In this study, we developed a technique for estimating soil C sequestration from crop production with detailed spatial differences in production practices, tillage effects, and soil textures often overlooked when modeling state-level implications of climate change policies. The model also tracks C equivalent (CE) emissions from fertilizer, fuel, and agricultural chemical use. Using Arkansas as an example, a model that maximizes crop returns to producers in conjunction with C offset payments allowed estimation of probable changes in county-level cropping patterns and income as a result of varying C prices. While income ramifications of a C-offset climate change policy are positive, significant uncertainty about resultant greenhouse gas (GHG) effects are demonstrated. Crops included were corn ( Zea mays L.), cotton ( Gossypium hirsutum L.), grain sorghum [ Sorghum bicolor (L.) Moench], soybean [ Glycine max (L.) Merr.], rice ( Oryza sativa L.) and wheat ( Triticum spp.). As a result of this detailed analysis, two caveats are that (i) policy recommendations hinge on a baseline scenario that would change with changes in input and output price levels, with these interactions not modeled within, and (ii) monitoring costs of a C-offset market could be significant.
