Submitted to: Journal of Environmental Hydrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/26/2011
Publication Date: 11/21/2011
Citation: Gowda, P., Westra, J.V., Petrolia, D.R., Dalzell, B.J., Mulla, D.J. 2011. Impact of targeted removal of residue cover on water quality in the sand creek watershed. Journal of Environmental Hydrology. 19(25):1-12. Interpretive Summary: Conservation tillage is recommended for reducing soil erosion and surface runoff from highly erodible agricultural land. Another benefit associated with adoption of conservation tillage is that it reduces farm operation costs. However, adoption of such practices on flat landscapes may increase nitrogen losses through tile drainage. Recent demand for crop residue to produce biofuels may present a win-win scenario for producers. In this study, a simulation model was used to evaluate the effects of targeted and non-targeted removal of crop residue cover on water quality. Model results indicated that the targeted removal of residue cover from flat landscapes would lower sediment losses when compared to non-targeted residue removal from all agricultural land.
Technical Abstract: Conservation tillage methods are recommended by environmental protection agencies to reduce soil erosion and runoff from highly erodible cropland. Consequently, it gained wide acceptance among producers in the Upper Midwest and elsewhere. However, remote sensing based tillage mapping studies have shown that conservation tillage has also been adopted on flatter terrain to reduce farm operation costs. Recent demand for harvests of crop residues cover for biofuel production may present a win-win scenario for producers by decreasing tile drainage volumes while adding an additional income stream. The objectives of this study were to: (1) calibrate the Agricultural Drainage and Pesticide Transport (ADAPT) model for monthly flow, sediment, and nutrient losses; and (2) evaluate the effects of targeted vs. non-targeted removal of crop residue cover for biofuel production on water quality in the Sand Creek watershed located in south-central Minnesota. Comparison of model predictions for the calibration period against measured monthly flow, sediment, nitrate-N and P losses were in good agreement with r**2 values of 0.75, 0.69, 0.70 and 0.50, respectively. Results indicate that removal of residue cover from all cropland significantly increased average annual sediment losses, with a slight increase in nitrate-N and P losses. Targeted removal of residue cover from flat landscapes had no significant effect on sediment and P losses when compared with non-targeted residue removal on all cropland. Therefore, removal of crop residue on flat lands may lead to increased revenue for producers, without significantly increasing sediment or phosphorus losses to surface waters.