THE AUTHOR 



RESEARCH SUMMARY 



JEANNE C. CHAMBERS is a research plant ecologist with 

 the Mined Land Reclamation research work unit at the For- 

 estry Sciences Laboratory in Logan, UT. She joined the staff 

 of the Intermountain Research Station in 1981 . She holds a 

 B.S. degree (1975) in wildlife conservation from Idaho State 

 University and an M.S. degree (1978) in range science and 

 a Ph.D. degree (1987) in biology-ecology from Utah State 

 University. Her primary research responsibility is reclama- 

 tion of severely disturbed alpine and desert ecosystems. 



ACKNOWLEDGMENTS 



The cooperation of Philips Petroleum Company and the 

 Wasatch-Cache National Forest is sincerely appreciated. 

 Contributions made by Eugene E. Farmer, Bland Z. 

 Richardson, and Bryan D. Williams are gratefully 

 acknowledged. 



The effects of introduced grass seeding density and fertil- 

 izer on native species establishment were examined on an 

 oil drill pad site in the Uintah Mountains, UT. Seeding den- 

 sity treatments consisted of seeding native species at a rate 

 of 215/m 2 with three levels of introduced grasses: (1 ) none, 

 (2) 215/m 2 , and (3) 545/m 2 . The fertilization treatments were 

 nonfertilization and a one-time fertilization that consisted of 

 56 kg/ha of N applied as NH 4 N0 3 , 56 kg/ha of P applied as 

 P 2 O s , and 28 kg/ha of K applied as K 2 0. Increasing intro- 

 duced grass seeding density resulted in significantly higher 

 introduced grass biomass (p < 0.05), but native biomass 

 showed no response and colonizer biomass decreased 

 (p < 0.05). Of the seeded introduced grasses, smooth 

 brome, intermediate wheatgrass, and orchardgrass had 

 consistently higher biomass than meadow foxtail and Timo- 

 thy. The native species, slender wheatgrass, muttongrass, 

 tufted hairgrass, and western yarrow had high establish- 

 ment, while spike trisetum, everlasting, silky phacelia, 

 serviceberry, mountain big sagebrush, and Woods rose ex- 

 hibited poor establishment. Two years after fertilization 

 there were no significant differences in soil N0 3 -N or ex- 

 changeable K between fertilized and unfertilized treatments, 

 but significantly higher available soil P in fertilized treatments 

 (p< 0.01). Fertilization resulted in significantly higher bio- 

 mass of introduced grasses, natives, and colonizers in year 

 1 (p < 0.001 ), but by year 3 there were no significant differ- 

 ences between fertilized and unfertilized treatments for any 

 of the species. Native species biomass exibited less ex- 

 treme responses to the one-time fertilizer application than 

 introduced grasses and showed relatively larger yearly in- 

 creases in unfertilized treatments. During the 3-year study 

 colonizer biomass exhibited large yearly declines regardless 

 of fertilizer treatment (p < 0.01). Methods used in the re- 

 vegetation of similar sites should be determined by the inher- 

 ent regenerative capacity of the site and the desired end 

 land use. 



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 and does not imply endorsement by the U.S. Department of Agriculture of 

 any product or service. 



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