Leveraging Crop Budgets to Assess the Environmental Impact of Agricultural Operations

Highlights Agriculture Extension Resources should be used for regional life cycle assessments of agriculture. Fertilizer is the major contributing factor of environmental impact, when using a spatial functional unit. Ecoinvent may under-estimate the environmental impact of maize production. Abstract . Current attempts to quantify the sustainability of agricultural operations are hampered by the lack of information to adequately address variation of farming operations. Differences in weather, soil, local consumers, and transportation pathways affect the agricultural operation of a given parcel of land. These differences may significantly influence life cycle assessments involving agricultural systems. Agricultural extension publications and human expertise may fill gaps present in commonly utilized databases for environmental impact calculations. A methodology was developed integrating information from Nebraska Crop Budgets with Ecoinvent 3.6 in OpenLCA, to investigate pesticide production contribution and compare environmental impacts on a per acre and per bushel basis. Seven budgets were selected, outlining no-till corn production under no-rotation, soybean/corn rotation, and ecofallow schemes. Of thirteen tested pesticides, only five were greater than 5% of the total impact relative to 19-Corn in at least one impact category. Pesticide contribution was greatest for products containing multiple active ingredients and with higher yearly applied amounts. Exclusion of pesticide production in agricultural life cycle assessments may not significantly impact results. Relative impacts between budgets were greater than 83% on a per acre and per bushel basis compared to Ecoinvent, demonstrating life cycle assessments can be impacted by operational differences within similar production systems. Per acre impacts were 4% less to 227% greater than published maize grain production in Ecoinvent 3.6 for the United States. Per bushel impacts were similar at 6% to 280% greater. Result differences are dependent on the crop budget used and impact category considered. Fertilizer was the greatest contributor toward all tested categories. Per acre calculations were defined by applied nitrogen while per bushel calculations followed nitrogen productivity. With simple integration and specificity granted with crop budgets, extension resources should be used for region-specific life cycle assessments of agricultural and bio-based products to replace general assumptions. Keywords: Crop production, Extension, Food energy water nexus, Life cycle assessment, Sustainability.