Targeted subfield switchgrass integration could improve the farm economy, water quality, and bioenergy feedstock production
Brandes, E; Mcnunn, GS; Schulte, LA; Muth, DJ; Vanloocke, A; Heaton, EA
| HERO ID | 5043644 |
|---|---|
| In Press | No |
| Year | 2018 |
| Title | Targeted subfield switchgrass integration could improve the farm economy, water quality, and bioenergy feedstock production |
| Authors | Brandes, E; Mcnunn, GS; Schulte, LA; Muth, DJ; Vanloocke, A; Heaton, EA |
| Journal | Global Change Biology: Bioenergy |
| Volume | 10 |
| Issue | 3 |
| Page Numbers | 199-212 |
| Abstract | Progress on reducing nutrient loss from annual croplands has been hampered by perceived conflicts between short-term profitability and long-term stewardship, but these may be overcome through strategic integration of perennial crops. Perennial biomass crops like switchgrass can mitigate nitrate-nitrogen (NO3-N) leaching, address bioenergy feedstock targets, and - as a lower-cost management alternative to annual crops (i.e., corn, soybeans) - may also improve farm profitability. We analyzed publicly available environmental, agronomic, and economic data with two integrated models: a subfield agroecosystem management model, Landscape Environmental Assessment Framework (LEAF), and a process-based biogeochemical model, DeNitrification-DeComposition (DNDC). We constructed a factorial combination of profitability and NO3-N leaching thresholds and simulated targeted switchgrass integration into corn/soybean cropland in the agricultural state of Iowa, USA. For each combination, we modeled (i) area converted to switchgrass, (ii) switchgrass biomass production, and (iii) NO3-N leaching reduction. We spatially analyzed two scenarios: converting to switchgrass corn/soybean cropland losing >US$ 100 ha(-1) and leaching >50 kg ha(-1) (conservative scenario) or losing >US$ 0 ha(-1) and leaching >20 kg ha(-1) (nutrient reduction scenario). Compared to baseline, the conservative scenario resulted in 12% of cropland converted to switchgrass, which produced 11 million Mg of biomass and reduced leached NO3-N 18% statewide. The nutrient reduction scenario converted 37% of cropland to switchgrass, producing 34 million Mg biomass and reducing leached NO3-N 38% statewide. The opportunity to meet joint goals was greatest within watersheds with undulating topography and lower corn/soybean productivity. Our approach bridges the scales at which NO3-N loss and profitability are usually considered, and is informed by both mechanistic and empirical understanding. Though approximated, our analysis supports development of farm-level tools that can identify locations where both farm profitability and water quality improvement can be achieved through the strategic integration of perennial vegetation. |
| Doi | 10.1111/gcbb.12481 |
| Wosid | WOS:000424241200004 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Keyword | corn; DeNitrification-DeComposition; ecosystem services; eutrophication; hypoxia; landscape analysis; nitrate leaching; Panicum virgatum; precision agriculture; precision conservation |