Wheat and sorghum residue removal for expanded uses increases sediment and nutrient loss in runoff

J Environ Qual. 2009 Oct 29;38(6):2365-72. doi: 10.2134/jeq2009.0021. Print 2009 Nov-Dec.

Abstract

Crop residue removal for expanded uses such as feedstocks for cellulosic ethanol production may increase loss of sediment and nutrients in runoff. We assessed on-farm impacts of variable rates of residue removal from no-till winter wheat (Triticum aestivum L.) and plow till grain sorghum [Sorghum bicolor (L.) Moench] on sediment, soil organic carbon (SOC) and nutrient losses in runoff in western Kansas. Five treatments with three replications consisting of removing residues at 0, 25, 50, 75, and 100% after harvest under two tillage levels for wheat (no-till and freshly tilled) and grain sorghum (spring tilled and freshly tilled) were established on 1x2 m plots. Simulated rainfall was applied at 115+/-3 mm h(-1) for 30 min. Compared with plots without residue removal, complete removal increased runoff by 61% in freshly tilled wheat plots, 225% in spring-tilled sorghum plots, and 94% in freshly tilled sorghum plots. Residue removal at rates as low as 50% increased loss of sediment. Complete removal doubled the sediment loss to 14 Mg ha(-1) in tilled wheat, whereas it increased sediment loss from 0.9 to 7.2 Mg ha(-1) in no-till wheat. No-till with 100% residue removal lost as much sediment as freshly tilled wheat plots with 0 or 25% removal. Residue removal at 75 and 100% increased losses of total N, total P, and SOC associated with sediment. Overall, excessive residue removal led to large losses of sediment, sediment-bound SOC, and nutrients in runoff. Furthermore, erosion protection provided by no-till management is lost when residue removal exceeds 25%.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Agriculture / methods*
  • Environmental Pollution*
  • Geologic Sediments* / analysis
  • Kansas
  • Organic Chemicals / analysis*
  • Rain
  • Soil / analysis*
  • Sorghum
  • Triticum

Substances

  • Organic Chemicals
  • Soil