Ph.D. 1983, University of Minnesota; M.S. 1978, North Dakota State University; B.S. 1975, University of Maine. Soil nutrient management and nutrient cycling.  Current research interests include investigations of fertilizer management strategies for enhancing N recovery by crops using 15N enriched labelled fertilizers; soil emissions of greenhouse gases (nitrous oxide, methane, and carbon dioxide) as affected by cropping systems; soil carbon sequestration and characterization of dissolved organic matter in croplands; urea-fertilizer induced emissions of ammonia and mitigation with urease inhibitors; and soil acidification and aluminum toxicity of Montana soils. 

Recent Publications


  • Romero, C. M., R.E. Engel, J. D’Andrilli, C. Chen, C. Zabiniski, P.R. Miller, and R. Wallander, 2017.  Bulk optical characterization of dissolved organic matter from semiarid wheat-based cropping systems.  Geoderma 306:40-49.

  • Engel, R., Romero, C., Jones, C. and Wallander, R.  2017. Late-fall, winter and spring broadcast applications of urea to no-till winter wheat I. Ammonia loss and mitigation by NBPT.   Soil Sci. Soc. Am. J.  81 322-330. 
  • Romero, C., Engel, R., Chen, C., Wallander, R., Jones, C. 2017.  Late-fall, winter and spring broadcast applications of urea to no-till winter wheat II. Fertilizer N recovery, yield and protein as affected by NBPT.  Soil Sci. Soc. Am. J.  81:331-340. 
  • Engel, R., Miller, P., McConkey, B., Wallander, R., Holmes, J. 2017/ Soil organic C changes to increasing cropping system intensity and no-till in a semiarid climate. Soil Sci. Soc. Am. J.  81:404-413
  •  Long, D., McCallum, J., Reardon, C., Engel, R. 2017. Nitrogen requirement to change protein concentration of spring wheat in semiarid Pacific Northwest. Agron. J. 109:675-683. 
  • Engel, R., Gravens, E., Towey, B. D.  2015. Degradation of the urease inhibitor NBPT as affected by soil pH. Soil Sci. Soc. Am. J 79:1674-1683. 
  • Ehlert, K. A., Engel, R., Mangold, J. 2015. Imazapic activity in a semiarid climate at downy brome (Bromus tectorum)-infested rangeland and CRP sites. Weed Technology 29:472-479. 
  • Long, D., Whitmus, J., Engel, R., Brester, G.  2015. Net Returns from Terrain-based Variable-Rate Nitrogen Management. Agronomy Journal 107:1055-1067. 
  • Miller, P., Bekkerman, A., Jones, C., Burgess, M., Holmes, J. A., Engel, R. 2015. Pea in rotation with wheat reduced uncertainty of economic returns in southwest Montana.  Agron. J. 107:541-550.
  • Romero, C. M., Engel, R., Chen, C., Wallander, R. 2015. Microbial Immobilization of Nitrogen-15-Labeled Ammonium and Nitrate in an Agricultural Soil from Central Montana. Soil Sci. Soc. Am. J 79:595-602.



Recent Grants

  • 2017: $264,015. Engel, R., Carr, P, and Jones, C. Soil acidity management of long-term no-till fields in Montana to prevent crop failure. USDA-Western Sustainable Agricultural Research and Education Program.
  • 2017:  $18, 672. Engel, R. Evaluation of Koch Agronomic Services’ (“KSA”) experimental urease inhibitor KAS_060K001 (K32) for control of NH3 volatilization from urea fertilizers over a soil pH gradient.  Koch Agronomic Services. 
  • 2016: $12,980.  Engel, R., Carr, P., Jones, C. Understanding acidification and management of Montana soils.  Montana Fertilizer Advisory Committee. July 1, 2016-June 30, 2017. 
  • 2016: $56,275. Engel, R., Jones, C., Perry, M. Fertilizer management strategies for enhanced N recovery and reducing N losses in no-till wheat. Montana Fertilizer Advisory Committee. 
  • 2016: $9,000.  Engel, R. Pushing the limits of fertilizer N recovery in a semiarid climate with improved N management. Internal Plant Nutrition Institute. 
  • 2014:  $499,990. Menalled, F., Lehnhoff, E., Bekkerman, A.  Burrows, M., Engel, R., Gedeon, T., Glunk, E., Hatfield, P., Miller, P., Miller, Z.  Assessing the resiliency of integrated crop-livestock organic systems in water-limited environments under current and predicted climate