Developing Profitable and Sustainable Cropping Systems for North Central Oregon and South Central Washington

Investigator(s)

Dr. Stephen Machado (PI), Dryland Cropping Systems Agronomist, OSU, CBARC, Pendleton

Dr. Steve Petrie (Co-PI), Soil Scientist, and Superintendent, OSU, CBARC, Pendleton

Dr. Dan Ball (Co-PI), Weed Scientist, OSU, CBARC, Pendleton

Dr. Richard Smiley (Co-PI), Plant Pathologist, OSU, CBARC, Pendleton

Dr. Don Wysocki (Co-PI), Extension Soil Scientist, OSU, CBARC, Pendleton

University Cooperators

Christopher Humphreys, Faculty Research Assistant, OSU, CBARC, Pendleton

Erling Jacosen, Sherman Station Manager, OSU, CBARC, Moro

Karl Rhinhart, Farm Manager, OSU, CBARC, Pendleton

Sandy MacNab, Extention Specialist, OSU, Sherman County, Moro

Brain Tuck, Extention Specialist, OSU, Sherman County, Moro

Dr. William Schillinger, Dryland Systems Agronomist, WSU, Lind

USDA-ARS Cooperators

Dr. Stephan Albrecht, Soil Microbiologist, USDA-ARS, CPCRC, Pendleton

Dr. Hero Gollany, Soil Scientist, USDA-ARS, CPCRC, Pendleton

Dr. John Williams, Hydrologist, USDA-ARS, CPCRC, Pendleton

Dr. Stewart Wuest, Soil Scientist, USDA-ARS, CPCRC, Pendleton

Grower Advisory Group and Cooperators

Ernie Moore, Producer, Chairman of the Sherman Station Liaison Committee, and Research and Production co-chair of the Oregon Wheat Growers League, Sherman County.

Chris Kaseberg, Producer, Member of the Sherman Station Liaison Committee, President of Sherman County Wheat League, Sherman County.

Tom McCoy, Producer, former President, Oregon Wheat Growers League, Sherman County.

Walter Powell, Producer, Gilliam County.

John Hilderbrand, Producer, Sherman County.

David Brewer, Producer, Wasco County.

Agronomic zone of interest

Research will be targeted for Agronomic Zones 4 and 5 in north-central Oregon and south-central Washington. The investigations will emphasize dryland production with increased cropping intensity under reduced tillage and direct seed cropping systems.

Statement of problem to be addressed

Wheat/fallow rotation is used on 4.5 million acres in north-central Oregon and south-central Washington where rainfall is considered inadequate to produce a crop every year. Fallowing is used primarily to store winter precipitation, accumulate nutrients (N, S), and control weeds and is economical where rainfall is less than 13 inches (Leggett et al, 1974; Bolton and Glen, 1983). This system, however, reduces soil organic carbon, exacerbates soil erosion and it is not biologically sustainable (Rasmussen and Parton, 1994). The development of high yielding semi-dwarf wheat varieties with high water-use efficiency and disease resistance has not been able to overcome the decline in biological sustainability in the PNW (Duff et al, 1995). Trends after the 1950s indicate that economic sustainability is also declining in PNW fallow cropping systems because costs are continuing to rise while wheat prices remain static (Duff et al, 1995). Conservation tillage, modified fallow, annual cropping, and the introduction of alternative crops into wheat-based rotations are potential ways to improve biological sustainability of cropping systems in the region. Unfortunately, long-term data that show benefits and shortcomings of alternative cropping systems in this region are lacking. Long-term research to develop biologically and economically sustainable farming systems is needed in north-central Oregon and south-central Washington. We hypothesize that reduced tillage systems that leave more residues on the surface, modified fallow, and intensive cropping will increase soil OM, increase soil available moisture, reduce water and wind erosion, and sustain soil productivity compared to the traditional fallow system

Justification

Despite concerns of decline in soil resources and sustainability, most farmers in low rainfall regions of the PNW remain skeptical about alternative production systems. This is primarily because there is no long-term information on the biological and economic sustainability of alternative cropping systems, particularly intensive cropping and direct seed cropping systems in this region. Long-term research that was conducted at the Sherman Experiment Station in the 40s and 50s and concluded in the early 60s indicated that occasional crop failures occur under continuous cropping systems (Hall, 1955; 1960; 1963). Recent commercial experiences with these systems have shown the predictions to be accurate. With the advent of new varieties and agronomic practices such as direct seeding, research is needed to enhance benefits and reduce risks for annual cropping. Possible research avenues include the use of varieties more tolerant to drought, low temperature, and pests and conservation tillage systems that can ensure good stands and economical weed and disease control. The transition from the traditional fallow to more intensive cropping and less tillage presents a great challenge. Growers need to know how new cropping systems will affect other farm operations, how to control diseases and weeds, how to handle residues, and whether some of their farming equipment can be modified effectively to operate under the new systems. At a recent Oregon Wheat Growers League Annual Meeting (September 5, 2001) held at the Dalles, Oregon, there was a strong call for establishing long-term experiments at the Sherman Experiment Station to address grower concerns. A subsequent meeting between scientists and growers at Moro Fairgrounds on September 24, 2001 further emphasized the need for long-term experiments.

Although direct seeding research is underway at Ralston and Jarava sites, similar long-term experiments are needed at Moro, which represents a region with a unique climate. The winters are mild with little likelihood of winter-kill. The soils are relatively fine-textured (Walla Walla silt loam) and shallow in many areas.

Grower Advisory Committee

A grower advisory committee was established in 2002. The committee members are Ernie Moore (Sherman County), Tom McCoy (Sherman County), Walter Powell (Gilliam County), John Hilderbrand (Sherman County), Chris Kaseberg (Sherman County), and David Brewer (Wasco County). The committee will work together with the scientists to develop profitable and sustainable cropping systems for north-central Oregon and south-central Washington.

Site Characterization

The site for the experiment was selected at the CBARC, Sherman Experiment Station in Moro. The 28-acre site was characterized in the spring of 2002 to establish base-line data. Soil was sampled at one-foot intervals to a depth of 5ft or to restricting layer at 126 geo-referenced locations on a 100 ft grid. The samples were sent to Kuo Testing labs, Inc., Othello, WA for chemical analyses. The site slopes from the north to nearly all directions and the slope ranges from 0.03 to >5% (Figure 1). Depth to restricting zone or bedrock was recorded during soil sampling (Figure 2). We set the probe to drill as deep as 5 ft and we assume that the soil is more than 5ft deep in areas where the probe reached 5 ft without going through a restrictive layer. The characteristics of the site make it suitable to analyze the effects of aspect, slope, and depth on the proposed alternate cropping systems.

Total soil N in soil profile was fairly uniform with most of the site under 45 lb/a N (Figure 3). The average soil test for sulfur in the top 2 ft was above 2 ppm, the critical soil test level below which additions are needed (Figure 4). Phosphorus was below 10 ppm only in the shallow, south-western part of the site (Figure 5). Organic matter was generally high in the north-facing slope (Figure 6). Soil pH was high in the south-western part of the site (Figure 7).

After soil sampling the site was solid seeded with spring wheat in March to homogenize the soil. At maturity, the crop was harvested at each grid location to determine how uniform the site was. Twenty by five foot plots were harvested by a Hege plot combine at each location and the spatial distribution of the grain yield was determined. The grain yields were generally higher in the east than in the shallow western end (Figure 8).

Information obtained from site characterization is useful in deciding where to locate plots. If uniform conditions are required for this experiment, then the western one third should not be used. This western one-third could, however, be used to determine the effects of depth on the proposed cropping systems. This area could be blocked and considered as a replication.

Objectives:

The overall focus of this project is to develop profitable and sustainable cropping systems for north-central Oregon and south-central Washington. The main objectives include determining systems that increase residue cover, increase soil OM, increase available soil moisture, reduce wind and water erosion, reduce soil water evaporation, and sustain soil productivity. Information to address these objectives will, however, be obtained only after long-term experimentation.

The specific objective of this experiment is, therefore, to establish a long-term experiment that will compare the effects of a conventional wheat/fallow system with potential alternative and intensive crop systems and crop management practices such as direct seeding.

Procedures:

The experiments will be established at the Sherman Experiment Station in Moro in the fall of 2003. A 28-acre site was selected at the Sherman Experiment Station in Moro. The site has areas that are more than 5 ft deep and other areas that are less than one foot deep (Figure 2). The effects of aspect, slope (up to 5%), and depth on crop productivity under different cropping systems can be captured at this site. The Station receives an average of 11.5 inches of annual precipitation. Rainfall and soils at station are representative of the average conditions in the target area.

Treatments

After a series of meetings between scientists and growers, 8 core treatments were chosen. The rotations will include:

1. Winter wheat- conventional fallow (2 strips in rotation)
2. Winter wheat- chem. fallow (2 strips)
3. Continuous winter wheat (1 strip)
4. Continuous spring wheat (1 strip)
5. Continuous spring barley (1 strip)
6. Winter wheat – spring cereal (barley) – chem. fallow (3 strips)
7. Winter wheat – legume (2 strips)
8. Flex crop (2 strips)

Each phase of each rotation will appear every year (Table 1).

Table 1. Long-term treatments.

Rotation#.	Treatment#	†Year 1	†Year 2	†Year 3	†Year 4
1A	1	WW-Conv	Fallow-Conv	WW-Conv	Fallow-Conv
1B	2	Fallow-Conv	WW-Conv	Fallow-Conv	WW-Conv
2A	3	WW-DS	Fallow-Chem	WW-DS	Fallow-Chem
2B	4	Fallow-Chem	WW-DS	Fallow-Chem	WW-DS
3	5	WW-DS	WW-DS	WW-DS	WW-DS
4	6	SW-DS	SW-DS	SW-DS	SW-DS
5	7	SB-DS	SB-DS	SB-DS	SB-DS
6A	8	WW-DS	SB-DS	Fallow-Chem	WW-DS
6B	9	SB-DS	Fallow-Chem	WW-DS	SB-DS
6C	10	Fallow-Chem	WW-DS	SB-DS	Fallow-Chem
7A	11	WW-DS	WP-DS	WW-DS	WP-DS
7B	12	WP-DS	WW-DS	WP-DS	WW-DS
8A	13	Flex-crop	Flex-crop	Flex-crop	Flex-crop
8B	14	Flex-crop	Flex-crop	Flex-crop	Flex-crop

†DS-direct seed; Chem-chemical; Conv-conventional tillage; Flex-crop-cropping system decided based on prevailing soil moisture conditions and grain price; SB-spring barley; SW-Spring wheat; WP-winter pea; WW-winter wheat.

The treatments will be replicated 3 times. There will be 14 plots per replication and the minimum plot size will be 48 ft x 350 ft bringing the minimum total experimental area to 13.88 acres. Plot layout is shown in figure 9. Agronomic practices (planting date, planting rate, and fertilizer, herbicides, seed-treatment fungicide, and insecticide application) will be based on the treatment in question (see appendix for details). Direct seeding will be done using the FabroÒ Drill purchased with assistance from the Sherman Station Liaison Committee.

Treatment procedures

1. Winter Wheat/Fallow

Traditional “trashy” summer fallow practiced in this region.

Time	Field operations
July	Harvest wheat
August to September	Post harvest stubble management as needed
September to mid-April	Uncultivated wheat stuble, glyphosate as needed,
April to May	Primary tillage-spring chisel or sweep, rod weed
May to October	Secondary tillage-rod weeding, fertilize using shank applicators
September to November	Plant wheat at 22 seeds/ft^2
Late September to late June	Wheat growth, broad leaf weed control

2. Winter Wheat-Chemical Fallow

Herbicides used to control weeds during fallow.

Time	Field operations
July	Harvest wheat (if after wheat),
August to September	No tillage, post harvest stubble management as needed, glyphosate as needed
September to next year’s October	No tillage, glyphosate or LandmasterÒ as needed
September to November	Plant wheat (25 seeds/ft^2) and fertilize with drill (one pass system)
Late September to late June	Wheat growth, broad leaf weed control

3. Continuous Winter Wheat-Direct Seeding

This system can be made possible by a combination of “Clearfield technology”, MaverickÒ, and traditional downy brome control paying particular attention to herbicide resistance and cost.

Time	Field operations
July	Harvest wheat (if after wheat),
August to September	Post harvest stubble management as needed,
October to November	Glyphosate as needed, and plant (25 seeds/ft^2) and fertilize with a drill (one pass system)
October to late June	Wheat growth, broad leaf and grass weed control

4. Continuous Spring Wheat-Direct Seeding

Weeds controlled before seeding.

Time	Field operations
July	Harvest wheat
August to September	Post harvest stubble management as needed
October to March	Glyphosate as needed
February to March	Plant wheat (29 seeds/ft2) and fertilize with drill (one pass system)
March to Late June	Wheat growth, broad leaf weed control

5. Continuous Spring Barley-Direct Seeding

Weeds controlled before seeding.

Time	Field operations
July	Harvest wheat
August to September	Post harvest stubble management as needed
October to March	Glyphosate as needed
February to March	Plant barley (29 seeds/ft2) and fertilize with drill (one pass system)
March to Late June	Barley growth, broad leaf weed control

6. Winter Wheat-Spring Barley-Chemical Fallow-Direct Seeding

Chemical Fallow to Winter Wheat

Time	Field operations
July	Harvest spring barley or wheat
August to September	Post harvest stubble management as needed
October to October	Glyphosate or LandmasterÒ as needed to control weeds.
September to October	Plant wheat (25 seeds/ft^2)and fertilize with drill (one pass)
October to Late June	Wheat growth, broad leaf weed control

7. Winter Wheat-Winter Pea (Modified fallow)

This treatment aims to halt organic matter decline by introducing winter pea in the rotation. Winter pea is planted after winter wheat and either chemically killed (green manure) in early spring before it uses a substantial amount of moisture, or let to grow for seed production depending on soil moisture conditions and the market. Our 2001-2002 crop year results indicate that winter pea can produce over 5000 lb/a of dry matter and produced up to 1700 lb/a with < 8 inches of rainfall.

Time	Field operations
July	Harvest wheat, post-harvest residue management
August to September	Post harvest stubble management as needed
October to November	Glyphosate as needed to control cheatgrass and volunteer weeds
October to November	Plant winter pea (7 seeds/ft^2 )and apply starter fertilizer, and pre-emergence broadleaf herbicide (Prowl or Treflon or Sonalon pre-plant drill incorporated)
November to March	Pea growth, weed control (AssureÒ), decide on green manure or seed
March to June	Pea growth for seed
May to June	Harvest seed

8. Flex crop (A and B)

Flex crop (A) involves season to season decisions by the grower advisory group and scientists on the crop to be grown, tillage, and weed control. Flex crop (B) will be a back-up and an alternative to Flex crop (A). Use of computer models (ModWht3 and Crop Syst) to help in decision making will be employed in Flex crop (B).

S. Machado, C. Humphreys, and E. Jacobsen

Data collection

12’

24’

12’

Data will be collected from 12 ft x 350 ft areas on either side of the plot leaving 24 ft x 350 ft in the center for harvest.

Soil sampling

A representative soil sample will be collected at 12-inch intervals to 60 inches or to restricting layer using a GiddingsÒ probe at 5 locations in each plot every 5 years and analyzed for pH, OM, P, K, NO₃, NH₄, SO₄, Zn, Mn, Fe, Cu, Cl, Soluble salts, in the 0 to 12 inch samples, NO₃ and SO₄ in the 12 to 24 inch samples, and NO₃ in the 24 to 60 inch samples. Part of the samples will be analyzed for soil texture using the hydrometer method only in the first year. In other years the soil will be analyzed for NO₃, NH₄, and SO4 in the first 12 inches and NO₃ in the 12 to 48 ft samples to determine fertilizer recommendations.

S. Machado, S. Petrie, D. Wysocki

Agronomical and phonological data

Basic data on the timing of agronomic practices, dates of plant emergence, plant counts, anthesis, and maturity, biomass, yield, diseases, weeds, insect pests, soil moisture, erosion, will be collected every year. Plants will be considered emerged when >50% of the plot has emerged plants. Plants will be counted 10 to 14 days after emergence in at least 6 -3 ft quadrats in the sampling areas (one quadrat in the center of every 50 ft section of each plot). The plot will be considered to have flowered or matured when >50% of the plants have flowered or matured. Total plant biomass from at least 6-3 ft quadrats will be collected from the sampling areas for the determination of harvest index. The rest of the plot area will be harvested by commercial size combine to obtain grain yield. Grain weight will be measured using a weigh wagon.

S. Machado

Pests

Diseases will be monitored at least twice annually in each planted plot. All procedures are routinely performed in on-going disease-management research with wheat and rotational crops (Smiley et al., 1996). Planted plots will be sampled for disease assessments during early winter (late November or early December) and late spring (May), and whiteheads, if present, will be quantified during mid- to late-June. Winter and spring samples involves removing 20 to 40 plants per plot, washing soil from roots, and scoring each plant individually for presence and severity of diseases such as Fusarium foot rot, take-all, Rhizoctonia root rot, strawbreaker foot rot, or Cephalosporium stripe. If present, the incidence and/or damage by insect pests is also quantified.

S. Smiley, S. Machado

Evaluations will be made on changes in density and species composition of weed populations. Emphasis will be placed on downy brome and jointed goatgrass, two weeds of primary importance in this agronomic zone. Weed density and species composition estimates