MULTI-SCALE EVALUATION OF LAND USE MANAGEMENT SYSTEMS IN THE UPPER MIDWEST
Location: Soil Management Research
Title: Spatiotemporal analyses of simulated biophysical processes in the Chippewa River Watershed, Minnesota
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 30, 2011
Publication Date: September 30, 2011
Citation: Jaradat, A.A., Boody, G. 2011. Spatiotemporal analyses of simulated biophysical processes in the Chippewa River Watershed, Minnesota [abstract]. The Fourth Interagency Conference on Research in the Watersheds. p. 34. Available: http://www.hydrologicscience.org/icrw/docs/ICRW4-Program.pdf.
Annual crops predominate in the Chippewa River Watershed (CRW) which drains 5387 km2 of mixed natural and managed ecosystems in West Central Minnesota. Intensive crop production in the watershed has altered the dynamics and nature of water, sediment, and nutrients and resulted in biophysical changes within and beyond the watershed. Opportunities to improve the ecological functioning of managed and natural ecosystems in the CRW include reducing soil erosion, runoff, and nutrient leaching. We hypothesized that increasing perennial land-use in managed ecosystems will improve environmental health through sustained carbon sequestration and the concomitant reduction in soil erosion, runoff, and nutrient leaching. We calibrated, validated, and used a modular modeling framework to simulate the impact of 100-year historical weather variables in combination with soil data and current and alternative crop rotations on biophysical processes of the predominant farming systems in 12 locations representing different soil types across the CRW. Results of simulation modeling and multivariate statistical analyses indicated that differences between locations accounted for 89.0, 30.7, 82.1, and 78.4% of total variation in sequestered carbon, inorganic nitrogen leaching, runoff, and soil erosion, respectively. Differences between crop rotations and their interaction with locations accounted for major portions of the remaining total variation. Total replacement of row crops by a perennial on sensitive lands is projected to reduce nitrogen leaching, runoff and soil erosion by 40, 24, and 48%, respectively. When compared to the predominant corn-soybean rotation, a perennial crop, if continuously grown for ~60% of the duration of a corn-soybean-small grain-perennial crop rotation, is expected to reduce nitrogen leaching, runoff, and soil erosion across the CRW by 12, 16, and 32%, respectively. Results of annual simulations, using historical and projected weather variables, and spatio-temporal multivariate analyses are being used by a multi-disciplinary team to (1) develop robust and transferable approaches based on principles of multifunctional agriculture, (2) identify site-specific and environmentally-friendly land-use changes with synergistic positive impacts at the farm and watershed levels, and (3) develop perennial biomass and food production scenarios to diversify farm income and meet future local market needs.