Jac Varco

Jac Varco

Triplett Endowed Chair in Agronomy

Agronomy - Nutrient Management

Mailing Address:
Box 9555
Mississippi State, MS 39762
Mailing Address:
117 Dorman Hall
Mississippi State, MS 39762
Research/Extension Assignments:
  • Developing management strategies for improving nutrient utilization in no-till crop production
  • Use of advanced spatial technologies such as remote sensing and GIS/GPS for implementing nutrient management strategies at the field scale
  • Determining efficacy of inorganic and organic fertilizers and fertilizer additives

  • Ph.D., University of Kentucky
  • M.S., University of Florida
  • B.S., University of Florida

  • PSS 3303 Soils
  • PSS 3301 Soils Laboratory
  • PSS 4313/6313 Soil Fertility and Fertilizers

Society Membership:
  • American Society of Agronomy
  • Soil Science Society of America
  • Mississippi Turfgrass Association
  • Sigma XI Scientific Research Society
  • Soil and Water Conservation Society


  • Samples, C. A., D. M. Dodds, J. Gore, A. L. Catchot, B. R. Golden, J. J. Varco, J. M. Riley. 2019. Impact of nitrogen application rate on tarnished plant bug (Heteroptera: Miridae) populations and management in cotton. Journal of Cotton Science 23(1):28-37. Download
  • Sankar, M. S., P. Dash, Y. Lu, V. Paul, A. E. Mercer, Z. Arslan, J. J. Varco, J. C. Rodgers. 2019. Dissolved organic matter and trace element variability in blackwater-fed bay following precipitation. Estuarine, Coastal, and Shelf Science 231:106452.  Download
  • Seman-Varner, R., J. J. Varco, M. E. O'Rourke. 2019. Winter cover crop and fall-applied poultry litter effects on winter cover and soil nitrogen. Agronomy Journal 111(6):3301-3309.  Download
  • Stefanini, M., J. A. Larson, D. M. Lambert, X. Yin, C. N. Boyer, P. Scharf, B. S. Tubana, J. J. Varco, D. Dunn, H. J. Savoy, M. J. Buschermohle. 2019. Effects of optical sensing based variable rate nitrogen on yields, nitrogen use and profitability for cotton. Precision Agriculture 20:591-610. Download
  • Williams, J. J., W. B. Henry, J. J. Varco, D. B. Reynolds, N. W. Buehring, L. J. Krutz, L. L. Falconer, D. L. Boykin. 2018. Deficit irrigation, planting date, and hybrid selection impacts on a mid-south corn production system. Crop Forage & Turfgrass Management 4(1):1-8. Download
  • Dodds, D. M., T. H. Dixon, A. L. Catchot, B. R. Golden, E. J. Larson, J. J. Varco, C. A. Samples. 2017. Evaluation of wheat stubble management and seeding rates for cotton grown following wheat production. Journal of Cotton Science 21(2):104-112. Download
  • Varco, J. J., C. J. Graham. 2017. The effects of stabilized urea and split-applied nitrogen on sunflower yield and oil content. American Journal of Plant Sciences 8(8):1842-1854. Download
  • Varco, J. J., R. Seman-Varner, M. O'Rourke. 2017. Nitrogen benefits of winter cover crop and fall-applied poultry litter to corn. Agronomy Journal 109(6):2881-2888. Download
  • Varco, J. J., J. Zhang. 2017. Short-term and seasonal soil nitrogen dynamics and recovery by bermudagrass irrigated with 15N labelled swine lagoon effluent. Plant and Soil 410(1-2):437-451. Download
  • Zhao, X., G. Bi, R. Harkess, J. J. Varco, E. K. Blythe. 2016. Spring Nitrogen Uptake, Use Efficiency, and Partitioning for Growth in Iris Germanica 'Immortality'. HortScience 51(5):563-566. Download
  • Zhao, X., G. Bi, R. L. Harkess, J. J. Varco, T. Li, E. K. Blythe. 2016. Nitrogen fertigation rates affect stored nitrogen, growth and blooming in iris germanica 'immortality'. HortScience 51(2):186-191. Download
  • Samples, C. , D. M. Dodds, A. L. Catchot, J. Gore, B. R. Golden, J. J. Varco. 2015. Determining Optimum Plant Growth Regulator Application Rates in Response to Fruiting Structure and Flower Bud Removal. Journal of Cotton Science. 19:1-9. Download
  • Varco, J.J. 2015. Nitrogen fertilizer best practices. Bristol: International Innovation 189:76-78. Download
  • Baird, R.E., A.K. Wood-Jones, J.J. Varco, C. Watson, W.D. Starrett, G. Taylor, and K. Johnson. 2014. Rhododendron decline in the Great Smoky Mountains and surrounding areas: intensive site study of biotic and abiotic parameters associated with the decline. Southeastern Naturalist, The, Vol. 13(1):1-25. Download
  • Fitts, P.W., T.W. Walker, L.J. Krutz, B.R. Golden, J.J. Varco, J. Gore, J.L. Corbin, and N.A. Slaton. 2014. Nitrification and Yield for Delayed-Flood Rice as Affected by a Nitrification Inhibitor and Coated Urea . Agronomy Journal, Vol. 106(5):1541-1548. Download
  • Baird, R.E., A.K. Wood-Jones, J.J. Varco, C. Watson, W.D. Starrett, G. Taylor, and K. Johnson. 2013. All taxa biodiversity inventory survey of select soil and plant ecological parameters associated with rhododendron decline in the Great Smoky Mountains and surrounding areas. Southeastern Naturalist, The, Vol. 12(4):703-722. Download
  • Lemus, R., K. Crouse, M.S. Cox, J.J. Varco, J. White, and J.I. Morrison. 2013. Effect of AVAIL and Nutrisphere-N Application on Annual Ryegrass Production and Quality. Journal of the American Society of Farm Managers and Rural Appraisers, Vol. 6(2). Download
  • Raper, T., J.J. Varco, and K.J. Hubbard. 2013. Canopy-Based Normalized Difference Vegetation Index Sensors for Monitoring Cotton Nitrogen Status. Agronomy Journal, Vol. 105(5):1345-1354. Download
  • Dillon, K.A., T.W. Walker, D.L. Harrell, L.J. Krutz, J.J. Varco, C.H. Koger, III, M.S. Cox. 2012. Nitrogen source and timing efforts on nitrogen loss and uptake in delayed flood rice. Agronomy Journal 104:466-472. Download
  • Knoblauch, R., P.R. Ernani, T.W. Walker, L.J. Krutz, J.J. Varco, L.C. Gatiboni, F.C. Deschamps. 2012. Ammonia volatilization in waterlogged soils influenced by the form of urea application. Brazilian Soil Science Journal 36(3):813-822.
  • Adeli, A., J.J. Varco, K.R. Sistani, D.E. Rowe. 2005. Effects of swine lagoon effluent relative to commercial fertilizer applications on warm-season forage nutritive value. Agronomy Journal 97(2):408-417. Download