Carbon and Nitrogen Mineralization of a Semiarid Shrubland Exposed to Experimental Nitrogen Deposition
- Marcelo S. Biudesa and
- George L. Vourlitis *b
High atmospheric N inputs to southern Californian shrublands can alter organic matter quantity and quality and influence decomposition and N mineralization rates. We conducted a laboratory experiment to test the hypothesis that N addition would increase microbial respiration and net N mineralization. Intact soil cores and litter from Artemisia californica Less. were collected from field plots exposed to either ambient or elevated N (50 kg N ha−1 yr−1) over a 7-yr period. Microbial respiration was significantly higher in control soil, and litter amendment, regardless of origin, significantly increased respiration. In contrast, net N mineralization was significantly higher in added N soil, and litter addition significantly depressed net N mineralization. Our results suggest that chronic N deposition causes a decline in litter decomposition and microbial N demand. If indicative of the longer-term decomposition kinetics, these results suggest that chronic N inputs may increase soil C storage and N availability in these semiarid shrublands.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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