|Stewart, Bobby - WEST TEXAS A&M UNIVERSITY|
|Guo, Wenxuan - WEST TEXAS A&M UNIVERSITY|
|Robinson, Clay - WEST TEXAS A&M UNIVERSITY|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 21, 2001
Publication Date: October 21, 2001
Technical Abstract: Vegetation in a shortgrass pasture next to a large feedyard changed during 30 years of feedyard operation. Pre-1970 plant composition was determined from archives and published studies. Plant cover (C,%) in 2000 was estimated in each of 12 90-m by 120-m plots with 50 0.1 m2 quadrats. Blue grama (Bouteloua gracilis) and buffalograss (Buchloe dactyloides) dominated dpre-1970 vegetation, but annual grasses and forbs dominated plots nearest the feedyard in 2000. Annual grasses, mostly Hordeum pusillum, decreased with distance (D,m) from the feedyard (C=57.3-0.083D, r2=0.84). Annual forbs, mostly Kochia scoparia, decreased with D (C=39.5-0.067D, r2=0.85). Perennial grass cover was much reduced near the feedyard and increased with D to near pre-1970 cover more than 500 m away (C=-4.4+0.044D, r2=0.71). Blue grama cover increased from <4% near the feedyard to 23% at >500 m, similar to its pre-1970 cover (19%). Vegetation less than 500 m from the feedyard showed the most change, while vegetation at more than 500 m was similar to that before feedyard operation.