research is being conducted to improve insecticide resistance management (IRM) programs. Significant resistance to pyrethroid insecticides has been identified in clover seed weevil (Tychius picirostris) populations in Oregon white clover grown for seed. This is the first documentation of pyrethroid resistance development for an economic pest in Oregon seed production, highlighting the need for robust IRM programs to enhance the detection and management of insecticide resistance development.
Accomplishments
1. The development of an interactive tool quantifies the climate benefits of conservation management practices. Conservation agricultural practices have the potential to reduce greenhouse gas emissions. Implementation of these practices must be balanced with the need to produce food, fiber, and fuel for a growing global population. To provide land managers, producers, and researchers estimates of greenhouse gas reduction potential from the implementation of climate-smart practices, ARS researchers in Corvallis, Oregon, and Fort Collins, Colorado, developed the Carbon Reduction Potential Evaluation (CaRPE) tool. CaRPE is a web-based, interactive tool to visualize and estimate the climate benefits of implementing conservation practices on croplands and grazing lands. This tool allows users to build and export scenarios of new conservation practice adoption on desired acreages and locations at state, regional or national scales. This tool is available at https://carpe.shinyapps.io/CarpeTool/ or through the Northwest Climate Hub.
Review Publications
Kowalewski, A.R., Schmid, C.J., Braithwaite, E.T., McNally, B.C., Elmore, M.T., Mattox, C.M., McDonald, B.W., Wang, R., Lambrinos, J.G., Fitzpatrick, G., Rivedal, H.M. 2023. Comparing methods to quantify cover in turfgrass research. Crop Science. 63:1581-1591. https://doi.org/10.1002/csc2.20908.
McCurdy, J.D., Bowling, R.G., de Castro, E.B., Patton, A.J., Kowalewski, A.R., Mattox, C.M., Brosnan, J.T., Ervin, D.E., Askew, S.D., Goncalves, C.G., Elmore, M.T., McElroy, S.J., McNally, B.C., Pritchard, B.D., Kaminski, J.E., Bagavathiannan, M.V. 2023. Developing and implementing a sustainable weed management program for herbicide-resistant Poa annua in turfgrass. Crop, Forage & Turfgrass Management. 9(1). Article e20225. https://doi.org/10.1002/cft2.20225.
Lawton, D., Huseth, A., Kennedy, G., Morey, A., Hutchison, W., Reisig, D., Dorman, S.J., Dillard, D., Venette, R., Groves, R., Adamczyk Jr., J.J., Barbosa Dos Santos, I., Baute, T., Brown, S., Burkness, E., Dean, A., Dively, G., Doughty, H., Fleischer, S., Green, J., Greene, J., Hamilton, K., Hodgson, E., Hunt, T., Kerns, D., Leonard, B., Malone, S., Musser, F., Owens, D., Palumbo, J., Paula-Moraes, S., Peterson, J., Ramirez, R., Rondon, S.I., Schilder, T., Seaman, A., Spears, L., Stewart, S., Taylor, S., Towles, T., Welty, C., Whalen, J., Wright, R., Zuefle, M. 2022. Pest population dynamics are related to a continental overwintering gradient. Proceedings of the National Academy of Sciences (PNAS). 119(37). Article e2203230119. https://doi.org/10.1073/pnas.2203230119.
Lescallette, A.R., Dunn, Z.D., Manning, V., Trippe, K.M., Li, B. 2022. Biosynthetic origin of formylaminooxyvinylglycine and characterization of the formyltransferase GvgI. Biochemistry. 61(19):2159-2164. https://doi.org/10.1021/acs.biochem.2c00374.
Gent, D.H., Block, M., Massie, S.T., Phillips, C.L., Richardson, B.J., Shellhammer, T.H., Trippe, K.M., Wiseman, M.S. 2023. Nitrogen and sulfur fertility practices: Influences on hop chemistry, aroma, and nitrate accumulation. Journal of the American Society of Brewing Chemists. https://doi.org/10.1080/03610470.2023.2204412.
Sales, B.K., Bryla, D.R., Trippe, K.M., Scagel, C.F., Strik, B.C., Sullivan, D.M. 2022. Biochar as an alternative soil amendment for establishment of northern highbush blueberry. HortScience. 57(2):277-285. https://doi.org/10.21273/HORTSCI16257-21.
Moore, J.M., Manter, D.K., Bowman, M., Hunter, M., Bruner, E., McClelland, S. 2023. A framework to estimate climate mitigation potential for US cropland using publicly available data. Journal of Soil and Water Conservation. 78(2):193-206. https://doi.org/10.2489/jswc.2023.00132.
Manter, D.K., Moore, J.M. 2022. CaRPE: the Carbon Reduction Potential Evaluation tool for building climate mitigation scenarios on US agricultural lands. Database: The Journal of Biological Databases and Curation. 2022. Article baac105. https://doi.org/10.1093/database/baac105.
Breza, L.C., Moore, J.M., Tomasek, A., Trippe, K.M. 2023. The effect of subsurface drainage in grass seed fields on soil carbon stocks. Seed Production Research at Oregon State University. 2022:15-19.
Bateman, C., Willette, A., Kaur, N., Dorman, S.J., Buckland, K., Anderson, N.P. 2023. Symphylan control in grass grown for seed, 2022. Arthropod Management Tests. 48(1). Article tsad013. https://doi.org/10.1093/amt/tsad013.
