Utah State University DigitalCommons@USU All Graduate Theses and Dissertations Graduate Studies 5-1996 An Integration of Tillage and Herbicides to Control Jointed Goatgrass (Aegilops Cylindrica Host.) in Winter Wheat Troy M. Price Utah State University Follow this and additional works at: https://digitalcommons.usu.edu/etd Part of the Plant Sciences Commons Recommended Citation Price, Troy M., "An Integration of Tillage and Herbicides to Control Jointed Goatgrass (Aegilops Cylindrica Host.) in Winter Wheat" (1996). All Graduate Theses and Dissertations. 4602. https://digitalcommons.usu.edu/etd/4602 This Thesis is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Theses and Dissertations by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. AN INTEGRATION OF TILLAGE AND HERBICIDES TO CONTROL JOINTED GOATGRASS (AEGILOPS CYLINDRICA HOST.) IN WINTER WHEAT by Troy M . Price f. thesis submitted in partial fu!fi!lrr.er:t of the requirements for the degree of MASTER OF SCIENCE in Plant Science UTAH STATE UNIVERSITY Logan, Utah 1996 ii ABSTRACT An Integration of Tillage and Herbicides to Control Jointed Goatgrass (Aegilops cylindrica Host.) in Winter Wheat by Troy M. Price, Master of Science Utah State University, 1996 Major Professor: Dr. John 0. Evans Department: Plants, Soils and Biometeorology An integrated management approach for jointed goatgrass control was investigated at two farms in northern Utah using three tillage regimes and three herbicides. The tillage regimes included no tillage, conservation tillage, and conventional tillage. Each regime was composed of different tillage practices common in the Intermountain West. A preemergence herbicide, clomazone, and two postemergence herbicides, 2,4-D and glyphosate, were investigated. Greenhouse studies were also conducted to investigate clomazone efficacy and depth of planting of winter wheat and jointed goatgrass. Differential sensitivity to clomazone between jointed goatgrass and winter wheat did not occur in the greenhouse for the rates tested. A treatment ofO.ll kg ai ha·1 clomazone reduced wheat and jointed goatgrass fresh weights similarly by 49 and 63%, respectively. Ill Jointed goatgrass did not germinate below 6.4 em and emergence was initially reduced at the 2.5 em soil depth. Winter wheat emergence was not lowered until the seed was planted 5.0 em deep or deeper and continued to 8.9 em deep. 2,4-D plus glyphosate provided over 95% jointed goatgrass control initially and by midsummer fallow especially when followed by tillage. However, extensive populations of jointed goatgrass seedlings and spikelets were found in the fall prior to initiation of the cropping season. Herbicides did not provide meaningful differences in the jointed goatgrass spikelet or seedling populations. Conventional tillage practices, such as fall or spring chiseling accompanied by three summer rodweedings, provided the greatest control ofjointed goatgrass spikelets and seedlings in the fall following the fallow season. Winter wheat yields reflected this relationship by having five times greater yields in the conventional tillage than in either no tillage or conservation tillage. (66 pages) iv ACKNOWLEDGMENTS I would like to thank Dr. John 0 . Evans for his help and assistance with this research project I greatly appreciate the patience and understanding he demonstrated on my behalf and encouragement to continue on. I also appreciate the help of Dr. Steven A Dewey for his advice and encouragement Special thanks goes to William Mace and Matt Larson for their assistance in getting the work done in the fields. I especially appreciate their fiiendship and patience throughout this entire process. Thanks goes out to Richard Peterson and Leo Erickson for the use of their farms and providing equipment when necessary. Without the use of these farms, this project would not have as easily been accomplished. I also thank my fellow students and other faculty members who provided assistance and encouragement. I would especially like to thank my wife, Julie, for her patience and love. Throughout this whole project, she was always there to pick me up and keep me going. thank my boys for their patience with their father and just for being there to support me. greatly appreciate the faith my family has in me. When times were difficult at home, they always showed their love and helped me to feel that I could accomplish this task. I also would want to thank any fiiends and family members who were always there for me. I love you all and will forever remember the sacrifices you all made to keep me going. TroyM. Price v CONTENTS Page ABSTRACT ii ACKNOWLEDGMENTS. iv LIST OF TABLES . vi LIST OF FIGURES . viii INTRODUCTION LITERATURE REVIEW. 3 MATERIALS AND METHODS . .14 Greenhouse Studies . .14 Fallow Season Evaluations .16 Within Crop Evaluations. .21 RESULTS AND DISCUSSION .23 Greenhouse Studies . .23 Fallow Season Evaluations .26 Within Crop Evaluations. .33 SUMMARY AND CONCLUSIONS . .40 LITERATURE CITED . .42 APPENDIX. .47 vi LIST OF TABLES Table Page I. Results of 1993 jointed goatgrass survey reported by Ogg. 4 2. A comparison of tillage regimes regarding number of fallow operations and plant surface residue. 20 3. Dry weights of wheat or jointed goatgrass plants following domazone treatments under subsurface and surface irrigation. 23 4. Percentage wheat and jointed goatgrass seedlings emerging at nine planting depths in the greenhouse. 25 5. Visual estimates of clomazone phytotoxicity to jointed goatgrass, Promontory, UT. (Aprill993) . .27 6. Number ofjointed goatgrass seedlings emerging in fallow following fall tillage and herbicide treatments, Promontory, UT. (April 1993) . 28 7. Number ofjointed goatgrass tillers in midsummer fallow following treatments of 2,4-D +glyphosate and spring and summer tillages, Promontory, UT. (July 1993) .29 8. Number ofjointed goatgrass tillers in midsummer fallow following treatments of clomazone and spring and summer tillages, Promontory, UT. (July 1993) . 31 9. Influence of selected herbicides on jointed goatgrass emergence in the absence of tillage, Beaver Dam, UT. (July 1994) . .33 10. Numbers ofjointed goatgrass spikelets at three soil depths in seedling winter wheat, Promontory, UT. (October 1993) . .34 II . Numbers ofjointed goatgrass seedlings for three soil depths, Promontory, UT. (October 1993) .35 12. Numbers of jointed goatgrass spikelets for three soil depths, Beaver Dam, UT. (October 1994) .36 vii 13. Numbers ofjointed goatgrass seedlings for three soil depths, Beaver Dam, UT. (October 1994) .37 14. Percentages ofjointed goatgrass and winter wheat in harvest samples and wheat yield, Promontory, UT. (September 1994) .38 15. Analysis of variance for dry weights for greenhouse clomazone study .. .48 16. Analysis of variance for greenhouse depth study. .49 17. Analysis of varia..11ce f.:>r visual estimates of c!oml!.Zcne phytotoxicity. .50 18. Analysis of variance for number of jointed goatgrass seedlings emerging in fallow following fall tillage and herbicide treatments, Promontory, UT. 51 19. Analysis of variance for number ofjointed goatgrass tillers in midsummer fallow following treatments oftillages and herbicides, Promontory, UT. .52 20. Analysis of variance for comparison of herbicides in spring fallow, Beaver Dam, UT. .53 21. Analysis of variance for fall counts of jointed goatgrass spikelets in fallow following fall wheat planting, Promontory, UT. 54 22. Analysis of variance for fall counts ofjointed goatgrass seedlings in fallow following fall wheat planting, Promontory, UT. 55 23 . Analysis of variance for fall counts of jointed goatgrass spikelets in fallow following fall wheat planting, Beaver Dam, UT. 56 24. Analysis of variance for fall counts of wheat seedlings in fallow following fall wheat planting, Beaver Dam, UT. 57 25. Analysis of variance for percent jointed goatgrass, percent wheat, and total winter wheat yield for harvest, Promontory, UT. 58 viii LIST OF FIGURES Figure Page I. Percent jointed goatgrass control in midsummer following herbicide and tillage treatments. .30 INTRODUCTION Jointed goatgrass is one of the worst weeds to invade small grains in the Intermountain West. Once started, it invades dryland and irrigated small grains, other crops, roadsides, rights-of-way, CRP acreage, and even rangelands. The seed is readily disseminated by wind, water, animals, and mechanically by human activities. It readily adapts to drought conditions that are prominent in dryland, winter wheat production and along dry gravelly roadsides. This allows jointed goatgrass to outcompete winter wheat and facilitates its increase. Jointed goatgrass is a winter annual grassy weed that is closely related to wheat both biologically and genetically and it negatively impacts crop quality and yield. Recent estimates place the cost ofjointed goatgrass to U.S. farmers at $35 million in direct losses and the combined direct and indirect losses at probably over $145 million. A 1993 survey in Utah revealed that of the 270 thousand acres of small grains, 52 thousand acres were infested with jointed goatgrass. Due to the genetic similarities, chemical control ofjointed goat grass appears difficult to improbable because selective herbicides for jointed goatgrass are unlikely in winter wheat. Other control alternatives must be investigated, especially the integration of several control strategies. The primary objective of this