Alternative Crop Rotations Using No-Till

in Low-Rainfall Dryland Areas

 

AUTHORS:

William Schillinger (PI), WSU Dryland Research Agronomist, Lind, WA

Ron Jirava, Grower, Ritzville, WA

Brad Wetli, Grower, Mansfield, WA

R. James Cook, USDA-ARS Research Plant Pathologist, Pullman, WA

Robert Papendick, WSU Soil Scientist, Pullman, WA

Roger Veseth, WSU/UI Extension Conservation Tillage Specialist, Moscow, ID

Harry Schafer, WSU Agricultural Research Technician, Ritzville, WA

Robert Gillespie, WSU Extension Entomologist, Wenatchee, WA

Ann Kennedy, USDA-ARS Soil Microbiologist, Pullman, WA

Joe Yenish, WSU Extension Weed Scientist, Pullman, WA

Keith Saxton, USDA-ARS Hydrologist, Pullman, WA

Don Wysocki, OSU Extension Soil Scientist, Pendleton, OR

 

DURATION: First of six years

OBJECTIVES: To determine the long-term feasibility of diverse, no-till annual cropping systems for low-rainfall dryland areas of the inland Pacific Northwest. Specific objectives are:

1. Develop long-term rotations which include alternative crops such as yellow mustard and safflower, and measure their effects on root diseases and grain yield of subsequent wheat and barley crops.

2. Document the long-term cumulative effects of minimum disturbance no-till planting practices on physical and biological properties of the surface soil.

3. Demonstrate and promote no-till farming practices and alternative crop rotations to growers and agricultural support personnel.

KEY WORDS: Alternative crops, no-till, low-rainfall, dryland

STATEMENT OF PROBLEM: A wheat-summer fallow rotation has been practiced for more than 100 years in low-rainfall dryland areas of the inland Pacific Northwest. Soil organic carbon, and associated soil quality, are declining under the wheat-fallow system because of limited crop residue production, tillage, and the unproductive fallow period. Blowing dust from excessively tilled summer fallow is a major soil loss and air quality concern. In addition, water erosion from fall-planted wheat after fallow is often severe when rain or snowmelt occur on frozen soils. Growers in dryland areas are interested in no-till planting techniques and potential alternative crop rotations which reduce erosion, decrease soil-born diseases of cereals, enhance crop marketing opportunities, and hold potential to increase soil quality.

ZONE OF INTEREST: The low-rainfall (6-to 12-inch annual) dryland area of east-central Washington and north-central Oregon. This zone encompasses 3.5 million cropland acres.

ABSTRACT OF RESEARCH FINDINGS: A long-term study was initiated in 1997 to evaluate alternative cropping systems for low-rainfall dryland areas using minimum disturbance no-till. The on-farm experimental sites are in Adams and Douglas counties. We are interested in how a 4-year rotation, which includes two years of cereals followed by two years of broad leaf crops, will effect cereal root diseases, cereal yields, weed ecology, insects, farm economics, and soil quality. In Adams county, were 1997 crop year precipitation was 17 inches (average is 11.5 inches), grain yields of spring wheat, spring barley, safflower, and yellow mustard were excellent. In Douglas county, broadleaf weed infestation in the safflower and yellow mustard was extensive, and grain yield for these crops was poor. We plan to conduct this study for six years at both locations. Data will become increasingly meaningful in future years.

RESULTS AND INTERPRETATION:

This project, which began in April 1997, is evaluating diverse, annual, no-till cropping systems as a substitute for winter wheat - summer fallow. Research sites are located at the Ron Jirava near Ritzville in Adams county, and the Brad Wetli farm NW of Mansfield in Douglas county. At both sites, a 4-year crop rotation of: spring wheat - spring wheat - safflower - yellow mustard are being evaluated (Table 1). For comparison, annual spring wheat and continuous spring wheat - spring barley are also included in the study (Table 1). Treatments are replicated four times in a randomized block design at each location. Soil and climatological differences between the two sites are shown in Table 2.

 

Table 1. The seven no-till treatments in the alternative cropping systems research study in Adams and Douglas counties. Each crop in the 4-year rotation (treatments 1 - 4) appears each year. Continuous wheat (treatment 5) and continuous wheat-barley (treatments 6 -7) are also included.

Year

Treatment

1997

1998

1999

2000

1

Spring Wheat

Spring Wheat

Safflower

Yellow Mustard

2

Spring Wheat

Safflower

Yellow Mustard

Spring Wheat

3

Safflower

Yellow Mustard

Spring Wheat

Spring Wheat

4

Yellow Mustard

Spring Wheat

Spring Wheat

Safflower

5

Spring Wheat

Spring Wheat

Spring Wheat

Spring Wheat

6

Spring Wheat

Spring Barley

Spring Wheat

Spring Barley

7

Spring Barley

Spring Wheat

Spring Barley

Spring Wheat

 

 

Table 2. Soil and climatological comparisons of the on-farm research sites in Adams and Douglas counties.

 

Adams Co. - Jirava

Douglas Co. - Wetli

Annual ave. precip.

11.5 inches

10.5 inches

Soil type

Ritzville silt loam

Touhey loam

Soil depth

More than 6 feet

2.5 feet

Elevation

1850 feet asl

2700 feet asl

Slope

Less than 2%

Less than 2%

Adams County: Plots were sprayed with glyphosate herbicide for weed control in early April. Planting was with a Flexicoil 6000 no-till air drill with disc openers spaced 7.5 inches apart. The seedbed had 2,300 lbs/acre of undisturbed year-old hard red spring wheat residue. Over-winter precipitation was higher than average, and there was 9.4 inches of available water in the six foot soil profile at time of planting. Planting rates were: spring wheat (Penawawa) 70 lbs/acre; spring barley (Baronese) 70 lbs/acre; safflower 20 lbs/acre; and yellow mustard 7 lbs/acre. Planting of crops was completed between April 17-24. Fertilizer rate, held constant for all crops, was 40 lbs N/acre as aqua NH3 delivered with coulters between the seed rows, and 8-10-0-7 lbs/acre of N-P-K-S as granules with the seed. Wheat and barley plots were sprayed with 6 ounces of Salvo + one-third ounce of harmony extra with 10 gallons of water per acre in May. Broadleaf herbicides could not be used in the safflower and yellow mustard plots.

Stand establishment (plants/ft2) was spring wheat 9; spring barley 9; safflower 2.5; and yellow mustard 1.8. We were concerned about the low stand counts in the broadleaf crops, but both yellow mustard and safflower grew rapidly to fill empty niches. Spring wheat and spring barley plots remained weed free throughout the growing season. The main weed species in the yellow mustard and safflower were Russian thistle, lambs quarter, horse tail, and China lettuce, but populations were low, i.e. less than 1 weed per 100/ft2 for each weed species. Rainfall occurring between planting and harvest was 3.6 inches.

Bumper yields of spring wheat (64 bu/acre) and spring barley (2.3 ton/acre) were harvested from the plots in August. Yellow mustard and safflower yields were also high, exceeding 1400 lbs/acre (Table 2).

Douglas County: Plots were sprayed with glyphosate herbicide in April and planted with the USDA-ARS cross-slot no-till drill on May 1. The cross-slot is a minimum soil disturbance disc drill with 10-inch spacing between seed rows. All crops were planted the same day. Fertilizer rate for all crops was 40 lbs N, 10 lbs P, and 7 lbs S per acre as liquid delivered to the side and slightly below the seed. Seeding rates for spring wheat, spring barley, safflower, and yellow mustard were 70, 70, 20, and 10 lbs/acre, respectively. Wheat and barley were sprayed in June with 2,4-D (we wanted 16 ounces/acre but applied 21 ounces).

Stand establishment (plants/ft2) was: wheat 11; barley 10; safflower 5; and yellow mustard 7. Unlike the Adams county site, yellow mustard and safflower did not produce many branches and growth was slow throughout the spring and summer. Infestation of Russian thistle, cutleaf night shade, and spiny cocklebur was extensive. At the time of harvest in late September, these weeds had collectively produced 2260 lbs/acre of total dry matter vs. 1280 lbs/acre for yellow mustard; and 1680 lbs/acre total dry matter vs. 2015 lbs/acre for safflower. The slow growth of safflower and yellow mustard points toward damage by residual sulfonyurea herbicide in the soil. However, the only herbicides used on the land during the past 5 years are glyphosate, 2,4-D, and Banvel. Yield of all four crops are shown in Table 3.

Table 3. Yields (lbs/acre) of four crops planted no-till in Adams and Douglas counties in 1997. These are first year results of a planned six-year alternative cropping systems project.

 

Spring Wheat

Spring Barley

Safflower

Yellow Mustard

Adams Co. (Jirava)

3860

4600

1420

1430

Douglas Co. (Wetli)

1150

2400

630

410

 

Other measurements: Insect populations in all crops were measured several times throughout the growing season at both sites (Bob Gillespie). Herbicide screening experiments for broadleaf weed control in yellow mustard and safflower were conducted on the Jirava farm (Joe Yenish). A yellow mustard variety trial was conducted at the Lind Dryland Research Station by Jack Brown from the University of Idaho. Baseline soil samples were collected at both sites and stored for future analysis (Ann Kennedy). Root disease scoring will begin in 1998 (Jim Cook).

 

PUBLICATIONS AND PRESENTATIONS:

Schillinger, B., R.J. Cook, B. Papendick, R. Veseth, K. Saxton, B. Gillespie, J. Yenish, A. Kennedy, H. Schafer, and J. Driessen. 1997. Alternative annual crop rotations for low-rainfall dryland using no-till. Wheat Life Vol. 40, 6:58-59.

Schillinger, W. F., and R.I. Papendick. 1997. Making no-till work for low-rainfall dryland in the inland Pacific Northwest. Agronomy Abstracts.

Schillinger, B., R. Jirava, R.J. Cook, J. Yenish, D. Wellsandt, and F. Young. Alternative cropping systems for traditional wheat-fallow areas. A day-long Adams county field tour held on June 5, 1997 with 110 grower and ag. industry participants.

Schillinger, B., and R. Jirava. Alternative cropping using no-till. WSU/SARE workshop, Oct. 24, 1997, Harrington, WA. Seventy participants.

Schillinger, B. Yellow mustard and safflower as rotation crops in dry areas using direct seeding. Pacific Northwest Canola Conference, Nov. 9-11, 1997, Moscow, ID. One hundred participants.

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