| This dissertation demonstrates how large, spatially explicit data sets can be used in both empirical and modeling contexts to study agricultural and environmental phenomena up to the global scale. Chapters 1 and 2 explore the use and re-use of the "DeNitrification-DeComposition" model (DNDC) for modeling nitrous oxide (N2O) emissions from agricultural soils at the national and global scales. Most centrally, these chapters address a set of methodological issues that would not present themselves at the "site" scale where DNDC was originally developed. Chapter 3 makes use of globally available fire data, along with globally available biome maps, to characterize differences in spatiotemporal fire characteristics across biomes and continents, with the goal of refining our understanding of fire heterogeneity globally. Finally, Chapter 4 examines changes in the spatial distribution of four major US row crops and weighs these movement effects against climate change in terms of the realized impact on average growing temperature. |
