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1999 STEEP III Progress ReportRESEARCH PROJECT TITLE: Alternative Crop Rotations Using No-Till in Low-Rainfall Dryland Areas. INVESTIGATORS:
DURATION: Third of three years OBJECTIVES: The objective of
the study is to determine the long-term feasibility of diverse, cereal-based,
no-till cropping systems for low-rainfall dryland areas of the inland
Pacific Northwest. Specific objectives are:
KEY WORDS: No-till, low-rainfall, alternative rotations, dryland STATEMENT OF PROBLEM: Farming in the dryland
areas of the Pacific Northwest (less than 12 inch annual) has been mostly
an intensive tillage-based wheat-fallow system since the land was broken
out of native grassland and sage in the 1880s. Tillage is well known to
accelerate the loss of soil organic matter by increasing biological oxidation
and often by increasing soil erosion. The loss is exacerbated with fallow
because oxidation of carbon exceeds carbon input from crop residues during
the 2-year cycle. Because of the decline in organic matter and associated
soil quality, most tillage-based farming systems in dryland environments
are not sustainable in the long-term. Options for maintaining and improving
soil quality in the drylands are to simultaneously increase the cropping
intensity and reduce or eliminate tillage. 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: We have completed
three years of a planned six-year study to compare three no-till annual
spring cropping systems: (i) a 4-year safflower/yellow mustard/wheat/wheat
rotation; (ii) a 2-year wheat/barley rotation, and (iii); continuous wheat.
Experiment sites are located in Adams and Douglas counties. Lack of spring rainfall
in 1999 reduced yields at both sites compared with previous years. There
were no differences in wheat yield due to rotation at either site. Rhizoctonia
root rot bare patches in wheat and barley covered 5% of total plot area
in Adams county. Previous crop history had no significant effect of level
of rhizoctonia infection in wheat. Russian thistle was again the dominant
weed in 1999 at both sites. Marestail and prickly lettuce are troublesome
in safflower and yellow mustard but can be brought under control when
the rotation reverts to wheat. To date, we have found no differences in
the population of any weed species in wheat due to rotation. Safflower
and yellow mustard extract more water from the soil profile than does
spring wheat, and the soil water shortfall carries over to the next spring. RESULTS AND INTERPRETATION: This study was initiated in 1997 at two locations. The Adams county site is on the Ron Jirava farm near Ritzville. Precipitation at the Jirava site averages 11.5 inches, elevation is 1850 ft asl, and the soil is a deep Ritzville silt loam. The second research site is located northwest of Mansfield in Douglas county on the Brad Wetli farm. Annual precipitation at the Wetli site is 10.5 inches, elevation is 2700 ft asl, and depth of the Touhey loam soil averages only 2.5 feet. The dominant cropping pattern on these shallow soils in Douglas county is winter wheat/summer fallow. The plot design is the same for both Adams and Douglas county sites. We are testing three spring-sown cropping systems: 1) a 4-year safflower/yellow mustard/wheat/wheat rotation; 2) a 2-year wheat/barley rotation and; 3) continuous wheat. Each system is replicated four times in a randomized block design with each sequence of all rotations sown each year (i.e., 28 plots at each site). The experiment covers 20 acres in Adams county and 8 acres in Douglas county. At the Adams county site, crops are sown with a 30-foot-wide Flexi-coil 6000 no-till disc drill which bands fertilizer near the seed with double-shoot disc openers in one pass through the field. The Douglas county site is sown with an 8-foot-wide Cross-slot drill which causes minimal soil disturbance and also delivers seed and all fertilizer in one pass. Fertilizer rate (nitrogen, phosphorous, and sulfur) is held constant in all plots at each site and is based on soil test and soil moisture availability. Sowing in 1999: Fertilizer rate in Adams county was 48-10-0-10 lb./acre, applied as 40 lb. N and 10 lb. S in an aqua NH3 mix, plus an additional 8 lb. N and 10 lb. P as granular starter. Extensive soil water measurements taken in mid-March in Adams county showed significant differences (P < 0.001) in water content as affected by the previous crop. There was 9.5" and 9.6" of water in the 6-foot soil profile when the previous crop was safflower and yellow mustard, respectively, versus an average of 10.9" of water when the previous crop was wheat or barley. Glyphosate was applied at 16 oz./acre to plots in early April and all crops were sown between April 10-19. Sowing rates per acre were: wheat 70 lb., barley 70 lb., safflower 36 lb., and yellow mustard 7.5 lb. Yellow mustard seedlings were killed by frost and the plots were re-sown on April 30. In Douglas county, plots were sprayed with 16 oz./acre glyphosate in late April and all crops were sown on May 5. Total water content in the 2.5 foot soil profile was 5.5". Fertilizer rate was 30-8-0-8 applied in Solution 32 formulation. Sowing rates for all crops were the same as in Adams county. Plant Stand Establishment: As in previous years, plant stand establishment of safflower and yellow mustard were hampered in 1999 at the Adams county site where plots are sown with the Flexi-Coil 6000 drill (Table 1). The Flexi-Coil 6000 drill has fertilizer and seed + starter fertilizer disc openers (i.e., double shoot) in the same row. The problems we have experienced are due variable soil cover among rows. Plants stands of all crops sown with the Cross-slot drill in Douglas county have been excellent during all years (Table 1). We may use the Cross-slot to sow broadleaf crops at the Adams county site beginning in the year 2000. Table 1. Plant stand establishment of four crops sown no-till in Adams and Douglas counties in 1997, 1998, and 1999. Plots in Adams county were sown with a Flexi-coil 6000 disc drill and in Douglas county with a Cross-slot disc drill.
We were surprised to find the high incidence of rhizoctonia severity in the four-year rotation where wheat follows two years of broadleaf crops. We plan to superimpose experiments in the plots in the 2000 crop year to study the possible association of zinc, copper, and other micro-nutrients with rhizoctonia disease (Cook). Table 2. Percent land area in wheat and barley plots with rhizoctonia bare patches at the Adams county site in 1999 as measured by a global positioning system. There were no significant differences in rhizoctonia patches among rotations.
Weeds: Populations of all weed species and the dry biomass they have produced by time of crop harvest were again measured in 1999. A 3-sq.-yard sampling frame was used to collect weeds from three locations in each plot at both Adams and Douglas county locations. Russian thistle is the dominant weed at both sites. Marestail, prickly lettuce, tumble mustard, tansy mustard, and lambsquarter were present in safflower and yellow mustard crops (for which there are no labeled in-crop herbicides) (Tables 3 and 4). However, these weeds have been brought under control with 8 oz. of Salvo (2,4-D) plus 3 oz. Harmony extra applied in the tillering stage when the rotation reverts back to wheat. To date in Adams county, there have been no significant differences in any weed species in wheat as affected by crop rotation treatment (Tables 3 and 4). In addition to Russian thistle, marestail and annual bursage are problem weeds in Douglas county. The proliferation of weeds in safflower and yellow mustard may be largely due to the slow growth rate of these broadleaf crops at this northerly and high elevation site (see crop yields section). In-crop weed control for cereals in Douglas county has been with 2,4-D (1997) and 1.5 pints of Bronate (1999). Russian thistles produced more than 400 lb./acre biomass in 1998 when we missed the opportunity to spray weeds in cereals in Douglas county (Table 5), but populations in cereals were brought under control in 1999 (Table 6). We plan to continue monitoring weed ecology and possible weed species shifts at both sites. Table 3. Dry biomass
produced by four weed species, as well as total weed biomass, in 1998
in Adams county as affected by crop and crop rotation.†
Table 4. Dry biomass
produced by five weed species, as well as total weed biomass, in 1999
in Adams county as affected by crop and crop rotation.
Table 6. Dry biomass
produced by three weed species, as well as total weed biomass, in 1999
in Douglas county as affected by crop and crop rotation.
Crop Yields: Although over-winter precipitation was greater than average, total precipitation at the Adams county site was only 7.81 inches from September 1, 1998 to August 31, 1999. March through June cumulative rainfall was 1.18 inch. Below freezing temperatures occurring on May 22 and July 3 severely reduced yellow mustard yields. Safflower produced 1050 lb./acre despite harsh growing conditions. Wheat averaged 26.7 bu./acre with no significant difference in yield among rotations. Barley yields were a disappointing 0.76 ton/acre. Yields of all crops in all rotations since 1997 in Adams county are shown in Table 7. In Douglas county, precipitation from September 1, 1998 to August 31, 1999 was 10.3 inches. Yellow mustard and safflower do not appear well adapted to the very shallow soils and cool temperatures at this site as growth and yield from these crops in 1999 were low for the third straight year (Table 8). Wheat yield was 18.3 bu./acre averaged across treatments and there were no significant differences in yield due to crop rotation. Barley was difficult to harvest because of short plant height with grain yield only 0.35 tons/acre. Yields of all crops in all rotation combinations in Douglas county since 1997 are shown in Table 8. Table 7. Crop yields in three rotations in Adams county: a 4-year safflower/yellow mustard/wheat/wheat rotation; a 2-year wheat/barley rotation and; continuous spring wheat. All crops were direct sown with a Flexi-Coil 6000 drill as part of a long-term cropping systems study.
Table 8. Crop yields in three rotations in Douglas county: a 4-year safflower/yellow mustard/wheat/wheat rotation; a 2-year wheat/barley rotation and; continuous spring wheat. All crops were direct sown with a Cross-slot drill as part of a long-term cropping systems study.
INTERACTION WITH OTHER SCIENTISTS CONDUCTING RELATED ACTIVITY: : In addition to the co-investigators of this project, the PI is cooperating with: Tim Fiez, WSU Pullman, on research concerning row spacing effects of no-till spring wheat and barley; Bill Payne, OSU Pendleton, on evaluation of narrow leaf lupines; Steve Dofing, WSU Pullman, on sowing rates for no-till vs. conventionally sown wheat, barley, and oats; Jim Cook, WSU Pullman, as co-authors of a scientific journal article on no-till barley; Doug Young, WSU Pullman, on economic evaluation of reduced tillage systems at Lind; Frank Young, USDA-ARS, on the Ralston integrated spring cereal project as well as co-author of a scientific journal article on soil water use by Russian thistle; Roger Veseth, WSU/UI Moscow, on cropping systems technology transfer; Keith Saxton, USDA-ARS Pullman, on Cross-slot drill technology; Tom Lumpkin, WSU Pullman, on evaluation of millet; Kim Campbell, USDA-ARS Pullman, on winter wheat seedling emergence; Joe Yenish, WSU Pullman, on residual herbicides for Russian thistle control and; Ed Donaldson (deceased) on publishing his research on straw production and yield component relationships in winter wheat. PUBLICATIONS AND PRESENTATIONS: Schillinger, W.F.,
R.J. Cook, K.E. Saxton, R.I. Papendick, A.C. Kennedy, D.L. Young, R.J.
Veseth, and R.L. Gillespie. 1999. Direct seeding and intensive cropping
research in typical wheat-fallow areas. Western Society of Crop Science
annual meeting, Powell, Wyoming, 28-29 June. ASA, CSSA, and SSSA Abstracts
p. 445. Schillinger, W.F.
1999. Farming without tillage: Possibilities for inland Pacific Northwest
drylands. Chelan, WA, 13-14 Sept. Northwest Biosolids Management Conference
Abstracts p. 28-29. Schillinger, W.F.
and K.E. Saxton. 1999. Wind erosion control for low-organic, non-aggregated
agricultural soils. Soil Science Society of America annual meeting, Salt
Lake City, Utah, 31 Oct. - 4. Nov. ASA, CSSA, and SSSA Abstracts p. 285. Schillinger, W.F.
and C.W. Shelton. 1999. Water use and growth of dryland alternative crops
in the inland Pacific Northwest. American Society of Agronomy annual meeting,
Salt Lake City, Utah, 31 Oct. - 4 Nov. ASA, CSSA, and SSSA Abstracts p.
61. Schillinger, W.,
R.J. Cook, K. Saxton, R. Papendick, H. Schafer, D. Young, R. Gillespie,
A. Kennedy, J. Yenish, T. Lumpkin, R. Veseth, J. Driessen, and B. Sauer.
1999. Long-term alternative cropping systems research for the drylands.
p. 105-109. In: 1999 Field Day Proceedings: Highlights of Research Progress.
Department of Crop and Soil Science Technical Report 99-1, Washington
State University, Pullman, WA. Schillinger, W.,
R. Jirava, B. Wetli, R.J. Cook, R. Papendick, R. Veseth, H. Schafer, R.
Gillespie, A. Kennedy, J. Yenish, K. Saxton, and D. Wysocki. 1999. Alternative
crop rotations using no-till in low-rainfall dryland areas. pp. 69-72.
In: Proceedings of the National No-Tillage Conference, F. Lessiter (ed.),
21-23 Jan., 1999, St. Louis, MO. Schillinger, W.F.
1999. Oral presentations on this project were made at the Farm Forum in
Spokane on Jan. 12 (35 attendance); Ritzville growers meeting on Jan.
20 (85 attendance); Douglas county growers meeting on Jan. 26 (70 attendance);
Khazakstan scientist tour on April 14 (12 attendance); fifth graders field
tour on May 19 (75 attendance); Benton county wheat growers field tour
on June 8 (50 attendance); Lind field day on June 17 (160 attendance);
Washington association of wheat growers legislative field tour on June
23 (50 attendance); National wind erosion task force (30 attendance) on
June 23; Adams county wheat growers research field tour on June 24 (55
attendance). Schillinger, W.F.
Soil water use and growth of dryland alternative crops in the inland Pacific
Northwest. Agronomy Journal (in preparation). Gillespie, R.L., and W.F. Schillinger. Insects of no-till yellow mustard and safflower. Journal of Economic Entomology (in preparation). |
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