A clipping study was set up to examine the optimal defoliation timing, intensity (stubble height), and frequency for maximum seed reduction and to prepare an effective seedbed for native reseeding projects in semiarid environments. The two study sites chosen are located in Malheur County, Oregon, referred to as Lincoln Bench (lat 43Ã‚Â° 54Ã¯Â¿Â½ N, long 117Ã‚Â° 9Ã¯Â¿Â½ W) and Succor Creek (lat 43Ã‚Â° 34Ã¯Â¿Â½ N, long 117Ã‚Â° 6Ã¯Â¿Â½ W). At both sites, treatments included clipping at two phonological stages, boot (the moment when inflorescences were beginning to emerge from the sheath) and purple (the moment when caryopses and/or glumes turned red or purple), at two heights, 2.5 cm and 7.6 cm, and either once or twice in the season. Clipping at the boot stage occurred on 26 April for the first clipping and 10 May for the second. At the purple stage, clipping occurred on 24 May and there was no second clipping. Seed density was estimated at midseason and end-of-season. Mid-season estimates were collected at the times of clippings. End-of-season estimates were collected on 31 May by clippings and collecting all plants retaining an inflorescence in the center of each treatment plot and also by taking litter samples and soil samples to a depth of 3 cm. Seed viability tests were conducted 4 months after collection.
Defoliation effects on Bromus tectorum seed production: Implications for grazing
native plant restoration