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Web URL(s): | http://www.newss.org/proceedings/proceedings_1996_vol50.pdf#page=9 Last checked: 07/24/2013 Requires: PDF Reader Notes: Item is within a single large file |
Publication Type:
| Report |
Content Type: | Abstract or Summary only |
Author(s): | Fidanza, M. A.;
Demoeden, P. H.;
Zhang, M. |
Author Affiliation: | Graduate Reasearch Assistant, Professor, and Graduate Research Assistant; Department of Agronomy, University of Maryland, College Park, MD 20742 |
Title: | Constructing a degree-day based method for predicting smooth crabgrass emergence |
Section: | Research posters Other records with the "Research posters" Section
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Meeting Info.: | Williamsburg, VA; January 2-5, 1996 |
Source: | Proceedings of the 50th Annual Meeting of the Northeastern Weed Science Society. Vol. 50, 1996, p. 9. |
Publishing Information: | College Park, MD: Northeastern Weed Science Society |
# of Pages: | 1 |
Keywords: | TIC Keywords: Crabgrass control; Digitaria ischaemum; Emergence; Growing degree days; Lolium perenne; Microclimate; Mowing height; Poa pratensis; Temperatures
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Abstract/Contents: | "A limited amount of information exists regarding the microclimatic conditions necessary for smooth crabgrass [Digitartia ischaemum (Schreb. ex Schweig) Schreb. ex Muhl.] emergence. Efficient control of smooth crabgrass could be acheived by targetin and limiting management strategies tha correspond to smooth crabgrass emergence. Therefore, the objectives of this research were to develop a method for predicting initial smooth crabgrass emergence and for describing smooth crabgrass emergence throughout the season. Preliminary results from 1992 and 1993 appeared previously in the Northeastern Weed Science Society Abstracts.The study sites consisted of a mature stand of `Fylking' Kentucky bluegrass (Poa pratensis L.) in 1992, and `Sydsport' and `Merion' Kentucky bluegrass in 1993. In 1994, the field study was conducted on an unknown blend of perennial ryegrass (Lolium perenne L.). All field sites had a previous record of heavy smooth crabgrass infestation. Experimental plots were arranged in a randomized complete block design with four replications, and measured 1.5 by 3.0 m. Plots were mowed bi-weekly with a rotary mower. In 1993 and 1994, smooth crabgrass emergence was assessed weekly by counting and removing newly germinated seedlings from three, 625 cm₂ fixed grids per plot. A different method for evaluating smooth crabgrass emergence was used during 1992. Air and soil temperatures were monitored, measured, and recorded with a computer-driven datalogger (CR10 Measurement and Control Module, Campbell Scientific, Logan, Utah). Microenvironmental information was collected from 1 April through 31 August. Air temperature were measured 15 cm above the soil surface. Soil temperatures were measured beneath turfgrass stands from both mowing heights at three depths: 1) 0.0 cm where sensors were placed adjacent to plant crowns; 2) 2.5 ± 0.5 cm soil depth; and 3) 5.0 ± 0.5 cm soil depth. Air and soil temperatures were recorded and data collected at five minute intervals and averaged each hour. The information was stored in the datalogger until transferred to a laptop computer for additional processing and statistical analysis. A greater number of smooth crabgrass seedlings were visually observed in turf mowed to a height of 3.7 cm verses 6.4 cm, however, the differences were not significant between mowing heights on most rating dates in 1993 and 1994. From 1992 to 1994, crabgrass was first observed between 26 April to 4 May , and two major emergence periods were observed between 17 May to 29 July. During the seven day period prior to first emergence, minimum and mean soil temperatures at the 2.5 cm depth ranged from 10.4 to 12.5° C,and 13.9 to 17.5° C; respectively. During the major crabgrass emergence periods, minimum and mean soil temperatures at the 2.5 cm depth ranged from 19.5 to 21.1° C, and 22.8 to 24.9° C, respectively. Degree-day units calculated from air temperature and soil temperature at all depths were considered, however, soil temperatures measured at the 2.5 cm were used to calculate degree-days (DD). Data from all three years were used to determine a base temperature of 12° C for use in calculating degree-day units. A degree-day range of 42 to 78 was associated with the first appearance of smooth crabgrass. The major emergence period was related to a degree-day range of 140 to 230 DD. Degree-day units were used to construct a regression model (r2=0.96) that described cumulative percent smooth crabgrass emergence." |
Language: | English |
References: | 0 |
Note: | This item is an abstract only! |
| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete): Fidanza, M. A., Zhang Demoeden, and Demoeden M. 1996. Constructing a degree-day based method for predicting smooth crabgrass emergence. Proc. Annu. Meet. Northeast. Weed Sci. Soc. 50:p. 9. |
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| Web URL(s): http://www.newss.org/proceedings/proceedings_1996_vol50.pdf#page=9 Last checked: 07/24/2013 Requires: PDF Reader Notes: Item is within a single large file |
| MSU catalog number: SB 610 .N62 v. 50 |
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