Sjoerd Willem Duiker, Ph.D., CCA

Sjoerd Willem Duiker, Ph.D., CCA

  • Professor of Soil Management and Applied Soil Physics
408 Agricultural Sciences and Industries Building
University Park, PA 16802

Areas of Expertise

  • No-tillage
  • Cover crops
  • Soil compaction
  • Soil health
  • Soil erosion
  • Soil conservation
  • Nitrogen fixation


  • Ph.D., Soil Science, The Ohio State University, 2000
  • M.S., Tropical Crop Science, Wageningen Agricultural University, The
  • Netherlands

Responsibilities and Interests

My specialization focuses on the effects of soil management practices on soil physical properties and processes. This includes the effect of no-tillage and tillage on soil physical properties, how soil compaction affects soil and crops, what effect crop rotation plays in maintaining soil quality, and the benefits and challenges of cover crops. The use of a systems approach to no-tillage, soil compaction and crop rotations is a crucial element in all my work. Research takes place on Penn Stateís research farms as well as in collaboration with farmers and field agronomists in Pennsylvania.


  • 75% Extension
  • 25% Research


Professional Background

  • Associate Professor, Department of Crop and Soil Sciences, The Pennsylvania State University, 2006–present
  • Assistant Professor, Department of Crop and Soil Sciences, The Pennsylvania State University, 2000–2006

Selected Publications

  1. Duiker, S.W. 2014. Establishment and termination dates affect fall-established cover crops. Agronomy Journal 106:670-678.
  2. Duiker, S.W. and P. Maina. 2014. Haybaling as a business for former street children in Kenya. Livestock Research for Rural Development 26(1) article 17.
  3. Derpsch, R., A.J. Franzluebbers, S.W. Duiker, D.C. Reicosky, K. Koeller, T. Friedrich, W.G. Sturny, J.C.M Sa, and K. Weiss. 2014. Why do we need to standardize no-tillage research? Soil and Tillage Research 137:14-22
  4. Duiker, S.W. 2013. Mowing with scythes. Small Farmer Journal 237(2):72-75.
  5. Fouli, Y., S.W. Duiker, D.D. Fritton, M.H. Hall, J.E. Watson, and D.H. Johnson. 2012. Double cropping efects on forage yield and the field water balance. Agricultural Water Management 115:104-117.
  6. Verbree, D.A., S.W. Duiker, and P.J.A. Kleinman. 2010. Runoff losses of sediment and phosphorus from no-till and cultivated soils receiving dairy manure. J. Environ.Qual. 39:1-9.

  7. Mischler, R.A., W.S. Curran, S.W. Duiker and J.A. Hyde. 2010. Use of rolled rye cover crop for weed suppression in no-till soybeans. Weed Technol.
  8. Mischler, R., Duiker, S.W., W.S. Curran, and D. Wilson. 2010. Hairy vetch management for no-till organic corn production. Agron. J.102:355-36
  9. Rhoton, F., and S.W. Duiker. 2008. Erodibility of a Soil Drainage Sequence in the Loess Uplands of Mississippi. Accepted for Publication in Catena.
  10. Sidhu, D., and S.W. Duiker. 2006. Soil compaction in conservation tillage: Crop impacts. Agron. J. 98:1257-1264.
  11. Duiker, S.W., J.F. Haldeman Jr., and D.H. Johnson. 2006. Tillage x maize hybrid interactions. Agron. J. 98:436-442.