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Assessment of high-input soybean management in the US Midwest: Balancing crop production with environmental performance

Greer, Kristin, Martins, Camila, White, Marshal, Pittelkow, Cameron M.
Agriculture, ecosystems & environment 2020 v.292 pp. 106811
Glycine max, agrochemicals, conventional tillage, crop rotation, energy costs, energy efficiency, energy use and consumption, environmental performance, global warming potential, grain yield, insecticides, leaching, management systems, nitrogen, nitrogen fertilizers, no-tillage, pesticide application, risk, soybeans, Illinois
There are growing efforts to increase soybean yields in the US Midwest through high-input crop management practices. While practices such as increased nutrient inputs and agrochemical applications may increase grain yields, few studies have assessed additional environmental performance indicators to examine tradeoffs between crop production and sustainability goals. The objective of this study was to evaluate grain yields and environmental performance in terms of energy efficiency, nitrogen (N) leaching potential, partial global warming potential (pGWP), and agrochemical contamination risk in reduced-input, standard, and high-input management systems in Illinois, USA over a three-year period (2015–2017). Relative to standard management, the reduced-input system had no tillage, a reduced seeding population, and no addition of fertilizer or pesticides, whereas the high-input system had conventional tillage, an increased seed rate, and additional fertilizer and pesticide applications. Treatments were implemented in the soybean phase of a two-year maize-soybean crop rotation. Mean results showed that the high-input system significantly increased soybean grain yield, but this came at the cost of decreased energy efficiency, increased pGWP per unit production, and elevated agrochemical contamination risk. These impacts can be attributed to greater fuel consumption and external inputs, including N fertilizer and insecticides. However, the addition of N fertilizer in the high-input system did not translate into increased N leaching potential. In contrast, the reduced-input and standard systems had comparable yields while improving sustainability outcomes. This study highlights the need for quantifying system performance based on a holistic set of indicators to identify strategies for optimizing yields and resource use efficiencies while mitigating negative environmental tradeoffs.