Energy Use Life Cycle Assessment for Global Cotton Production Practices

Energy Use Life Cycle Assessment for Global Cotton Production Practices


Prepared for:
Cotton Incorporated
World Headquarters
6399 Weston Parkway
Cary, North Carolina 27513


Prepared by:
Marty Matlock, Ph.D., P.E., C.S.E.
Greg Thoma, Ph.D., P.E.
Darin Nutter, Ph.D., P.E.
Thomas Costello, Ph.D., P.E.


Center for Agricultural and Rural Sustainability
University of Arkansas Division of Agriculture
233 Engineering Hall
Fayetteville, AR 72701



March 15, 2008



Energy Use Life Cycle Assessment for Global Cotton Production Practices

Executive Summary

The goal of this project was to use Life Cycle Assessment (LCA) to quantify the energy required for cotton production over a range of global cotton production practices. Energy use is only one measurement of agricultural sustainability, but represents a method for unifying measurements of a variety of other inputs into agricultural production. The Center for Agricultural and Rural Sustainability at the University of Arkansas developed a model of energy usage by identifying a range of production practices across the globe and using these practices as parameters for the model. The LCA quantified various forms of energy inputs including direct mechanical, animal, and human energy required to produce a unit of raw cotton (expressed as a tonne or 1000 kg). The LCA also quantified energy embodied in the fertilizer, mechanical components and manure. The production of secondary products (seed, oil, etc.) was analyzed to quantify potential recoverable energy. The model quantifies energy used to perform various cotton production tasks including field preparation, planting, field operations and harvesting.
The average embodied energy of production of a tonne of cotton from the ten regions of the world ranges from 5,600 MJ/tonne (North America East) to 48,000 MJ/tonne (South America Non-Mechanized). The LCA of energy associated with use of manure as fertilizers in cotton production clearly demonstrated the large quantity of energy embodied in manure. Quantifying this opportunity cost (where manure energy can be practically utilized, e.g., using manure as a fuel for heating or cooking), increases the expressed embodied energy of cotton production of those systems almost tenfold. The LCA of net energy costs of production, measured as embodied energy minus potentially recovered energy (cottonseed oil and meal), showed that six of the ten regional production scenarios have the potential to be net energy-producing systems. The most sensitive variables for net energy production for cotton were yield and irrigation.