Plant and Soil N Response of Southern Californian Semi-arid Shrublands After 1 Year of Experimental N Deposition |
| |
Authors: | George L Vourlitis Sarah Pasquini Gypsi Zorba |
| |
Institution: | (1) Department of Biological Sciences, California State University, San Marcos, California 92096, USA |
| |
Abstract: | Large inputs of atmospheric N from dry deposition accumulate on vegetation and soil surfaces of southern Californian chaparral
and coastal sage scrub (CSS) ecosystems during the late-summer and early-fall and become available as a pulse following winter
rainfall; however, the fate of this dry season atmospheric N addition is unknown. To assess the potential for dry season atmospheric
N inputs to be incorporated into soil and/or vegetation N pools, an in situ N addition experiment was initiated in a post-fire
chaparral and a mature CSS stand where 10 × 10 m plots were exposed to either ambient N deposition (control) or ambient +50 kg
N ha−1 (added N) added as NH4NO3 during a single application in October 2003. After 1 year of N addition, plots exposed to added N had significantly higher
accumulation of extractable inorganic N (NH4−N + NO3−N) on ion exchange resins deployed in the 0–10 cm mineral soil layer and higher soil extractable N in the subsurface (30–40 cm)
mineral soil than plots exposed to ambient N. Chaparral and CSS shrubs exposed to added N also exhibited a significant increase
in tissue N concentration and a decline in the tissue C:N ratio, and added N significantly altered the shrub tissue δ
15N natural abundance. Leaching of inorganic N to 1 m below the soil surface was on average 2–3 times higher in the added N
plots, but large within treatment variability cause these differences to be statistically insignificant. Although a large
fraction of the added N could not be accounted for in the shrub and soil N pools investigated, these observations suggest
that dry season N inputs can significantly and rapidly alter N availability and shrub tissue chemistry in Mediterranean-type
chaparral and CSS shrublands of southern California. |
| |
Keywords: | Adenostoma fasciculatum Artemisia californica biogeochemistry chaparral coastal sage scrub Mediterranean-type ecosystems Salvia mellifera |
本文献已被 SpringerLink 等数据库收录! |
|