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The grass is always greener (than the forest): is it the N?. Hannah Tremblay Carleton College, 2014. Background. Fertilization and fossil fuels have more than doubled amount of available N in biosphere Expansion of suburbs is one of the fastest growing land uses
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The grass is always greener (than the forest): is it the N? Hannah Tremblay Carleton College, 2014
Background • Fertilization and fossil fuels have more than doubled amount of available N in biosphere • Expansion of suburbs is one of the fastest growing land uses • Recent evidence suggests that urban soils may be a sink for atmospheric N (Raciti et al. 2008)
The experiment • To quantify the differences in total soil nitrogen, available nitrate, and nitrification rates between residential lawns and forested areas in northern New Hampshire. • How does the land use shift from forests to lawns affect nitrification and mineralization rates?
Methods: site selection • 12 clusters • 58 sites • Personal interview and questionnaire
Methods:In the field • 5 volumetric, 5.8cm diameter, 15cm deep cores from lawns and adjacent forests • Vegetative cover and tree inventory recorded • Measured area of property
Methods: In the lab • Soil sieved and homogenized • Two 20 gram subsamples • “Time 0” extraction: placed in a 250 ml Nalgene bottle with 100ml of 2M KCl. Settled for 24 hours. • “Time final” extraction: incubated for 21 days in a 1 pint mason jar and fanned every 3 days. • Soil samples filtered and analyzed
Results P-value < .05
Moving forward • Nitrification and mineralization rates • Investigation of historical land use • Relationship with vegetation • Demographic information
Thank you • Craig See • Adam Wild • Clarissa Lyons • Austin McDonald • ShinjiniGoswami • Russell Auwae • Ruth Yanai • Melany Fisk • Tim Fahey • Paul Lilly • Peter Groffman • Paige Warren • Matt Vadeboncoeur
References • Raciti SM, Groffman PM, Fahey TJ. 2008. Nitrogen retention in urban lawns and forests. Ecol Appl 18(7):1615–26.