Transitioning CRP to wheat production. Daniel A. Ball Oregon State University Columbia Basin Ag. Research Center Moro, OR

Transcription

1 Transitioning CRP to wheat production Daniel A. Ball Oregon State University Columbia Basin Ag. Research Center Moro, OR A study was established at the Columbia Basin Agricultural Research Center in Moro, OR to evaluate various dryland cropping practices to optimize operations for the transition of Conservation Reserve Program (CRP) acreage back to dryland winter wheat production. The study location is characteristic of the low rainfall, winter wheat - summer fallow, dryland production region in much of the Pacific Northwest (PNW) receiving a mean annual precipitation of 282 mm (-2 inches). Operations began in October of 20 with some treatment plots receiving a glyphosate treatment to suppress established CRP grasses. Predominant CRP grasses consisted of sheep fescue (Festuca ovina), and intermediate wheatgrass (Thinopyrum intermedium). The following spring, all plots received a glyphosate application to suppress CRP grasses. Some treatment plots (tmts # -4) were seeded to soft white spring wheat (var. Louise ) in April of 202. Other treatment plots were chemically fallowed during spring and summer of 202 (tmts # 5-8). An additional treatment plot (tmt #9) received multiple tillage operations and was designated as conventional summer fallow. Tillage operations included an undercutter sweep (x), chisel plowing (x), followed by multiple (x) diskings, multiple (2x) rodweedings, and multiple (2x) roller harrowings with the intent of reducing sod clumps, leveling the soil surface, and conserving seed bed soil moisture to facilitate winter wheat seeding. Cropping practice treatments are summarized in Table. Individual plots were 20 by 00 in size. The experiment was arranged in a randomized complete block design with 4 replications. Spring wheat yields, test weights, and percent grain protein are summarized in Table 2. All treatment plots were planted to winter wheat (var. ORCF-0 ) in late 202. Winter wheat stand counts, yields, test weights, and grain protein are summarized in Table. Tmt # Table. Cropping system treatments for transitioning CRP to winter wheat production. Tillage 202/ 20 Fall 20 Spring 202 herbicide herbicide fertilizer regime 2 wireworm seed treatment 202 planted crop 4 202/20 planted crop 4 No till Yes Yes Soil test N Yes Spring wheat Winter wheat 2 No till No Yes Soil test N Yes Spring wheat Winter wheat No till Yes Yes 0% higher N Yes Spring wheat Winter wheat 4 No till No Yes Soil test N No Spring wheat Winter wheat 5 No till Yes Yes Soil test N Yes Chem fallow Winter wheat 6 No till No Yes Soil test N Yes Chem fallow Winter wheat 7 No till Yes Yes 0% higher N Yes Chem fallow Winter wheat 8 No till No Yes Soil test N No Chem fallow Winter wheat 9 Tillage No Yes Soil test N Yes Tillage fallow Winter wheat Herbicide treatments were glyphosate at 64 fl oz/a plus non-ionic surfactant at qt/00 gal and AMS at 7 lb/00gal. Herbicide treatments were applied in fall (5, November 20) and repeated in spring (5, March 202), or applied in a spring treatment, alone. 2 N fertilizer band applied below seed at planting. Application rate was based on a preplant soil test. Treatment # and #7 applied N rate was 0% higher than soil test recommendation (increased for both the spring and winter wheat plantings). Spring and winter wheat seed treated or untreated with an insecticide for wireworm control. All treatments received a standard fungicide seed treatment. 4 Spring and winter wheat crops were seeded using a JD 560 disk type, no-till drill. All spring wheat was seeded 28, March 202, and winter wheat was seeded 2, September 202 (tmt#9) and 5, October 202 (tmts# -8). Two seeding times for winter wheat plots was due to differences in seed bed soil moisture from different fallowing methods (Figure ).

2 Table 2. Spring wheat preplant treatments, grain yield, test weights, and grain protein, 202. Moro, OR. Tmt # Tillage Herbicide N Fertilizer 2 Wireworm Spring wheat Test weight Grain Protein treatment yield (lb/a) (bu/a) (lb/bu) (%) No till Fall/Spring 65 Yes No till Spring 65 Yes No till Fall/Spring 85 Yes No till Spring 65 No ns ns ns Herbicide treatments were glyphosate at 64 fl oz/a plus non-ionic surfactant at qt/00 gal and AMS at 7 lb/00gal. Herbicide treatments were applied in fall and repeated in spring, or applied as a spring treatment, alone. 2 N fertilizer band applied below seed at planting. Application rate was based on preplant soil test. Treatment # applied N rate was 0% higher than soil test recommendation. Spring wheat seed treated or untreated with an insecticide for wireworm control. All treatments received a standard fungicide seed treatment. Table. Transitioning CRP to wheat production. Winter wheat grain yields, test weight, and protein. 20, Moro, OR. Tillage Fall 20 herbicide Spring 202 herbicide wireworm seed treatment 202 planted crop 202 / 20 fertilizer regime 2 Winter wheat stand counts Winter wheat yield 20 Test weight Grain protein (#/ft 2 ) (bu/a) (lb/bu) (%) No till Yes Yes Yes Spring wheat Soil test N d No till No Yes Yes Spring wheat Soil test N e No till Yes Yes Yes Spring wheat 0% higher N e No till No Yes No Spring wheat Soil test N e No till Yes Yes Yes Chem fallow Soil test N b No till No Yes Yes Chem fallow Soil test N c No till Yes Yes Yes Chem fallow 0% higher N b No till No Yes No Chem fallow Soil test N c Tillage No Yes Yes Tillage fallow Soil test N a LSD (0.05) ns.4 Herbicide treatments were glyphosate at 64 fl oz/a plus non-ionic surfactant at qt/00 gal and AMS at 7 lb/00gal. Herbicide treatments were applied in fall and repeated in spring, or applied as a spring treatment, alone. 2 Preplant fertilizer N based on soil test recommended application rate, or 0% higher than recommended. The fertilizer regime was applied to both spring wheat (202 crop) and winter wheat (20 crop). Spring and winter wheat seed treated or untreated with an insecticide for wireworm control. All treatments received a standard fungicide seed treatment. Soil gravimetric moisture content was obtained prior to seeding winter wheat in September 202 (Figure ). Volumetric moisture content was obtained at periodic intervals during the winter wheat growing season with a Delta Devices HH2 moisture probe from a 4 inch to 40 inch depth for representative treatments (Figures 2A-2E). Treatment 2 (no-till, spring wheat recrop), treatment 6 (no-till, chemical fallow), treatment 9 (tillage, summer fallow), and undisturbed CRP immediately adjacent to the plot area were sampled (Figures 2A-2E).

3 Figure. Gravimetric soil moisture at time of winter wheat seeding. Moro, OR.

4 Figure 2A-2E. Volumetric soil moisture during the 20 winter wheat growing season. Moro, OR. A B C D E Results and Discussion: Early and mid-spring, soil moisture was more abundant at depths greater than 5 inches in plots receiving conventional (tillage) summer fallow in comparison with plots that were no-till fallowed (Figures 2A-2C). Late-season soil moisture was similar in the cropped plots (Figure 2D and 2E). Early and mid-season soil moisture in the undisturbed CRP was similar to the soil moisture in no-till plots planted to wheat (Figures 2A-2B), but appeared to utilize moisture more conservatively as the growing season progressed such that late-season soil

5 moisture in undisturbed CRP was greater at depths greater than 2 inches than in plots planted to wheat (Figures 2C-2D). Winter wheat stand counts indicated a slightly reduced stand density in the conventionally tilled treatment plots compared to stand counts in the direct-seeded plots (Table ). At time of winter wheat seeding, the greater soil moisture in conventionally tilled and fallowed plots (treatment 9, Figure ) allowed for an earlier seeding date (2, September 202) compared to the no-till plots (5, October 202). The greater early and midseason soil moisture and earlier seeding date were likely the major contributors to the substantially greater winter wheat grain yield (Table ) compared to no-till treated plots. It was also evident that the additional N fertilizer in a 0% greater amount than recommended from a commercial soil test tended to produce a slight, but statistically non-significant increase in spring wheat yield (Table 2), and a significant increase in winter wheat yield, when winter wheat was planted after a fallow period (Table ). Preplant sampling for wireworm populations indicated very low numbers of this insect pest (data not shown). Consequently, the addition of a wireworm seed treatment insecticide had a negligible impact on winter wheat stand counts or grain yields. The overall objective of this study was to develop recommendations for transitioning CRP acreage to winter wheat production, ideally using direct-seeding operations to minimize soil disturbance reduce soil erosion potential, increase sequestered soil carbon, and reduce economic inputs, particularly mechanical tillage. The findings from this one study indicate that the more conventional approach to preparing CRP land for winter wheat production utilizing tillage produced a substantially greater winter wheat grain yield than did direct-seeding. Economic analysis of the various treatment operations will be needed to determine the relative advantages of these various crop production systems. Another related study was conducted at the Columbia Basin Agricultural Research Center in Moro, OR to evaluate the use of Clearfield wheat and imazamox (Beyond ) herbicide with and without undercutter tillage for suppression of sheep fescue during the transition from CRP to winter wheat production. A Haybuster type undercutter sweep, set to run at a 5 inch depth was operated across half of the plot area on April 2, 202 and the area subsequently maintained as chemical fallow. Clearfield winter wheat var. ORCF-0 was seeded October 5, 202 across the entire area. Beyond herbicide treatments were applied the following spring either on March 2 (early) or April 25 (late). All Beyond herbicide treatments included a nonionic surfactant at 0.25% v/v and liquid nitrogen solution (2%). Beyond treatment suppressed sheep fescue, but control was complete only when combined with spring undercutter tillage (Table 4). Table 4. Influence of fallow undercutter tillage and in-crop herbicide treatments on sheep fescue suppression in Clearfield winter wheat. Preplant Tillage Treatment Application Timing Sheep Fescue Control Winter wheat grain yield (%) (bu/a) No Tillage Huskie April No Tillage Huskie + Beyond March No Tillage Huskie + Beyond April Undercutter Huskie April Undercutter Huskie + Beyond March Undercutter Huskie + Beyond April Huskie applied at oz/a, Beyond at 6 oz/a. All Huskie + Beyond treatments received a non-ionic surfactant at qt/00 gal. and 2% N solution at 2.5 gal/00 gal. ###