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A comparative life cycle assessment of flood and drip irrigation for guayule rubber production using experimental field data

Eranki, P.L., El-Shikha, D., Hunsaker, D.J., Bronson, K.F., Landis, A.E.
Industrial crops and products 2017 v.99 pp. 97-108
Hevea, Parthenium argentatum, bagasse, decision making, energy, environmental impact, field experimentation, flood irrigation, furrow irrigation, furrows, gate-to-gate, guayule, irrigation water, microirrigation, rubber, shrubs, sulfuric acid, Southwestern United States
Guayule (Parthenium argentatum) is a woody, perennial desert shrub, native to the arid American Southwest. It produces natural rubber that can be used to replace Hevea natural rubber for U.S. domestic rubber demands. Irrigation water application and practices form an important component of its agricultural cultivation process. A comparative gate-to-gate lifecycle assessment (LCA) was conducted to examine two different irrigation practices in guayule rubber production-blocked furrow irrigation (denoted as flood) and sub-surface drip irrigation (SDI, denoted as drip). In flood irrigation, furrows are used to convey water flooded from one end of the field. In drip irrigation, the plant is irrigated more frequently with lighter amounts using drip tapes buried beneath crop rows. All relevant field data to conduct the LCA were obtained from experimental plots in Maricopa, AZ.This study, the first of its kind for guayule, compares the metrics of energy consumption, lifecycle environmental impacts and irrigation water productivity. Drip irrigation showed a more efficient use of the applied water by generating higher rubber (46%) and bagasse (dry matter) yields (49%) compared to flood irrigation. Percent change calculations (with drip irrigation as the reference), showed that as a result of greater efficiency of water application in the drip irrigation system, it has between close-to-equal to 51% lower environmental impacts in various categories (with 23% lower impacts averaged over all impact categories). On the other hand, drip irrigation showed 13% higher energy consumption than flood because of the additional burdens of water pumping. Whereas water application was the foremost contributor to impact burdens in both flood and drip irrigations, the additional burdens of water pumping and sulfuric acid use for maintaining blockage-free drip tape were also noteworthy in the drip system. Experimental field operations were the central contributor to energy consumption in both irrigation methods. By separating a crucial stage of guayule production, namely irrigation, connections emerge between various key parameters in the two irrigation methods; accordingly, the outcomes from the evaluation of these two irrigation systems can assist with decision-making in the lifecycle framework of guayule rubber production.