|Todd, Richard - Rick|
Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/21/2002
Publication Date: 2/2/2003
Citation: Todd, R.W., Wenxuan, G., Stewart, B.A., Robinson, C. 2003. Long-term changes in shortgrass prairie adjacent to a beef cattle feedyard. In: Society for Range Management 56th Annual Meeting, February 2-6, 2003, Casper, Wyoming.
Technical Abstract: Shortgrass prairie downwind from a cattle feedyard near Bushland, Texas changed during 30 years after stocking the feedyard in 1970. Objectives of the study were to determine pre-1970 vegetation, quantify current vegetation, and describe changes in vegetation, soil P and dust deposition with distance from the feedyard. Pre-1970 vegetation was determined by historical descriptions and published measurements. In 2000, plant cover and composition were quantified using 600, 0.1 m2 quadrats. Soil P, an indicator of manure dust deposition because it is conserved in the local soil, was measured in soil samples collected at 119 locations. Dust was collected at 12 locations across the pasture. Pre-1970 vegetation was predominantly blue grama and buffalograss. From 1966 to 1972, cover was 18.8% blue grama and 7.4% buffalograss. In 2000, perennial grass (75-99% blue grama) cover averaged 3.7% at <150 m from the feedyard, and increased exponentially to 28% at >525 m from the feedyard. Conversely, annual grass (67% little barley) and annual forb (72% kochia) covers were 49% and 35% nearest the feedyard and decreased linearly to 9% and 1%, respectively, at >525 m. Over a similar distance, soil P decreased from 75 to 17 mg kg-1, a level typical of undisturbed soil. Dust deposition rate decreased exponentially with distance from the feedyard. Manure in dust ranged from negligible to as much as 89%. An estimated 20-30 kg N/ha/yr were deposited over 30 years to areas nearest the feedyard Dust impacts on soil fertility and vegetation were greatest nearest the feedyard, but were minimal at >500 m.