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Stevens, R
Griffin-LaHue, D
Leytem, A
Jolley, V
Ruth, M
Peterson, G
Nelson, T
Mookodi, K
Khalsa, S.S
Ewing, S
Stark, J
Moore, E
Miller, P
Sullivan, T
Rothlisberger, D
Shiwakoti, S
Casanova, J
Pritchett, J
Evans, C
Slaton, N
Pan, W
Jones, C
Maharjan, B
Verhoeven, B
Jacobson, A.R
Selman, J
Sullivan, D
Sutton, L
Jones, C
Getts, T
Ellsworth, J
Silverstein, K
Deenik, J
Kok, H
Sanchez, C
Long, R
Girma, K
Pryor, M
Madsen, I
Robinson, D
McClintick, J
Tiedje, J
Pond, A
Sherman, J
Peachey, R.E
Carlock, E
Murch, J
Singh, S
Donaldson, A
Collins, H
Campbell, C
Lawley, J
Griffin, D
Elliott, A
Janni, K
Chen, L
Steenwerth, K
Ellison, E
Nelson, S.V
Moore, J
Christensen, R.C
Paustian, K
Packham, J
Collins, D
Neville, B
Cardon, G
Christiaens, R
Nouwakpo, K
Das, A.K
Cole, D.L
Schott, L
Savidge, M
Stephens, S
Murrell, T
Yi, Q
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Authors
Stacey, N
Collins, D
Evans, C
Moore, A
Sullivan, D
Cole, D.L
Heidenreich, D.T
Stapley, S.H
Lambert, A.M
Buck, R.L
Hopkins, B.G
Deakin, J.W
Potter, M
Cartwright, A
Hortin, J
Sparks, D
McLean, J.E
Britt, D.W
Anderson, A.J
Jacobson, A.R
Moore, A
Gent, D
Verhoeven, B
Yi, Q
Horwath, W
Haas, S
Zhu-Barker, X
Sarpong, K.A
Mcilquham, M
Michel, L
Griffin, D
Moore, E
Norton, U
Sullivan, D
Peachey, R.E
Donaldson, A
McIlquham, M
Griffin-LaHue, D
Sarpong, K
Michel, L
Huggins, D
Shiwakoti, S
Verhoeven, B
Moore, A
Sullivan, D
Gonzalez-Mateu, M
Zapata, D
Zhu-Barker, X
Steenwerth, K
Horwath, W
Khalsa, S.S
Brown, P.H
Webb, B
Hopkins, B
Ellsworth, J
Barben, S
Nichols, B
Jolley, V
Bary, A
Sullivan, D
Cogger, C
Cardon, G
Kotuby-Amacher, J
Davenport, J
Stevens, R
Perry, E
Deenik, J
Fukuda, S
Hamasaki, R
Shimabuku, R
Uchida, R
G. Davis, J
Elliott, A
Marcillac, N
Pritchett, J
Stewart, C
Mink, A
Hopkins, B
Stephens, S
Shiffler, A
Webb, B
Hopkins, B
Ellsworth, J
Jolley, V
Callahan, R
Moberg, D
Sullivan, D
Johnson, R
Stark, J
Love, S
McIntosh, C
Sullivan, D
Hopkins, B
Taysom, T
Shiffler, A
Stephens, S
Walworth, J
Pond, A
Nunez, H
Wood, B
Kilby, M
Cardon, G
Barnhill, J
Pace, M
Israelsen, C
Miner, D
Greenhalgh, L
Banks, S
Shao, M
Rothlisberger, D
Olsen, S
Hole, P
Deenik, J
McClellan, A
Uehara, G
Hawks, A
Cardon, G
Webb, B
Hopkins, B
LeMonte, J
Taysom, T
Jolley, V
Hopkins, B
Webb, B
Marcroft, K
Christenson, R
Jolley, V
Moore, A
Alva, A
Collins, H
Boydston, R
Peterson, G
Webb, B
Hopkins, B
Pletsch, M
Cook, D
Vickery, M
Jolley, V
Tarkalson, D
Brown, B
Bjorneberg, D
Kok, H
Andrews, N
Sullivan, D
Julian, J
Pool, K
Sullivan, D
Costello, R
Bryla, D
Strik, B
Owens, J
Deenik, J
McClellan, T
Sullivan, D
Horneck, D
Holcomb, J
Clough, G
Holcomb, J
Horneck, D
Clough, G
Sullivan, D
Sullivan, D
Andrews, N
Datta, R
Pool, K
Hopkins, B
leMonte, J
Summerhays, J
Jolley, V
Deenik, J
Penton, C
Popp, B
Bruland, G
Engstrom, P
Mueller, J
Tiedje, J
Machado, S
Girma, K
Smith, R
Blaylock, A
Ellison, E
Sanchez, C
Murrell, T
Murrell, T
Hopkins, B
Sutton, L
Ransom, C
Blair, T
Moody, J
Manning, K
Bergsten, S
Blair, T
Ransom, C
Hosford, P
Svedin, J
Sutton, L
Winchester, A
Manning, K
Hopkins, T
Hopkins, B
Davenport, J
Pollard, A
Sullivan, T
Del Moro, S
Sullivan, D
Horneck, D
Heerema, R
Sherman, J
Hopkins, B
Stark, J
Sullivan, D
Light, S
Horneck, D
Hopkins, B
Black, B
Neville, B
Ewell, C
Geary, B
Pearce, A.W
Johns, J
Robinson, D
Hansen, N
Hopkins, B
Fernelius, K
Pryor, M
Hopkins, B
Ransom, C
Ruth, M
Blair, T
Sutton, L
Bradshaw, D
Campbell, K
Hopkins, B
Blair, T
Selman, J
Ransom, C
Hopkins, T
Sullivan, D
Walsh, O
Pandey, A
Christiaens, R
Walsh, O
Pandey, A
Christiaens, R
Walsh, O
Pandey, A
Christiaens, R
Walsh, O
Pandey, A
Christiaens, R
Campbell, C
Hansen, N
Hopkins, B
Evans, S
Campbell, E
Campbell, A
Rivera, L
Cobos, D
Pan, W
Maaz, T
Madsen, I
Hammac, W
Reese, M
Shapiro, C
Ferguson, R
Wortmann, C
Shaver, T
Krienke, B
Hergert, G
Maharjan, B
Sanchez, C
Heinrich, A
Sullivan, D
Leytem, A
Moore, A
Deenik, J
Loo, M
Del Moro, S
Davenport, J
Jones, C
Walsh, O
Torrion, J
Liang, X
McClintick, J
Blanscet, S
Jones, C
Engel, R
Ewing, S
Miller, P
Olson-Rutz, K
Paustian, K
Deenik, J
Carlock, E
Weigel, A
Searle, T
Hopkins, T
Williams, J
Hopkins, B
Neuman, J
Sullivan, D
Moore, A
Pound, C
Yost, M
Creech, E
Cardon, G
Russell, K
Despain, D
Gale, J
Heaton, K
Kitchen, B
Pace, M
Price, S
Reid, C
Palmer, M
Nelson, M
Long, R
Sullivan, D
Clark, N
Lundy, M
Nelsen, T
Leinfelder-Miles, M
Light, S
Galdi, G
Getts, T
Mathesius, K
Sullivan, D
Andrews, N
Yost, M
Baker, M
Gale, J
Creech, E
Cardon, G
Yost, M
Baker, M
Gale, J
Cardon, G
Creech, E
Stapley, S.H
Whitaker, C.C
Hansen, N.C
Christensen, R.C
Jensen, R.R
Yost, M.A
Hopkins, B.G
Mathesius, K
Geisseler, D
Savidge, M
Lundy, M
Nelson, T
Andersen, N
Schott, L.R
Hines, S
Packham, J
Loomis, G
de Haro Marti, M
Willmore, C
Desjardins, M
Bary, A
Ippolito, J
Cappellazzi, S
Liptzin, D
Griffin-LaHue, D
Bohl Bormann, N.L
Wilson, M.L
Cortus, E.L
Janni, K
Silverstein, K
Gunderson, L
Schott, L
Robison, C
Brooks, E
Bjorneberg, D
Nouwakpo, K
Chen, L
Kruger, K
Coyotl, A
Murch, J
Khalsa, S.S
Horwath, W.R
Yost, M
Slaton, N
Spargo, J
Kaiser, D
Buol, G
Gatiboni, L
Lukas, S
Singh, S
Hopkins, B
Nelson, S.V
Cardon, G
Lawley, J
Hopkins, T.J
Auld, R
Moore, A
Moore, J
Zhang, Y
Rogers, C
Hopkins, B
Kerr, R
Nelson, S.V
Hopkins, B
Bell, G
Nelson, S.V
Sannar, R.E
Das, A.K
Chen, L
Islam, M
He, B
Chen, L
Sanchez, C
Sanchez, C
Sanchez, C
Hopkins, B
Foster, M.J
Nelson, S.V
Nelson, S.V
Lawley, J
Hopkins, T.J
Cardon, G
Hopkins, B
Huggins, D
Casanova, J
Phillips, C
Topics
Manure and Compost Management
Liming and Soil Acidity
Crop Nutrient Management
Fertilizer Evaluations
Nutrient Management of Horticultural Crops
Organic Amendments, Cover Crops, and Soil Health
Sensors and Other Technologies for Nutrient Management
Nutrient Cycling in Regenerative Agriculture
4R's for N, P, K, S
General
Environmental and Agricultural Nutrient Management
Invited Oral Presentation
General Posters
Student Posters
Type
Oral
Poster
Year
2021
2007
2009
2011
2013
2015
2017
2019
2023
2025
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Authors

Filter results108 paper(s) found.

1. The Elasticity of Biochar Across the Farm: Nutrient Capture, Compost Feedstock, and Soil Amendment

When 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 Washington... N. Stacey, D. Collins

2. Evaluation of Lime Requirement Estimation Methods for Oregon Agricultural Soils

Soil 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 acidic... C. Evans, A. Moore, D. Sullivan

3. New Hydroponic System for Testing Mineral Nutrient Deficiencies: Quinoa

Correlating plant tissue nutrient concentrations with visual symptoms is valuable in combating mineral nutrient deficiencies and toxicities. Major crops tend to have adequate information regarding nutrient concentrations and visual symptoms of deficiencies, but this is often lacking for minor crops, including quinoa (Chenopodium quinoa L.) Because nutrient concentrations can be easily controlled, hydroponics effectively demonstrate isolated specific nutrient related symptoms. However,... D.L. Cole, D.T. Heidenreich, S.H. Stapley, A.M. Lambert, R.L. Buck, B.G. Hopkins

4. Is Mitigation of Drought Stress By Zinc Oxide Nanoparticles Driven By a Nano-Specific Mechanism or Alleviation of Micronutrient Deficiency?

It has been reported that zinc oxide (ZnO) nanoparticles (NPs) can promote drought tolerance in crops when used as soil amendments. However, many of these experiments were conducted in Zn-deficient growth media with no comparison to currently available Zn fertilization methods, making it unclear if the benefits from adding ZnO NPs were caused by a nano-specifc mechanism or simply by the mitigation of a micronutrient deficiency. A review of the literature shows that of 12 published experiments... J.W. Deakin, M. Potter, A. Cartwright, J. Hortin, D. Sparks, J.E. Mclean, D.W. Britt, A.J. Anderson, A.R. Jacobson, L. Yen

5. Assessing Nutrient Uptake and Accumulation in Oregon Hop Production

Commercial 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, many... A. Moore, D. Gent, B. Verhoeven

6. Compost Application in California Tomato Cropping Systems

With 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 conducted... Q. Yi, W. Horwath, S. Haas, X. Zhu-barker

7. Developing a Soil Health Assessment Framework for Specialty Crop Systems and Soils of Washington State

To 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 systems... K.A. Sarpong, M. Mcilquham, L. Michel, D. Griffin

8. Cover Crop Suitability for High Altitude Specialty Crop Organic Food Production

There 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, and... E. Moore, U. Norton

9. Refining Nitrogen Management for Organic Broccoli Production

Specialty 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 sidedress... D. Sullivan, R.E. Peachey, A. Donaldson

10. 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.   Soil... M. Mcilquham, D. Griffin-lahue, K. Sarpong, L. Michel

11. Long-term Soil Profile Acidification: Obvious and Hidden Dangers

Soil 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

12. 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 removal... B. Verhoeven, A. Moore, D. Sullivan, M. Gonzalez-mateu

13. Evaluating Cover Crops for Nitrogen Management in a Walnut Orchard

Cover 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 walnut... D. Zapata, X. Zhu-barker, K. Steenwerth, W. Horwath

14. Estimating Nitrogen Credits from Organic Matter Sources in Orchards

Orchard 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 credits... S.S. Khalsa, P.H. Brown

15. Soil Acidification: Identification, Prevention, Adaptation and Restoration

Low soil pH is becoming far more common in Montana soils, with at least 23 counties having at least one field with pH less than 5.5. Soil pH levels in the top 6 inches as low as 3.8 have been measured, resulting in complete crop failure insome locations, yet the problem is highly variable across fields and within soil profiles. Nitrogen fertilizer rates applied above crop nitrogen needs are the largest cause of the acidification. Low soil pH should be verified before managementpractices... C. Jones, R. Engel, S. Ewing, P. Miller, K. Olson-rutz

16. Managing Soils for CO2 Drawdown: Boon or Boondoggle?

Consensus is growing that meeting the goal of a two degree or less global warming will not only require aggressive greenhouse gas emission reductions across all sectors of the global economy, but also active measures to remove CO2from the atmosphere. Among the broader suite of CO2 removal (CDR) strategies, soil C sink approaches have been deemed as being among the most ready for early deployment and having the greatest net environmental benefits. A variety of existing... K. Paustian

17. Soil Diversity and Agricultural Adaptation Across Micronesia

Micronesia, a sub-region of Oceania, comprises approximately 2,100 small islands belonging to five sovereign nations scattered across 2.9 million square miles of the Western Pacific. A majority of the islands are low-lying, sandy coralatolls, but high volcanic islands and raised limestone islands are major population centers in the region. Palau, in the west, was first settled by seafaring peoples as early as 4000-4500 BP and the colonization of Marshall Islands at the eastern edge... J. Deenik

18. Polymer Coated Urea and Urea Blends on Potato

Potato (Solanum tuberosum L.) is a globally important crop with significant economic and environmental impacts. Nitrogen (N) has a large impact in both instances. Polymer coated urea (PCU) is a N source with the ability of improving production and the environment. Environmentally Smart Nitrogen (ESN) is a PCU that may reduce the need for continual N application throughout the season. The objective of this research was to evaluate the impacts on potato tuber yield and quality with uncoated... E. Carlock, A. Weigel, T. Searle, T. Hopkins, J. Williams, B. Hopkins

19. Cover Crops As A Source Of Plant-Available Nitrogen: Effect Of Residual Soil N And Cover Crop Species

Fall-planted brassica and small grain cover crops have the potential to serve as catch crops by taking up residual soil nitrogen (N) in the soil. While plant species is often considered when estimating N release rates from cover crop residues, variation in residual soil N is rarely considered. The first objective of this study was to quantify the effect of N fertilizer application rate (to simulate varying residual soil N levels) on tissue N concentrations of several cover... J. Neuman, D. Sullivan, A. Moore

20. Nitrogen Management in Small Grains After Alfalfa

Small grains are commonly grown following alfalfa in Utah and the Intermountain West, especially during drought years as small grains require less irrigation than corn. Several studies across the country have shown that corn following alfalfa rarely needs N fertilizer, yet relatively few have evaluated the N needs of small grains. Furthermore, research on the N needs of small grains grown as forage vs. grain are even more sparse. The objectives of this research are to quantify the... C. Pound, M. Yost, E. Creech, G. Cardon, K. Russell, D. Despain, J. Gale, K. Heaton, B. Kitchen, M. Pace, S. Price, C. Reid, M. Palmer, M. Nelson

21. Dry Bean Production in California

There are four species and eight market classes of dry beans grown in California. These include lima beans (baby and large, Phaseolus lunatus), common beans (kidney, pink, white, cranberry, black turtle, P. vulgaris), blackeye (cowpea, Vigna unguiculata), and garbanzo beans (chickpea, Cicer arietinum). Dry beans are an important specialty market for California. In 2017, growers harvested 50,000 acres of dry beans valued at $60 million. Lima beans accounted for about... R. Long

22. Interpreting Compost Analyses

This outreach publication is designed for wholesale buyers of compost for resale, nursery managers, public/private landscape managers, farm advisors, and farmers. The publication provides guidance on how to select a laboratory, based on intended compost end use (field application vs. potting soil). Interpretations are provided for laboratory tests available from commercial laboratories, including chemical tests (pH, soluble salt, macro- and micro-nutrients), physical tests... D. Sullivan

23. Soil Water and Plant Canopy Sensor Technologies to Optimize Water and Nutrient Use

In many respects, agricultural technology is doing things now that were only imagined 20 to 30 years ago. Yet, grower tools that provide information and actionable knowledge on water and nutrient availability still remain a challenge. Clearly, rapid development of data transfer and processing platforms to date has provided rich maps of grower fields with overlays of location-specific information but their utility is still limited by our ability to accurately measure the parameters that are the... C. Campbell, N. Hansen, B. Hopkins, S. Evans, E. Campbell, A. Campbell, L. Rivera, D. Cobos

24. Canola Roots of Water and Nitrogen Use Efficiency: New Lessons for PNW Wheat Growers

The semi-arid inland Pacific Northwest (iPNW) has primarily produced wheat for 125 years due to favorable climate, soils, economics and policy drivers. Shifting drivers over the past decade related to energy, climate change, regional and global markets have created new opportunities for the integration of canola into iPNW wheat-dominated rotations. Traditional wheat grower mindsets required an agronomic reboot, forged by an understanding of canola vs. wheat physio morphology, an explosion of variety... W. Pan, T. Maaz, I. Madsen, W. Hammac, M. Reese

25. Nebraska Nitrogen Management Present and Future

University of Nebraska faculty have been refining their N rate recommendation procedure since the 1970s. At that time, they introduced a procedure for predicting soil nitrate-N availability and effect on subsequent corn N needs. In the 1990’s this procedure was refined based on 81 state wide N rate experiments. In 2003-2006 it was re-confirmed with 32 state wide irrigated corn trials. The current algorithm is the following: N need (lb/ac) = [35 + (1.2 x EY) - (8 x NO3- N ppm) - (0.14 x EY... C. Shapiro, R. Ferguson, C. Wortmann, T. Shaver, B. Krienke, G. Hergert, B. Maharjan

26. N Management Tools for Desert Vegetables

Over the past two decades studies have been conducted to evaluate diagnostic tools and practices aimed at the development of more efficient N management in desert vegetable cropping systems. In all cases initial studies were conducted in small plots at University Research Farms. However, practices that were found to be promising were scaled up into large experiment-demonstration in commercial production fields. Studies show that while tissue tests were often reasonable diagnostic tools for N deficiency... C. Sanchez

27. Measuring Ammonia Loss Using Field-scale and Laboratory Techniques

Following the surface application of urea to soil, there is the potential for nitrogen (N) loss from ammonia (NH3) volatilization until sufficient rain or irrigation has moved it into the soil. Many studies measuring NH3 loss have used laboratory and microplot field studies. The limitation of these techniques is that they do not represent NH3 loss under natural conditions because enclosures alter air movement, humidity, and soil and air temperature inside the chambers. However, they... A. Heinrich, D. Sullivan

28. The Performance of the Soil Health Tool in Irrigated Calcareous Soils of the Western U.S.

The Soil Health Tool (SHT), utilizes an integrated approach to soil testing for quantification of soil health and estimation of available nutrients for crop growth. The SHT is designed to mimic nature’s approach, as closely as possible, in order to estimate soil nutrient availability in the laboratory. The test itself includes extraction with water to measure soluble nutrients (C, N, P), a soil microbiological measurement, and a weak organic acid extraction to mimic additional nutrients... A. Leytem, A. Moore

29. Preliminary Assessment of the Solvita-CO2 Test in Characterizing Management Effects on Soil Biological Activity in Some Soils of Hawaii

The health of agricultural soils depends to a great degree on management practices that promote soil organic matter accumulation. While total soil organic carbon (C) is the standard measure of soil organic matter, it changes slowly and does not provide a sensitive enough test to assess short term management effects on soil health. However, a key indicator of healthy soil is potential biological activity, which can be measured rapidly with soil testing via short-term carbon (C) mineralization following... J. Deenik, M. Loo

30. Cover Crops for Hop Production in Semi-arid Climates

Tilling interrows to control weeds is a common practice in hop production, especially in the Yakima Valley of Washington which receives 8 inches average annual precipitation and produces 74% of US hops. Dry, tilled interrows leaves topsoil prone to erosion and decreases soil organic matter over time. The goal of this three-year study is to determine cover crop species that would be profitable weed control alternatives to tillage for hop producers in semi-arid climates by providing ground cover,... S. Del moro, J. Davenport, C. Jones

31. Response of Spring Wheat to Varied Nitrogen and Water Applications

This study’s objectives were to 1) determine the minimum N and water requirements for optimum wheat grain yield and quality; 2) develop a sensor- based system for identifying – and distinguishing between – N and water stress; 3) produce grower recommendations based on the developed model; and 4) improve grower adoption of efficient water and N application practices and enhance grower understanding of sensor-based technologies. This was the first year of the study, project will... O. Walsh, J. Torrion, X. Liang, J. Mcclintick, S. Blanscet

32. Phosphorus and Organic Acid Bonding Impacts at Varying Soil pH

Phosphorus (P) fertilizer is essential for crop production, but reductions are warranted to conserve resources and minimize environmental impacts. Several lab, glasshouse, growth chamber, and field studies have been performed over the past six years with a new P fertilizer (Carbond P; CBP; Land View Fertilizer, Rupert, ID, USA) mostly in calcareous, low OM soil. Studies comparing CBP to ammonium polyphosphate (APP) and monoammonium phosphate (MAP) applied to soil show season-long increases in... T. Blair, C. Ransom, P. Hosford, J. Svedin, L. Sutton, A. Winchester, K. Manning, T. Hopkins, B. Hopkins

33. Siderophores to Increase Iron Availability

Siderophores are biologically produced low molecular weight amino acids that act to chelate metals. These can be generated by soil microorganisms and some plants, most notably grasses, also produce siderophores. These compounds are associated with improved availability of iron in the soil. This manuscript presents a survey of microbial siderophores present in soils under chlorotic and non- chlorotic ‘Concord’ grapevines. ... J. Davenport, A. Pollard, T. Sullivan

34. Ammonia Volatilization from Urea Vs. Alternative Nitrogen Fertilizers

Substantial ammonia (NH3) volatilization can occur from surface application of urea on sandy soils with low pH buffering capacity such as those in the semi-arid Columbia Basin. Previous studies have reported loss of up to 60% of urea-N as ammonia on these soils. The objective of this study was to quantify ammonia loss per acre for urea and for alternative N fertilizer products, including: sulfur-coated urea (SCU), urea coated with NBPT urease inhibitor (urea + Agrotain), ammonium sulfate... S. Del moro, D. Sullivan, D. Horneck

35. Manganese Nutrition and Photosynthesis of ‘Pawnee’ Pecan

Southwestern pecan (Carya illinoinensis) orchard soils are alkaline and calcareous which negatively affects manganese (Mn) availability for root uptake. Mn is essential for photosynthesis because of its roles in the photosystem II complex and chlorophyll biosynthesis. Levels of leaf Mn for optimum photosynthesis (Pn) in pecan is not known. Our objective was to characterize the relationship of widely different leaf tissue Mn concentrations on Pn. The experiment was conducted from 2011 through 2012... R. Heerema, J. Sherman

36. Nitrogen Cycling and Fertilization in Legume Inclusive Cropping Systems

Among other benefits, legumes contribute nitrogen (N) to subsequent crops. However, predicting the impact on yield and the timing of the N release is difficult. Regardless, adjustments in the N recommendation need to be made to avoid yield and crop quality problems, as well as negative environmental and social issues. Ideally, a reduction of pre-plant/early season N fertilizer is made based on field research. Two possible approaches are used, namely the Fertilizer Replacement Value (FRV) or the... B. Hopkins, J. Stark

37. Chloride Effects on Nitrogen Uptake in Potato Production

Potassium (K) can be supplied by potassium chloride (KCl) or sulfate (K2SO4) salts. Past research has shown that potatoes can take up and accumulate large amounts of chloride (Cl). Plant uptake of Cl can sometimes reduce petiole nitrate-N (NO3-N) concentration and it may have other effects on potato tuber yield and quality. In contrast, sulfate-S (SO4-S) typically does not compete strongly with NO3-N for plant uptake. This research was designed to evaluate the effect of Cl application on petiole... D. Sullivan, S. Light, D. Horneck

38. Nitrogen Nutrition Impact on Incidence of Rhizoctonia Infection of Agrostis Stolonifera

Creeping bentgrass (Agrostis stolonifera L.) is tolerant of short mowing and high traffic, but these conditions increase pathogen susceptibility. A prevalent disease on bentgrass golf course greens and tee boxes is Brown Patch (Rhizoctoniasolani). One potential component of integrated pathogen management is correct nitrogen (N) fertilization. Bentgrass was grown in a chamber hydroponically at deficient, optimum, and excessive levels of N (2.5, 10, and 80 mM; equivalent to 6.9, 27.5, and 220... B. Hopkins, B. Black, B. Neville, C. Ewell, B. Geary

39. Applying a Phosphorus Risk Index in a Mixed-use Mountain Watershed

Surface waters in the Wallsburg, UT watershed have been identified as a relatively high contributor of phosphorus (P) to nearby Deer Creek Reservoir. Identifying the major contributors of P is critical for developing effective management practices. Phosphorus Risk Indices have been widely developed as a tool to identify areas with high risk of P movement, but these tools have mostly been applied to watersheds dominated by agricultural land use. While agriculture is often a source of nutrient pollution,... A.W. Pearce, J. Johns, D. Robinson, N. Hansen

40. Summarization of 471 Field Comparisons of Avail®

Phosphorus (P) is a commonly deficient essential nutrient required for crop production. Economic, environmental, and conservation issues have motivated significant efforts to enhance fertilizer efficiency. AVAIL® is a specialty fertilizer product with claims of enhancing P use efficiency to potentially increase crop yield and quality. There have been at least 471 field comparisons to evaluate the effectiveness of AVAIL with a wide variety of crops. The objective of this summarization... B. Hopkins, K. Fernelius, M. Pryor

41. Turf Response to Reduced Rates of Polymer-coated Urea

Polymer-coated urea (PCU) is a controlled-release fertilizer which can enhance nitrogen (N) use efficiency (NUE), reduce N pollution, reduce the need for repeated fertilizer applications, and reduce turfgrass shoot growth and associated costs. A PCU fertilizer rated for 120 d was applied at 50, 75, and 100% of the recommended full rate and compared to an unfertilized control and urea, applied either all at once or split monthly at the full recommended rate. Spring applied PCU showed no initial... B. Hopkins, C. Ransom, M. Ruth, T. Blair, L. Sutton, D. Bradshaw, K. Campbell

42. Phosphorus and Organic Acid Bonding Enhances Uptake Efficiency and Yield Response in Crop Plants

Phosphorus (P) fertilizer is essential for crop production, but reductions are warranted to conserve resources and minimize environmental impacts. Several lab, glasshouse, growth chamber, and field studies have been performed over the past seven years with a new P fertilizer (Carbond P; CBP; Land View Fertilizer, Rupert, ID, USA) in calcareous, low OM soil. This paper will be a review of a portion of that data. Studies comparing CBP to ammonium polyphosphate (APP) and monoammonium phosphate (MAP)... B. Hopkins, T. Blair, J. Selman, C. Ransom, T. Hopkins

43. Nitrogen Budgeting for Organic Production

Nitrogen management for high value vegetable crops under organic management is challenging. Organic systems rely on N mineralization processes in soil to deliver nitrate-N in adequate amounts with appropriate timing. The traditional nutrient management planning process (checkbook method: matching nutrient supply and demand over a production cycle) contains too many assumptions for accurate forecasting of plant-available N supply for organic systems. Organic fertilizers fall into three... D. Sullivan

44. Sensor-based Technologies for Nitrogen Management in Spring Wheat

Crop sensor-based systems with developed algorithms for making mid-season fertilizer nitrogen (N) recommendations are commercially available to producers in some parts of the world. Although there is growing interest in these technologies by grain producers in Montana, use is limited by the lack of local research under Montana’s semiarid conditions. A field study was carried out at two locations in 2011, three locations in 2012, and two locations in 2013 in North West Montana. The objectives... O. Walsh, A. Pandey, R. Christiaens

45. Evaluation of Micro-carbon Technology-based P Fertilizer, Super Phos®, in Spring Wheat

Super Phos® (SP; 0-50-0) by Bio Huma Netics Inc. (Gilbert, AZ) is a Micro Carbon TechnologyTM – based phosphorus (P) fertilizer specifically formulated to resist “tie-up” with calcium (Ca) and magnesium (Mg) to remain water soluble and available to plant roots. The objective was to compare the efficiency and effectiveness of topdress and foliar application of SP, with traditional P fertilizers – ammonium polyphosphate (APP; 10-34-0), diammonium phosphate (DAP;... O. Walsh, A. Pandey, R. Christiaens

46. Environmentally Smart Nitrogen Performance in Northern Great Plains’ Spring Wheat Production Systems

Field trials were conducted at three locations in Montana to evaluate the efficacy of Environmentally Smart Nitrogen (ESN) (44-0-0) as a nitrogen (N) source for spring wheat. The ESN, urea (46-0-0), and a 50%-50% urea-ESN blend was applied at seeding at three rate levels - low, medium, and high - with actual rated dependent on the yield goal at each location, followed by urea application of 0 or 40 lb N/a at Feekes 5. Grain yield (GY) varied from 265 to 815 lb/a and grain protein (GP) content... O. Walsh, A. Pandey, R. Christiaens

47. Liquid N Fertilizer Evaluation in Spring Wheat

Several liquid N products are currently marketed for fertilization in various crops, including spring wheat. Urea ammonium nitrate (UAN) - the most commonly used liquid N fertilizer - is associated with crop damage due to corrosiveness. This study aimed to answer the following questions: (1) Are liquid urea (LU) and High NRG-N (HNRGN) superior to UAN in improving spring wheat grain yield and protein content? And (2) what is the optimum dilution ratio of foliar fertilizers and the threshold at... O. Walsh, A. Pandey, R. Christiaens

48. Nitrogen Transformations in Flooded Agroecosystems: a Case Study with Taro (Colocassia Esculenta)

Wetland agriculture covers an estimated 170 million ha and contributes significantly to global food supply. Nitrogen fertilizers are subject to numerous potential transformation pathways in flooded systems. The present research was focused on improving our understanding of N transformations in a flooded agricultural system by addressing the following two broad objectives: 1) determine whether the presence of anammox bacteria and its activity contribute significantly to N losses, and 2) evaluate... J. Deenik, C. Penton, B. Popp, G. Bruland, P. Engstrom, J. Mueller, J. Tiedje

49. Use of Non-replicated Observations and Farm Trials for Guiding Nutrient Management Decisions

Replication or repetition is the means by which experimental error is estimated in replicated trials. In farm trials, it is sometimes not possible to replicate demonstration and test plots due to manageability and costs. In these situations, non-replicated observations and on-farm trials are used. In addition, nutrient response studies are often needed to calibrate the fertilizer requirement of a field. In this paper, we will define on-farm trials and observations, discuss the nature and underlying... S. Machado, K. Girma

50. Exploring Controlled Release Nitrogen Fertilizers for Vegetable and Melon Crop Production in California and Arizona

Various forms of polymer coated urea (PCU) were examined as sources of controlled release nitrogen for production of cauliflower, watermelon, carrot, and spinach in Arizona or California. Studies were designed to demonstrate the effectiveness of PCU for supplying 100 percent of the fertilizer nitrogen needed for an entire growing season in a single pre-plant application. In each study, two or more N rates were tested. PCU having an appropriate release time for a given set of growing conditions... R. Smith, A. Blaylock, E. Ellison, C. Sanchez

51. Nutrient Efficiency Concepts for Phosphorus and Potassium

Two measures of phosphorus (P) and potassium (K) efficiency that are of interest to producers are agronomic efficiency (AE) and partial nutrient balance (PNB). Agronomic efficiency considers crop response to a nutrient addition while PNBmeasures nutrient removal to nutrient use. Proper evaluation of AE requires long term monitoring. A single, large application of P or K can, over many years, result in an AE similar to smaller, annual applications. A larger initial dose will increase... T. Murrell

52. On-farm Trials and Statistics

New technologies have made on-farm research easier to do. On-farm research networks exist in several states and are also being run by some national programs. These networks are becoming more common. University and/or government agency scientists and educators typically provide statistical expertise. Historical guidance for experimental design has focused on the randomized complete block design (RCBD). Statistical analyses that can be run easily are for an RCBD conducted in one site and one year.... T. Murrell

53. Polymer Coated Urea (Duration) in Turfgrass: Impacts on Mowing, Visual, and Loss to Environment

Fall and spring applied N fertilizer trials were conducted over two years in an effort to determine if various slow and controlled release N fertilizers were equivalent to traditional urea and to determine if a reduced rate of controlled release N could be used for improved N use efficiency. An unfertilized control was compared to sulfur coated urea (SCU), polymer and sulfur coated urea (XCU), polymer coated urea (Duration 75 or 125; DR) at 50, 75, and 100% (full) rate, and urea either applied... B. Hopkins, L. Sutton, C. Ransom, T. Blair, J. Moody, K. Manning, S. Bergsten

54. Development and Use of the OSU Organic Fertilizer and Cover Crop Calculator

Farm advisory visits in Oregon highlighted the need for decision tools to help farmers and agricultural professionals estimate nitrogen (N) mineralization from organic fertilizers and cover crops, design balanced fertilizer plans and identify the most cost effective nutrient management options. Laboratory and field research was conducted to develop N mineralization models for organic fertilizers and compost based on the total percent N. Field methods for estimating cover crop biomass and total... N. Andrews, D. Sullivan, J. Julian, K. Pool

55. Highbush Blueberry Response to Compost and Sulfur

Highbush blueberry is adapted to soils with high organic matter and acidic pH, and it is often grown in Oregon with coniferous sawdust as a soil amendment or mulch. Composts could provide an alternative to sawdust, but acidification is needed to overcome high pH. Our objectives were to (i) predict the quantity of acidity needed to reduce compost pH to 4.8 (ideal for blueberry), (ii) determine compost characteristics suited for blueberry, and (iii) evaluate plant growth response and soil pH response... D. Sullivan, R. Costello, D. Bryla, B. Strik, J. Owens

56. The Use of Biochar As a Fertility Amendment in Tropical Soils

Biochars made from modern pyrolysis methods have attracted widespread attention as potential soil amendments to improve plant productivity in the infertile soils of the tropics. Feedstock and pyrolysis conditions affect the physico-chemical properties of biochar with important implications for soil fertility and plant growth. Specifically, biochar volatile matter (VM) significantly affect soil inorganic nitrogen (N) status and ash content impacts soil elemental composition and pH. This paper highlights... J. Deenik, T. Mcclellan

57. Choosing Your Nitrogen Fertilizers Based on Ammonia Volatilization

Until recently we have not been able to measure ammonia volatilization without impacting the surrounding environment. In the past we have used closed chambers with acid traps. These closed chambers did not reflect surrounding weather conditions, at the minimum both temperature and wind were influenced. The use of the vertical flux method allows ammonia in the air to be monitored and modeled to reflect ammonia loss without any interference of the surrounding environment. ... D. Sullivan, D. Horneck, J. Holcomb, G. Clough

58. Ammonia Volatilization

Little work has been reported on the loss of ammonia from soils where fertilizers have been applied in an undisturbed environment. There are a multitude of studies that have used a chamber of some sort to estimate ammonia loss. The use of a chamber of some sort means that the environment has to be altered making the data derived suspect when translated into a loss number such as kg/ha. The advent of passive vertical flux method by Wood et al., 2000 at Aubrn University in Alabama, allows for the... J. Holcomb, D. Horneck, G. Clough, D. Sullivan

59. Predicting Plant-available Nitrogen Release from Cover Crop Residues

Improved methods are needed to estimate the timing and amount of plant- available N (PAN) release from cover crops. The OSU Organic Fertilizer and Cover Crop Calculator, a downloadable spreadsheet tool, assists agricultural professionals in estimating N fertilizer replacement value of organic inputs. We conducted a series of laboratory incubations with cover crop biomass incorporated into soil to determine: (i) speed of PAN release, (ii) amount of PAN release, and (iii) robustness of the OSU Calculator... D. Sullivan, N. Andrews, R. Datta, K. Pool

60. Polymer Coated Urea: Impacts on Water/air Quality with Surface Applicaton to Permanent Sod

Nitrogen (N) is the most commonly used fertilizer and is essential to sustain the world’s populations. However, inherent inefficiencies in the soil-plant system result in losses of N to air and water, which can result in environmental quality problems. Two permanent sod turfgrass sites were fertilized with coated and uncoated urea and compared to an unfertilized control at 224 lb-N/ac. The polymer coated urea (PCU) was Duration 45 CR®. Fertilization resulted in increased growth and verdure... B. Hopkins, J. Lemonte, J. Summerhays, V. Jolley

61. Micro-nutrients in Alfalfa Production: is There Need/opportunity for Cost Effective Management?

The management of soil fertility for optimum alfalfa productivity requires that all nutrient-related limitations be manipulated where warranted and cost-effective. It has been the policy of the Utah State University Analytical Laboratory to not promote soil testing for micronutrient sufficiency based on a lack of general need, historically, for nutrients such as sulfur, boron, zinc and others. This study undertook to accomplish two things, 1) to provide an initial inventory of micronutrient... G. Cardon, J. Barnhill, M. Pace, C. Israelsen, D. Miner, L. Greenhalgh, S. Banks, M. Shao, D. Rothlisberger, S. Olsen, P. Hole

62. Biochar Volatile Matter Content Effects on Plant Growth and Nitrogen Transformations in a Tropical Soil

Biochars made from modern pyrolysis methods have attracted widespread attention as potential soil amendments with agronomic value. A series of greenhouse experiments and laboratory incubations were conducted to assess the effects of biochar volatile matter (VM) content on plant growth, nitrogen (N) transformations, and microbial activities in an acid tropical soil. High VM biochar inhibited plant growth and reduced N uptake with and without the addition of fertilizers. Low VM charcoal supplemented... J. Deenik, A. Mcclellan, G. Uehara

63. A Low Volume Continuous Gradient Dosing System for Rapid Plant Response Screening

Early tolerance experiments required a tedious and time consuming delivery process that additionally limited the number of replications and treatments performed (DeMalach et al., 1996). Many treatment delivery systems have been used in tolerance screening experiments, the more flexible of these being a trickle irrigation system known as the double emitter source (DES), or double drip line system. The techniques of the DES were adapted in this study by providing for a larger number of treatment... A. Hawks, G. Cardon

64. Residual Soil Nitrate and Potato Yield with Polymer Coated Urea

Potato (Solanum tuberosum L.) requires steady, but not excessive nitrogen (N) supply for maximum tuber yield, size, and solids, as well as minimal internal and external defects. Although more costly and labor intensive than dry broadcast applications, growers typically apply a majority of N via fertigation. A controlled release N fertilizer, polymer coated urea (PCU), is a possible alternative to this growers’ standard practice. A newly formulated PCU may meet plant demand... B. Webb, B. Hopkins, J. Lemonte, T. Taysom, V. Jolley

65. Elemental Sulfur with Iron: Kentucky Bluegrass

Iron (Fe) is known to improve greenness of Kentucky bluegrass (KBG; Poa pratensis L.), although applications are relatively costly and labor intensive. A new fertilizer material, elemental sulfur impregnated with Fe (ES-Fe), may provide an alternative source of Fe for KBG. The effects of ES-Fe on KBG was evaluated comparing 55 lb-Fe ac-1 ES-Fe to ferrous sulfate (FS) at the same rate and chelated Fe as a foliar (CF) or soil applied (CS) in a glasshouse study. A separate... B. Hopkins, B. Webb, K. Marcroft, R. Christenson, V. Jolley

66. Biofuel Byproducts As Nitrogen Sources for Crops

The new development of ethanol and biodiesel plants in the United States is creating a large, and potentially excessive, quantity of byproducts in the forms of distillers grains and oilseed meals. The organic nitrogen (N) compounds in these byproducts rapidly mineralize in soils, showing the potential to be used as a N fertilizer source to plants. The objective of this research is to evaluate the application of biofuel byproducts on yield, size distribution, and nutrient uptake for Russet Umatilla... A. Moore, A. Alva, H. Collins, R. Boydston

67. Dig It! the Secrets of Soil a Primer on the Smithsonian Soils Exhibit

This past summer the Soil Science Society of America (SSSA) opened an exhibition entitled, “Dig It! The Secrets of Soil”. It resides at the Smithsonian Museum of Natural History in Washington D.C., and represents a huge step forward in our Society’s efforts to educate youth about soils and to pique their interest in studying soils. ... G. Peterson

68. Comparing Nutrient Availability in Low Fertility Soils Using Ion Exchange Resin Capsules and Plant Bioavailability Under Greenhouse Conditions

Commonly used soil resin analysis procedures have generally been developed to determine nutrient levels in agriculture soils. The purpose of the resin capsule procedure is to determine the amount of nutrient that correlates to that which is plant available. Desert soils contain lower levels of nutrients than agricultural soils, thus the validity of using resin capsules for desert soils is uncertain. In a previous incubation study it was determined that ion exchange resin capsules can be used as... B. Webb, B. Hopkins, M. Pletsch, D. Cook, M. Vickery, V. Jolley

69. Irrigated Small Grain Residue Management Effects on Soil Properties and Nutrient Cycling

The effects of straw removal from irrigated wheat and barley fields on soil properties and nutrient cycling is a concern due to its potential impact on the sustainability of agricultural production. The demand for animal bedding and the potential development of cellulosic ethanol production will likely increase straw demand in the future. Previous reviews addressing changes in soil properties when crop residues are removed focused primarily on rain-fed systems. This paper reviews published research... D. Tarkalson, B. Brown, D. Bjorneberg, H. Kok

70. Phosphorus and Zinc Interactions in Potato

Potato production requires high soil phosphorus (P) application with potential negative environmental and nutrient uptake effects. Impacts of high available P on species in potato cropping rotations are not adequately understood, nor have the causes of reduced yield and quality from excess P been fully explored. Antagonistic interactions with cationic micronutrients such as zinc (Zn) are plausible explanations. Two hydroponic experiments were conducted with Burbank potato to elucidate P and Zn... B. Webb, B. Hopkins, J. Ellsworth, S. Barben, B. Nichols, V. Jolley

71. Agronomic Biosolids Application Rates for Dryland Wheat Across a Range of Northwest Climate Zones

Predicting agronomic rates is important to derive optimum economic and environmental benefits from biosolids fertilizer applications. We conducted this research to 1) evaluate dryland wheat response to biosolids applications over a range of climate zones in the Pacific Northwest and 2) compare agronomic application rates predicted from yield curves with those predicted from published extension guidance. We applied a range of biosolids rates during the fallow year in ten on-farm dryland wheat experiments... A. Bary, D. Sullivan, C. Cogger

72. New Tools in Soil and Manure Test Information Interpretation in Utah

An effort is underway to update the USU Analytical Laboratory’s (USUAL) procedures and data presentation/interpretation capabilities. Modern database management tools and analytical instruments have, in many cases, gone under-exploited in reducing sample turn-around time, in improving data dissemination and interpretation, and in providing research and extension personnel with access to comprehensive historical and current trend data on soil fertility, and manure and plant analysis. This... G. Cardon, J. Kotuby-amacher

73. Non-destructive Measurement of Perennial Crop N Status

Little research has been conducted to evaluate the use on hand-held leaf meters as tools to assess plant N status in perennial crops. In this study, using replicated N rate plots in place for up to four years, we used two hand-held leaf meters (the Minolta SPAD meter and the Field Spec CM1000) to monitor tissue N status in apple and one meter (CM1000 only) in wine grape. In both crops, relationships were found between leaf meter readings and both fertilizer N rate as well as tissue N concentration.... J. Davenport, R. Stevens, E. Perry

74. Soil Testing to Improve Phosphorus Management on Intensive Vegetable Farms in Hawaii

According to a recent survey of soil samples sent to the Agricultural Diagnostic Service Center (ADSC) at the University of Hawaii between October 2002 and September 2003, a majority of the samples showed soil test P (STP) levels in the high or excessive categories. Despite high soil test P, many farmers in Hawaii continue to apply P fertilizers. We began a project to evaluate soil P status on a range of vegetable farms throughout the state, to determine crop response to P fertilizers on soils... J. Deenik, S. Fukuda, R. Hamasaki, R. Shimabuku, R. Uchida

75. Best Management Practices (Bmps) for Ammonia Emissions Reduction from Animal Feeding Operations: a Colorado Case Study

Ammonia emissions from agriculture are a growing concern, in particular, in Colorado where nitrogen deposition in Rocky Mountain National Park has highlighted public concerns. Due to the high level of political pressure on agriculture to reduce its emissions, the agricultural community in Colorado has recently developed a Rocky Mountain National Park Ag Strategy for decreasing ammonia emissions from agriculture and nitrogen deposition in the park. The strategy includes the completion of a thorough... J. G. davis, A. Elliott, N. Marcillac, J. Pritchett, C. Stewart, A. Mink

76. Optical Sensing for Nitrogen Management

Although nitrogen (N) nutrition is as or more important than other nutrients, it has been largely ignored by those applying variable rate fertilizer (VRF) due to its loss potential for VRF applications that occur many weeks prior to crop need. Applications of N are best applied as close to crop uptake as possible in order to avoid leaching, denitrification, and other losses. Spatial variability for crop N need is often considerable due to differences in yield potential and, to a lesser degree,... B. Hopkins, S. Stephens, A. Shiffler

77. Boron Fertilization in Potato

The high value of potato (Solanum tuberosum L.), its inefficient rooting system and the low organic matter content of sandy soils on which potatoes are cultivated result in widespread application of boron (B) and other micronutrients. However, in times of cost trimming, B may become an omitted input regardless of soil test values. Further, soil tests for B may need to be updated for higher yields, better management or improved soil test methods. Russet Burbank potato was grown at... B. Webb, B. Hopkins, J. Ellsworth, V. Jolley, R. Callahan

78. Cool Season Mineralization of Recalcitrant Organic N in Undisturbed Cores of Manured Soils

The objectives of this study were to (1) quantify cool season N mineralization from recalcitrant organic N in soils with a long history of manure application and (2) examine the relationship between cool season recalcitrant organic N mineralization and a fall mineralizable N index. “Cool season” was defined as October to February for fields with winter crops and October to May for fields with no winter crops. Two in situ trials were conducted with undisturbed soil... D. Moberg, D. Sullivan, R. Johnson

79. Evaluation of N Uptake Analysis As a Tool for Determing Potato N Status

Plant tissue testing has become the primary method for evaluating nitrogen availability for potatoes during the growing season. This study was conducted to determine if plant N uptake rates referenced to absorbed solar radiation could also be used as a tool to quantitatively assess plant N status of different potato varieties. Nitrogen fertilizer, as NH4NO3 (34-0-0), was applied to Russet Burbank, Gem Russet, Bannock Russet and Summit Russet at three rates (0, 100, or 300 kg N/ha) using two... J. Stark, S. Love, C. Mcintosh

80. Developing Extension Guidance for Management Effects on Ammonia Loss: a Computer Simulation Modeling Approach

Computer simulation models provide insight into ammonia loss processes and the sensitivity of ammonia loss predictions to environmental and management variables. As an example of how a simple computer simulation model can inform the Extension guideline development process, the ALFAM (Ammonia Volatilization from Field-Applied Animal Slurry) model was used to estimate NH3 loss from surface- applied municipal biosolids: liquid (3% dry matter) and dewatered (22% dry matter). Model output... D. Sullivan

81. Polymer Coated Urea in Potato Production

Nitrogen (N) is the most important mineral nutrient in potato (Solanum tuberosum) production. Studies show a steady, but not excessive, supply of N is important for maximum tuber yield, size, and solids, as well as minimal internal and external defects. Although more costly and labor intensive dry broadcast applications, growers typically apply the majority of N through the irrigation water in-season in order to maximize yield components. A controlled release N fertilizer, in the form of polymer-coated... B. Hopkins, T. Taysom, A. Shiffler, S. Stephens

82. Soil Zinc Application for Southwestern Pecan

Pecan trees grown in the alkaline soils of the southwestern United States are prone to zinc deficiency unless supplemental zinc is regularly applied. Standard treatment involves multiple foliar zinc applications. Soil zinc application would provide several advantages. A field study was initiated in 2005 with three soil zinc treatments: no zinc (control), ZnSO4 (74 kg.ha-1 Zn), or ZnEDTA (19 kg.ha-1 Zn) were applied one time in March, 2005 in bands 18 cm deep and 1.2 m on both sides... J. Walworth, A. Pond, H. Nunez, B. Wood, M. Kilby

83. Improved Small Grain Nitrogen Use Efficiency with California Site-specific Decision Support

Small 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 volatility,... N. Clark, M. Lundy, T. Nelsen, M. Leinfelder-miles, S. Light, G. Galdi, T. Getts, K. Mathesius

84. Monitoring Soil Nitrate to Estimate Cover Crop N Contribution in Organic Vegetable Production Fields

Organic vegetable growers rely on legume cover crops as an economical source of plant-available N. This research evaluated N contributions to summer vegetable crops by cover crops (CC) residues by monitoring soil nitrate (NO3-N) concentrations during the summer crop growing season. Replicated field plots were established with three CC mixes: solo common vetch (V),  phacelia + V (PV), and cereal rye + V (RV), plus a winter fallow (F) control in grower fields in the north Willamette Valley... D. Sullivan, N. Andrews

85. Performance of Public and Private Fertilizer Recommendations for Corn, Alfalfa, and Small Grains

There are many sources that growers utilize to determine fertilizer needs for crops such as private and public labs, crop advisors, and fertilizer dealers. In many cases, these sources provide recommendations for a specific crop that can vary greatly, and the resulting fertilizer and application rates recommended can lead to large differences in costs for the grower. Evaluating the effectiveness and economics of current fertilizer guidelines and recommendations will help growers to make better-informed... M. Yost, M. Baker, J. Gale, E. Creech, G. Cardon

86. Evaluating Zinc Requirements of Corn, Small Grains, and Alfalfa

Many growers and crop advisors in the Intermountain west have recently reported Zn deficiencies in major cereal and forage crops. Further, many common fertilizer blends now include Zn. Most Zn fertilizer guidelines indicate that 5-10 lbs of Zn per acre should be applied when critical soil test Zn levels are less than about 0.8 ppm Zn. These guidelines in Utah and many other states in the region were developed decades ago and need to be reassessed. Therefore, we established Zn response and rate... M. Yost, M. Baker, J. Gale, G. Cardon, E. Creech

87. Stacking 4R Nutrient Management: Potato

The 4Rs of nutrient management are research-based guidelines with the aim to improve the sustainability of major cropping systems and the environment without compromising crop yield and quality. The term “4R” represents fertilizer applied at the Right rate with the Right source, Right timing, and Right placement. The objective of this project is to evaluate the interactions of individual and combined 4R management practices. In 2020, potato (Solanum tuberosum L.) was grown... S.H. Stapley, C.C. Whitaker, N.C. Hansen, R.C. Christensen, R.R. Jensen, M.A. Yost, B.G. Hopkins

88. Biosolids-based Fertilizers as a Nitrogen Source in California Small Grains Systems

Situation/ conditions In response to regulatory and economic pressure, California growers are becoming more familiar with nitrogen budgets. In addition to seeking out ways to improve nitrogen management strategies, growers can possibly benefit by incorporating alternative sources of nitrogen to feed their crops. Liquid injected or pelletized biosolids-based fertilizers from local waste streams and processing facilities are one source that growers are beginning to explore. As... K. Mathesius, D. Geisseler, M. Savidge, M. Lundy, T. Nelson, N. Andersen

89. Helpful or Not?- Biostimulant Use in Corn Silage Production

There has been a recent increase in both the availability and marketing of biostimulant products to local producers, particularly to dairymen, in southern Idaho. These products claim to increase yield and nutrient use efficiency while improving soil health on agricultural fields. If these claims are true, the use of these products would ultimately aid in promoting the overall sustainability of Idaho farms. However, there is a lack of objective data to support these claims, leaving producers uncertain... L.R. Schott, S. Hines, J. Packham, G. Loomis, M. De haro marti, C. Willmore

90. Effects of Long-term Biosolids Applications in Two Dryland Agroecosystems on Physical, Biological, and Chemical Soil Health Properties

Biosolids can be important sources of organic matter to semi-arid dryland grain systems and have the potential to mitigate some of the soil health challenges specific to these areas while providing an alternative to synthetic fertilizers. Biosolids are an important avenue for beneficially reusing and redistributing nutrients from high population urban areas to more rural agricultural areas. We explored how long-term (20+ year) applications of biosolids at two field sites affected physical, biological... M. Desjardins, A. Bary, J. Ippolito, S. Cappellazzi, D. Liptzin, D. Griffin-lahue

91. ManureDB: Creating a Nationwide Manure Test Database

Manure nutrients serve an important role in crop production, however compared with commercial fertilizers there is a lack of standardized information. When exact manure values are not known, manure book values have been referenced. Recent data from midwestern United States (US) labs indicates manure nutrient levels have changed from book values published by Midwest Plan Service (2004) and American Society of Agricultural and Biological Engineers (2005). Manure laboratory analysis has improved... N.L. Bohl bormann, M.L. Wilson, E.L. Cortus, K. Janni, K. Silverstein, L. Gunderson

92. How Variable is Variable for Production Fields in Southern Idaho?

Idaho ranks in the top 10 in the US for dairy, potato, barley, hay, sugar beet, corn silage, and dry bean production. The highest producing areas in the state for these commodities are in Southern Idaho. Agricultural producers in this region, just like many other regions, are tasked with managing irrigation water and soil fertility on large fields with spatial heterogeneity in a way that results in homogeneous crop production.  Management... L. Schott, C. Robison, E. Brooks, D. Bjorneberg, K. Nouwakpo

93. Flushed Liquid Dairy Manure Solid Particle and Nutrient Distributions

Large dairies often use liquid manure handling systems because of their ease of mechanization and low labor requirements. Some of Idaho Magic Valley dairies use flushing systems that result in large amounts of liquid dairy manure that are applied via irrigation systems to adjacent cropland during the growing season. Solids and nutrients found in liquid dairy manure pose challenges to manure handling processes and cause environmental concerns. Separating solids and nutrients from liquid dairy manure... L. Chen, K. Kruger

94. Soil Greenhouse Gas Dynamics in Response to Dairy Manure Compost in an Almond Orchard

Application of dairy manure compost in soils under almond production may confer benefits such as increased carbon sequestration, improved crop nutrient use efficiency, and reduction of greenhouse gas emissions. Elucidating the mechanisms of greenhouse gas emissions and mitigation is a primary concern in the management of agricultural soils and it is directly linked to nutrient management. Presently, agricultural soils account for 11.2% of U.S. greenhouse gas emissions. Of particular concern is... A. Coyotl, J. Murch, S.S. Khalsa, W.R. Horwath

95. What You Need to Know About the National Fertilizer Recommendation Team Called FRST

The Fertilizer Recommendation Support Tool (FRST) team is a national effort to improve coordination of soil test recommendations in the United States. There are over 125 partners involved in FRST with representation of all four regional soil testing committees including WERA-103. The team has developed a national tool for P and K soil test calibrations (identifying critical soil test values for response to fertilizer), and are working on developing P and K calibration, tools for S calibration,... M. Yost, N. Slaton, J. Spargo, D. Kaiser, G. Buol, L. Gatiboni

96. Management Techniques to Optimize Soil pH in Organic Highbush Blueberry

A 3-year study was established in eastern Oregon, USA, in a new organic planting of ‘Duke’ northern highbush blueberry (NHB) to evaluate soil acidification methods. Six techniques of applying elemental sulfur (S) prills, with or without additional acidification of irrigation water were tested. Treatments consisted of: 1) a grower standard of soil incorporated S prills at 1700 kg·ha-1 applied 8 months pre-plant; 2) 8-weeks of fertigation totaling 150 kg·ha-1... S. Lukas, S. Singh

97. Soil Test Method Precision, Correlations, and Trends: SSSA-NAPT Historical Data

The Soil Science Society of America’s (SSSA) North American Proficiency Testing (NAPT) operates as a not-for-profit service laboratory resource since 1998 to assist/evaluate agricultural and environmental testing laboratories with quality assurance and quality control. Soil (n5 samples each quarter), plant (n3), and/or water (n3) samples collected nationwide are submitted quarterly to ~150 participating laboratories who choose which method(s) to use for which analytes they are interested... B. Hopkins, S.V. Nelson, G. Cardon, J. Lawley, T.J. Hopkins

98. Soil Property Effect on Nitrogen Mineralization of Dairy Manure in the Pacific Northwest

Growers often use total nitrogen (N) concentration of dairy to manure to estimate plant available N for crop production. This estimate, however, ignores the role that soil properties may have on N mineralization (Nmin) rates. This study aims to determine how soil physiochemical properties impact Nmin rates of dairy manure and composted dairy manure by aerobic incubation. Sixteen soils, sampled from 0-12 inch depths (0-30.5 cm) were collected from dairy production regions in Oregon, Washington,... R. Auld, A. Moore, J. Moore, Y. Zhang, C. Rogers

99. Effectiveness of Kitchen Compost in Germinating Tomato and Lettuce

Food waste in developed countries is a large input to landfills. Ideally, it is composted and added to soil on-site to reduce environmental impacts. A “kitchen composter” (ReencleTM) effectively decomposes waste within 24 hours (>90% reduction in mass), followed by formation of stable compost within a few weeks after curing outside the composter. Our preliminary research demonstrates that the compost has excellent nutrient composition. However, it was not adequately cured,... B. Hopkins, R. Kerr, S.V. Nelson

100. Quinoa Mineral Nutrient Deficiency Symptoms and Concentrations

Major crop nutrient symptoms are well documented. In contrast, there is often minimal or no similar information for minor crops, including quinoa (Chenopodium quinoa Willd.). This knowledge gap can be efficiently filled by using hydroponic systems. However, creating multiple nutrient deficiencies with plants in the same study is challenging because nutrients are often added as dual nutrient salts. For example, if potassium sulfate is the potassium (K) source, varying K concentrations... B. Hopkins, G. Bell, S.V. Nelson, R.E. Sannar

101. Ammonia Recovery from Anaerobically Digested Dairy Wastewater Facilitated by In-situ Acid and Base Generation in a Transmembrane Electro-chemisorption System

Nitrogen (N) is essential for living organisms and is a critical element in agricultural production. Ammonia (NH₃), a vital component in the nitrogen cycle, can be produced naturally by nitrogen-fixing bacteria or artificially through the energy-intensive Haber-Bosch process. Anaerobically digested dairy wastewater (ADDW) could contain high concentrations of ammonia nitrogen (NH3-N) due to the conversion of organic N into NH3-N during the anaerobic digestion process. Ammonia... A.K. Das, L. Chen

102. Hydrothermal Carbonization of Dairy Manure for Phosphorus Recovery and Runoff Risk Mitigation: Effect of Temperature and CaO Addition

Dairy manure contains a significant amount of phosphorus (P) and nitrogen (N), which are essential for soil fertility and crop productivity, but are currently underutilized due to ammonia emissions, P runoff and leaching, and manure N to P ratios do not match crop nutrient needs. Meanwhile, there is a growing concern about P depletion as a non-renewable resource. To address both the excessive use of synthetic P fertilizers and inefficiently direct use of dairy manure, a logical strategy is to... M. Islam, B. He, L. Chen

103. Efficacy of FUSN as an N Source for Irrigated Vegetable Crops

The Department of Homeland Security Ammonium Nitrate Security Program regulates the distribution and sale of granular ammonium nitrate fertilizer (AN).  Due to the bureaucracy of these regulations, the sale of dry AN has been discontinued in many areas.  While liquid AN20 remains available, there is a preference for granular fertilizer for many agricultural applications.  FUSN (20-0-0-14S) is a Honeywell and JR Simplot proprietary technology whereby ammonium nitrate is fused with... C. Sanchez

104. Response of Desert Vegetable Crops to “40 Rock”- a P and Zn Fertilizer Source

Crops produced on calcareous soils in low desert region of the southwestern United States show a large response to P fertilizer.  The most commonly used P source has been mono-ammonium phosphate (MAP or 11-52-0).  These same soils are also reported to be marginal with respect to Zn availability but responses to Zn fertilization had been infrequent in the past.  More recently, we have observed crop responses to Zn fertilization with increasing frequency and we have revised Zn fertilizer... C. Sanchez

105. Updated Fertilizer Guidelines for Vegetable Crops in Arizona

The vegetable production industry in the lower Colorado River region of Arizona is valued at over 19 billion dollars.  Comprehensive fertilizer guidelines for vegetable crops historically produced in Arizona had not been updated in decades.  Furthermore, we had no data to support guidelines for newer vegetable crops introduced into the region during the past two decades. The updated guidelines consolidate decades of research, incorporating historical databases, augmented with relevant... C. Sanchez

106. Banana Fiber as a Soil Amendment in Potato and Corn

Banana (Musa spp. L.) pseudostem fiber has unique properties that may prove helpful in plant and soil management, including a high water holding capacity. Increased capacity could be useful in water conservation efforts in areas experiencing long-term drought. In the agricultural space, banana fiber could be used to maintain soil moisture, thus lowering the frequency and/or amount of irrigation. The objectives of irrigated field studies in Provo, UT, USA were to measure the impact of... B. Hopkins, M.J. Foster, S.V. Nelson

107. Plant Test Method Precision, Correlations, and Trends: SSSA-NAPT Historical Data

The Soil Science Society of America’s (SSSA) North American Proficiency Testing (NAPT) operates as a not-for-profit service laboratory resource since 1998 to assist/evaluate agricultural and environmental testing laboratories with quality assurance and quality control. Soil (n = 5 samples each quarter), plant (n = 3), and/or water (n = 3) samples collected nationwide are submitted quarterly to ~150 participating laboratories who choose which method(s) to use for which analytes they... S.V. Nelson, J. Lawley, T.J. Hopkins, G. Cardon, B. Hopkins

108. A Classification System for Assessing Applied N Performance in Dryland Wheat Crops of the Inland PNW

Wheat crops in the inland Pacific Northwest demand nitrogen (N) fertilizers at high levels to achieve yield and grain protein objectives. Inefficiencies in N use can accelerate soil acidification, contribute to N2O emissions and result in unnecessary input costs. More precise applications, using wheat performance maps at the field-scale, could lead to increased N use efficiency but requires a multidimensional assessment of performance including grain protein, yield, and N efficiency.... D. Huggins, J. Casanova, C. Phillips