1998 Table of Contents

1998 STEEP III Progress Report

PRINCIPLE INVESTIGATOR: Richard Smiley, Oregon State University, Pendleton

COOPERATORS: STEEP III scientists in research projects near Pilot Rock and Ralston

Pilot Rock Project -- PI=s: Dan Ball (OSU, weeds), Penny Diebel (OSU, economics and risk), Don Wysocki (OSU, fertility & crop residue), Bill Payne (OSU, agronomy). Coops: Bob Adelman (NRCS, conservation compliance), Tom Golke (NRCS, technology transfer), Dick Smiley (OSU, diseases), Mike Stoltz (OSU, aphids & tours), Dale Wilkins (ARS, weeds). Grower Advisory Comm: 6 growers. Funding: STEEP III, OSU, USDA-ARS, Oregon Wheat Comm., and agribusiness.

Ralston Project -- PI=s: Frank Young (USDA-ARS, weeds), Kim Kidwell (WSU, spring wheat), and Bill Pan (WSU, soil fertility, crop residue, & water). Coop=s: Rich Alldredge (WSU, design and analysis), John Burns (WSU, tours & meetings), Steve Clement (ARS, aphids), Ann Kennedy (ARS, residue decomp.), Gary Lee (UI, weeds), Bob Papendick (PM-10 Coord.), Bill Schillinger (WSU, water), Dick Smiley (OSU, diseases), Steve Ullrich (WSU, barley), Roger Veseth (UI, education & publicity), Doug Young (WSU, economics and risk). Grower Advisory Comm: 12 members including representatives of the Wash. Wheat Comm. and Wash. Assoc. of Wheat Growers. Funding: STEEP III, USDA-ARS, WSU, OSU, Wash. Dept. of Energy (PM-10), Wash. Wheat Comm., Oregon Wheat Comm., agribusiness, and Adams, Lincoln, & Whitman Co.

Oregon ASatellite@ Experiments -- PI: Dick Smiley. Coop=s: Russ Karow (OSU, Cereals Extension), Penny Diebel (OSU, Ag Economist), Lisa Patterson, Karl Rhinhart, & Erling Jacobsen (OSU technical staff), and Farmer-Cooperators Frank & Yvonne Mader and Tim & Shannon Rust.

PROJECT OBJECTIVES:

1. Quantify the impact of diseases in the STEEP III APilot Rock@ and ARalston@ projects.

2. Develop disease management recommendations that reduce constraints to adoption of

resource-conserving annual cropping systems in low-rainfall regions.

KEY WORDS: wheat, barley, diseases, cropping systems

STATEMENT OF PROBLEM: Most dryland wheat in low rainfall regions of the Pacific Northwest (PNW) is produced in a winter wheat/summer fallow rotation. The fallow system reduces soil quality, increases soil erosion, and is plagued with winter-annual weeds, surface crusting, and diseases of early planted wheat. Each of these conditions could be resolved by including spring crops in the rotation. Primary impediments to diversified annual cropping have been more erratic crop yield due to rainfall variability, non-profitable adapted crops, and dis-incentives placed on crop rotation by Federal farm programs. Two STEEP III teams are examining annual cropping systems to further reduce the amount of land fallowed between winter wheat crops. Changes in the prevalence and importance of diseases is anticipated with changes in crop management systems. Diseases must be considered as new management practices are developed.

ZONE OF INTEREST: Agronomic Zones 4 and 5; low rainfall (9-16 inch) areas of Oregon and Washington, where winter wheat is rotated mostly with summer fallow.

ABSTRACT OF RESEARCH FINDINGS: The spectrum and intensity of diseases often shifts in concert with changes in cropping systems. The objective of the pathology team is to monitor diseases in each treatment and season, and to suggest modifications, if necessary, to minimize damage and economic loss from diseases. Special emphasis is given to root diseases known to occur in the semi-arid region, especially Rhizoctonia root rot, take-all, and Fusarium foot rot. Root diseases damaged wheat and barley in experiments near Ralston, WA and Pilot Rock, Echo, and Moro, OR. Benefits of crop rotation were shown at Ralston and Pilot Rock. Benefits of wheat cultivar selection, applying a seed treatment insecticide, and placing starter fertilizer directly below the seed at the time of planting were shown at Echo and Moro. Experiments are being continued and refined to capture the benefits detected each year these trials are conducted. Inputs and output data from all four locations are now being subjected to economic analysis.

RESULTS AND INTERPRETATION:

Objective 1. Diseases in the Pilot Rock and Ralston Projects:

Pilot Rock Project -- Replicated on-farm research was conducted on two shallow soil sites in a 12-inch rainfall zone near Pilot Rock OR. Scientists, extension agents and growers met in 1993 to establish experimental parameters. Rotations were established with farm-size equipment during the spring of 1993. Duplicate sites (Gilliland and Shaw farms) contain four replicates of plots in randomized complete blocks. Best management practices are used for tillage, residue management, fertilizers, varieties, pesticides and planting dates. Data is managed centrally to facilitate economic and risk analysis, and an integrated result. Seven systems are being compared: continuous no-till spring wheat, spring barley-fallow-winter wheat with conventional or chemical fallows, fallow-canola-winter wheat with chemical fallow, and winter wheat-fallow with fallow prepared by moldboard plow, chisel, or herbicides. Annual no-till hard red spring wheat is being evaluated as an additional treatment at the Shaw farm. The goal of the study is to examine difficulties that may be encountered by converting the moldboard plow-based wheat-fallow system to a higher residue and/or a more intensive cropping system. Evaluations include pest and agronomic considerations, profitability and economic risk, and compliance with conservation regulations.

Winter and spring wheat plants were collected on February 25 and June 1, 1998, respectively. Plants were taken to the laboratory at Pendleton for identification and quantification of diseases on roots, crowns, and foliage. Data was submitted to the project director (Dan Ball) for incorporation into the master databank. Grain yields and other results for this project are reported in Dr. Ball=s STEEP III progress report.

Emphasis during early years was given to establishing benchmark observations for diseases present in crops produced on these fields. During the latter portion of the six-year experiment the intensity of sampling was increased to focus on differences in plant health in each treatment. Data sometimes failed to provide clear differences among treatments when viewed in isolation at a single site during a single year. It was only after the majority of the experiment was completed at both sites that important trends became evident. Stress from diseases was reduced by longer-term rotations away from cereal crops, and was amplified by shorter rotations and higher amounts of surface residue.

The Shaw farm experiment was started one year later than at the Gilliland farm. As such, comparisons of similar treatments at the two sites are offset by one year; e.g., data from the Gilliland and Shaw farms for the 1995 and 1996 crop years represent the same experimental treatments for this experiment.

During 1995 and 1996 there was a comparison of three 3-year rotation treatments: winter wheat produced in a winter wheat/spring barley/summer fallow rotation (tillage vs chemical fallow), and in a winter canola/winter wheat/summer fallow rotation. Rhizoctonia root rot and take-all tended to be more damaging in rotations that only included cereal crops than in the rotation that included canola. This trend was not statistically significant at the Gilliland farm (1995) but was significant at the Shaw farm (1996). Other diseases were present in minor amounts but none differed among treatments.

During 1996 and 1997 there was a comparison of winter wheat in three 2-year rotation treatments: winter wheat/summer fallow (tillage fallow), and winter wheat/summer fallow (tillage vs chemical fallow). The only differences among treatments at the Gilliland farm (1996) was that Rhizoctonia root rot was slightly more damaging in the conservation tillage systems than in the moldboard plow system. There were no differences among treatments for any of the diseases at the Shaw farm during 1997.

All six primary treatments at the Gilliland farm were planted to winter wheat in 1998; this will occur at the Shaw farm in 1998-1999. At the Gilliland farm take-all was more damaging in the 2-year rotations where conservation tillage had been practiced, as compared to using the moldboard plow. In the 3-year rotations take-all was less damaging (almost non-existant) where canola was included as the second crop, rather than spring barley. Rhizoctonia root rot was also least damaging where canola was inserted into the rotation, as compared to all other treatments. Strawbreaker foot rot was most prevalent in the 2-year chem-fallow rotation treatments and least prevalent in the rotation that includes canola.

Annual no-till hard red spring wheat at the Shaw farm was heavily damaged by Rhizoctonia root rot (93% plants infected; severity of 3.1 on a 5.0 scale). Take-all was also damaging but was present on fewer plants (16% plants infected; severity of 3.2 on a 5.0 scale). Root lesion nematode damage occurred on 15% of the plants.

Ralston Project -- Replicated on-farm research was conducted on a 20-acre site in an 11-inch rainfall zone near Ralston WA. Scientists, extension agents and growers met in 1995 to establish experimental parameters. Rotations were established with farm-size equipment during August 1995. Plots (30 x 500 ft) are in randomized complete blocks with four replicates. The experiment is duplicated so that each crop in each rotation is grown each year. Best management practices are used for tillage, residue management, fertilizers, varieties, pesticides and planting dates. Data is managed centrally to facilitate bioeconomic and risk analysis, and an integrated result. Five systems are being compared: continuous spring wheat, spring wheat-spring barley, spring wheat-fallow, winter wheat-fallow, and a grower-directed flexible cropping system (growers determine tillage, crops, and timing). The focus of this study is on conversion of the winter wheat-fallow rotation to annual cropping, over five years (1995-2000). Evaluations include all pest and agronomic considerations, profitability and economic risk, and compliance with conservation regulations. Results for the overall project are in the STEEP III report by project leaders Frank Young et al.

Winter wheat plants at Ralston were collected on February 17, 1998, at which time plants were 8-10 inches tall. Twenty plants from each replicate were taken to the OSU laboratory in Pendleton to identify and quantify diseases on roots, crowns, and foliage. All spring and winter cereals were evaluated by the same process on May 4 and June 4 (late boot). Data were submitted to the project director, at Pullman, for incorporation into the master databank.

As in 1997, damage from Rhizoctonia root rot was present on winter wheat seedlings during February. Disease incidence was high (>90% of the plants affected) and severity was moderate to high (ratings of 3 on a 5-point scale; indicating significant Apruning@ of main root axes). Other diseases were not important during February. Plants were 20-inches high when assessed on May 4. Damage from Rhizoctonia root rot was readily apparent, as evidenced by patches of stunted plants; the Abare patch@ phase of this disease. Subcrown internode lesions caused by Fusarium foot rot were also present on 35% of the plants, and was considered significantly damaging (lesion severity of 2-3 on a 4-point scale). Strawbreaker foot rot occurred on 9% of the tillers (29% of the plants) and physiologic leaf spot was present on foliage of most plants. Take-all occurred on 0-15% of the plants but the severity was considered minor and unlikely to affect yield. Stem darkening up to five inches above the soil, with varying levels of stem maceration on 2% of tillers, was tentatively attributed to an atypical expression of Rhizoctonia disease (R. solani AG-8 was isolated).

Rhizoctonia root rot and take-all were the most important diseases of spring wheat on May 4. Although specific details of disease incidence and severity are important for these plots, it was clear that irregularities were occurring in disease severity for specific treatments over the first three years of this experiment. Reversals of disease importance were occurring within comparable treatments during alternate years, depending on the positional effect for the two fields (east- vs west-side of road) being alternated in this study. For instance, in 1997 root damage was least where spring barley followed hard red spring wheat, and the opposite occurred during 1998. Further examination of these disease observations revealed that the two fields do not have comparable management histories. The east side of the road has a high level of root disease damage and had four cereal crops during the five years preceding this experiment; winter wheat in 1994-1995, summer fallow in 1993-1994, spring barley in 1994-1995 and 1995-1996, and winter wheat in 1996-1997. Diseases are minor on the west side of the road, where only one cereal crop was grown during the previous five years; summer fallow, winter wheat, summer fallow, winter canola, and then summer fallow. This finding has caused the research team to discuss merits and/or necessity to extend the life of the experiment beyond the original six-year target. The original objective could be redefined such that each site (side of the road) becomes a separate but parallel experiment.

Pythium root rot and root lesion nematodes pruned branch roots from the main root axes of seminal roots on both spring barley and wheat. Nematode damage was observed on up to 25% of the plants in some treatments but, due to the Aside-of-the-road@ effect described above, it is still unclear whether there are significant differences among treatments. Fusarium foot rot has been barely detectable on the spring crops at this location. It was also noted that neither take-all nor Rhizoctonia root rot were significantly more damaging in the continuous spring wheat monoculture than in the spring wheat/chemical fallow rotation.

Satellite Experiments in Oregon:

Three satellite experiments were established in northeast Oregon to complement work at Ralston. Precipitation at the Oregon and Washington sites is comparable in amount (about 11 inches) and distribution. Two tests were near Moro and one was near Echo. Experiments near Moro were on the OSU Sherman Experiment Station. The experiment near Echo was on the 66 Ranch operated by the Mader and Rust families. Dr. Penny Diebel, OSU-La Grande, is performing an economic analysis of these experiments.

Cultivar Screening at Moro -- Twenty spring wheat cultivars evaluated during 1996 and 1997 at both Oregon locations were planted again at Moro during 1998. The 1996 experiment followed summer fallow and the 1997 and 1998 plantings were placed over the same site to simulate a second-year and third-year recrop. Weeds in standing stubble were killed by applying Roundup on February 10, 1998. On March 11, the area was tilled lightly with a chisel plow at three-inch depth to break up the stubble and chaff rows. On March 19 seed was planted into 5 x 30 ft plots with a plot drill equipped with four John Deere HZ openers and split-packer wheels spaced at 14-inch intervals. Seed was placed 1-inch deep into moist, cool (56^oF) soil. Seed was treated with Dividend+Apron+Gaucho (1.0+0.045+2.0 fl oz/cwt), and planted into five replicated plots at the rate of 20 seeds/square foot. All fertilizer needs, as determined by soil test, were placed directly under the seed at the time of planting. The fertilizer was a dry mixture of 16-20-0-24 (8 lb N/ac) plus 0-0-60 (8 lb K₂0/ac). Harmony Extra was applied to control weeds on May 1. Diseases on roots, subcrown internodes, crowns, basal stem and foliage were assessed in all replicates for one cultivar (Vanna) on June 1. Grain was harvested on July 30.

Seedling emergence was excellent. Primary contraints to yield included Rhizoctonia root rot (40-75% of plants), take-all (5-75% plants), Fusarium foot rot (lesions on 0-20% of subcrown internodes), Hessian fly (5-30% plants), and root lesion nematode (50-85% plants). Yield may have also been influenced by a drought that extended through winter and early spring, then plentiful rain during May, and the onset of hot, dry weather during late June and July.

Grain yield (Table 1) varied from 34 to 48 bu/ac (lsd=5.7, mean=41) and test weight from 59 to 63 lb/bu (lsd=0.9, mean=61). Cultivars with highest yield (>45 bu/ac) included two that are resistant to Hessian fly; Wawawai and WB 926. This insect appeared to reduce yields of susceptible cultivars (Alpowa, Treasure, & Vanna) that had highest yields in previous years at Moro. Cultivars with lowest yields continued to include Klasic, WPB 881, and Yecora Rojo.

Integrated No-Till Management Systems at Echo and Moro -- Experiments with continuous minimum-till spring wheat have been performed at the two Oregon locations since 1996 to determine if root disease damage can be minimized without altering the overall philosophy of a cropping system designed to stabilize erosive soil. During 1996 and 1997 we determined that yields could be improved through selection of cultivars, treating seed with a broad-spectrum seed treatment, and placing fertilizer below the seed at the time of planting. These practices were examined as an integrated management system during 1998.

The experiments included a factorial design with three cultivars, four seed treatments, and with or without fertilizer below the seed. Cultivars included WB 936 (hard red spring) and the best yielding soft white and hard white spring wheats (Vanna and ID 377S) at these sites during 1996 and 1997. Seed treatments included Raxil Thiram+Gaucho, Dividend+Apron, Dividend+Apron+Gaucho, and Dividend+Apron+Gaucho+Bacillus L324. Starter fertilizer was either applied or not, using the blend and rates described previously for the cultivar screening experiment at Moro. Site-specific management practices are described separately.

The experiment at Moro was placed into standing stubble from a winter wheat crop harvested in August 1997; i.e., second-year direct seeding. The experiment at Echo followed six spring wheat crops planted annually with no tillage except a post-harvest sweep to control Russian thistle. The experimental design and equipment for the two sites were identical. Weeds at Moro were killed by Roundup applied on February 10 and March 17, 1998. Based on soil testing, 50 lb N/ac was applied as a surface broadcast of urea on February 20. On March 19 seed was planted into 5 x 30 ft plots with the drill described earlier. Seed was placed 1-inch deep into moist, cool (52^oF) soil in each of five replicated plots at the rate of 20 seeds/square foot. Harmony Extra was applied to control weeds on May 1. At Echo, the site was treated with Roundup on January 21, 1998. Soil tests indicated sufficient residual nitrogen to produce the crop. Seed was planted 1-inch deep into moist, cold (42^oF) soil on March 4.

Diseases on roots, subcrown internodes, crowns, basal stem and foliage were assessed on May 21 (Echo) or June 10 (Moro) for all seed treatments applied to WB 936, and for all three cultivars treated with Dividend+Apron+Gaucho. Grain was harvested on July 23 (Moro) or 30 (Echo), and yield, test weight, and protein concentration were determined.

Emergence was excellent for all cultivars and treatments at both locations, and the stands looked exceptionally good for direct-drilled wheat. Primary contraints to yield at both locations, other than low plant density (e.g., the 14-inch row spacing), included Rhizoctonia root rot (80-90% of plants), take-all (35-55% plants), Fusarium foot rot (lesions on 4-13% of subcrown internodes), Hessian fly (3-17% plants), and root lesion nematode (7-22% plants at Moro only). Field mice caused considerable damage at Moro; an adjacent 10-yr-old CRP grassland was plowed at a time when the plot was the only nearby Agreen island@. Yield at both sites may have also been influenced by a drought that extended through winter and early spring, plentiful rain during May, and onset of hot, dry weather during late June and July.

There were no differences in disease incidence and severity among fungicide seed treatments at either location. Starter fertilizer led to an increase in incidence of take-all, Rhizoctonia root rot, and pupae of Hessian fly, and an increase in tillering and plant height. Yield at Moro was improved 2.5 bu/ac (from 34.0 to 36.5 bu/ac; lsd=2.1) when Gaucho insecticide was added to the Dividend+Apron treatment. Yields did not vary for the fungicide seed treatments. Vanna and ID 377S yielded higher than WB 936 (Table 1). Starter fertilizer boosted yield by 7 bu/ac at Moro (from 31 to 38 bu/ac; lsd=2) and 3 bu/ac at Echo (from 21 to 24 bu/ac; lsd=2). Test weights varied among cultivars (Vanna was 1 to 2 lb/bu less than the others). Test weights were not affected by seed treatment but were increased by starter fertilizer; 0.4 lb/bu (lsd=0.3) at Moro and 1.3 lb/bu (lsd=0.5) at Echo. Protein content differed among cultivars (ID 377S=12%, WB 936=12%, Vanna=10%; lsd=0.7% at Moro, and ID 377S=15%, WB 936=16%, Vanna=14%; lsd=0.9% at Echo) but were not affected by starter fertilizer.

Objective 2. Develop disease management recommendations: This research and extension activity will contribute to the determination as to whether annual cropping systems can reduce soil erosion, improve soil quality, and improve farm profitability. The goal of this work is to contribute information that can be used to establish profitable and ecologically advanced cropping systems. As such, the primary objective of this work is to quantify diseases that have potential to limit profitability and production efficiency, and to develop guidelines for fine-tuning cropping systems of interest by reducing the importance of diseases as the limiting factor in the adoption of these systems by growers.

INTERACTION (COOPERATION) WITH OTHER SCIENTISTS CONDUCTING RELATED ACTIVITY: Routine interactions occurred with other STEEP III scientists participating in this project (listed at the beginning of this report) and with other scientists located at Pullman, Pendleton and Corvallis.

PUBLICATIONS AND PRESENTATIONS:

Oral and written information was presented during field tours at Ralston, Echo, Moro and Pendleton. Results for work in Oregon were posted on Dr. Russ Karow=s OSU Cereals Extension WebPage: Ahttp://www.css.orst.edu/cereals/@. At this early stage of experimentation there have been no publications prepared or presentations of results at professional meetings. The first semi-technical paper will be published in the Pendleton Station Special Report during June 1999.

*Rankings include duplicate entries (more than one #8, etc.) for entries with equal yield. Management trials (^H ) in 1998 had 3 varieties and were not included in means averaged for each location.

^H Management trials. Seed treatments did not boost yields. Starter fertilizer below seed boosted yields at Echo and Moro 3.2 and 6.8 bu/ac, respectively.

Echo: Minimum-till annual spring wheat; the 5th, 6th and 7th years were harvested in 1996, 1997 and 1998. The plot area was tilled once with a shallow (3-inch deep) sweep following each harvest, and was otherwise handled as Ano-till@. For comparison, winter wheat varieties in an adjacent WW/fallow rotation yielded 40-77 bu/ac in 1998; Stephens yielded 69 bu/ac and was boosted to 77 bu/ac when treated with Gaucho.

Moro: Spring wheat in 1996 followed winter wheat harvested in 1994 and fallowed in 1995. The variety trial area was cropped annually thereafter, and was tilled between crops. Winter wheat yields were 50-86 bu/ac in nearby experiments during 1998; Stephens was 86 bu/ac. The management trial during 1998 was direct drilled into standing winter wheat stubble.

Contact us: Hans Kok, (208)885-5971 | Accessibility | Copyright | Policies | WebStats | STEEP Acknowledgement
Hans Kok, WSU/UI Extension Conservation Tillage Specialist, UI Ag Science 231, PO Box 442339, Moscow, ID 83844 USA Redesigned by Leila Styer, CAHE Computer Resource Unit; Maintained by Debbie Marsh, Dept. of Crop & Soil Sciences, WSU