350-9 Alternative Statistical Distributions and Transformation of Nitrous Oxide Soil Flux Data.

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Sources and Rates of Greenhouse Gas Emissions From Agriculture

Wednesday, November 6, 2013: 10:15 AM
Tampa Convention Center, Room 15

Alan P. Moulin, 2701 Grand Valley Road, Government of Canada, Brandon, MB, CANADA, Aaron Glenn, Science and Technology Branch, Agriculture and Agri-Food Canada, Brandon, MB, Canada, Mario Tenuta, Soil Science, University of Manitoba, Winnipeg, MB, Canada, David A. Lobb, University of Manitoba, Winnipeg, MB, Canada, Adedeji Dunmola, Dept. of Soil Science, University of Manitoba, Winnipeg, MB, Canada and Priyantha Yapa, Sabaragamuwa University of Sri Lanka, Belihuloya, Sri Lanka
Abstract:

Title:  Alternative statistical distributions and transformation of nitrous oxide soil flux data

 

Alan P. Moulin1, Aaron Glenn1, Mario Tenuta2,3, David A. Lobb2 , Adedeji S. Dunmola4, and Priyantha Yapa5

 

1Agriculture and Agri-Food Canada, Brandon, MB Canada R7A 5Y3 2 Department of Soil Science, University of Manitoba, Winnipeg, MB Canada R3T 2N2; 3 Canada Research Chair in Applied Soil Ecology, University of Manitoba, Winnipeg, MB Canada R3T 2N2; 4 Shell Canada Limited, Calgary, Alberta, 5Sabaragamuwa University of Sri Lanka, Belihuloya, Sri Lanka

 

Probability distributions of N2O fluxes are often non-normal due to large temporal and spatial variability of environmental factors.  The most common approaches to statistical analyses of these fluxes in the scientific literature are to transform data with a log function, or conduct non-parametric tests.  These data are transformed to ensure that analysis of variance and regression based on least squares, meet the assumption of normality for the distribution of data and equality of variances.  Analysis of N2O flux data for 128 sites within a 16 ha field, taken on 20 dates in 2005 and 2006 near Brandon, Manitoba, show that the Johnson Su and generalized log probability distributions provided the best fit for the majority of sample dates.  Further analysis of N2O data for 30-minute and daily fluxes of N2O in Manitoba, show that continuous functions such as the Johnson Su and Sl, Generalized Log or normal quantile may be an alternative to the lognormal which was relatively less effective in transforming data, though each transformation should be evaluated on a case-by-case basis.

 

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Sources and Rates of Greenhouse Gas Emissions From Agriculture