Joseph D. Grande, K. G. Karthikeyan,* Paul S. Miller, and J. Mark Powell

Abstract

There is growing interest in evaluating the effects of corn silageharvesting methods on erosion control. Increasing the silage cuttingheight will increase residue cover and could conceivably minimizeconoff- site migration of sediments compared with conventional silageharvesting. The effects of residue level and manure application timingon runoff and sediment losses from no-till corn were examined. Treatments included conventional corn grain (G) and silage (SL) and nonconventional, high-cut (60–65 cm) silage (SH). Corn harvesting treatments were subjected to different manure application regimes: no manure (N) or surface application in fall (F) or spring (S). Simulatedrainfall (76 mm/h; 1 h) was applied in spring and fall for two years(2002–2003), runoff from 2.0-x1.5-m plots collected, and a subsampleanalyzed for sediment concentration and aggregate size distribution.Runoff volume was inversely related to residue cover. Manure addition to silage plots reduced spring runoff by 71 to 88%, attributableto an increase in soil organic matter content, compared with SH–Nand SL–N. Differences in sediment concentration between SH andSL were not significant. For silage plots, spring-applied manure hadthe greatest influence on sediment export reducing it by 84 to 93%in spring runoff compared with corresponding N plots. Sediment loadswere also 85 to 97% lower from SH–S compared with SL–N in allfour seasons. Except for spring 2003, sediment export was lower fromG compared with SL. The combination of manure and higher residueassociated with high-cut silage often lowered sediment export compared with low-cut silage. Nearly identical aggregate size distributionswere observed in sediments from SH and SL plots. High residue levelsWiswere observed in sediments from SH and SL plots. High residue levelscombined with spring-applied manure led to enrichment in the claysized fraction of runoff sediment. Recently applied manure and higherresidue levels achieved by high-cutting silage can substantially lowersediment losses in spring runoff when soil is most susceptible to erosion.

Keywords: Sediment Losses, erosion control, soil organic matter, soil erosion, Organig farming.