Creation of life cycle assessment estimates using APEX-simulated results following application of best management practices historically and under future climate scenarios
Abstract
Simulation studies are crucial for quantifying impacts of management choices and climate change on hydrologic components. Runoff and water quality are influenced by management decisions at the field-scale within a watershed. Integrating the eutrophication potential (EP) associated with agricultural activity presents a challenge to life cycle assessment (LCA) due to annual variability in nutrient flux, often despite consistent nutrient inputs. This study is conducted to evaluate performance of best management practices, specifically cover crop plantings, crop rotation, and no-till practices over historic and future climate timeframes (RCP 8.5, ensemble of GCM data) within the Goodwater Creek Experimental Watershed (GCEW), Field1, Missouri. GCEW is part of the USDA's Long-term Ecological Research program. Input data, e.g., fertilizer applied and machinery operations, are integrated into an LCA framework and compared to nutrient flux estimated by the Agricultural Policy Environmental eXtender (APEX) for each simulated historic and future year. The specific objectives are: i) to compare Business-As-Usual (BAU) and Aspirational (ASP) management over the historic period; ii) to compare the BAU and ASP management options under future climate to determine if future climate exacerbates water quantity or quality parameters and, whether ASP can mitigate these impacts; and iii) compute and compare LCA global warming potential and EP for BAU and ASP, historic to future periods and compare with APEX-simulated nutrient runoff. The APEX model is calibrated and validated for runoff and water quality using data collected at the edge of field. The results indicate environmental benefit of crop rotation and cover crop with reduction in runoff and nutrient losses. The change in management alone from BAU to ASP during the historic period (1981- 2010) resulted in 25% reduction in surface runoff as well as an increase in subsurface flow. The average annual runoff loss is reduced by 16.5% and 18.8% in ASP scenario compared to BAU for ensemble of RCP 8.5 for near and far future, respectively. Average ensemble annual soluble nitrate loss is 14 kg/ha for BAU compared to 12 kg/ha for ASP management for baseline historic period. Further analysis on LCA is in progress and will be included in the presentation.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H54G..06C
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCESDE: 0496 Water quality;
- BIOGEOSCIENCESDE: 1879 Watershed;
- HYDROLOGYDE: 1880 Water management;
- HYDROLOGY