Miscanthus 9 giganteus is a C 4 perennial grass that shows great potential as a high-yielding biomass crop. Scant research has been published that reports M. 9 giganteus growth and biomass yields in different environments in the United States. This study investigated the establishment success, plant growth, and dry biomass yield of M. 9 giganteus during its first three seasons at four locations (Urbana, IL; Lexington, KY; Mead, NE; Adelphia, NJ) in the United States. Three nitrogen rates (0, 60, and 120 kg ha À1 ) were applied at each location each year.Good survival of M. 9 giganteus during its first winter was observed at KY, NE, and NJ (79-100%), and poor survival at IL (25%), due to late planting and cold winter temperatures. Site soil conditions, and growing-season precipitation and temperature had the greatest impact on dry biomass yield between season 2 (2009)

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Environmental factors like drought impact the quality of biomass entering a bioconversion process. Drought often reduces the sugar content in lignocellulosic biomass, which could have economic impacts, particularly when compounded with losses in dry biomass yield; however, the effects on conversion efficiency are not completely understood. This study investigated how drought may impact biomass composition and sugar yields from dilute-acid pretreatment and enzymatic hydrolysis of Miscanthus, a tall fescue mixture, and switchgrass from Nebraska, Missouri, and Oklahoma, respectively, grown as part of Regional Feedstock Partnership field trials. Samples were grown and harvested in 2010 during non-drought conditions and in 2012 during extreme drought conditions. Non-structural glucose and proline were significantly greater in 2012 compared with 2010 for Miscanthus, which suggests drought stress occurred. Structural glucan and xylan were significantly decreased in 2012 for Miscanthus; however, reactivity and sugar yields from dilute-acid pretreatment and enzymatic hydrolysis were significantly greater in 2012 compared with 2010, suggesting that although structural sugars may decrease during drought conditions, sugar yields and reactivity may increase. For the tall fescue mixture, proline was greater, and structural sugars were lower in 2012, indicating drought stress, but minimal differences were observed in the conversion experiments. Few differences were observed for switchgrass composition and reactivity between years. The observed patterns are likely because of site-specific climatic conditions combined with the tolerance each species may have to drought. As drought occurrence and severity have increased, it is necessary to understand drought impacts to mitigate risks to future bioenergy industry growth.

Annual bluegrass (ABG) (Poa annua L.) is a prolific seed producer in the spring on golf courses that in turn decreases aesthetic quality and trueness of ball roll on coolseason putting greens. Proxy (ethephon) applied twice in the spring after green-up is the current industry standard after the loss of Embark (mefluidide) from the turf and ornamental market. However, plant growth regulators including Proxy have been used for years to help suppress ABG seedheads with inconsistent success. The primary objective of this study was to determine if ABG seedhead suppression is improved by adding a late fall application of Proxy to the two traditional spring applications of plant growth regulators at nine locations with diverse environments. A second objective was to determine the importance of including Primo Maxx (trinexapac-ethyl) in fall and spring applications. Adding a late fall application of Proxy prior to the two spring applications (F+S+S) improved control of ABG seedheads over the traditional two spring applications (S+S), but the magnitude of improvement varied among locations. Abbreviations: ABG, annual bluegrass; AUSCPC, area under seedhead cover progress curve; CBG, creeping bentgrass; DAISA, days after initial spring application; F+S+S, Proxy + Primo Maxx applied once in fall plus twice in spring; GDD, growing degree day; S+S, Proxy + Primo Maxx applied twice in spring. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Aerification of golf course putting greens in the summer rather than in the early fall does not decrease annual bluegrass cover.• Monthly applications of iron sulfate were ineffective at reducing annual bluegrass.• Methiozolin, paclobutrazol, or bispyribac-sodium provided the greatest reduction of annual bluegrass when used over multiple years. AbstractAnnual bluegrass (Poa annua L.; ABG) is among the most common weeds of highly maintained turf in the United States. Though many labeled active ingredients exist for control in golf course fairways, few labeled options exist for putting greens. Further, ABG has demonstrated resistance to several herbicide modes of action commonly used on fairway turf. The use of a systems approach coupling cultural and chemical controls with diverse modes of action could limit the potential for further ABG resistance development. Our objective was to evaluate a systems approach to ABG control on putting greens by examining seven season-long programs of plant growth regulators, herbicides, and/or iron sulfate fertilizer with July or September hollow tine aerification over 2 or 4 years in three Midwestern US states. Aerification timing did not influence annual bluegrass cover at any of the three locations. The effectiveness of season-long treatments varied by location, but methiozolin, paclobutrazol, or bispyribac-sodium consistently reduced ABG. Monthly applications of iron sulfate alone did not effectively control ABG. Several treatments reduced ABG, but none completely removed annual bluegrass. Currently, methiozolin and bispyribac-sodium are not registered for use on putting greens in the US but show potential to control ABG. As such, paclobutrazol was the most effective product of those tested that is currently available for use on US putting greens. Future availability of herbicides such as methiozolin and bispyribac-sodium would provide needed options to allow for the rotation or addition of multiple-control strategies in an ABG control system to limit resistance development.