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Department of Agronomy

Department of Agronomy
Kansas State University
2004 Throckmorton PSC
1712 Claflin Road
Manhattan, KS 66506-0110

Ph: +1-785-532-6101
Fx: +1-785-532-6094

Dr. Dorivar Ruiz Diaz

Dr. Dorivar Ruiz-Diaz

Associate Professor

Soil Fertility and Nutrient Management
Email Dr. Ruiz Diaz

Kansas State University
2711 Throckmorton PSC
1712 Claflin Road
Manhattan, KS 66506

Ph: +1-785-532-6183
Fx: +1-785-532-6094


  • Ph.D. Soil Fertility, Iowa State University, 2007
  • M.S. Soil Science, University of Illinois at Urbana-Champaign, 2004
  • B.S. Agronomy, PanAmerican School of Agriculture, Zamorano, 2000


  • Mueller, N.D., D.A. Ruiz Diaz, J.A. Dille, D.E. Shoup, D.B. Mengel, and L.W. Murray. 2013. Winter Annual Weed Management and Nitrogen Rate Effects on Corn Yield. Agron. J. 105:1077–1086
  • Liesch, A.M., D.A. Ruiz Diaz, D.B. Mengel, and K.L. Roozeboom. 2012. Interpreting relationships between soil variables and soybean iron deficiency using factor analysis. Soil Sci. Soc. Am. J. 76:1311-1318.
  • Ruiz Diaz, D.A., D.B. Mengel, R.E. Lamond, S.R. Duncan, D.A. Whitney, and T.M. Maxwell. 2012. Meta-analysis of winter wheat response to chloride fertilization in Kansas. Commun. Soil Sci. Plant Anal. 43: 2437-2447.
  • Ruiz Diaz, D.A., J.E. Sawyer and D.W. Barker. 2012. Residual Poultry Manure Nitrogen Supply to Corn the Second and Third Years after Application. Soil Sci. Soc. Am. J. 76:2289-2296
  • Ruiz Diaz, D.A., J.E. Sawyer, and A.P. Mallarino. 2011. On-farm Evaluation of Poultry Manure as a Nitrogen Source for Corn. Soil Sci. Soc. Am. J.75:729-737.
  • Holmes, J.D., J.E. Sawyer, P. Kassel, and D.A. Ruiz Diaz. 2011. Using ground eggshells as a liming material in corn and soybean production. Crop Management. doi:10.1094/CM-2011-1129-01-RS.
  • Ruiz Diaz, D.A., J.E. Sawyer, and A.P. Mallarino. 2011. On-farm evaluation of poultry manure as a nitrogen source for corn. Soil Sci. Soc. Am. J.75:729-737.
  • Liesch, A.M., D.A. Ruiz Diaz, K.L. Martin, B.L. Olson, D.B. Mengel, and K.L. Roozeboom. 2011. Management Strategies for Increasing Soybean Yield on Soils Susceptible to Iron Deficiency. Agron. J. 103:1870-1877.
  • Sawyer J.E., P. Pedersen, D.W. Barker, D.A. Ruiz Diaz, and K.A. Albrecht. 2010. Intercropping Corn and Kura Clover: Response to Nitrogen Fertilization. Agron. J. 102: 568-574
  • Ruiz Diaz, D.A., R.G. Darmody, J.C.Marlin, G.A. Bollero, and F. W. Simmons. 2010. Trace metal bioaccumulation and plant growth on dredged river sediments and biosolids mixtures. Water, Air, & Soil Pollution. 206:321-333.
  • Ruiz Diaz, D.A., J.E. Sawyer, D.W. Barker, and A.P. Mallarino. 2010. Runoff Nitrogen Loss with Simulated Rainfall Immediately Following Poultry Manure Application for Corn Production. Soil Sci. Soc. Am. J. 74:221-230
  • Ruiz Diaz, D.A., P. Pedersen, and J.E. Sawyer. 2009. Soybean Response to Inoculation and Nitrogen Application Following Long-Term Grass Pasture. Crop Sci. 49: 1058-1062.
  • Ruiz Diaz, D.A. and J.E. Sawyer. 2008. Plant-Available Nitrogen from Poultry Manure as Affected by Time of Application. Agron. J. 100:1318-1326.
  • Ruiz Diaz, D.A., J.A. Hawkins, J.E. Sawyer, and J.P. Lundvall. 2008. Evaluation of In-Season Nitrogen Management Strategies for Corn Production. Agron. J. 100: 1711–1719.
  • Ruiz Diaz, D.A., J.E. Sawyer, and A.P. Mallarino. 2008. Poultry Manure Supply of Potentially Available Nitrogen with Soil Incubation. Agron. J. 100:1310-1317.


My research program in soil fertility and nutrient management emphasizes applied field experiments to develop efficient, cost effective, and environmentally sound nutrient management practices for agronomic crop production in Kansas. Areas of interest include the efficient use of fertilizers, soil test interpretations and fertilizer recommendations, and land application of manure and biosolids with emphasis on crop-available nitrogen. My program also assesses environmental risks associated with nutrient management and tillage.

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