POTENTIAL WIND DISTRIBUTION OF ITALIAN RYEGRASS SEED

Authors: Williams, Robert; Bartholomew, Paul

Submitted to: Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2003
Publication Date: 10/1/2003
Citation: Williams, R.D., Bartholomew, P.W. 2003. Potential wind distribution of Italian ryegrass seed [abstract]. Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting. Paper No. c06-williams203285-poster. 2003 CDROM.

Interpretive Summary: Abstract Only.

Technical Abstract: During June through August, mean wind speeds of 2 to 3 m/sec, with gusts of 12 to 17 m/sec, at our field location are not uncommon. Generally, the prevailing summer wind is from the south, but strong winds produced by convection thunderstorms can occur from the northwest. Here we examine the potential effect of wind on ryegrass (Lolium multiflorum L.) seed distribution. Ryegrass was established in the spring of 2003 and, before heading, the area was mowed leaving four one meter-square, uniform, grass blocks. Seed traps (15-cm dia.) were placed at intervals of 0, 0.3, 0.6, 0.9, 1.2, and 1.8 m from the edge of the stands in eight cardinal directions (N, NE, E, SE, S, SW, W, and NW). Trapped seed were counted every 7 to 10 days until the ryegrass was harvested. Using a simple ballistic equation, mean wind speed at the canopy height collected at the site, and assuming a terminal velocity of 0.32 m/sec, the estimated travel distance was between 0.7 to 3.0 m for a ryegrass seed shed from a height of 0.6 m. The estimated median travel distance was 0.35 m. Data from the seed traps indicated that 76% of the seed fell within 0.3 m from the edge of the stand. The majority of the seed were trapped north of the stands. These results will be discussed in relation to potential ryegrass self-seeding.