Abstract:
This research examined the biology of barb goatgrass (Aegilops triuncialis L.) a weedy annual grass that is invading the rangelands of California. Germination and root growth characteristics of barb goatgrass were compared to soft chess (Bromis mollis L.), medusahead rye (Taeniatherum caput-medusae (L.) Nevski), slender wild oats (Avena barbata L.), and subterranean clover (Trifolium subterrraneum L.) to determine what advantages barb goatgrass might have when establishing in a plant community. Barb goatgrass germinated under a wide range of temperatures, between 5 and 25 C. This was a wider temperature range than associated species. Root growth rates under greenhouse conditions that simulate spring conditions on California annual grasslands were greatest for barb goatgrass and slender wild oats. Rooting area observed in glass sided boxes was greatest for goatgrass. Barb goatgrass populations increased with sheep grazing. Increasing grazing pressure resulted in increasing goatgrass density. Barb goatgrass invades both grazed and ungrazed pastures however higher density of this noxious weed was found in grazed pastures. Barb goatgrass can be controlled with 1.12 kg ai/ha glyphosate (Roundup) but desirable plant species will likely need to be reseeded to occupy the site.
