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| Web URL(s): | http://www.newss.org/proceedings/proceedings_1994_vol48.pdf#page=78
Last checked: 07/24/2013
Requires: PDF Reader
Notes: Item is within a single large file |
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| Publication Type:
| Report |
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| Content Type: | Abstract or Summary only |
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| Author(s): | Fidanza, M. A.;
Dernoeden, P. H.;
Zhang, M. |
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| Author Affiliation: | Department of Agronomy, University of Maryland, College Park, MD 20742 |
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| Title: | Developing a degree-day model to predict smooth crabgrass emergence |
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| Meeting Info.: | Hyall Regency Hotel, Baltimore, MD, January 3-6, 1994 |
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| Source: | Proceedings of the 48th Annual Meeting of the Northeastern Weed Science Society. Vol. 48, 1994, p. 79. |
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| Publishing Information: | Ithaca, NY: Northeastern Weed Science Society |
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| # of Pages: | 1 |
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| Keywords: | TIC Keywords: Digitaria ischaemum; Models; Poa pratensis; Emergence; Air temperature; Soil temperature; Mowing height; Seed germination
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| Abstract/Contents: | "Current information on the environmental requirements for smooth crabgrass [Digitaria ischaemum (Schreb.) Muhl.] seed germination is limited. A reliable method is needed to determine when to expect major crabgrass germination periods and when germination ceases during a season. Although effective control of smooth crabgrass can be obtained with pre- and postemergence herbicides, the ability to predict crabgrass seed germination and subsequent germination periods would allow turfgrass managers to implement more efficient control strategies. Therefore, the objectives of this study were to develop a method of predicting when initial smooth crabgrass seed germination occurs, when the major germination period(s) occur, and how long into the season to expect smooth crabgrass seed germination. Air and soil temperature measurements were used to develop degree-day models to predict the timing and extent of crabgrass seedling emergence. In 1992 and 1993 field studies were conducted on stand of Kentucky bluegrass (Poa pratensis L.) with a history of a heavy smooth crabgrass infestation. Plots were 1.5 by 3.0 m and were arranged in a randomized complete block with four replications. Smooth crabgrass emergence was monitored weekly from April to August under two mowing heights of 3.7 cm and 6.4 cm. The site was mowed bi-weekly with a rotary mower. Crabgrass seedlings were counted weekly and removed from three, 100 cm(2) fixed grids per plot. An environmental monitoring system (CR10 Measurement and Control Module, Campbell Scientific, Logan, Utah) was installed on 1 April 1993 to record air and soil temperatures. Air temperatures were measured 30 cm above the soil surface. Soil temperatures were measured under both mowing heights at three depths: 1) 0.0 cm where sensors were placed adjacent to plant crowns; 2) 2.5 + or - 0.5 cm soil depth; and 3) 5.0 + or - 0.5 cm soil depth. Air and soil temperatures were measured and recorded at 5 minute intervals, averaged on an hourly basis, and stored in the CR10 Control Module until transferred to a laptop computer for data processing and analysis. In 1992, a similar method for monitoring crabgrass seed germination and temperatures was employed. Fewer smooth crabgrass seedlings emerged in turf maintained at 6.7 cm versus 3.4 cm in both years. In 1992, crabgrass emergence was first observed on 26 April. Average minimum and maximum air temperatures for the week of 19 to 25 April 1992 were 8 and 21 degrees C; respectively, and average minimum and maximum soil temperatures at crown level were 13 and 20 degrees C; respectively. During the 1992 major emergence period of 15 June to 13 July, average minimum and maximum air temperatures were 14 and 27 degrees C; respectively, and average minimum and maximum soil temperatures at crown level were 20 and 31 degrees C; respectively. In 1993, crabgrass emerged on 21 April. Average minimum and maximum air temperatures for the week of 13 and 20 April 1993 were 6 and 19 degrees C; respectively. The average minimum and maximum soil temperatures at crown level were 10 and 18 degrees C; respectively. During the major emergence period of 17 May to 12 July 1993, average minimum and maximum air temperatures were 16 and 28 degrees C; respectively. The average minimum and maximum soil temperatures at crown level were 20 and 30 degrees C; respectively at this time. From the 1992 and 1993 field data measurements 12 degrees C was determined as the threshold temperature used to construct smooth crabgrass seed germination degree-day models. Degree-day models to predict the timing and extent of crabgrass emergence were developed for the turf at both mowing heights using air and soil temperatures separately." |
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| Language: | English |
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| References: | 0 |
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| Note: | This item is an abstract only! |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Fidanza, M. A., P. H. Dernoeden, and M. Zhang. 1994. Developing a degree-day model to predict smooth crabgrass emergence. Proc. Annu. Meet. Northeast. Weed Sci. Soc. 48:p. 79. |
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| Web URL(s):
http://www.newss.org/proceedings/proceedings_1994_vol48.pdf#page=78
Last checked: 07/24/2013
Requires: PDF Reader
Notes: Item is within a single large file |
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MSU catalog number: SB 610 .N62 |
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