Browsing by Author "D'Imperio, Elizabeth Anne"

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Nitrogen dynamics of Centaurea maculosa and native species
(Montana State University - Bozeman, College of Agriculture, 2005) D'Imperio, Elizabeth Anne; Chairperson, Graduate Committee: Bret E. Olson; Jon M. Wraith (co-chair)
Centaurea maculosa has invaded millions of hectares of disturbed and undisturbed semi-arid grasslands. Its success may be due to an ability to conserve nitrogen (N) or use N more efficiently than native species. It may also be able to acquire more N from early spring pulses than native vegetation. Growth response, N acquisition, allocation, resorption and use efficiency of C. maculosa was compared with Pseudoroegneria spicata, Pascopyrum smithii, and Rudbeckia hirta by growing plants in high and low N supplies, which mimic disturbed and undisturbed sites. 15Nitrogen acquired per unit of root mass was highest in R. hirta. Centaurea maculosa had the lowest C:N ratio. Resorption proficiency was lower in C. maculosa for Harvest 2 and 3, and similar among all species at Harvest 4. Centaurea maculosa had the highest mean residence time (MRT) and lowest N productivity. Centaurea maculosa had the highest nitrogen use efficiency (NUE) for plants receiving the high N supply whereas NUE was similar for all species receiving the low N supply.