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Department of Agronomy

Dr. Dorivar Ruiz Diaz

Dr. Dorivar Ruiz-Diaz


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 Fertility, University of Illinois at Urbana-Champaign, 2004
  • B.S. Agronomy, PanAmerican School of Agriculture, Zamorano, 2000


  • Sweeney, D.W., J.K. Farney, J.L. Moyer, and D.A. Ruiz Diaz. 2020. Nitrogen Fertilization for Hay and Seed from Endophyte-free and Endophyte-infected Tall Fescue. Agrosyst Geosci Environ. https://doi.org/10.1002/agg2.20124
  • Sweeney D.W. and D.A. Ruiz Diaz. 2020. Long‐term in‐season grain sorghum and soybean response to tillage and nitrogen management. Agrosyst Geosci Environ. https://doi.org/10.1002/agg2.20084
  • Perin, V., E.A. Santos, R. Lollato, D.A. Ruiz Diaz, and G.J. Kluitenberg. Impacts of Ammonia Volatilization from Broadcast Urea on Winter Wheat Production. Agron. J. doi:10.1002/agj2.20371
  • Sweeney, D. W. and D.A. Ruiz Diaz. 2020. Utilizing Soil Phosphorus and Potassium While Growing Soybean without Fertilizer on a Claypan Soil. Agron. J. 112:4386-4394 https://doi.org/10.1002/agj2.20389
  • Coelho, M.J, D.A Ruiz Diaz, M. Rodrigues, F.B. Ono, C. Kappes, L. Zancanaro, and S. Pavinato. 2020. Soil phosphorus fate and its lability after a long-term phosphorus fertilizers strategy in Brazilian Oxisol. Archives of Agronomy and Soil Science. DOI: 10.1080/03650340.2020.1803492
  • Rosa, A.T.; D.A. Ruiz Diaz and F.D. Hansel. 2020. Phosphorus fertilizer optimization is affected by soybean varieties and placement strategy, Journal of Plant Nutrition, 43:15, 2336-2349, DOI: 10.1080/01904167.2020.1771583
  • Maeoka RE, Sadras VO, Ciampitti IA, Diaz DR, Fritz AK and R.P. Lollato. 2020. Changes in the Phenotype of Winter Wheat Varieties Released Between 1920 and 2016 in Response to In-Furrow Fertilizer: Biomass Allocation, Yield, and Grain Protein Concentration. Front. Plant Sci. 10:1786. doi: 10.3389/fpls.2019.01786
  • Preston, C.L. D.A. Ruiz Diaz and D.B. Mengel. 2019. Corn response to long-term phosphorus fertilizer application rate and placement with strip-tillage. Agron. J. 111:1–10.
  • Preza Fontes G., P.J. Tomlinson, K.L. Roozeboom, J. Warren, and D.A. Ruiz Diaz. 2019. Nitrogen fertilization offsets the N2O mitigating effects of cover‐crops and double‐crop soybean in a wheat‐sorghum system. Agron. J. https://doi.org/10.1002/agj2.20095
  • Obour, A.K., A.J. Schlegel, R. Perumal., J.D. Holman, and D.A Ruiz Diaz. 2019. Evaluating grain sorghum hybrids for tolerance to iron chlorosis. J. Plant Nutrition. DOI: 10.1080/01904167.2018.1549677
  • Arruda M.J., D.A. Ruiz Diaz, F.D. Hansel, G. Hettiarachchi and P. Pavinato. 2019. Long-term fertilizer placement in a corn-soybean rotation affect soil phosphorus fractions and legacy. Geoderma. https://doi.org/10.1016/j.geodrs.2019.e00228
  • Rosa, A.T., D.A. Ruiz Diaz, F.D. Hansel, V.S.J. Sunoj and P.V.V. Prasad. 2019. Effect of genotypic variation on root growth and nutrient uptake in corn and soybean. Agrosystems, Geosciences & the Environment. doi:10.2134/age2019.03.0018
  • Hansel, F.D., D.A. Ruiz Diaz, A.T. Rosa, C.J. Moorberg. 2019. Phosphorus fertilizer placement and rate affect soybean root growth and nutrient uptake under a high fertility soil. Agronomy Science and Biotechnology. DOI: 10.33158/ASB.2019v5i1p62
  • Sweeney, D. W., D.A. Ruiz Diaz, and D. J. Jardine. 2018. Nitrogen management and uptake by corn on no-till and ridge-till claypan soil. Agrosystems, Geosciences & the Environment 1:180034. doi:10.2134/age2018.09.00
  • Lollato, R.P., D.A. Ruiz Diaz, E. De Wolf, M. Knapp, D. Peterson and A. Fritz. 2018. Agronomic practices for reducing wheat yield gaps: a quantitative appraisal of progressive producers. Crop Science 59:333-350. doi:10.2135/cropsci2018.04.0249
  • Jaenisch, B.R., A.O. Silva, E. DeWolf, D.A. Ruiz Diaz and R.P. Lollato. 2018. Plant population and fungicide economically reduced winter wheat yield gap in Kansas. Agron. J. 111:1–16. doi:10.2134/agronj2018.03.0223
  • Ferreira, A.O., T.J.C. Amado, C.W. Rice, D.A Ruiz Diaz, C. Briedis, T.M. Inagaki. 2018. Driving factors of soil carbon accumulation in Oxisols in long-term no-till systems of South Brazil. Science of the Total Environment. 622:735-742.
  • Hansel, F.D., T.J.C. Amado, D.A. Ruiz Diaz, L.H.M. Rosso, F.T. Nicoloso, M. R. W. Schorr. 2017. Phosphorus fertilizer placement and tillage affect soybean root growth and drought tolerance. Agron. J. 109:2936-2944
  • Preza Fontes, G., P. Tomlinson, K. Roozeboom, and D.A. Ruiz Diaz. 2017. Grain Sorghum Response to Nitrogen Fertilizer Following Cover Crops Planted after Winter Wheat. 2017. Agron. J. 109:2723-2737
  • Eagle, A.J., L.E. Christianson, R.L. Cook, R.D. Harmel, F.E. Miguez, S.S. Qian, and D.A. Ruiz Diaz. 2017. Meta-analysis Constrained by Data: Recommendations to Improve Relevance of Nutrient Management Research. Agron. J. 109:2441-2449
  • Hansel, F.D., D.A. Ruiz Diaz, T.C. Amado, L.M. Rosso. 2017. Deep banding increases phosphorus removal by soybean grown under no-tillage production systems. Agron. J. 109:1091-1098
  • Ferreira, A.O., T. Amado, C.W. Rice, D.A. Ruiz Diaz, C. Keller, T.M. Inagakia, 2016. Can no-till grain production restore soil organic carbon to levels natural grass in a subtropical Oxisol? Agriculture, Ecosystems & Environment. 229:13-20.
  • Adee E, F. Hansel, D.A. Ruiz Diaz and K. Janssen. 2016. Corn response as affected by planting distance from the center of strip-till fertilized rows. Front. Plant Sci. 7:1232-1235.
  • Adee, E., D.A. Ruiz Diaz and C. Little. 2016 Effect of soil test and phosphorus fertilization on soybean sudden death syndrome severity. Crop, Forage and Turfgrass Manag. doi: 10.2134/cftm2015.0193
  • Woli, K.P., D.A. Ruiz Diaz, D.E. Kaiser, A.P. Mallarino, and J.E. Sawyer. 2015. Field-scale evaluation of poultry manure as a combined nutrient resource for corn production. Agron. J. 107:1789–1800
  • Sweeney, D.W. and D.A. Ruiz Diaz. 2014. Assessing the residual from fertilizer nitrogen applied to failed corn on the following wheat crop. Crop Management 13:1-2. doi:10.2134/CM-2014-0005-BR.
  • 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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