Submitted to: American Water Resources Association Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/3/2014
Publication Date: 3/13/2014
Citation: Jokela, W.E., Casler, M.D., Bertram, M.G., Borchardt, M.A. 2014. Surface runoff from manured cropping systems assessed by the paired-watershed method, part 1: P, N, and sediment transport. American Water Resources Association Conference Proceedings. March 13-14, 2014.
Technical Abstract: Transport of P, N, and sediment via runoff from crop fields can contribute to degradation of surface waters. We established a paired-watershed study in central Wisconsin to evaluate surface runoff losses of nutrients, sediment, and pathogens from different manure/crop/tillage management systems for silage corn production. During the 2-yr calibration period the four 1.6-ha “watersheds”, or fields, were treated identically with fall dairy manure application and chisel plowing. That management was maintained as a control in one watershed, while alternative management systems were carried out on the three treatment fields from Oct 2008 to Apr 2012: fall surface-applied manure with spring chisel plowing, fall-seeded rye cover crop with spring manure and chisel plowing, and fall manure and chisel plowing with grass-legume buffers. Runoff and nutrient export varied by treatment; averaged across treatments, snowmelt-derived runoff was 39% of the total runoff and contributed 11 to 65% of the total and dissolved P and N export. Fall surface-applied manure left over winter increased concentration of dissolved P (DP) and total P (TP) and export of DP (>200%). Fall-seeded rye cover reduced concentrations of suspended sediment (SS), TP, and total N and export of SS; effectiveness was limited by minimal fall growth due to difficulty achieving timely seeding. The vegetative buffer treatment reduced both concentration and export of SS, TP (but not DP), and total N, making it the most effective system evaluated in this study.