A Scan LEVEL COTTON CARBON LIFE Cycle ASSESSMENT:

Has Bio-Tech Reduced the Carbon Emissions from Cotton Production in the US?

Using data from one farm with many fields, multiple practices and over multiple years, we assess the changes in Greenhouse Gas (GHG) emissions over time using Life Cycle Assessment methodology. In addition, where possible, we differentiate the GHG emissions by production practice and seed type.

We use data from a farm in Eastern Arkansas with detailed records of over 7,000 acres of Cotton under cultivation. Data includes production, seed and yield data from 1997, 2005 and 2008 for approximately 100 fields. From this data we estimate emissions from fuel use, as well as emissions from the production of the inputs required for production, including fertilizers and agrochemicals, fuel, and irrigation pumping. In addition, we estimate soil N2O emissions from nitrogen application.

Fuel use is estimated from the Mississippi Budget Generator using the specific tractors and implements used on the field combined with the number of passes per acre per tractor and implement.   Fertilizer, pesticide and other agrochemical application rates are based upon the actual application of the active ingredient.  Life Cycle Greenhouse Gas emission values are taken from literature for each of the different inputs.  Irrigation is held constant for our purposes since it is assumed that all seed types and tillage use the same irrigation and because irrigation needs may vary dramatically over the years based on climatic conditions, rather than seed and production practice.

Seed types are conventional in 1997, Roundup Ready ® Boll Guard in 2005 and Boll Guard II Roundup Ready® Flex in 2008. Tillage was conventional in 1997. In 2005 and 2008 tillage included No-Till and Reduced Till.