Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/3/2014
Publication Date: 1/14/2014
Citation: Jokela, W.E., Casler, M.D., Bertram, M. 2014. Runoff losses from corn silage-manure cropping systems. Meeting Proceedings. Vol. 53. Interpretive Summary:
Technical Abstract: Transport of P, N, and sediment via runoff from crop fields, especially where manure has been applied, can contribute to eutrophication and degradation of surface waters. We established a paired-watershed field site in central Wisconsin to evaluate surface runoff losses of nutrients and sediment from different manure/crop/tillage management systems for silage corn production. During the 2-yr calibration period the four 4-acre “watersheds”, or fields, were treated identically with fall dairy manure application and chisel plowing; and runoff was monitored, sampled, and analyzed for suspended sediment (SS) and total and dissolved forms of P and N. 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 field-edge grass-legume buffers. During the calibration period both concentrations and export (losses), of SS and total and dissolved P and N varied by field, and more than 50% of runoff and dissolved P and N losses were from snowmelt runoff. Implementation of treatments significantly affected concentration and/or total losses of sediment and nutrients compared to the control. Fall surface-applied manure left over winter increased both concentration and loss of dissolved P (DP) and concentration of total P (TP). Fall-seeded rye cover reduced concentrations of SS, TP, and total N and loss of SS; effectiveness was limited by minimal fall growth due to difficulty achieving timely seeding. The vegetative buffer treatment reduced both concentrations and losses of SS, TP (but not DP), and total N, making it the most effective system evaluated in this study.