Degrees

• B.S., Botany/Secondary Science Education, Montana State University, 1988
• M.S., Agronomy (Weed Population Biology), University of Minnesota, 1994
• Ph.D., Agronomy(Weed/Crop Ecophysiology), University of Nebraska, 1997

Research Interests

My lab has interest in a broad range of agroecological issues ranging from the mechanisms of interplant competition to gene flow in sorghum species to ecological weed management in organic production systems to the use of systems simulation to optimize the efficiency and sustainability of our agricultural production systems.

Courses Taught

• Agronomy 426 – Invasive Plants. This course is taught every spring semester at UNL. The course provides a background on the identification, biology and ecology of weedy and invasive plants. Principles of invasive plant management by preventive, cultural, biological, mechanical and chemical means using an adaptive management framework. Herbicide terminology and classification; plant-herbicide and soil-herbicide interactions; equipment calibration and dosage calculations.
• Agronomy 896 – Interplant Competition in Managed Ecosystems. This course is taught in alternate years during the spring semester. This course will focus on whole plant physiological response to solar radiation, water, and nutrients, and on interplant competition for these resources. Quantitative relationships useful for integrating the interactive affects of these factors on plant growth and interplant competition will be stressed. The course will be a mixture of lecture, discussion of relevant literature, and homework sets.
• Agronomy 896 – Weed Science Colloquium. This 1-credit course is taught in the fall and is designed to familiarize graduate students with our science and contemporary literature. I co-coordinate this course with Dr. Mark Bernards.
  

Major Project Activities

We currently have three foci in my group, but these are not the limits of our interest.

1. Gene Flow in Sorghum bicolor. There has been considerable interest in modifying the quality traits of grain sorghum using transgenic technology to enhance its nutritional value to both humans and animals raised for human consumption. There is inherent risk in deploying genetically modified grain sorghum because several related species (e. g. johnsongrass, shattercane) are capable of interbreeding with grain sorghum. There is no published research on the potential gene flow from grain sorghum to its weedy relative shattercane, which is common to sorghum production regions of the USA. The goal of this project is to quantify the potential for pollen-mediated gene flow from grain sorghum to shattercane. Our specific objectives are to: 1) Quantify the synchrony of flowering of multiple genotypes of grain sorghum and shattercane in situ, 2) Quantify duration of pollen viability and its settling velocity in several grain sorghum hybrids, 3) Quantify the fitness of the shattercane x grain sorghum F2 population relative to the wild type shattercane, and 4) Utilize models and data gathered on critical parameters in the proposed and our previous research to predict pollen-mediated gene flow and the probability distribution of escape time of a transgene. This research will provide the background data needed to assess the risk of pollen-mediated gene flow from grain sorghum to wild shattercane populations. Results of this research also will provide valuable science-based information useful for identifying management practices that could minimize the biological risk of deploying transgenic sorghum. Funded by the USDA NIFA Biotechnology Risk Assessment Grants Program. 2010–2013.
2. Ecological Weed Management in Organic Agriculture. Many studies have demonstrated the weed suppressive potential and fertility contributions of individual cover crop species, but the value of diverse cover crop mixtures and soil fungi have received less attention. The objective of this project is to determine the effects of cover crop diversity, termination method, and a soil-borne fungus on weed populations, soil microbial community composition, soil nutrient availability, soil water content, grain yield and profitability. Spring-sown mixtures of 2, 4, 6 and 8 cover crop species are planted in a sunflower – soybean – corn certified organic crop rotation. Fusarium lateritium, a soil-borne weed pathogenic fungus, is combined with a mixture of 8 cover crop species to determine additional weed suppressiveness of the fungus. Cover crops are planted before April 1st and terminated before May 21st, using a field disk or a sweep plow undercutter. Crops are planted within one week of cover crop termination. Project results will provide innovative solutions for organic farmers seeking to increase productivity, profitability, and system resilience by increasing biodiversity and reducing off-farm inputs. Funded by the Ceres Trust Organic Research Initiative. 2010–2012.
3. Mechanisms of Interplant Competition. We’ve recently completed some research on the effects of variable water supply on corn and velvetleaf growth, water use, and interplant interference. The goal of this research was to understand how water supply influences interplant competition and obtain sufficient data to forecast the risks associated with variable water supply in specific environments across Nebraska and the Great Plains. Our goal is to obtain funding to build this knowledge into an ecophysiological model of interplant competition that can be used to explore the effects of climate change and agroecosystem management on weed competitiveness, potential range expansion of important herbicide resistant C4 weeds, multispecies competition, and soil water and nutrient management to optimize crop production in varying environments, to name a few.

Extension Interests

I'm very interested in applying what we've learned through our research by incorporating results and important concepts about plant ecology into educational programs that aid producers in making decisions about best management practices in specific Nebraska environments.

Selected Publications

• Wortman, S. E., A. S. Davis, B. J. Schutte and J. L. Lindquist. 2011. Integrating management of soil nitrogen and weeds. Weed Science (in press).
   
• Okalebo, J. A., G. Yuen, R. Drijber, E. Blankenship and J. L. Lindquist. 2011. Biological suppression of velvetleaf (Abutilon theophrasti) in an eastern Nebraska soil. Weed Sci. (in press).
   
• Schmidt, J. J., E. E. Blankenship, and J. L. Lindquist. 2011. Corn and velvetleaf (Abutilon theophrasti) transpiration in response to drying soil. Weed Sci. 59:50-54.
   
• Wortman, S. E., J. L. Lindquist, M. J. Haar and C. A. Francis. 2010. Increased weed diversity, density and aboveground biomass in long-term organic crop rotations. Renewable Agriculture and Food Systems 25:281-295.
   
• Sahoo, L., J. J. Schmidt, J. F. Pedersen, D. J. Lee and J. L. Lindquist. 2010. Growth and fitness components of wild x cultivated Sorghum bicolor (Poaceae) hybrids in Nebraska. Am. J. Bot. 97(10):1-8.
   
• Popovic, Z. S. and J. L. Lindquist. 2010. Evaluation of INTERCOM model for predicting growth of forest herbs. Arch. Biol. Sci., Belgrade 62:175-183.
   
• Lindquist, J. L., S. P. Evans, C. A. Shapiro, and S. Z. Knezevic. 2010. Effect of nitrogen addition and weed interference on soil nitrogen and corn nitrogen nutrition. Weed Technology 24:50-58. http://digitalcommons.unl.edu/agronomyfacpub/420
   
• Bonifas, K. D. and J. L. Lindquist. 2009. Effects of nitrogen supply on the root morphology of corn and velvetleaf. Journal of Plant Nutrition 32:1371-1382.
   
• Terra, B. R. M., A. R. Martin and J. L. Lindquist. 2007. Corn-velvetleaf (Abutilon theophrasti) interference is affected by sublethal doses of postemergence herbicides. Weed Science 55:491-496.
   
• Williams, M. M. II and J. L. Lindquist. 2007. Influence of planting date and weed interference on sweet corn growth and development. Agronomy Journal 99:1066-1072.
   
• Lindquist, J. L., D. C. Barker, S. Z. Knezevic, A. R. Martin and D. T. Walters. 2007. Comparative nitrogen uptake and distribution in corn and velvetleaf (Abutilon theophrasti). Weed Science 55:102-110.
   
• Wang, G., M. E. McGiffen, Jr., J. L. Lindquist, J. D. Ehlers and I. Sartorato. 2007. Simulation study of the competitive ability of erect, semi-erect, and prostrate cowpea (Vigna unguiculata) genotypes. Weed Research 47:129-139.
   
• Gustafson, T. C., S. Z. Knezevic, T. E. Hunt and J. L. Lindquist. 2006. Simulated insect defoliation and duration of weed interference affected soybean growth. Weed Science 54:735-742.
   
• Gustafson, T. C., S. Z. Knezevic, T. E. Hunt and J. L. Lindquist. 2006. Early season insect defoliation influences the critical time for weed removal in soybean. Weed Science 54:509:515.
   
• Hock, S. M., S. Z. Knezevic, A. R. Martin and J. L. Lindquist. 2006. Performance of WeedSOFT for predicting soybean yield loss. Weed Technology 20:478-484.
   
• Barker, D. C., S. Z. Knezevic, A. R. Martin, D. T. Walters and J. L. Lindquist. 2006. Effect of nitrogen addition on the comparative productivity of corn and velvetleaf (Abutilon theophrasti). Weed Science 54:354-363.
   
• Bonifas, K. D. and J. L. Lindquist. 2006. Predicting biomass partitioning to root versus shoot in corn and velvetleaf (Abutilon theophrasti). Weed Science 54:133-137.
   
• 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 and Tillage Research 88:8-15.
   
• Hock, S. M., S. Z. Knezevic, A. R. Martin and J. L. Lindquist. 2006. Soybean row spacing and weed emergence time influence weed competitiveness and competitive indices. Weed Science 54:38-46.
   
• Davis, A. S., J. Cardina, F. Forcella, G. A. Johnson, G. Kegode, J. L. Lindquist, E. C. Luschei, K. A. Renner, C. L. Sprague and M. M. Williams II. 2005. Environmental factors affecting seed persistence of annual weeds across the U.S. corn belt. Weed Science 53:860-868.
   
• Bonifas, K. D., D. T. Walters, K. G. Cassman and J. L. Lindquist. 2005. Nitrogen supply affects root:shoot ratio in corn and velvetleaf (Abutilon theophrasti). Weed Science 53:670-675.
   
• Lindquist, J. L., T. J. Arkebauer, D. T. Walters, K. G. Cassman and A. Dobermann. 2005. Maize radiation use efficiency under optimal growth conditions. Agronomy Journal 97:72-78.
   
• Hock, S. M., S. Z. Knezevic, A. R. Martin and J. L. Lindquist. 2005. Influence of soybean row width and velvetleaf emergence time on velvetleaf (Abutilon theophrasti). Weed Science 53:160-165.
   
• Waltz, A. L., A. R. Martin, F. W. Roeth, and J. L. Lindquist. 2004. Glyphosate efficacy on velvetleaf varies with application time of day. Weed Technology 18:931-939.
   
• Fischer, D. W., R. G. Harvey, T. T. Bauman, S. Phillips, S. E. Hart, G. A. Johnson, J. J. Kells, J. Lindquist, P. Westra. 2004. Chenopodium album interference with Zea mays across the north central USA. Weed Science 52:1034-1038.
   
• Burton, M. G., D. A. Mortensen, D. B. Marx, and J. L. Lindquist. 2004. Factors affecting the realized niche of common sunflower (Helianthus annuus L.) in ridge tillage corn. Weed Science 52:779-787.
   
• Yang, H. S., A. Dobermann, J. L. Lindquist, D. T. Walters, T. J. Arkebauer, and K. G. Cassman. 2004. Hybrid-Maize - a maize simulation model that combines different crop modeling approaches. Field Crops Research 87:131-154.
   
• Deen, W., R. Cousens, J. Warringa, L. Bastianns, P. Carberry, K, Rebel, S. Riha, C. Murphy, L. R. Benjamin, C. Cloughley, J. Cussans, F. Forcella, T. Hunt, P. Jamieson, J. Lindquist, and E. Wang. 2003. An evaluation of four crop:weed competition models using a common data set. Weed Research 43:116-129.
   
• Evans, S. P., S. Z. Knezevic, J. L. Lindquist, and C. A. Shapiro. 2003. Influence of nitrogen and duration of weed interference on corn growth and development. Weed Science 51:546-556.
   
• Evans, S. P., S. Z. Knezevic, J. L. Lindquist, C. A. Shapiro, and E. E. Blankenship. 2003. Nitrogen application influences the critical period for weed control in corn. Weed Science 51:408-417.
   
• Knezevic, S. Z. S. P. Evans, E. Blankenship, R. Van Acker, and J. L. Lindquist. 2002. Critical period of weed control: The concept and data analysis. Weed Science 50:773-786. http://digitalcommons.unl.edu/agronomyfacpub/407
   
• Murphy, C. A. and J. L. Lindquist. 2002. Growth response of velvetleaf to three post emergence herbicides. Weed Science 50:364-369. http://digitalcommons.unl.edu/agronomyfacpub/408
   
• Traore, S., J. L. Lindquist, A. R. Martin, D. A. Mortensen, and S. C. Mason. 2002. Comparative ecophysiology of grain sorghum and Abutilon theophrasti in monoculture and in mixture. Weed Research 42:65-75.
   
• Lindquist, J. L. 2001. Light-saturated CO2 assimilation rates of corn and velvetleaf in response to leaf nitrogen and development stage. Weed Science 49:706-710. http://digitalcommons.unl.edu/agronomyfacpub/405
   
• Lindquist, J. L. 2001. Performance of INTERCOM for predicting Zea mays - Abutilon theophrasti interference across the north central USA. Weed Science 49:195-201. http://digitalcommons.unl.edu/agronomyfacpub/406