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1997 Report

Contents

 SPECIFIC PROJECT RESULTS
 RESULTS AND DISCUSSION
 POTENTIAL CONTRIBUTIONS

		Annual Report to the Western Region Sustainable Agriculture Research and Education Program January, 1998
Project Title: Project Contact:			Development and Demonstration of Integrated Vegetable Production Systems for the Maritime Pacific Northwest
John Luna Department of Horticulture, Oregon State University Corvallis, OR 97331 541-737-5430FAX541-737-3479E-maillunaj@bcc.orst.edu
Reporting Period:			From December, 1996 to December, 1997
Participating Farmers and Extension Personnel
Dan McGrath Oregon State University Salem, OR Bill and Karla Chambers Stahlbush Island Farms Corvallis, OR Peter Kenagy Kenagy Family Farms Albany, OR PROJECT OBJECTIVES				Mark and Mike Dickman Dickman Farms Silverton, OR Ray Stafford Kraemer Farms Mt. Angel, OR Keith Grover Grover Farms Salem, OR	Carl Hendricks Hendricks Farms Scio, OR Dick Strunk Northwest Farm Tillers Yakima, WA Mary Staben Oregon State University Corvallis, OR
	To develop, evaluate and demonstrate integrated vegetable production systems for the maritime Pacific Northwest which improve farm profitability, protect water quality, and enhance long-term soil productivity.

	To improve methodologies for enhancing farmer and agribusiness participation in the design and implementation of on-farm research and demonstration projects for integrated, sustainable agriculture. To conduct a multi-faceted educational program which accelerates information transfer among producers, extension specialists and agents, agribusiness representatives, governmental agency personnel, and the university research community.
ABSTRACT The goals of this project are to develop and demonstrate integrated vegetable production systems which enhance economic viability, environmental quality, and soil stewardship. We seek to understand fundamental ecological processes occurring in agricultural systems in order to more effectively design farming systems which are economically productive, and minimize need for agricultural inputs and minimize deleterious impacts on soil and water quality. This project has focused on developing and evaluating strip-tillage vegetable production systems which integratethe use of winter-annual cover crops for enhancing soil and water quality, suppressing weeds, and providing a habitat for beneficial organisms. In five on-farm trials in 1997 involving sweet corn production in Oregon's Willamette Valley, an integrated strip-till production system increased economic net return by an average of $47 an acre compared to the conventional tillage system. In one farm, herbicide costs were reduced by $17.53 per acre. In a replicated trial conducted at the OSU Vegetable Research Farm, strip-till systems for broccoli production using legume cover crops produced a yield increase of approximately 2 tons per acre compared to the conventionally-tilled system. In another on-farm research trial involving the planting of beneficial insectary flowers to increase the abundance of predatory insects, the blocks using the insectary plant Alyssum maritima showing a significant increase in predacious syrphid flies caught in traps and in number of syrphid eggs laid on broccoli leaves. In another on-farm trial involving cover crops for nitrogen contribution, the use of legume cover crops reduced fertilizer N inputs by 60 lbs N/acre. The integrated vegetable production systems explored in this project offer potential to not only increase net profit to the growers, but also improve water quality through reduction of leaching and surface runoff and enhance soil quality through conservation of soil organic matter and biological diversity. There is also a proven potential to reduce pesticides and fertilizer inputs. SPECIFIC PROJECT RESULTS Findings and Accomplishments  Seven experiments were conducted in 1997 to address the objectives of this project; six on-farm research trials and one trial conducted at the OSU Research Farm near Corvallis.

Description of Procedures On-Farm Trials.Since most of the growers involved in this project utilize 6-row planting equipment, a new 6-row strip-tillage machine was developed by Northwest Farm Tillers (Yakima, WA) for the 1997 trials. This machine was initially equipped with modified 'L' tines to till a 6" wide strip on 30" row centers. This configuration was used in one trial, a snap-bean trial at Dickman Farms. Because of the unusually wet spring, this tine configuration would not function well in wet soil conditions and the "L" tines were replaced with "saber" tines, with the tilled width increasing from 6" to 8". The tilled depth also increased from approx. 5" to approx. 7". Five trials involving sweet corn were established, one field each at Kraemer Farms (Monitor) and Grover Farms (Keizer) and three trials on Hendricks Farm (Stayton). One trial involving snap beans were planted at the Dickman Farms near Mt. Angel. Winter annual cover crops were planted on most of the fields in the trial by the cooperating growers in the fall of 1996. These cover crops were killed with glyphosate prior to spring tillage. Each on-farm trial consisted of two tillage treatments: "Standard" tillage and strip-tillage. Standard tillage procedures varied among the cooperating farms and fields within farms, depending on soil conditions. The strip-tillage treatment consisted of a single pass of the 6-row Northwest Farm Tiller machine, which incorporated cover crop residue and other vegetation on the soil surface. Plot sizes for the tillage treatments varied among farms, but were all at least one acre. Vegetable crops were planted using the standard planting equipment used by each collaborating grower. Fertilization and pest management decisions were made by the growers. Crop harvests were made using the growers' equipment and whole truck weights and grades were determined at the processing plant. One additional sub-soiling tillage treatment was added to two of the Hendricks Farms trials. A patented "winged subsoiler" developed by Ed Fields, of Monroe, OR, was used prior to strip-tillage to see if additional subsoil tillage would affect sweet corn yields. Economic analysis : A comparison of the relative economic benefit of the strip-till system compared to the standard tillage systems was conducted using two components: (1) economic value of the crop (yield, grade and price) and (2) calculating costs of tillage for the two systems. Tillage costs were estimated using The Cost of Owning and Operating Farm Machinery in the Pacific Northwest (Willett and Smathers, 1992) and information on specific equipment used by the collaborating. Soil Arthropod Sampling . Relative activity of predacious soil-dwelling insects and spiders were estimated by placing pitfall traps in each tillage block on Hendricks Farms Shimanek Bridge field. Pitfall traps consisted on one-pint plastic containers buried in the soil with the lip of the cup flush with the soil surface. The traps will

filled approximately half way with antifreeze (to kill and preserve the trapped arthropods), and a 9" x 9" plywood cover was suspended over the trap to protect from rainfall and irrigation. Six traps were randomly placed in each tillage treatment; trapped arthropods were removed weekly and the traps refilled with antifreeze. Soil Temperature . Soil temperature measurements were taken approx. 2" below the soil surface in each tillage treatment in four fields using Hobo electronic temperature loggers. Temperature loggers were buried within the planted row and temperatures recorded on an hourly basis to determine daily maximum and minimum temperatures. Growing season degree days were calculated using a lower threshold temperature of 50 degrees F; degree-days for the germination period were calculated for the first 7 days after the logger was installed (from 3-5 days after the vegetable crop was planted). OSU Vegetable Research Farm Trials.This project was conducted as part of the M.S. Thesis of Tim O'Brien and complete details of this project are found in his thesis, Integration of Conservation Tillage and Cover Crops in Broccoli Production Systems of the Pacific Northwest , OSU Dept. of Horticulture, 1997. This experiment involved comparing strip-tillage with conventional tillage for transplanted broccoli production. Experimental treatments examined included two tillage method and two cover crop mixtures. A randomized block design experiment was used with three replications; individual plot sizes were 4.6 m by 15.2 m. Two cover crop mixtures (Monida oats plus common vetch, and Dacold rye plus common vetch) were drilled Sept. 24, 1996, and irrigated to accelerate germination. Cover crop biomass was sampled in the spring prior to desiccation by clipping two 0.25 m2quadrats within each plot and drying and weighing the sample. Glyphosate herbicide was used to kill the cover crops (strip-till plots were sprayed April 2; conventional till plots were sprayed April 18). All plots were flail mowed on May 7 and tillage conducted on both conventional and strip-till on May 12. A 4-row Northwest Farm Tillers machine was used to till 6" wide strips on 30" centers. (This machine was used in on-farm trials in 1996 and had a modified tine configuration using a combination of straight, 'L' and angled tines). A mixture of oxyfluorfen (Goal) and glyphosate was applied May 14 to all plots and all plots received broadcast NPK fertilizer. Broccoli (var. = 'Arcadia') was transplanted on May 16 using transplants grown by Northwest Transplants (Molalla, OR). Chlorpyriphos insecticide was applied on May 23 to control seed corn maggots and flea beetles and a sidedress application of ammonium nitrate was made on June 18. Broccoli was hand harvested and yields determined July 24 and July 27. RESULTS AND DISCUSSION Yield and Economic Analysis . The strip-tillage system produced higher sweet corn yields than the standard tillage practices on 4 of the 5 fields in the trial. Economic

analysis showed that for sweet corn production averaged across the three farms and five fields in the 1997 trial, the strip-tillage system produced an economic advantage of $47 per acre greater than the standard tillage systems. This value is based on an average increase in crop value (a combination of yield, grade and price) of $27 per acre (see Table 1) and an estimated savings in tillage costs of $20 per acre (see Table 2). The highest increase in economic value associated with strip-tillage was in the Hendricks Farms Shelburn Road field, with a $126 advantage over standard tillage ($98 in product value; $27 in tillage cost savings). Strip-tillage was not economically advantageous in all fields, however. The strip-till system produced lower yields at the Grover Farms (standard tillage producing a crop worth $65 more per acre than the strip-till system), however there was a savings of $21 per acre by strip-tillage compared to standard tillage. At the Kraemer Farms trial, standard tillage produced a corn crop worth $13 per acre greater than strip-tillage, and standard tillage costs were $1.63 per acre less than with strip- till. In both the Grover and Kraemer Farms, because the cover crops were sprayed out early in the season (nearly two months prior to planting), there was a minimal cover crop residue at planting time, which may have contributed to reduced yields. In the subsoiled plus strip-tillage plots in two fields at Hendricks Farms, there was a increase in economic crop value compared to standard tillage by $59 and $128 per acre (Table 1). There was a smaller increase in economic value compared to the strip-tillage alone ($29 and $30 per acre). Because this is a relatively new, patented implement, no information was available to estimate costs of using this subsoiler, but because of the high horsepower tractor required to pull it, this will be a relatively expensive tillage operation. There were differences in the quantity and quality of the cover crop residues in these fields. We sampled cover crop biomass within a week prior to application of glyphosate. In some cases the field was not actually tilled and planted for up to two months later. The strip-tillage machine had no difficulty in incorporating the residue at either Dickman or Hendricks Shimanek Bridge fields. The snap bean trial at the Dickman Farms revealed a potential for strip-tillage production, however a mistake in placement of the tillage treatments in the field reduces the ability to draw conclusions from this experiment. Tillage treatments were placed adjacent to one another, but were mistakenly placed in fields with differing cropping history. The strip-till block was planted into a field in which sweet corn was grown in 1996, followed by a winter cover crop of oats and peas. This cover crop was sprayed out with glyphosate several weeks prior to strip-tillage. The standard tillage treatment block had a crop of wheat in 1996, and was winter- fallowed with wheat stubble and volunteer wheat prior to tillage in the spring of 1997. The snap beans were planted in both tillage treatments on the same day and were managed similarly (except for reduced herbicide inputs in the strip-till, as is described later). Clearly these are major field history differences that could affect the 1997 bean crop yield and maturity independently of the experimental tillage treatments. This trial was also pummeled by two intense rain storms within a few days following bean planting, causing soil crusting and uneven emergence in both tillage treatments.

	Keeping these considerations in mind, we did measure a higher yield and a higher grade of beans in the strip-till treatment compared to the conventional till treatment, producing an economic advantage of $308 per acre for the strip-till system (Table 1). There was also a tillage cost savings of $30 per acre with strip-tillage. In addition, no pre-emergence herbicides were applied in the strip-till block, whereas Eptam and Treflan was applied in the conventional till block. Weed suppression was quite good in the strip-till block, however both tillage treatment blocks received a mid-season application of Basagran. Savings in herbicide costs in the strip-till block was calculated to be $17.53 per acre compared to the standard tillage treatment (based on 1997 chemical prices). As stated earlier, because of confounding effects in the experimental design we cannot draw firm conclusions from this trial. However, there is clearly a potential for integrated cover crop/strip-tillage systems for snap bean production. Table 1. Effects of tillage systems on yield, grade and economic value of sweet corn and snap beans in on-farm research trials, Willamette Valley, OR 1997.

Soil Arthropod Activity . A major generalist predator that colonizes agricultural fields is the carabid beetle, Pterostichus mellanarius . This beetle preys upon a wide array of hosts, including important crops pests such as cutworm and slugs. More adult P. mellanarius were found over the trapping season in the strip-tillage block (177) compared to the standard tillage block (101), however most of this difference occurred late in the season (Fig. 1). More spiders were found in the standard tillage treatment (109) than in the strip-till block (90). Fig. 1. Average number of insects per trap in sweet corn at Hendricks Farms, Shimanek Bridge field, 1997.
		Date
Soil Temperature Effects . There was no consistent pattern in tillage treatment effect on soil temperatures in these trials. In the Hendricks field, strip-till plots were generally cooler during the latter part of the season. Overall accumulated degree days were similar for the tillage treatments within each of the four fields sampled (Dickman: Strip-till 1,027, standard till 998; Grover: strip-till 1,895, standard till 1,996; Hendricks: strip-till 1,537, standard-till 1,566; Kraemer: strip-till 1,869, standard till 1,828). Strip-till Broccoli, OSU Vegetable Research Farm Trial. The 'Dacold' rye and common vetch mixture contained a much higher proportion of vetch in the spring when the cover crops were killed with glyphosate than did the 'Monida' oat and vetch cover crop mixtures (Table 2). The Dacold rye grew very slowly in the fall, allowing the vetch to be competitive, whereas the Monida oat grew very vigorously

in fall, suppressing the vetch growth. Although the conventional till plots were sprayed with herbicide 16 days later than the strip-till plots, there was very little difference to total biomass or nitrogen accumulation. Table 2. Estimated cost of tillage for 1997 on-farm research trials1. Percent GrowerStandard tillStrip-tillcostCost Savings ($/A)($/A)savings($/A)
	Hendricks Grover Kraemer Dickman	$61.94 36.31 37.10 61.94		$32.38 14.90 38.74 32.38			48 59 -4 Average: 48			$29.56 21.41
									-1.63
										$20.152 $29.56
2This average include 3 fields at Hendricks Farm. The Dacold rye/vetch mixture produced statistically higher broccoli yields than the Monida oat/vetch mixture in the strip-till plots (p = .04) (Table 3). Although the Dacold rye/vetch mixture produced more than 2 tons per acre greater yield in the strip-till plots than in the conventional till plots, there was a fairly low statistical probability that these differences were due to tillage treatment effects (p = .29). Yields were similar across the tillage treatments for the Monida oat/vetch cover crop treatment, and there was not cover crop effect within the conventional tillage treatment (Table 3). Table 3. Effect of cover crops and tillage treatment on broccoli yield and soil nitrate content within the top 6" of soil, OSU Vegetable Research Farm, 1997. Broccoli yield1 Tilllage and(tons perSoil nitrate (ppm) cover crop treatmentacre)May 21 June 18 Strip-tillage
	'Monida oat' + vetch 'Dacold' rye + vetch Conventional Tillage 'Monida' oat + vetch		4.1 7.0 4.9			7.7		2.2 2.5 2.8
					19.9
						5.8

	'Dacold' rye + vetch Pairwise comparisons Strip MO vs. Conv. MO Strip DR vs. Conv. DR Strip DR vs. Strip MO		5.3	8.3	2.8
		p-values of test2
			.40 .29 .04	.68 .05 .04	.15 .37 .38
Conv. DR vs. Conv. MO.68.58.90 1Broccoli yield of grade 1 broccoli using grading standards of Norpac Foods, Inc. 2P-values represent the level of "statistical significance" in testing whether the mean values of the comparison are different due to actual treatment differences rather than random chance. Lower p-values represent a higher probability that the treatments are actually different. The Dacold rye/vetch cover crop produced a spike of soil nitrate of 19.9 ppm in the strip-till plots when sampled on May 21 (five days after broccoli transplanting), compared to soil nitrate values in other plots of 7.7, 5.8, and 8.3 ppm (Table 3). At the later season June 18 sampling date, however, no differences were detected for soil nitrate among any of the cover crop and tillage treatments. The higher levels of nitrogen release from the Dacold rye/vetch cover crop early in the season in the strip-till system may have accounted for the increased broccoli yield. Dissemination of Findings Presentations to Growers and Agricultural Professionals 1997Cover Crops for Soil Improvement, Water Quality and Pest Management Workshop. Corvallis, OR. Extension In-Service Education Program. (90 growers and agricultural professionals) Conservation FarmingField Day. Corvallis, OR. Extension In-Service Education Program. (45 agricultural professionals) Crop management practices for surface and groundwater protection. Natural Resources Staff Orientation and Training, Oregon Department of Agriculture and the Department of Environmental Quality, Salem, OR. (45 attendees) Sustainable gardening practices. Master Gardener Training, OSU Extension Service, Newport, OR. (26 attendees) Sustainable agriculture: principles and practice. Northwest Center for Sustainable Resources. Salem, OR. (12 attendees)

Minimum-tillage vegetable production systems. Oregon Processed Vegetable Growers Meeting, Salem, OR. (125 attendees) Presentations at Scientific Meetings Luna, J. M., T. J. O'Brien, and M. L. Staben. 1997. Integrating strip-tillage and cover crops for vegetable production systems. National Meeting, Amer. Soc. Hort. Sci., Salt Lake City, UT. Luna, J. M., M. L. Staben, and T. J. O'Brien. 1997. Integration of cover crops and strip- tillage systems for vegetable production in the Pacific Northwest. National Conf. Cover Crops, Soil Quality and Ecosystems, Sacramento, CA. Colley, M. and J. M. Luna. 1997. Relative attractiveness of potential insectary plants to hoverflies (Diptera: Syrphidae) and parasitic wasps (Hymenoptera: Ichneumonidae and Braconidae). National Mtg., Entomol. Soc. Amer., Nashville, TN. POTENTIAL CONTRIBUTIONS Positive Benefits or Impacts  Strip-tillage systems for sweet corn production using cover crops were shown to be more profitable than conventional tillage treatments in on-farm trials conducted in 1997. There is the potential to dramatically reduce tillage requirements by 500-700%. This reduction in tillage will reduce soil erosion and movement of soil and agricultural chemicals into surface water systems through runoff. There is also a dramatic reduction in wind erosion of soil through this conservation tillage system. A major impact associated with adoption of these conservation tillage systems could also be improved conservation of soil organic matter by reducing microbial oxidation following tillage. Fall-planted winter annual cover crop mixtures of cereals and legumes can significantly reduce soil erosion and leaching of soil nitrate into the groundwater during the rainy Pacific Northwest winters. These cover crops, when managed correctly, can reduce nitrogen fertilizer requirements for the following vegetable crop by 80-100 lbs. N/acre. Allelopathic cover crops, coupled with reduced tillage systems, form important components of integrated weed management strategies, with dramatic opportunities to reduce herbicide inputs and costs. Beneficial insectary plantings offer promise in increasing the effectiveness of naturally-occurring predacious and parasitic insects in biological insect pest management. We are developing strategies and specific management recommendations to utilize beneficial insectary plants in both annual and perennial cropping systems. These strategies, combined with other integrated pest management tactics, may reduce pesticide inputs into these systems.

Farmer Adoption and Changes in Practices  There is an increasing number of vegetable growers in the Willamette Valley who are growing cover crops, largely due to on-farm demonstration tours and other educational events associated with this project. Changes in cover crop practices are also occurring. For example, Stahlbush Island Farms, a 1,400 acre vegetable production operation near Corvallis, switched from growing Austrian field pea cover crops to using fava beans, crimson clover, and common vetch as direct result of being involved with this project. Austrian field pea is subject to a root disease and our on-farm research showed this species to less desirable than the other legumes for our climate. One farmer involved in our on-farm research project has converted approximately one third of his 300 acre farm to strip-tillage and is producing above average crop yields using this system. Several of the growers involved with the on-farm strip-till evaluation are expanding the acreage on their farms to be planted using the strip-till system in 1998. The equipment manufacturer collaborating on this project (Northwest Farm Tillers, Yakima, WA) has committed significant financial resources to completely redesigning their strip-till machine to accommodate the needs of the growers in our project. Operational Recommendations We recommend mixtures of cereal crops and legumes, preferably planted from September 15-October 21. Maximum N contribution is obtained by planting a pure stand of legume. Spring cover crop management should be based on projected vegetable crop planting date, with total above-ground cover crop dry matter biomass managed not to exceed 3 tons/acre. Glyphosate herbicide should be applied approx. 3-4 prior to strip-tillage. Strip-tillage systems for sweet corn use a flailed cover crop, strip-tillage of 6-8" wide strips on 30" centers, with appropriate pre-emergent herbicide banded in 10" strips over the row. Strip-tillage should precede corn planting by approx. 7-10 days to allow cover crop decomposition and soil warming. A high-residue cultivator should be used approximately 3-4 weeks after corn planting if weed control is required in the row middles. These recommendations are tentative, however, as specific timing of cover crop management, tillage and vegetable crop plantings will be further refined based on 1998 experiments. Producer Involvement Five Willamette Valley vegetable growers were involved with this project in 1997. These growers have been actively involved since 1994 in setting research priorities, determining appropriate experiment design, laying out plots, selecting and planting cover crops, providing land, machinery and labor, operating strip- tillage and cultivating equipment, and in harvesting and weighing crop yields. All of these growers attending a project planning meeting in December, 1996, to discuss

project results and plans for the 1997 season. Owners and manufacturing representatives of the Northwest Tiller Company (Yakima, WA) attended this meeting to discuss increased participation in the project, including financial contributions of equipment. Numbers of Farmers and Agricultural Professionals in Attendance at:
	161 125 57	Workshops Conference Field Days
NEW HYPOTHESES In the 1997 strip-tillage trials, yield increases were noted in 5 of the seven trials; yield decreases were observed in two trials. Possible hypotheses for why tillage systems affect crop yield include: (1) nutrient availability, (2) changes in soil structure affecting root growth (3) moisture storage and availability, (4) unknown pests (insects or pathogens) which are favored or suppressed by the tillage systems. GENERAL DISCUSSION AND FUTURE RESEARCH NEEDS The integrated strip-tillage system utilizing winter annual cover crops clearly shows potential to increase vegetable crop yields and well as reduce tillage costs. By reducing tillage from 6-7 passes over the field to a single pass, there will likely be a reduction in soil compaction and loss of organic matter through oxidation, and enhanced conservation of biological resources within the system. Although not part of this project, another study we conducted this past year showed significantly higher numbers of earthworms in strip-till systems compared to conventional tillage. More work is needed to modify the strip-tillage machine to increase ground speed and to improve seedbed preparation within the tilled row. Peter Kenagy, one of the growers collaborating in this project, has build his own strip-tiller and has added a disk coulter and a small shank in front of each set of tillers to break the soil and allow the machine to be operated at a higher ground speed. The 6-row machine used in the 1997 trials could only be operated from 1.8 to 2.5 mph. Increasing this speed to 3.5-4 mph would greatly increase the ability to prepare land during frequently narrow breaks in the weather and would reduced the cost of operating this machine. There is also a need for a roller/packing devise to follow the tillers and firm the seedbed prior to planting. The research at the OSU Vegetable Research Farm shows the importance of cover crop selection on maximizing vegetable crop yield. Cover crops with a higher proportion of legume will release nitrogen faster to the following vegetable crop, and potentially reduce the amount of nitrogen fertilizer to be applied. There is a significant opportunity to reduce herbicide costs with the integrated strip-till/cover

crop system. Extensive research has shown that tillage stimulates weed germination and that reducing tillage reduces weed germination. Banding herbicides within the tilled row and using post-emergence herbicides when needed or using cultivation may also offer to opportunity to reduce weed control costs. Additional on-farm trials are being planned for 1998, with larger plot sizes and more growers involved. Because of the favorable results with the snap-bean trial in 1997, additional strip-till snap bean trials will be established. Additional work will also focus on optimal timing of glyphosate killing of the cover crop to maximize weed control and optimize cover crop residue biomass and quality. More research is also needed to better understand and optimize cover crop N release to the vegetable crop. Continued research is needed in the area of selecting and managing beneficial insectary plants for enhancing biological control. We have made significant initial progress in this area, identifying key insectary plants and the general fauna of associated predacious syrphid flies. More work is needed to define specific flower/insect relationships, determine which of the 20 species of syrphids collected in our studies are predacious on key insect pests, and what are the appropriate strategies for utilizing these beneficial insectary plants to affect practical biological pest control.