Subsurface water retention technology (SWRT) is a system of contoured engineered membranes made of a blend of linear low and low density polyethylene, and drip irrigation installed below the root zone to increase water use efficiency. It is claimed that SWRT is capable of increasing crop yields by 50 to 400% through extending the water retention time in the root zone. More than four million hectares of sandy soil area in the U.S. creates a great opportunity for using SWRT to improve the soil use efficiency; however, SWRT's environmental footprint (EFP) is still unknown. The focus of this LCA study was to determine the EFP of SWRT compared to control methods and previous benchmark studies in growing corn. The functional unit was selected as 1000 kg of corn grain grown in sandy soil in Michigan, U.S. The study boundary and temporal condition was cradle-to-gate with data obtained from 2000 to 2013. The ReCiPe 1.07 (H) midpoint impact assessment methodology was used. Six different treatments (15" -row spacing- SWRT, 30" SWRT, 15" Control, 30" Control, Irrigated SWRT, and Nonirrigated Control) planted on Sandhill farm, Michigan State University were evaluated. A simulation of continuous corn production on the Sandhill farm was also performed to estimate the pay-off time for the additional burden of installing SWRT. The benchmark comparison confirmed that the study results were in a reasonable range. The study identified climate change, fossil fuel depletion, and terrestrial acidification as the largest impacts for SWRT. Contribution analysis indicated that irrigation was a hotspot activity. The parameter of corn grain yield was highly sensitive.
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