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Progress Report-2002 |
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NOTICE |
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1. TITLE: Determining Best Crop Rotation for Effective Jointed Goatgrass Control Using Imidazolinone Resistant Wheat.
2. PERSONNEL: Principal Investigators: Frank L. Young Joseph P. Yenish John Burns
3. TIME LINE: Initiation: August 2000 Termination: August 2005. This project is on schedule.
4. ORIGINAL HYPOTHESIS: Crop rotation strategies can prevent the development and spread of herbicide-resistant weeds when imidazolinone-resistant (Clearfield®) wheat is used to manage jointed goatgrass.
5. SUMMARY OF PROGRESS: Researchers collected data during the third year of a long-term study in eastern Washington to determine the frequency and time to use a herbicide-resistant crop to manage jointed goatgrass (Aegilops cylindrica). Research activities continued at two locations: 1) 46-56 cm (high) rainfall zone with a winter wheat/spring cereal/grain legume rotation, located near Pullman, WA; and 2) 23-28 cm (low) rainfall zone with a winter wheat/summer fallow rotation, located near Pasco, WA. At Pullman, imidazolinone-resistant winter wheat planted in the fall of 2000 was treated in April 2001 with imazamox herbicide at the rate of 0.045 kg ha-1, non-ionic surfactant at 0.25%, and 2.5% UAN solution v/v. Control of jointed goatgrass with imazamox in imidazolinone-resistant winter wheat plots was nearly 100%, and crop safety was excellent. The conventional winter wheat at Pullman not treated with imazamox was heavily infested with jointed goatgrass, averaging 4 jointed goatgrass spikes 0.5m-2, and 8 spikelets/spike. Average yields (clean grain) at Pullman included 7795 kg ha-1 for the imidazolinone-resistant winter wheat, and 7190 kg ha-1for the conventional winter wheat. The Pullman site is on schedule to go into the second cycle of the study, with imidazolinone-resistant and conventional winter wheat being seeded in the fall of 2003, which will follow a spring legume.
At the Pasco north site, imidazolinone-resistant winter wheat planted in the fall of 2001 was treated in April 2002 with imazamox herbicide at the same rate used in Pullman. Control of jointed goatgrass was good, with imidazolinone-resistant winter wheat plots averaging only 5.7 spikelets m-2 , compared to a 56.7 spikelets m-2 average in conventional winter wheat plots. Average yields (clean grain) at Pasco north included 1880 kg ha-1 for the imidazolinone-resistant winter wheat, and 1480 kg ha-1 for the conventional winter wheat. The Pasco north site will be fallow in 2003 and then go into the second cycle of the study, with imidazolinone-resistant and conventional winter wheat being seeded in the fall of 2003. This was the first year of wheat production in the low rainfall zone
At the Pasco south site, both imidazolinone-resistant and conventional winter wheat were planted for the first time in the fall of 2002. Preliminary jointed goatgrass counts (during the summer-fallow period) in this field showed an average of 91 spikelets 0.5 m-2. The imidazolinone-resistant winter wheat will be treated with imazamox in the spring of 2003.
6. OBJECTIVES: a. Determine jointed goatgrass seed bank response to crop rotations, which include imidazolinone-resistant wheat and selective applications of imazamox.
b. Determine the risk of developing imidazolinone -resistant jointed goatgrass/winter wheat hybrids and populations of resistant jointed goatgrass biotypes.
c. Identify a stable crop production system based on time and frequency of introduction or HRC for the integrated management of jointed goatgrass.
7. EXPERIMENTAL DESIGN: At Pullman, plots were established in chickpea stubble and arranged in a randomized complete block with four replications, with a plot size of 7.5 x 125 m. The rotation for the experimental site will be winter wheat in 2000/01, spring cereal in 2002, grain legume in 2003, winter wheat in 2003/04, spring cereal in 2005, and grain legume in 2006. This experiment will continue through two rotation cycles at Pullman. Imidazolinone-resistant (Clearfield®) wheat and a standard local variety (Madsen) were planted in October 2000.
Plots were established in fallow at Pasco (Pasco north field) in February 2001. Jointed goatgrass seedling counts were made in February at this experiment site prior to summer fallow tillage. Plots will be managed in a wheat/summer fallow rotation at Pasco, with winter wheat in 2001/02, fallow in 2003, winter wheat in 2003/04, fallow in 2005, and winter wheat in 2005/06 in the Pasco north field. Plots were established in a second field (Pasco south field) in summer 2001, so experiments will be conducted every year at the Pasco location. At the Pasco south experiment site, the plots will be fallow in 2001/02, winter wheat in 2002/03, fallow in 2003/04, winter wheat in 2004/05, and fallow in 2005/06. Plots will be 7.5 x 125 m with four replications in a randomized design at both the Pasco north and south experiment sites.
At both Pullman and Pasco, plots planted with Clearfield® wheat will be treated during the spring of each winter wheat rotation year with ≥0.045 kg ha-1 imazamox, 0.25% nonionic surfactant, and UAN solution at 2.5% v/v for selective jointed goatgrass control. Clearfield® plots will also be managed using selected integrated management practices (deep banding fertilizer and preplant, nonselective herbicide applications for jointed goatgrass control). Plots planted with Madsen will be managed using recommended integrated management practices for jointed goatgrass control.
8. PROGRESS: Clearfield® winter wheat plots were treated with imazamox in April 2001 at Pullman. Broadleaf weeds were controlled with a separate application of bromoxynil herbicide in both conventional and Clearfield® wheat plots at Pullman. Jointed goatgrass spike and spikelet counts were made. Jointed goatgrass control was excellent in Clearfield® plots, with control near 100%. Plots with conventional Madsen wheat were heavily infested with jointed goatgrass. Imazamox crop safety was also excellent at the 0.045 kg ha-1 rate. This site will be seeded again with Clearfield® and Madsen winter wheat when it enters the second cycle of the study in the fall of 2003. Spring cereal was planted at this site in 2002.
Pullman Field Data:
It was extremely dry at Pasco during the 2000-2001 growing season. Precipitation was less than 18 cm during the crop year from September 2000 through August 2001.
All plots in the Pasco north field were fertilized before planting by deep banding anhydrous ammonia fertilizer. Actual fertilizer applied to the site in May 2001 included 50 kg ha-1 of nitrogen. The field was rod-weeded 3 times during the fallow period.
Winter wheat was planted on September 14, 2001 in the Pasco north field with a JD HZ deep-furrow drill with 40-cm spacing, 18-cm deep to the moisture line. Clearfield® winter wheat (variety Fidel) was planted at a rate of 50 kg ha-1, while conventional Madsen winter wheat was planted at a rate of 67 kg ha-1. Normal seeding rates for the area range from 45 to 56 kg ha-1. The Clearfield® plots were treated with imazamox in the spring of 2002. The plots planted with Madsen did not receive a herbicide application for selective jointed goatgrass control. Broadleaf weeds were controlled with a separate application of bromoxynil herbicide in both conventional and Clearfield® wheat plots at the Pasco north site. Jointed goatgrass spike and spikelet counts were made prior to harvest. Jointed goatgrass control was good in the Clearfield® plots with an average of only 5.7 spikelets m-2, compared to 56.7 spikelets m-2 in the Madsen plots.
Pasco North Field Data:
All plots in the Pasco south field were also fertilized before planting by deep banding anhydrous ammonia fertilizer. Actual fertilizer applied to the site in June 2002 included 50 kg ha-1 of nitrogen. The field was rod-weeded 3 times during the fallow period.
Winter wheat was planted on September 25, 2002 in the Pasco south field with a JD HZ deep-furrow drill with 40-cm spacing, 15-cm deep to the moisture line. Both Clearfield® (ClearFirst) and conventional (Madsen) winter wheat plots were seeded at a rate of 56 kg ha-1. The Clearfield® plots will be treated with imazamox in the spring of 2003. The plots planted with Madsen will not receive a herbicide application for selective jointed goatgrass control.
Pasco South Field Data:
9. PUBLICATIONS: none
10. TECHNOLOGY TRANSFER ACTIVITIES: Preliminary data presented and the experiment discussed at the Washington State Weed Conference, November, 2002. |
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