Contact Information:

422 Agricultural Sciences and Industries Building University Park, PA 16802

Appointment:

  • 70% Research
  • 30% Teaching

Links:

David A. Mortensen

David A. Mortensen
Professor of Weed Ecology / Biology

Responsibilities and Interests:

Climate, physiographic and soil variation combine to influence plant fitness and the performance of management practices. My interests lay in assessing cause and extent of such variation on cropping systems performance broadly. I am trained as an applied plant ecologist and have spent most of my plant science life studying aspects of weed ecology with a particular interest in seeing ways such studies would directly benefit farmers through enhancing production efficiency while at the same time identifying practices that offer enhanced environmental protection.

Education:

Selected Publications:

  1. Humston, R., D.A. Mortensen and D.Y. Wyse-Pester. 2007. Assessing management impacts on spatial dynamics of common sunflower (Helianthus annuus). Weed Science, in press.
  2. Dauer, J., D.A. Mortensen, and M. VanGessel. 2007. Spatial and temporal dynamics governing long distance dispersal of Conyza canadensis. Journal of Applied Ecology 44:105-114
  3. Scott A. Isard, David A. Mortensen, Shelby J. Fleischer and Erick D. De Wolf. 2007. Application of Aerobiology to IPM. In Integrated Pest Management Systems. CRC Press. In press.
  4. Dauer, J., D.A. Mortensen and R. Humston. 2006. Controlled experiments to predict horseweed (Conyza canadensis) dispersal distances. Weed Science 54:484-489.
  5. Burton, M.G., D.A. Mortensen, and J.L. Lindquist. 2006. Effect of cultivation and within-field differences in soil conditions on feral Helianthus annuus growth in ridge-tillage maize. Soil & Tillage Research 88:8-15.
  6. Ryan, M.R., Mortensen, D.A., Hulting, A.G., Grube, K.M., Wilson, D.O. and P.R. Hepperly. 2006. The Influence of Management System on Weed Tolerance. Proceedings Weed Science Society of America. Abstract. 46:290.
  7. Ryan, M.R., Mortensen, D.A., L. Bastiaans. 2006. Enhanced Tolerance to Weed Competition: Effects of Crop and Soil Management in a Long-Term Cropping Systems Trial. European Weed Science Society Crop-Weed Interactions Workshop. Rothamsted, September 12-15. Pp 16.
  8. Myers, M.W., W.S. Curran, M.J. Vangessel, B.A. Majek, D.A. Mortensen, D.D. Calvin, H.D. Karsten and G.W. Roth. 2005. Effect of soil disturbance on annual weed emergence in the northeastern United States. Weed Tech. 19:274-282.
  9. Burton, M.G. D.A. Mortensen and J.L. Lindquist. 2005. Environmental characteristics affecting Helianthus annuus distribution in a maize production system. Agricultural Ecosystems and the Environment 111, 30-40.
  10. Peskin, N., D.A. Mortensen, B.P. Jones and M.R. Booher. 2005. Herbicide management of Japanese stiltgrass (Microstegium vimineum) in a forest roadside community. Journal of Restoration Ecology, 23:1-2.
  11. Humston, R., D.A. Mortensen, and O.N. Bjornstad. 2005. Anthropogenic forcing on the spatial dynamics of an agricultural weed: the case of the common sunflower. Ecological Applications 42, 863-872.
  12. Hilgenfeld, K.L., A.R. Martin, D.A. Mortensen, and S.C. Mason. 2004.Weed management in Glyphosate Resistant Soybean: Weed emergence patterns in relation to glyphosate treatment timing. Weed Technology. 18:277-283.
  13. Hilgenfeld, K.L., A.R. Martin, D.A. Mortensen, and S.C. Mason. 2004. Weed management in a glyphosate resistant soybean system: Weed Species Shifts. (Glycine max). Weed Technology. 18:284-291.
  14. Neeser, C., J.A. Dille, G. Krishnan, D.A. Mortensen, J.T. Rawlinson, A.R. Martin, and L.B. Bills, 2004. WeedSOFT: A weed management decision support system. Weed Science 52:115-122.
  15. Meyer, G.E., T. W. Hindman, D.D. Jones, D. A. Mortensen. 2004. Digital camera operation and fuzzy logic classification of plant, soil, and residue color images. Engineering in Agriculture, 20(4):519-529.
  16. Myers, M.W., W.S, Curran, M..J. VanGessel, D.D. Calvin, D.A. Mortensen, B.A. Majek, H.D. Karsten, and G. W. Roth. 2004. Predicting weed emergence for eight annual species in the northeastern United States. Weed Science. 52:913-919.
  17. Traore, S., S.C. Mason, A.R. Martin, D.A. Mortensen, and J.J. Spotanski. 2003. Velvetleaf interference effects on yield and growth of grain sorghum. Agronomy Journal.
  18. Burton, M.G., D.A. Mortensen, D.B. Marx, and J.L. Lindquist. 2003. Niche effects on wild Helianthus annuus L. in maize (Zea mays L.): Seed germination, emergence and survival. Weed Science 52:779-787.
  19. Johnson, C.K., D.A. Mortensen, B.J. Wienhold, J.F. Shanahan, and J.w. Doran. 2003. Site-specific management zones based on soil electrical conductivity in a semiarid cropping system. Agron. J. 95:303-315.
  20. Dille, J.A., M. Milner, and J.J. Groeteke, D.A. Mortensen, and M.M. Williams. 2003. How good is your weed map? A comparison of spatial interpolators. Weed Sci. 51:44-55.
  21. Williams, M.M., D.A. Mortensen, W.J. Waltman, andd A.R. Martin. 2002. Spatial inference of herbicide bioavailability using a geographic information system. Weed Tech. 16:603-611.
  22. Traore, S., J.L. Lindquist, S.C. Mason, A.R. Martin, and D.A. Mortensen. 2002. Comparative ecophysiology of grain sorghum and Abutilon theophrasti in monoculture and in mixture. Weed Res. 42:65-75.
  23. Dille, J.A., D.A. Mortensen, and L.J. Young. 2002. Predicting weed species occurrence based on site properties and previous year’s weed presence. Prec. Agriculture 3:193-207.
  24. Padbury, G., S. Wlatman, J. Caprio, G. Coen, S. McGinn, D. Mortensen, G. Nielsen, and R. Sinclair. 2002. Agroecosystems and land resources of the Northern Great Plains. Agron. J. 94: 251-261.
  25. Williams, M.M., D.A. Mortensen, A.R. Martin, and D.B. Marx. 2001. Within-field soil heterogeneity effects on herbicide-mediated crop injury and weed biomass. Weed Science 49:798-805.
  26. L.B. Cutforth, C.A. Francis, G.D. Lynne, D.A. Mortensen, and K.M. Eskridge. 2001. Factors affecting farmers’ crop diversity decisions: An integrated approach. American Journal of Alternative Agriculture. 16 (4): 168-176.
  27. Mortensen, D.A., L. Bastiaans and M. Sattin. 2000. The role of ecology in developing weed management systems: an outlook. Weed Research 40:49-62.
  28. Williams, M.M., R. Gerhards and D.A. Mortensen. 2000. Two-year weed seedling population responses to a post-emergent method of site-specific weed management. Precision Agriculture 2:247-263.
  29. Williams, M.M. and D.A. Mortensen. 2000. Crop/Weed Outcomes from site-specific and uniform soil-applied herbicide applications. 2:377-388 Precision Agriculture 2:377-388
  30. Dieleman, J.A., D.A. Mortensen, D.D. Buhler, and R.B. Ferguson. 2000. Identifying associations among site properties and weed species abundance. Part II. Hypothesis generation based on data from two central Nebraska corn fields. Weed Science. 48: 576-587.
  31. Dieleman, J.A., D.A. Mortensen, D.D. Buhler, C.A. Cambardella, and T.B. Moorman. 2000. Identifying associations among site properties and weed species abundance. Part I. Multivariate analysis applied to data from a central Iowa corn-soybean field. Weed Science 48: 567-575.
  32. Mortensen, D.A., L. Bastiaans and M. Sattin. 2000. The role of ecology in developing weed management systems: an outlook. Weed Research 40:49-62.
  33. Williams, M.M., D.A. Mortensen, and J.W. Doran. 2000. No-tillage soybean performance in cover crops for weed management in the western cornbelt. J. Soil and Water Cons. 55:1 79-84.
  34. Dieleman, J.A.and D.A. Mortensen. 1999. Characterising the spatial pattern of Abutilon theophrasti seedling patches. Weed Research 39:455-467.
  35. Dieleman, J.A., D.A. Mortensen, and A.R. Martin. 1999. Influence of velvetleaf (Abutilon theophrasti) and common sunflower (Helianthus annuus) density variation on weed management outcomes. Weed Sci. 47:81-89.
  36. Lindquist, J.L., D.A. Mortensen, P. Westra, W.J. Lambert, T.T. Bauman, J.C. Fausey, J.J. Kells, S.J. Langton, R.G. Harvey, K. Banken, S. Clay, and B.H. Bussler. 1999. Stability of corn (Zea mays) — foxtail (Setaria spp.) interference relationships. Weed Sci. 47:195-200. (J. Series No. 12495)
  37. Lindquist, J.L. and D.A. Mortensen. 1999. Ecophysiological characteristics of four maize hybrids and velvetleaf (Abutilon theophrasti). Weed Res. 39:271-285. (J. Series No. 12018)
  38. Lindquist, J.L., D.A. Mortensen, and B.E. Johnson. 1998. Mechanisms of corn tolerance and velvetleaf suppressive ability. Agron. Journal 90:787-792. (J. Series No. 12034)
  39. Lindquist, J.L. and D.A. Mortensen. 1998. Tolerance and velvetleaf (Abutilon theophrasti) suppressive ability of two old and two modern corn (Zea mays) hybrids. Weed Sci. 46:569-574. (J. Series No. 12019)
  40. Williams II, M.M., D.A. Mortensen, and J.W. Doran. 1998. Assessment of weed and crop fitness in cover crop residues for integrated weed management. Weed Sci. 46:595-603. (J. Series No. 12028)
  41. Meyer, G.E., T. Mehta, M.F. Kocher, D.A. Mortensen, and A. Samal. 1998. Textural imaging and discriminant analysis for distinguishing weeds for spot spraying. Transactions of the ASAE 41:1189-1197. (J. Series No. 11355)
  42. Lindquist, J.L., J.A. Dieleman, D.A. Mortensen, G.A. Johnson, and D.Y. Pester-Wyse. 1998. Economic importance of managing spatially heterogeneous weed populations. Weed Tech. 12:7-13.(J. Series No. 12020)
  43. Williams II, M.M., R. Gerhards, S. Reichart, D.A. Mortensen, and A.R. Martin. 1998. Weed seedling population responses to a method of site-specific weed management. Precision Agriuclture: Proceedings of the Fourth International Conference, P. Robert and R.H. Rust (eds.), Madison, Wisconsin, USA, ASA-CSA-SSA In Press
  44. Mortensen, D.A. and J.A. Dieleman. 1998. Why weed patches persist: dynamics of edges and density, p. 14-19. In: R.W. Medd and J.E. Pratley (eds.), Precision Weed Management in Crops and Pastures. R.G. and F.J. Richardson, Melbourne.
  45. Martin, A.R., D.A. Mortensen, and J.L. Lindquist. 1998. Decision support models for weed management: in-field management tools, p. 363-369. In: J.L. Hatfield, D.D. Buhler, and B.A. Stewart (eds.), Integrated Weed and Soil Management. Ann Arbor Press, Inc., Chelsea, MI.
  46. Dieleman, J.A., and D.A. Mortensen. 1998. Influence of weed biology and ecology on development of reduced dose strategies for integrated weed management systems, p. 333-362. In: J.L. Hatfield, D.D. Buhler, and B.A. Stewart (eds.), Integrated Weed and Soil Management. Ann Arbor Press, Inc., Chelsea, MI.
  47. Mortensen, D.A., J.A. Dieleman, and G.A. Johnson. 1998. Weed spatial variation and weed management, p. 293-309. In: J.L. Hatfield, D.D. Buhler, and B.A. Stewart (eds.), Integrated Weed and Soil Management. Ann Arbor Press, Inc., Chelsea, MI.
  48. Gerhards, R., D.Y. Wyse-Pester, D.A. Mortensen, and G.A. Johnson. 1997. Characterizing spatial stability of weed populations using interpolated maps. Weed Sci. 45:108-119.
  49. Gerhards, R., M. Sokefeld, K. Schulze-Lohne, D.A. Mortensen, and W. Kuhbauch. 1997. Site specific weed control in winter wheat. J. Agron. & Crop Sci. 178:219-225.
  50. National Research Council Report. 1997. Precision Agriculture in the 21st Century: Geospatial and Information Technologies in Crop Management, p 118. National Academy Press, Washington, D.C. Report released by the National Academy of Science in September, 1997. Served as panel member and co-author of this peer-reviewed report.
  51. Johnson, G.A., J. Cardina, and D.A. Mortensen. 1997. Site specific weed management — current and future directions. Pg. 131-148 In Pierce, F.J. and E.J. Sadler (eds.), The State of Site-Specific Management for Agriculture. Amer. Soc. Agron. Inc.
  52. Urwin, C.P., R.G. Wilson, and D.A. Mortensen. 1996. Late season weed suppression from dry bean (Phaseolus vulgaris) cultivars. Weed Tech. 10:699-704. (J. Series No. 11299)
  53. Urwin, C.P., R.G. Wilson, and D.A. Mortensen. 1996. Response of dry edible bean (Phaseolus vulgaris) cultivars to four herbicides. Weed Tech. 10:512-518. (J. Series No. 11290).
  54. Johnson, G.A., D.A. Mortensen, L.J. Young, and A.R. Martin. 1996. Parametric sequential sampling based on multistage estimation of the negative binomial parameter k. Weed Sci. 44:555-559. (J. Series No. 11029)
  55. Johnson, G.A., D.A. Mortensen, and C. Gotway. 1996. Spatial and temporal analysis of weed seedling population using geostatistics. Weed Sci. 44:704-710. (J. Series No. 11238)
  56. Lindquist, J.L., D.A. Mortensen, S.A. Clay, R. Schmenk, J.J. Kells, K. Howatt, and P. Westra. 1996. Stability of corn (Zea mays)-velvetleaf (Abutilon theophrasti) interference relationships. Weed Sci. 44:309-313. (J. Series No. 11057)
  57. Sabatka, R.G., F.W. Roeth, A.R. Martin, and D.A. Mortensen. 1996. Shattercane (Sorghum bicolor) biotype variation in tolerance to primisulfuron. Weed Tech. 10:363-367.
  58. Teo-Sherrell, C., D.A. Mortensen, and M.E. Keaton. 1996. Fates of weed seeds in soil: A seeded-core method of study. J. Appl. Ecol. 33:1107-1113. (J. Series No. 10833).
  59. Mortensen, D.A., and H.D. Coble. 1996. Economic thresholds for weeds: management implications. In L.G. Higley and L.P. Pedigo (eds.) Economic Thresholds for Integrated Pest Management. Univ. Neb. Press. p. 89-113.
  60. Johnson, G.A., D.A. Mortensen, and A.R. Martin. 1995. A simulation of herbicide use based on weed spatial distribution. Weed Res. 35:197-205.
  61. Jordan, N., D.A. Mortensen, D.M. Prenzlow, and K.C. Cox. 1995. Simulation analysis of crop rotation effects on weed seedbanks. Am. J. Bot. 82(3):390-398.
  62. Woebbecke, D.M., G.E. Meyer, K. VonBargen, and D.A. Mortensen. 1995. Shape features for identifying young weeds using image analysis. Trans. ASAE 38:271-281.
  63. Woebbecke, D.M., G.E. Meyer, K. VonBargen, and D.A. Mortensen. 1995. Color indices for weed identification under various soil, residue, and lighting conditions. Trans. ASAE 38:259-269.
  64. Johnson, G.A., D.A. Mortensen, L.J. Young, and A.R. Martin. 1995. The stability of weed seedling population models and parameters in eastern Nebraska corn (Zea mays) and soybean (Glycine max) fields. Weed Sci. 43:604-611.
  65. Mortensen, D.A., G.A. Johnson, D.Y. Wyse, and A.R. Martin. 1995. Managing spatially variable weed populations. In Site Specific Crop Management, P. Robert and R.H. Rust (eds.) Agron. Soc. Amer. pp. 397-415.
  66. Mortensen, D.A., G.E. Meyer, and K. VonBargen. 1995. Plant sensing and intermittent herbicide application. Reviews in Weed Science, monograph 10605.
  67. Mortensen, D.A. 1994. Weed management and its relationships to insect management. In Handbook on Soybean Insects, Ent. Soc. Amer., p. 118-123.
  68. Smart, J.R., D.A. Mortensen, F.W. Roeth. 1993. Corn tolerance to sethoxydim under irrigated and non-irrigated conditions. Weed Tech. 6:567-572.
  69. Smart, J.R., A. Weiss, and D.A. Mortensen. 1993. Modeling the influence of postdirected sethoxydim on field corn yields: model development and validation. Agron. J. 85:1204-1209.
  70. Mortensen, D.A., A.R. Martin, T. Harvill, and T.A. Bauer. 1993. The influence of rotational diversity on economic optimum thresholds in soybean. In Weed and herbicide research and their practical application. Proc. Eur. Weed Res. Soc., 8:815-823.
  71. Frazier, T., S.J. Nissen, D.A. Mortensen, and L.J. Meinke. 1993. The influence of terbufos on primisulfuron absorption, translocation, and metabolism, in corn (Zea mays). Weed Sci. 41-664-668.
  72. Mortensen, D.A., G.A. Johnson, and L.J. Young. 1993. Weed distributions in agricultural fields, In Soil Specific Crop Management, P. Robert and R.H. Rust (eds.) Agron. Soc. Amer., p.113-124.
  73. Coble, H.D., and D.A. Mortensen. 1992. The threshold concept and its application to weed science. Weed Tech. 6:191-195.
  74. Bauer, T.A. and D.A. Mortensen. 1992. A comparison of economic and economic optimum thresholds for two annual weeds in soybeans. Weed Tech. 6:228-235.
  75. Mortensen, D.A., and H.D. Coble. 1991. Two approaches to weed control decision-aid software. Weed Tech. 5:445-452.
  76. Bauer, T.A., D.A. Mortensen, G.A. Wicks, T.A. Hayden, and A.R. Martin. 1991. Environmental variability associated with economic thresholds for soybeans. Weed Sci., 39:564-569.
  77. Shropshire, G.J., K. VonBargen, and D.A. Mortensen. 1990. Optical reflectance sensor for detecting plants. SPIE International Symposium 1379:222-235.
  78. Mortensen, D.A., H.D. Coble, J.R. Smart, and T.A. Bauer. 1990. Use of an expert system for integrating weed control strategies in a weed science laboratory. J. Agron. Educ. 19:181-183.
  79. Walters, D.T., D.A. Mortensen, C.A. Francis, R.W. Elmore, and J.W. King. 1990. Specificity: The context of research for sustainability. J. Soil & Wat. Cons. 1:55-57.
  80. Mortensen, D.A., H.D. Coble, J.R. Smart, and T. Bauer. 1990. Use of an expert system for integrating weed control strategies in a weed science laboratory. J. Agron. Educ. 19-2:181-183.
  81. Mortensen, D.A. and H.D. Coble. 1989. The influence of soil water content on common cocklebur (Xanthium strumarium) interference in soybeans. Weed Sci. 37:76-83.
  82. Sionit, N., D.T. Patterson, R.D. Coffin, and D.A. Mortensen. 1987. Water relations and growth of goosegrass (Eleusine indica L.) under repeated applications of drought stress. Field Crops Res. 17:163-173.
  83. Shropshire, G.J., K. VonBargen, and D.A. Mortensen. 1988. Machine vision as a potential control for agricultural field machines. M.C. Reg. Am. Soc. Ag. Eng.
  84. Patterson, D.T., A.E. Russell, D.A. Mortensen, R.D. Coffin, and E.P. Flint. 1986. Effects of temperature and photoperiod on Texas panicum (Panicum texanum) and wild proso millet (Panicum miliaceum). Weed Sci. 34:876-882.
  85. Patterson, D.T., and D.A. Mortensen. 1985. Effects of temperature and photoperiod on common crupina (Crupina vulgaris). Weed Sci. 33:333-339.
  86. Billings, W.D., J.O. Luken, D.A. Mortensen, and K.M. Peterson. 1984. Interactions in increasing atmospheric carbon dioxide and soil nitrogen on the carbon balance of tundra microcosms. Oecologia 65:26-29.
  87. Flint, E.P., D.T. Patterson, D.A. Mortensen, G.H. Riechers, and J.L. Beyers. 1984. Temperature effects on growth and leaf production in three weed species. Weed Sci. 32:655-663.
  88. Billings, W.D., J.O. Luken, D.A. Mortensen, and K.M. Peterson. 1983. Increasing atmospheric carbon dioxide: Possible effects on arctic tundra. Oecologia 58:286-289.
  89. Skarpaas, O., J. T. Dauer, C. M. Schwarz, E. S. J. Rauschert, E. Jongejans, R. Jabbour, D. A. Mortensen, S. A. Isard, D. A. Lieb, Z. Sezen, A. G. Hulting, M. J. Ferrari, K. Shea, and E. S. Long. 2007. Dispersal: a synthesis of concepts, patterns and processes across organisms. Ecology Letters (in review).