Cotton Research

All of the projects below were funded by Cotton Inc.

Carbon Life Cycle Assessment of United States Cotton: A View of Cotton Production Practices and their Associated Carbon Emissions for Counties in 16 Cotton Producing States

This study estimated the carbon-equivalent emissions (CE) from multiple agronomic production practices to produce one pound of cotton in the United States at county level resolution.  Using a life cycle assessment approach, greenhouse gas (GHG) emissions were estimated from cradle to farm-gate.  This analysis included GHG emissions from the manufacture of inputs, such as fertilizers and agrochemicals, as well as emissions from products themselves, such as diesel exhaust.  Production practices included irrigated vs. non-irrigated, genetically modified vs. conventional varieties, and reduced vs. conventional tillage.

Results indicated that while there were significant differences in the amounts of inputs by production practice and hence the CE per acre by region of the country, CEs on a per yield basis were fairly constant. Generally, input intensive production practices resulted in much higher yields, and thus reduced overall CE per pound of cotton.  Fertilizer and nitrogen in particular, contributed the largest portion of the carbon footprint. A significant portion of the carbon emissions was from nitrogen released as soil N2O. However, in regions that relied on irrigation, fuel use for pumping approached the level of emissions from fertilizer application. Developing methods to reduce soil N2O emissions could help reduce the impact significantly.

Contacts
Lanier Nalley, 479-575-6818, llnalley@uark.edu

 


Energy Use Life Cycle Assessment for Global Cotton Production Practices

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.

Contact
Marty Matlock, 479-575-2849, mmatlock@uark.edu


Evaluation of Toxicity in Cotton Production and Toxicity Impact Assessment Methods

This study attempted to assess toxicity of cotton under multiple production practices and to compare several toxicity assessment methods currently in use.  Five methods were selected for this analysis (CML, Impact 2002 +, ReCiPe, and TRACI).  These methods showed that no till cotton appears to reduce the toxicity of conventional cotton production. Additionally, dryland cotton appears to have lower toxicity than irrigated cotton. While all five of the impact methods provided index values for toxicity, only three were useful for comparison in this study.  Both CML and TRACI were missing index values for roughly two thirds of the pesticides used in cotton production.  Of the three methods used for final comparison, the pesticide rankings were fairly consistent between Impact 2002+ and ReCiPe, however EIQ did not correlate nearly so well with Impact 2002+ and ReCiPe.

Contact
Marty Matlock, 479-575-2849, mmatlock@uark.edu