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Title: FACTORS AFFECTING ITALIAN RYEGRASS (LOLIUM MULTIFLORUM L.) SEED DISTRIBUTION

Author
item Williams, Robert
item Bartholomew, Paul

Submitted to: International Grasslands Congress
Publication Type: Abstract Only
Publication Acceptance Date: 2/24/2005
Publication Date: 7/1/2005
Citation: Williams, R.D., Bartholomew, P.W. 2005. Factors affecting Italian ryegrass (Lolium multiflorum L.) seed distribution [abstract]. In: Murphy, J.J., editor. Utilization of Grazed Grass in Temperate Animal Systems. Wageningen Academic Publishers, The Netherlands. p. 248.

Interpretive Summary: ABSTRACT ONLY

Technical Abstract: Italian ryegrass (Lolium multiflorum L.) can be a productive and high-quality cool-season forage in the Southern Great Plains of the U.S.A, if it is managed to produce sufficient seed for effective re-establishment without compromising forage yield. Before the re-seeding dynamics of Italian ryegrass can be modeled an understanding of seed production, seed-shed, and seed dispersal is necessary. Here two factors affecting Italian ryegrass seed dispersal and distribution are examined: wind and cultivation practice (mowing and raking). Since prevailing wind was from the south, the majority of the trapped seed were found north of the plots. Mean wind speeds recorded at the site ranged from calm to 6 m/sec, while gusts ranged from calm to 12 m/sec. Using a simple ballistic equation and mean wind speeds travel distances were estimated at 0.7 to 3.0 m, while at maximum wind speeds the estimated travel distance exceeded 6.0 m. Although some seed (8%) were trapped at 183 cm, 80% of the seed were found at 1 m or less from the edge of the plot. Forage removal by cutting and raking increased the seed deposition up to 61 cm from the plot's edge, as compared to the pre-harvest (trapped) seed estimates. Less seed than anticipated was recovered after harvest, and examination of the baled forage showed significant material still attached to the seed heads. Passive seed distribution provides only limited dispersal of Italian ryegrass seed and is unlikely to allow uniform re-establishment by self-seeding.