Spatial Differences in Methane Emissions from Rice Production in the Mid-South

Abstract

This study estimates average county/parish and state-level CH4 emissions per hectare (kg CH4 ha-1) as well as CH4 efficiency levels (kg rice/kg CH4 ha-1) in rice production for Arkansas, Louisiana and Mississippi in order to meassure spatial differences in CH4 emissions. This study focuses on existing rice production practices, specifically, variety selection, crop rotation, and soil texture, which directly affect CH4 emissions. Historical data on varietal selection, crop rotations, and soil texture maps are used to estimate CH4 emissions from 2003-2014. Our findings suggest that on average Mississippi was the most efficient at converting CH4 into rice (267.46 kg rice/kg CH4 ha-1), followed by Arkansas (189.92) and Louisiana (178.80). Specifically, Louisiana was negatively impacted by its large ratoon crop in terms of CH4 use efficiency, with 38% of its primary rice crop being ratooned. Overall, these results provide rice buyers, producers and consumers with important information about the spatial aspects of sustainability in rice production. Furthermore, it gives insight to producers and policy makers about which production practices and locations could benefit from increased demand for sustainable products and more restrictive environmental policies.