|LYON, DREW - Washington State University|
Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/24/2015
Publication Date: 6/15/2015
Citation: Lyon, D.J., Young, F.L. 2015. Integration of weed management and tillage practices in spring barley production. Weed Technology. 29(3):367-373.
Interpretive Summary: Long-term, large scale cropping systems field studies are important research projects to identify profitable production systems, provide information on cumulative treatment effects, assess conservation tillage systems, and identify strategies for erosion control and pest management. In the wheat growing region of the Pacific Northwest, soil erosion is as high as anywhere in the United States and reduced profitability and lack of effective weed control have been major impediments to the implementation on conservation tillage for the reduction of soil erosion. Spring barley is an important rotational crop in the Pacific Northwest but there is no information on the response of barley to conservation tillage systems and weed management levels. Spring barley was an integral crop of a 3-yr rotation, conservation tillage crop production system that was profitable and met conservation compliance requirements. In this study, the effect of three weed management levels (WML) and two tillage systems on weed control and barley grain yield were examined. Lowest barley yields were realized with minimum WML in both tillage systems and highest yields occurred with the moderate and maximum WML in the conservation tillage system. These results should assist growers in adopting conservation barley production systems that reduce erosion and increase environmental quality and farm profit.
Technical Abstract: Spring barley can be used to diversify and intensify winter wheat-based production systems in the U.S. Pacific Northwest, but the response of barley to conservation tillage systems, which are needed to reduce the risk of soil erosion, is not well documented. The objective of this study was to describe the effects of tillage system and weed management level (WML) on weed control and spring barley grain yield when grown in a winter wheat-spring barley-spring dry pea rotation. A long-term integrated pest management field study examined the effects of three WMLs (minimum, moderate, and maximum) and two tillage systems (conservation and conventional) on weed control and barley grain yield. Total weed biomass at harvest ranged from 8.0 to 59.7 g m-2 for the maximum and minimum WMLs, respectively, in the conservation tillage system, but was similar and averaged 12.2 g m-2 for all three WMLs in the conventional tillage system. Barley grain yields were similar in both tillage systems at the minimum WML, with an average yield of 4,460 kg ha-1, but maximum grain yields, which averaged 5,360 kg ha-1, were obtained when conservation tillage was combined with moderate or maximum weed management. The benefits of conservation tillage, which include increased grain yield as well as reduced soil erosion, were not realized without adequate weed control provided in this study by increased herbicide inputs. Good stewardship of the herbicides currently labeled in barley is critical if barley production is to be maintained or increased in conservation tillage systems of the Pacific Northwest.