| Popis: |
Big sagebrush was controlled by rotobeating and spraying on both fair— and poor—condition ranges. A randomized block design was used with two replications of each treatment (untreated, sprayed, and rotobeaten). Data were taken from 10 permanent sampling units within each treatment plot. Numbers and crown cover of big sagebrush on treated range in fair condition changed little in 8 years after treatment. However, on poor—condition ranges sagebrush rapidly reoccupied mechanically treated areas. Some sagebrush increase occurred on sprayed poor—condition ranges, but brush numbers are strikingly lower than on rotobeaten plots. Herbage yields corrected to median—year precipitation varied considerably on untreated and treated plots, but herbage production was at least doubled, mostly from increaser—type species, on both sprayed and mechanically treated fair—condition range. On poor—condition ranges, herbage response was primarily from annuals with a marked trend toward an increasing amount of cheatgrass on treat... |
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