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1. Is Cover Crop Species Mixture and Diversity More Important at Building Soil Health than Shoot Biomass in a Semi-arid Region?Cover crop mixtures (CCMs) as partial fallow replacements have the potential to increase soil health, yet long-term studies on CCMs, especially in semi-arid environments are relatively rare. An eight-year study at two locations in semi-arid Montana sought to evaluate the effect of functional group (N fixer, tap roots, fibrous roots, brassicacae) and species richness (2, 6, and 8 species in a mix) on a range of biological, physical and chemical soil parameters. Although several soil healt... P. Miller, C. Jones, C. Zabinski, K. D'agati, M. Housman, S. Tallman |
2. The Elasticity of Biochar Across the Farm: Nutrient Capture, Compost Feedstock, and Soil AmendmentWhen biomass is thermochemically altered through pyrolysis, what results is biochar, a solid, porous material that is high in carbon (C) (e.g. 80%). Owing to its unique physicochemical properties, biochar has been evaluated as a soil amendment, a compost feedstock, a means to mitigate nutrient loss and a way to sequester carbon. Biochar is an appealing material as a farm management tool because its potential use is varied. As part of a Western SARE grant, soil scientists at ... N. Stacey, D. Collins |
3. The Fertilizer Recommendation Support Tool (FRST) Initiative: National Survey on Soil Fertility Recommendations and Correlation/Calibration DatabaseSoil fertility testing is an integral tool used in nutrient management planning, providing information needed to determine where nutrients are required and how much to apply. While a great deal of effort has been successfully invested in standardizing soil test methods in the U.S. over the last few decades, up-to-date correlation/calibration studies are lacking in many states. In most cases, soil test correlation/calibration efforts lead by land-grant universities are on a state-by-state or l... S.E. Lyons, J.T. Spargo, D.L. Osmond, A.W. Pearce, N.A. Slaton, D.K. Arthur, P.J. Kleinman, J.M. Mcgrath |
4. Repurposing Zinc from Mining Tire Waste to a Fertilizer ResourceZinc (Zn) deficiency is common on high pH soils when growing field crops like Corn, Barley and Wheat. Not only are crop yields and quality limited by low Zn, but more importantly the dilution of Zn in food stuffs and, thereby, Zn deficiency in the human diet has become a major concern as recognized by the World Health Organization. At the same time, there is a Global problem in proper repurposing/disposal of used tires that contain between 1-3% ZnO. In fact, in Chile, t... K. Greer, J. Wiebe, E. Bremer |
5. Evaluation of Lime Requirement Estimation Methods for Oregon Agricultural SoilsSoil testing labs in the Pacific Northwest are considering non-hazardous alternatives to the Shoemaker-McLean-Pratt (SMP) buffer method for lime requirement estimation (LRE). While alternative LRE methods have been adopted in other parts of the U.S., they have not been evaluated for Oregon soils. The goal of this study was to evaluate several LRE methods for agricultural soils from western and eastern Oregon, applying the lime incubation method for actual lime requirement. Twenty-four a... C. Evans, A. Moore, D. Sullivan |
6. Factors Influencing Efficacy of Elemental Sulphur FertilizersElemental sulfur is a byproduct of fossil fuel production and produced in large quantities in both the US and Canada. Fertilizers containing elemental S have a high S content and low manufacturing cost, but may not reliably meet crop requirements for S in the year of application due to the time required for elemental S to be oxidized. The main factors influencing the oxidation rate of elemental S are particle size, particle dispersion and environmental conditions. ... E. Bremer |
7. Denitrifying Woodchip Bioreactor Performance in the Pacific NorthwestRunoff and tile drainage from agricultural activity is known to be a significant contributor of nitrogen pollution to surface waters. Denitrifying woodchip bioreactors, also known as Permeable Reactive Barriers (PBR) have been studied as a possible edge-of-field technology for reducing nitrogen concentrations in agricultural runoff. These units have been studied mostly in the US Midwest and mostly for irrigated crop systems. Little work has been done in alternative climate r... E.M. Weisshaar |
8. Phosphorus and Potassium How Low Can You Go In Alfalfa?Tissues testing whole alfalfa plants at harvest can more accurately direct nutrient decisions. Developing critical nutrient levels in-season improves recommendations and applications, saving producers time, expense and effort since many growers take samples for hay quality. These three experiments were designed as follows: 1) Phosphorus (P) Rate study with differing rates of P2O5 using monoammonium phosphate (MAP); including: 0, 30, 60, 120, 240 lb P2O5... S. Norberg, S. Fransen, J. Harrison, D. Llewellyn, L. Whitefield |
9. Assessing Nutrient Uptake and Accumulation in Oregon Hop ProductionCommercial hop production practices and cultivars have changed in the past 25 years and there is a need for updated nutrient management information under cotemporary practices. Current nutrient accumulation curves are only available for nitrogen (N). Current regional nutrient management guides from Oregon State University and Washington State University date back to the 1990’s or earlier. In the meantime, market forces and breeding efforts have led to a proliferation of new varieties, m... A. Moore, D. Gent, B. Verhoeven |
10. Soil Health Changes Following Transition from an Annual Cropping to Perennial Management-Intensive Grazing AgroecosystemManagement-intensive Grazing (MiG) on irrigated, perennial pastures has steadily increased in the western US due to pressure for reducing public lands grazing, overall declining land available for pasture, and decreasing commodity prices. However, there are still many unknowns regarding MiG and its environmental impact, especially with regards to soil health. Over a two-year period, we studied changes in soil health under a full-scale, 82 ha pivot-irrigated perennial pasture system grazed wit... J. Ippolito, C. Shawver, J. Brummer, J. Ahola, R. Rhoades |
11. Twenty Years of Cotton Nitrogen Management and Cycling Trials in the Southwest: What Have We Learned?Over 20 site-years of nitrogen fertilizer management and cycling trials have been conducted in Lubbock Texas and Maricopa Arizona from 1998 to 2019. Furrow, overhead sprinkler (OSI), subsurface drip irrigation (SDI) were used. Soil profile nitrate (0-36 inches in Texas and 0-72 inches in Arizona) was sampled and tested for in all trials. Nitrogen-15 labeled fertilizer was used for two years in Texas and for two years in Arizona. Canopy reflectance was measured in every... K.F. Bronson |
12. Does Post-harvest Nitrogen Application Affect Blueberry Yield or Cold Hardiness?In central Washington, nitrogen (N) management in blueberries typically consists of all N being applied prior to harvest. For early cultivars, such as Duke, this means all fertilizer is applied before the end of June, leaving a long period of growth with no supplemental N. To evaluate the potential for splitting N fertilizer applications into pre- and post-harvest timings, we conducted an experiment in a randomized complete block design with four replicates on a commercial ‘... J.R. Davenport, G.A. Hoheisel, L.W. Devetter |
13. Compost Application in California Tomato Cropping SystemsWith the implementation of California Assembly Bill (AB) 341 the availability of composts such as green waste (GW) and co-composted green waste and food waste (FW) as a soil amendment is increasing. The use of those organic amendments in agricultural production systems has been recommended as an effective strategy to make full use of organic waste and improve soil health. However, little information is available to tomato growers to reassess N inputs from using GW and FW. This study was condu... Q. Yi, W. Horwath, S. Haas, X. Zhu-barker |
14. Developing a Soil Health Assessment Framework for Specialty Crop Systems and Soils of Washington StateTo ensure productive soils, agricultural sustainability, and food security, it is vital to maintain and improve soil health. However, over the decades, intensive agricultural practices have led to a decline in soil health. While most of these intensive agricultural practices negatively affect soil health, research has shown that it is possible to resuscitate soils with practices such as over cropping, and crop rotation. Much of the research on soil health in the US has been done in agronomic ... K.A. Sarpong, M. Mcilquham, L. Michel, D. Griffin |
15. Effects of Lime and Micronutrient Amendments for Acidic Soils of the Inland Pacific NorthwestThe soil pH of agricultural land in the inland Pacific Northwest has dropped precipitously from native soil levels of near 7.0 pH. Changes that were becoming evident in the 1980’s have reached critical levels, leaving tens of thousands of acres of previous prairie soil at pH under 5.0 and unable to grow an increasing number of aluminum-sensitive crops. Some farmers in the region are beginning to use lime application to neutralize soil acidity. However, pH changes and liming can als... R. Wieme, L. Carpenter-boggs, P. Carter, S. Van vleet |
16. Cover Crop Suitability for High Altitude Specialty Crop Organic Food ProductionThere is a growing interest in certified organic, specialty crop food production. With a larger population demanding organic products and organic products offering a higher premium for the producer, farmers are exploring the transition to organic farming. Organic producers in southeatstern Wyoming face multiple challenges in environments with high elevation, low precipitation, and have a short growing season. These challenges include management of persistent weeds, maintaining biodiversity, a... E. Moore, U. Norton |
17. Reuse and Reclamation of PhosphogypsumPhosphogypsum (PG) is a byproduct of phosphate fertilizer production. It is produced when phosphate rock is treated with sulphuric acid during the manufacture of phosphoric acid, and is composed primarily of gypsum (CaSO4.2H2O). It is estimated that over 3 billion tonnes of PG have been accumulated in stacks worldwide and over 150 million tonnes are produced annually. In North America, PG is stockpiled in stacks that can cover hund... C. Nichol |
18. Sugar Beet Lime Effects on High pH Soils and Crops in Northwest U.S.A viable solution to dispose of sugar beet precipitation calcium carbonate (PCC) is needed due to the unsustainable issues associated with storage. Sugar beet PCC is a lime material produced as a waste product from extracting sugar from sugar beet. The three main sugar beet processing factories in the Amalgamated Sugar Company growing area in Idaho and Oregon have stockpiled approximately 11.3 million Mg of PCC. Each year these three factories produce a total of 350,000 Mg annually. &nb... D.D. Tarkalson |
19. Dairy Manure and Fertilizer Effects on Microbial Activity of an Idaho SoilDairy manure applications that have occurred in the past can have long-term lingering effects on crop production. Understanding the cause is important for current and future management practices. This study was conducted to assess selected microbial activity among past manure application rates. In a past study (2014-2016) in Kimberly Idaho, historic manure applications have been shown to have significant positive and negative effects on sugar beet production. The manure treatment histor... D.D. Tarkalson, R. Dungan, D. Bjorneberg |
20. Residue Decomposition of Surface and Incorporated Barley, Corn, and Wheat at Varying Fertilizer-N RatesCereal crops are commonly grown in southern Idaho and most parts of the western United States. These cereal crops are routinely harvested for their grain with the remaining plant material (chaff, stems, leaves, etc.) left in the field to decompose prior to planting of following spring crops. Understanding the effects of post-harvest residue management on barley (Hordeum vulgare L.), corn (Zea mays L.), and wheat (Tritcum aestivum L.) residue is important for optimiz... C. Rogers, G. Thurgood, B. Dari, J. Marshall, O.S. Walsh, K. Schroeder, G. Loomis |
21. Soil Health and Ecological Resilience on the PalouseHealthy soil is critical for global food security and other essential ecosystem services but is threatened by processes of soil degradation, with at least 33% of global croplands estimated to be moderately or highly degraded. Current soil health assessments provide insight into soil functional performance but often lack diagnostic criteria that assess management effects on soil function over time. We integrate soil health assessments with ecological resilience theory to better understand mana... A.G. Davis, D.R. Huggins, J.P. Reganold |
22. Refining Nitrogen Management for Organic Broccoli ProductionSpecialty organic fertilizers used in organic vegetable production are expensive. So, from environmental and economic perspectives, growers want to maximize nitrogen (N) fertilizer use efficiency by the crop. This research was conducted to (1) determine sufficient N fertilizer rates for organic broccoli, (2) evaluate the efficacy of a specialty organic fertilizer (feather meal; 12-0-0), and (3) confirm the effectiveness of midseason soil nitrate analyses (0-30 cm) in determining appropriate s... D. Sullivan, R.E. Peachey, A. Donaldson |
23. Vineyard Soil Health: What Soil Properties are Most Important?Washington is the second leading producer of wine grapes (Vitis vinifera) in the US, with over 60,000 acres in vineyards. With such a substantial acreage, it is crucial to know how management practices may affect soil and vine health in wine grape systems. Soil health indicators and threshold values have been extensively studied in commodity crops in the Midwest and the northeastern US, but there is much less information available for specialty crops in the Pacific Northwest. &... M. Mcilquham, D. Griffin-lahue, K. Sarpong, L. Michel |
24. Comparative Analysis of Soil Tests for Soil Health and Nutrient ManagementOptions for soil tests to address soil health and nutrient management objectives have diversified. We compare different soil test methods to evaluate their similarities for providing recommendations. Traditional soil tests, ion exchange membranes and analyses using the Haney Soil Health Nutrient Tool and Soil Health Index were compared for soil sampled from long-term cropping system trials near Ritzville Washington and from the R.J. Cook Agronomy Farm near Pullman WA. Despite strong... D. Huggins, C. Rieser, J. Reganold |
25. Long-term Soil Profile Acidification: Obvious and Hidden DangersSoil acidification is occurring in the dryland farming region of the Northwest. Historically, soil acidification in the surface foot has been characterized; however, potential acidification of subsoil is unknown. We examined soil acidification for soil profiles (0 to 5 ft) at the R.J. Cook Agronomy Farm (92 ac) for 17 years following conversion from conventional tillage to continuous No-tillage (NT). Surface soil depths (0-12 in) acidified under continuous NT to below 5. Surprisingly, subsoil... D. Huggins, S. Shiwakoti |
26. Is Residue Management an Important Factor in the Soil Health of Perennial Grass Seed Production Systems?Residue management in agricultural systems is a crucial pathway of nutrient and organic matter flow and is predicted to affect soil health indices. In Western Oregon, perennial grasses for seed are a major crop, occupying roughly 150,000 ha in the Willamette Valley. Current estimates are that 80-85% of producers remove straw residue, exporting more than 650,000 US tons of straw annually. The primary objectives of this study were: i) evaluate soil health outcomes under residue retention and re... B. Verhoeven, A. Moore, D. Sullivan, M. Gonzalez-mateu |
27. Evaluating Cover Crops for Nitrogen Management in a Walnut OrchardCover crops provide numerous benefits in agricultural systems. From increasing soil water storage to reducing fertilizer inputs, quantifying cover crops benefits is crucial in nutrient management, crop productivity, environmental sustainability, and growers' adoption. The goal of this study was to quantify nitrogen (N) and carbon (C) inputs in a walnut (Juglans regia L. 'Chandler') orchard that implemented three cover crop mixtures. The study site was a 5-year-old w... D. Zapata, X. Zhu-barker, K. Steenwerth, W. Horwath |
28. Estimating Nitrogen Credits from Organic Matter Sources in OrchardsOrchard crops like almonds can effectively utilize different nitrogen (N) sources to meet the high annual N demand for fruit and tree growth. Different fertilizer formulations like urea ammonium nitrate, calcium ammonium nitrate, ammonium sulfate and potassium nitrate are widely and effectively used, and readily available for uptake. Yet, addressing N availability from organic matter sources in orchards, and in turn estimating appropriate N credi... S.S. Khalsa, P.H. Brown |
29. Effects of Semiarid Wheat Agriculture on Soil Microbial Properties: A ReviewAgricultural management decisions on factors such as tillage, fertilization, and cropping system determine the fate of much of the world’s soils, and ... J. Norton, H. Rodgers, L. Van diepen |
30. Soil Test Interpretation: Saturated Paste, EC, SAR and CECSoils of neutral to alkaline pH of the Western United States often contain elevated levels of soluble salts and / or higher concentrations of sodium. Elevated concentrations of soluble salts limit crop growth and sodium may impact water management. Competent agricultural management of these soils is dependent on laboratory analysis of: soil soluble salts and there composition and the irrigation water soluble salt constituents. Soil analysis based on the satura... R. Miller |
31. Impact of Soil Health Practices in an Irrigated AgroecosystemRegional farming practices in cold semiarid irrigated agroecosystems with short growing seasons are shifting to reduced tillage and overhead irrigation to stay economically viable, but more research is needed on the impact of soil health practices such as crop diversification, reduced tillage, and livestock integration on soil physical and chemical properties in these systems. A multi-year study from 2014-2020 in the Bighorn Basin of Northwest Wyoming used a three-crop rotation (diversificati... T. Vance, V. Crowe, J. Norton |
32. Improved Small Grain Nitrogen Use Efficiency with California Site-specific Decision SupportSmall grains are grown throughout the state of California (CA) on approximately 500,000 acres annually. They are generally fall-sown and grown during the winter months when most precipitation occurs. Because precipitation and irrigation patterns vary across CA and there is a strong interaction between total water and plant available nitrogen (N), determining fertilizer N application recommendations is particularly challenging in this cropping system. With recent fertilizer price vol... N. Clark, M. Lundy, T. Nelsen, M. Leinfelder-miles, S. Light, G. Galdi, T. Getts, K. Mathesius |