Location: Northwest Sustainable Agroecosystems Research
2018 Annual Report
Objectives
The overall project goal is to enhance the resilience and sustainability of cropping systems and increase their capacity to deliver multiple agroecosystem services (e.g., healthy, bio-diverse, resilient soil). During the next five years we will focus on the following objectives.
Objective 1: Improve agricultural practices to reduce soil erosion, associated particulate emissions, and losses of soil C and essential nutrients.
• Subobjective 1A: Conduct life-cycle assessment of wind erosion and associated losses of PM10 and nutrients.
• Subobjective 1B: Determine effect of irrigated and dryland management systems on wind erosion and associated emissions of PM10 and nutrients.
Objective 2: Develop precision conservation practices to enhance soil health, reduce greenhouse gas emissions, and increase carbon sequestration and nutrient-use efficiencies.
• Subobjective 2A: Conduct long-term, site-specific assessment of agroecosystem C, N, and P cycling and flows.
• Subobjective 2B: Develop and determine precision evaluation of agroecosystem performance and associated soil health metrics.
Objective 3: Develop biological control practices for weed management and enhanced soil biological functions.
• Subobjective 3A: Isolate, select, and screen for weed-suppressive bacteria that specifically inhibit annual grass weeds, do not injure crops, native or near native rangeland plants.
• Subobjective 3B: Evaluate the survival and efficacy of annual grass weed-suppressive bacteria to reduce annual grass weeds in the field.
Approach
1.a. A life-cycle assessment of wind erosion and associated losses of PM10 and nutrients will be conducted during each phase of a winter wheat – summer fallow rotation. Standard core methods will be implemented in assessing long-term wind erosion as outlined in “Standard Methods for Wind Erosion Research and Model Development.”
1.b. Effects of conventional and conservation crop and tillage systems on wind erosion and associated emissions of PM10 and nutrients will be quantified using a portable wind tunnel under both irrigated and dryland agricultural conditions.
2.a. Landscape scale, spatiotemporal variability of agroecosystem stocks and flows of C, N, and P following conversion from conventional tillage to no-tillage will be assessed at the Long-Term Agroecosystem Research (LTAR) site at the Cook Agronomy Farm. Understanding the long-term impacts of agroecosystems on stocks and flows of major elements is lacking and key to the development of sustainable agricultural systems.
2.b. Characterize spatiotemporal agroecosystem performance (e.g. productivity, nutrient-use efficiencies) and link to soil health metrics. Linking soil health metrics to agroecosystem performance is currently lacking and if achieved will foster a broader and more complete assessment of agricultural systems as well as provide science-based aids to agricultural management decisions. The LTAR site at the Cook Agronomy Farm is the setting for the experiment.
3.a. Isolate, select, and screen for weed-suppressive bacteria that specifically inhibit annual grass weeds, do not injure crops, native or near native rangeland plants. Select soil microorganisms are expected to reduce specific weeds in the field. Studies are a combination of: isolation of soil bacteria, Agar root bioassays, and growth-chamber plant/soil bioassays.
3.b. Evaluate the survival and efficacy of weed-suppressive bacteria to reduce annual grass weeds in the field. Weed-suppressive bacteria are expected to inhibit specific weed species under variable field conditions. Field studies will determine interactive effects among bacteria, herbicides, soil, residue, weed seed bank and non-weed plants on inhibition of annual grass weeds.
Progress Report
Objective 1: Significant progress was made in assessing wind erosion of soils varying in percent crust cover. Field observations in the Inland Pacific Northwest indicate a reduction in wind erosion of dryland agricultural soils during formation of a soil crust cover, but this reduction in erosion associated with soil crust formation is poorly described in current wind erosion models. Therefore, wind erosion and particulate matter (PM10) emissions were measured during formation of a crust cover on five major soil types found across the Inland Pacific Northwest using a portable wind tunnel.
Stability of soil aggregates influences their degradation and thus the susceptibility of soil to wind erosion. Precipitation, freeze-thaw, organic matter, and macro- and micro-organisms affect aggregate stability, but little is known if crop and tillage management practices influence aggregate stability in arid and semi-arid regions of the Inland Pacific Northwest. The stability of soil aggregates formed under a multitude of dryland crop and tillage management practices in the Inland Pacific Northwest was measured using the standard, vintage USDA aggregate crushing apparatus and a newly-acquired commercial penetrometer.
Objective 2: Long-term agro-ecosystem research at the Cook Agronomy Farm Long-Term
Agroecosystem Research (LTAR) site continues with field scale soil and plant analyses completed this year to assess management impacts on soil health metrics as well as soil carbon (C), nitrogen (N) and phosphorus (P) budgets. Performance metrics to evaluate the N use efficiency of spring wheat under precision management showed a 70 percent increase in N use efficiency for long-term continuous no-tillage combined with site-specific applied N as compared to reduced tillage and uniform N management. A long-term incubation to assess labile soil C pools was completed. Complementary research included continued instrumentation of eddy covariance flux towers for monitoring greenhouse gas flux and in-field lysimeters and flumes for assessing differences in hydrologic cycles between business-as-usual and aspirational LTAR treatments. At regional scales, crop modeling was used to assess flex cropping options for spring canola, spring wheat and spring peas as compared to fallow, the business-as-usual scenario.
Project 2090-21610-002-00D, "Cultural Practices and Cropping Systems for Economically Viable and Environmentally Sound Oilseed Production in Dryland of Columbia Plateau", has been combined with this project for FY19 and a new Objective 4 has been added. This will consolidate and strengthen complementary research.
Accomplishments
1. Soil carbon loss associated with wind erosion in the Inland Pacific Northwest. Carbon is influential in the formation of aggregates and sustaining biological activity in soils and therefore is the foundation for healthy soils. Substantial loss of carbon, however, can result in soil degradation and negatively impact agricultural production. ARS scientists in Pullman, Washington, in cooperation with scientists at Washington State University, measured the loss of carbon from dryland agricultural soils during severe wind storms in the Inland Pacific Northwest. Loss of carbon exceeded 15 pounds/activated carbon (lbs./ac), or about two percent of carbon contained in the topsoil. Interestingly, it was calculated that during particularly severe wind storms, carbon loss could approach 1500 lbs./ac. Farmers in the region must utilize conservation tillage practices to reduce wind erosion to protect the soil and associated carbon resources.
Review Publications
Trifunovic, B., Gonzales, H., Ravi, S., Sharratt, B.S., Mohanty, S. 2018. Dynamic effects of biochar concentration and particle size on hydraulic properties of sand. Land Degradation and Development. 29:884–893. https://doi:10.1002/ldr.2906.
Pi, H., Sharratt, B.S., Schillinger, W., Bary, A., Cogger, C. 2018. Wind erosion potential of a winter wheat–summer fallow rotation after land application of biosolids. Aeolian Research. 32:53-59. https://doi.org/10.1016/j.aeolia.2018.01.009.
Chi, J., Waldo, S., Pressley, S.N., Russell, E.S., O'Keeffe, P.T., Pan, W.L., Huggins, D.R., Stöckle, C.O., Brooks, E.S., Lamb, B.K. 2017. Effects of climatic conditions and management practices on agricultural carbon and water budgets in the Inland Pacific Northwest USA. Journal of Geophysical Research. 122(12):3142-3160. https://doi.org/10.1002/2017JG004148.
Pi, H., Sharratt, B.S., Schillinger, W., Bary, A., Cogger, C. 2018. Chemical composition of windblown dust emitted from agricultural soils amended with biosolids. Aeolian Research. 32:102-115. https://doi.org/10.1016/j.aeolia.2018.02.001.
Schlatter, D.C., Kahl, K., Carlson, B.R., Huggins, D.R., Paulitz, T.C. 2018. Fungal community composition and diversity vary with soil depths and landscape position in a no-till wheat cropping system. FEMS Microbiology Ecology. 94:1-15. https://doi.org/10.1093/femsec/fiy098.
Spiegal, S.A., Bestelmeyer, B.T., Archer, D.W., Augustine, D.J., Boughton, E., Boughton, R., Clark, P., Derner, J.D., Duncan, E.W., Cavigelli, M.A., Hapeman, C.J., Harmel, R.D., Heilman, P., Holly, M.A., Huggins, D.R., King, K.W., Kleinman, P.J., Liebig, M.A., Locke, M.A., McCarty, G.W., Millar, N., Mirsky, S.B., Moorman, T.B., Pierson, F.B., Rigby, J.R., Robertson, G., Steiner, J.L., Strickland, T.C., Swain, H., Wienhold, B.J., Wulfhorts, J., Yost, M., Walthall, C.L. 2018. Evaluating strategies for sustainable intensification of U.S. agriculture through the Long-Term Agroecosystem Research network. Environmental Research Letters. 13(3):034031. https://doi.org/10.1088/1748-9326/aaa779.
Schlatter, D.C., Schillinger, W.F., Bary, A.I., Sharratt, B.S., Paulitz, T.C. 2018. Dust-associated microbiomes from dryland wheat fields differ with tillage practice and biosolids application. Atmospheric Environment. 185:29-40.
Schlatter, D.C., Schillinger, W.F., Bary, A.I., Sharratt, B.S., Paulitz, T.C. 2017. Biosolids and conservation tillage: Impacts on soil fungal communities in dryland wheat-fallow cropping systems. Soil Biology and Biochemistry. 115:556-567.
Sharratt, B.S., Collins, H.P. 2018. Wind erosion potential influenced by tillage in an irrigated potato-sweet corn rotation in the Columbia Basin. Agronomy Journal. 110:842-849. https://doi:10.2134/agronj2017.12.0681.
Sharratt, B.S., Pi, H. 2018. Field and laboratory comparison of PM10 instruments in high winds. Aeolian Research. 32:42-52. https://doi.org/10.1016/j.aeolia.2018.01.006.
Sharratt, B.S., McGuire, A., Horneck, D. 2018. Early-season wind erosion influenced by soil-incorporated green manure in the Pacific Northwest. Soil Science Society of America Journal. 82:678–684. https://doi:10.2136/sssaj2018.01.0018.
Pi, H., Sharratt, B.S., Lei, J. 2017. Atmospheric dust events in Central Asia: Relationship to wind, soil type, and land use. Journal of Geophysical Research. 122:6652-6671. https://doi.org/10.1002/2016JD026314.
Pi, H., Sharratt, B.S., Lei, J. 2017. Windblown sediment transport and loss in a desert–oasis ecotone in the Tarim Basin. Scientific Reports. 7:7723. https://doi:10.1038/s41598-017-04971-4.
Zhang, X., Sharratt, B.S., Liu, L., Wang, Z., Pan, X., Lei, J., Wu, S., Huang, S., Guo, Y., Li, J., Tang, X., Yang, T., Tian, Y., Chen, X., Hao, J., Zheng, H., Yang, Y., Lyu, Y. 2018. East Asian dust storm in May 2017: observations, modelling and its influence on Asia-Pacific region. Atmospheric Chemistry and Physics. 18:8353–8371. https://doi.org/10.5194/acp-18-8353-2018.
Sharratt, B.S., Schillinger, W. 2018. Soil properties influenced by summer fallow management in the Horse Heaven Hills of Southcentral Washington. Journal of Soil and Water Conservation. 73:452-460. https://doi:10.2489/jswc.73.4.452.
