The unique, hilly topography of the inland Pacific Northwest causes great within-field variability in soil and water conditions. As a result, crop yield potential and crop response to nitrogen (N) applications will vary according to the hillslope position, steepness, and aspect of any planted location. Thus, variable rate N (VRN) application makes sense for growers in this region.
In a recently published case study, Variable Rate Nitrogen Application: Eric Odberg, a grower from Genesee, Idaho, shares his 10 years of experience using VRN application in a direct seeding (no-till) system. Although transitioning to VRN application is a big decision with many challenges along the way, Eric’s 10 years of experience has brought him numerous benefits. These benefits include reduced fertilizer input, reduced lodging, reduced risk of N losses to the environment, and increased financial gain. Furthermore, because Eric complements VRN application with direct seeding and diversified crop rotations, his farm’s soil quality has also improved.
For questions or comments, contact Georgine Yorgey (firstname.lastname@example.org) or Sylvia Kantor (email@example.com) at the Center for Sustaining Agriculture and Nature Resources, Washington State University, or Kathleen Painter (firstname.lastname@example.org) at the Department of Agricultural Economics and Rural Sociology, University of Idaho.
The winter of 2016-17 has been unusually long compared to the past few years, and the prolonged snow cover has raised concerns over potential for snow mold development in eastern Washington. On the Waterville Plateau in Douglas County where snow mold of wheat has been a chronic occurrence since the 1940s, snow has been on the ground for nearly 100 days since sometime in early November. In Pullman, near the opposite corner of wheat producing area, snow has covered the ground continuously since December 6, or about 60 days. Snow cover is like putting a blanket on your bed – it keeps the warmth in and the cold out. For the wheat crop, a blanket of snow cover provides a layer of insulation that helps wheat plants survive the winter by protecting them from bitterly cold temperatures and wind that can result in winterkill. However, if the snow stays too long, the potential for damaging snow mold can occur.
Snow mold is a generic name for any one of several diseases that can develop on wheat under snow. The pathogens that cause these diseases are specialized and able to grow in the wet, near-freezing environment under the snow and destroy most of the aboveground foliage. In eastern Washington, snow mold can be caused by one of four different fungal or fungal-like pathogens; however, speckled snow mold and pink snow mold are the most common and destructive. Speckled snow mold is the most destructive disease in eastern Washington and needs about 100 days of continuous snow cover with unfrozen soil before damage is likely to occur. This disease is most common in the wheat-growing area north of highway 2 beginning about Almira west to Waterville. Pink snow mold can occur alongside speckled snow mold, but is favored by slightly wetter conditions and usually doesn’t cause damage to wheat over large areas. Pink snow mold is more widespread than speckled snow mold because it doesn’t require as much snow cover to develop, so it’s also common in golf course turf and home lawns. There is another snow mold fungus that resembles the speckled snow mold fungus that occurs widely in eastern Washington; it is often called gray snow mold or Typhula root and crown rot because it often develops below ground and is distinguished by the reddish-colored speckles that develop on infected plants. This disease causes little damage to wheat, but can be very destructive to winter barley.
Most growers in the traditional snow mold area know that planting a resistant variety early is the best way to control snow mold. Outside of the Waterville Plateau, pink and gray snow mold likely will be apparent in some spots when the snow melts. However, they are unlikely to cause significant damage where snow cover was less than about 8” deep because the near-zero temperatures we experienced in late December and early January will have frozen the soil, which limits disease development. It is also likely that there will be some leaves killed by the cold temperatures. To determine whether snow mold was the cause, look closely at the dead plant parts for evidence of a cob-web-like growth on the surface. With pink snow mold, plants will have a salmon-pink color soon after snow melt; the color will fade leaving brown-colored tissue. For the speckled snow molds, evidence of disease is the presence of dark-colored survival structures known as sclerotia. Plant parts killed by cold may appear light brown or bleached without any of the signs of snow mold. Samples can also be submitted to Plant Pest Diagnostic Clinic for confirmation.
For more information, consult extension bulletin Snow Mold Disease of Winter Wheat in Washington (EB1880) available under publications in the Disease Resources section of the WSU Wheat and Small Grains website.
Soil water recharge and storage is important in the inland Pacific Northwest because approximately 70% of the region’s precipitation occurs between October and March. Of this 70%, approximately 35% is in the form of snow. Trapping more snow can increase soil water storage for the growing season and also provide insulation to protect plants from winterkill.
In the unique, hilly topography of the Palouse, ridge tops and south-facing slopes generally retain the least amount of snowpack and valley areas retain the most. This variable snow distribution is mainly caused by wind induced snow drifting and snowmelt runoff. These differences in depth and duration of snowpack can cause substantial spatial variation in soil-water availability. In addition, the excessive water in areas with heavier snow accumulations can cause nitrogen loss from leaching, runoff, and denitrification.
The redistribution of snow by wind and water can be substantially reduced by leaving crop residue standing and practicing no-till. At all topographic locations, no-till retains more soil water with less spatial variation in snow depth than conventional tillage. Compared with chopped residue left on the soil surface, standing crop residue such as wheat and sunflower stubble is more effective not only for reducing wind speed and evaporation, but also for increasing snow catch. In no-till, snow catch generally increases as stubble height increases.
One research project, conducted in the Palouse near Pullman, Washington, compared a no-till field with a conventionally tilled field during multiple snow events and after snowmelt in spring. Compared with the conventionally tilled field, no-till ridge tops with standing wheat residue at 3.5 to 13 inches tall retained 3.9 to 4.7 inches more snow. Similarly, no-till south-facing slopes with standing wheat residue at the same height retained 3.9 to 5.5 inches more snow. By spring, the no-till field stored 2.4, 1.1, and 0.5 inches more water in the 5-foot soil profile at ridge tops, south-facing slopes, and valley locations, respectively, compared to the conventionally tilled field. Another project, a long-term study in Saskatchewan, Canada, concluded that leaving 35 to 47 inch-wide strips of standing stubble residue, about 16 to 24 inches tall every 20 feet, trapped 1.6 times more snow than shorter stubble at 12 inches tall.
Tall standing stubble, achieved by harvesting with a stripper header and leaving stubble at full-crop height, can conserve water and reduce residue decomposition rates. Tall standing stubble is especially important for sparse stands. A 4-year study conducted in a low-rainfall area near Ralston, Washington, found that this practice can reduce soil surface temperatures and also slow soil surface wind speeds to less than one half of the average. The stripper header-managed winter triticale stubble also preserved greater amounts of soil moisture and resulted in more uniform soil moisture conditions in the 0 to 3-inch seed zone. These improved moisture conditions allow for timely planting and establishment of fall-seeded canola. Another 5-year study in Fort Collins, Colorado, also concluded that tall standing residue provides numerous benefits, including increased snow trapping; decreased decomposition rates, wind speeds, weed pressure, and soil temperatures during the fallow period; and substantially reduced within-field variation in snow cover and water storage.
These two articles discuss strategies of soil and water conservation in Pacific Northwest region: Crop Residue Management To Reduce Erosion and Improve Soil Quality and Soil and Water Challenges for Pacific Northwest Agriculture.
For questions, comments, or more information, please contact Dr. Haiying Tao (email@example.com), Assistant Professor in the Department of Crop and Soil Sciences at Washington State University.
The Wheat and Small Grains website has been updated to include a brand new page on grain quality. The Grain Quality Resources page was unveiled last month and will serve as a platform to deliver information related to the end-use quality of cereal grains.
Current information on the website includes falling number resources, the Preferred Wheat Varieties brochure, and information on some of the different market classes of wheat produced in the Pacific Northwest.
For the past 100+ years soil health has been declining across the Inland Northwest. This is not a problem just within the Inland Northwest but a global issue. Soil is the number one most important unit for sustaining agriculture production. A focus must be made to protect and enhance our productive soil for efficient and economically viable agriculture production for many generations to come.
On February 16 and 17th, soil health workshops will be held in Spokane and Walla Walla, Washington.
Mirabeau Park Hotel & Convention Center
1100 N Sullivan Road
Spokane Valley, WA 99037
The Marcus Whitman Hotel
6 West Rose Street
Walla Walla, WA 99362
Soil health and soil quality are two synonymous terms that are defined interchangeably by the Natural Resources Conservation Service (NRCS) as follows: “Soil health, also referred to as soil quality, is the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans”. As a complicated bioecological system, soil is a living system with an abundance of diverse bacteria, fungi, and other microbes that have significant effects on soil physical and biological properties. Healthy soils provide a healthy physical, chemical, and biological environment for optimal crop growth.
Inherent soil properties that contribute to soil health, such as soil texture, are determined by the natural parent material and the environmental conditions during soil formation, in the absence of human impacts. Soil health is dynamic, rather than static, and can be degraded or improved with time as a result of soil use and management by humans. Soil degradation causes soil organic matter, fertility, structure, and biodiversity to decline and soil acidification to increase. As a result, crop productivity can decrease, crop diseases and weed problems can increase, and environmental quality can suffer.
Building soil health is becoming increasingly important worldwide. Soil imbalances in essential crop nutrients can be addressed by applying fertilizer and organic amendments. And soil chemical, physical, and biological properties can be significantly improved by adopting management practices such as no-tillage or reduced tillage.
A recently published article, Best Management Practices for Summer Fallow in the World’s Driest Rainfed Wheat Region, compares the effects of three fallow management practices on soil water dynamics, wheat stand establishment, grain yield, and economic returns. This research was conducted on two farms in the driest rainfed wheat production region in Washington (WA). At the drier site, results from the 5-year study indicated that late-planted winter wheat on no-tillage fallow was as profitable as on tilled fallow. Additionally, the study found that, at the slightly wetter site, undercutter tillage resulted in equal or greater grain yield compared with both traditional tillage and no-tillage.
Another recently published article, Wheat Farmers Adopt the Undercutter Fallow Method to Reduce Wind Erosion and Sustain Profits, surveyed 47 farmers who had been practicing undercutter tillage for several years. Farms were located in the low-rainfall (< 12 inches annually) zone of east-central WA and north-central Oregon (OR). Interviewers asked farmers to compare the agronomic and economic performance between undercutter tillage and conventional tillage. Results of this survey concluded that, on average, undercutter and conventional tillage systems have equal profitability. However, the undercutter system offers a costless air quality gain and a soil health benefit in terms of reducing wind erosion.
For questions or comments, contact Dr. Douglas L. Young (firstname.lastname@example.org), Professor, in the School of Economic Sciences, or Dr. Bill Schillinger (William.email@example.com), Professor, in the Department of Crop and Soil Sciences at the Washington State University.
The 2016 WSU Weed Control Report is now available on the Wheat and Small Grains website. The annual report summarizes the results from field studies conducted by Ian Burke, Drew Lyon, and their staff. Financial support for the studies was provided by the Washington Grain Commission, the USA Dry Pea & Lentil Council, the Mel & Donna Camp Endowment, and by several agrichemical companies. The research was conducted in winter wheat, spring wheat, chemical fallow, grasslands, alfalfa, chickpeas, and dry pea.
Weeds investigated in 2016 included rattail fescue, mayweed chamomile (a.k.a. dog fennel), catchweed bedstraw, rush skeletonweed, Russian-thistle, common lambsquarters, wild oat, Italian ryegrass, downy brome, smooth scouringrush, and volunteer buckwheat. Two studies looked at Talinor, a new herbicide from Syngenta, in winter wheat. Several studies were conducted in chickpea to look at pyridate, previously sold as Tough herbicide, and paraquat applied at the cracking stage. Neither option is currently labeled for use in chickpea, but you can see what the potential for these treatments are. Data from these studies may be used to help support possible labeling in the future.
In addition to the 2016 report, annual reports dating back to 2013 are on the Wheat and Small Grains website.
For questions or comments, contact Dr. Drew Lyon at firstname.lastname@example.org or 509-335-2961.
Oilseeds, such as canola, are recognized as rotational crops that can benefit the agro-ecological and social-ecological systems within the traditional wheat-based cropping region of the inland Northwest Pacific. Although farmers can continue to use wheat-based farm equipment, management practices need to be adjusted specifically to canola physiology and morphology to optimize yield and quality.
A recently published article, Physiology Matters: Adjusting Wheat-Based Management Strategies for Oilseed Production, compares the physiological and morphological characteristics between wheat and oilseeds. Characteristics studied included the differences in seed size, shoot meristem, cold tolerance, and above and below ground morphology. Based on these differences, the article provides recommendations for modifying wheat management strategies, for example, planting date and fertility management, for canola production.
As many of you know, the 2016 crop season was very favorable for stripe rust due to the mild winter and early spring with temperature and moisture conditions that were favorable for rust development. In some cases, this resulted in severe rust in fields planted to susceptible varieties and/or multiple fungicide applications to limit rust damage. Following harvest, early rains resulted in good seeding conditions through much of our area and the fall wheat crop emerged and was infected by stripe rust spores from late-maturing fields. Consequently, stripe rust was well-established in many winter wheat fields heading into winter of 2016-2017.
Overwintering stripe rust infections are nothing new; stripe rust potential in spring depends on how well the rust survives over winter, with mild winter temperatures resulting in greater survival than cold temperatures. Dr. Chen, USDA-ARS Research Plant Pathologist in Pullman, uses models based on average temperatures from November to February to predict rust severity and just released his first stripe rust forecast of the 2017 season last week. The current forecast is positive with stripe rust predicted to be in the low range, i.e. 6% yield loss on susceptible varieties. Although this is good news, it needs to be tempered by the fact that Dr. Chen’s models don’t account for snow cover, which insulates the rust from cold temperatures. Many areas of eastern Washington have had protective snow cover since the middle of December. Rust potential going forward depends on how long the snow cover persists and temperatures through February. As a result, we won’t really know how well the rust survived and the potential for rust until winter has broken.
Stay tuned for more rust updates as conditions change. In the meantime, you can find additional information on stripe rust, including photos showing rust percentage, under the Foliar Fungal Diseases in the Disease Resources section of the WSU Wheat and Small Grains website.
Contact Tim Murray for questions/comments at email@example.com or 509-335-7515.
The first case of jointed goatgrass resistant to imazamox, the active ingredient in Beyond herbicide, has been confirmed in Eastern Washington. A team of Washington State University scientists, led by Dr. Ian Burke, publicly announced their findings in the January 2017 issue of Wheat Life magazine.
Clearfield wheat varieties were first planted in Eastern Washington on a widespread basis beginning in the fall of 2003. The fact that it has taken 13 years to discover the first imazamox-resistant jointed goatgrass biotype is a bit of a surprise. Ian Burke said “If you had asked me back when I started working on this in 2006 when to expect to see resistance to Beyond in jointed goatgrass, I would have said ‘we should see it already!’”
The resistant biotype is 144 times more resistant than susceptible goatgrass plants. To see even a little response in the resistant plants, researchers had to use 6x the labeled use rate of Beyond. Jeannette Rodriguez, a WSU graduate student, is working to identify the mechanism of resistance. It is known that resistance in this instance was not the result of a cross between Clearfield wheat and jointed goatgrass.
Growers and fieldmen should scout jointed goatgrass patches in fields that they manage and submit samples that they have concerns about to the WSU Herbicide Resistance Testing Program. The Extension publication “Strategies to Minimize the Risk of Herbicide-resistant Jointed Goatgrass” provides information on the control of jointed goatgrass with an emphasis on prevention and management of herbicide resistance.
BASF issued the following statement in response to this discovery: “BASF is supporting WSU research aimed at preserving the long-term benefits of the Clearfield® Production System – with an emphasis on resistant jointed goatgrass. A multifaceted resistance management program is essential to preserve the long-term benefits of Beyond herbicide and the Clearfield Production System. Wheat producers are asked to help protect and prolong the usefulness of these technologies by following the specific recommendations and requirements highlighted in the Clearfield Stewardship Guidelines to help prevent the onset of herbicide resistance in weeds.”
For more information, contact Dr. Ian Burke at firstname.lastname@example.org or 509-335-2858.