Carbon Allocation throughout the Supply Chain: Test Case Guayule

This study presents a detailed carbon balance analysis of guayule (Parthenium argentatum), a drought-tolerant shrub with significant potential for carbon credit (CC) generation through its biomass-derived products. Guayule biomass was fractionated into rubber, resin, and bagasse, with further processing of resin into terpenes and residuals and bagasse into biofuels and particle board. The carbon content was quantified using elemental analysis and gas chromatography–mass spectrometry, and conversion pathways were evaluated using literature data. Results indicate that up to 3.2 CCs/ha can be allocated to rubber, 6 CCs/ha to resin-based products, and 24 CCs/ha to biofuels, with an additional 17 CCs/ha credited to growers using no-til practices and biochar application. This analysis provides a transparent framework for tracking carbon through the guayule supply chain, supporting accurate CC allocation and helping to prevent double counting. The findings offer practical insights into how mass balance analysis enhances emissions trading systems and advances sustainable agricultural practices.