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ARS Home Midwest Area Ames, Iowa National Laboratory for Agriculture and The Environment People







John L Kovar    Research Soil Scientist I joined the NLAE in December of 1999 as a Research Soil Scientist. My research addresses a range of topics including nutrient management in grain production systems, phosphorus bioavailability in soil and water, root growth and development, soil testing methodology, and water quality improvement. I currently serve as Lead Scientist for the project “Sustainable and Resilient Cropping Systems for Midwestern Landscapes.” I also have a leadership role in the Upper Mississippi River Basin site of the ARS Long-Term Agroecosystems Research (LTAR) Network and hold the rank of Affiliate Associate Professor in the Department of Agronomy at Iowa State University. With support from the Alexander von Humboldt Foundation, I lived and worked in Germany twice (1996, IGZ, Grossbeeren and 2005, Georg August University, Göttingen). When I am not at the NLAE, I grow flowers and vegetables in my garden and ride my bicycle around town and on the many trails in central Iowa. When it is cold, my model railroad keeps me busy.
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 Publications(Clicking on the reprint iconReprint Icon  will take you to the publication reprint.)Winter camelina as an alternative cover crop for central Iowa corn-soybean systems-(Abstract Only) Kovar, J.L., O'Brien, P.L., Ruis, S.J., Emmett, B.D., Malone, R.W., Rogovska, N.P. 2023. Winter camelina as an alternative cover crop for central Iowa corn-soybean systems [abstract]. ASA-CSSA-SSSA Annual Meeting.Nutrient leaching from an artificially drained Midwestern Mollisol across various conservation practices-(Abstract Only) Rogovska, N.P., Kovar, J.L., Malone, R.W., O'Brien, P.L., Emmett, B.D., Ruis, S.J. 2023. Nutrient leaching from an artificially drained Midwestern Mollisol across various conservation practices [abstract]. ASA-CSSA-SSSA Annual Meeting.Long-term conservation practices reduce nitrate leaching while maintaining yields in tile-drained Midwestern soils-(Peer Reviewed Journal) Rogovska, N.P., O'Brien, P.L., Malone, R.W., Emmett, B.D., Kovar, J.L., Jaynes, D., Kaspar, T., Moorman, T.B., Kyveryga, P. 2023. Long-term conservation practices reduce nitrate leaching while maintaining yields in tile-drained Midwestern soils. Agricultural Water Management. 288. Article e108481. https://doi.org/10.1016/j.agwat.2023.108481.Sediment and phosphorus contributions from eroding banks in a large intensively managed watershed in western Iowa, United States-(Peer Reviewed Journal) Williams, F.F., Moore, P.L., Allen, J.V., Isenhart, T.M., Thomas, J.T., Kovar, J.L., Schilling, K.E. 2024. Sediment and phosphorus contributions from eroding banks in a large intensively managed watershed in western Iowa, United States. Journal of the American Water Resources Association. 60(1):148-162. https://doi.org/10.1111/1752-1688.13164.Does organic farming improve soil health indicators relative to conventional farming in the U.S. Midwest?-(Abstract Only) Ruis, S.J., Kovar, J.L., Wacha, K.M., Cambardella, C.A. 2023. Does organic farming improve soil health indicators relative to conventional farming in the U.S. Midwest? {abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts.Streambank erosion and phosphorus loading to surface waters: Knowns, unknowns, and implications for nutrient loss reduction 
research and policy-(Peer Reviewed Journal) Margenot, A.J., Zhou, S., Mcdowell, R., Hebert, T., Fox, G., Schilling, K.E., Richmond, S., Kovar, J.L., Wickramarathne, N., Lemke, D., Boomer, K., et al. 2023. Streambank erosion and phosphorus loading to surface waters: Knowns, unknowns, and implications for nutrient loss reduction research and policy. Journal of Environmental Quality. 52(6):1063-1079. https://doi.org/10.1002/jeq2.20514.Harvested winter rye energy cover crop: multiple benefits for North Central US-(Peer Reviewed Journal) Malone, R.W., Radke, A.G., Herbstritt, S., Wu, H., Qi, Z., Emmett, B.D., Helmers, M., Schulte, L., Feyereisen, G.W., O'Brien, P.L., Kovar, J.L., Rogovska, N.P., Kladivko, E.J., Thorp, K.R., Kaspar, T., Jaynes, D.B., Karlen, D., Richard, T. 2023. Harvested winter rye energy cover crop: multiple benefits for North Central US. Environmental Research Letters. 18(7). https://doi.org/10.1088/1748-9326/acd708.Uncertainty in phosphorus fluxes and budgets across the U.S. long-term agroecosystem research network-(Peer Reviewed Journal) Welikhe, P., Williams, M.R., King, K.W., Bos, J.H., Akland, M., Baffaut, C., Beck, G., Bierer, A.M., Bosch, D.D., Brooks, E., Buda, A.R., Cavigelli, M.A., Faulkner, J., Feyereisen, G.W., Fortuna, A., Gamble, J.D., Hanrahan, B.R., Hussain, M., Kovar, J.L., Lee, B., Leytem, A.B., Liebig, M.A., Line, D., Macrae, M., Moorman, T.B., Moriasi, D.N., Mumbi, R., Nelson, N., Ortega-Pieck, A., Osmond, D., Penn, C.J., Pisani, O., Reba, M.L., Smith, D.R., Unrine, J., Webb, P., White, K.E., Wilson, H., Witthaus, L.M. 2023. Uncertainty in phosphorus fluxes and budgets across the U.S. long-term agroecosystem research network. Journal of Environmental Quality. 52(4):837-885. https://doi.org/10.1002/jeq2.20485.Unraveling the role of ruzigrass in soil K cycling in tropical cropping systems-(Peer Reviewed Journal) Volf, M.R., Crusciol, C.A., Kovar, J.L., Rosolem, C.A. 2023. Unraveling the role of ruzigrass in soil K cycling in tropical cropping systems. Nutrient Cycling in Agroecosystems. 126:181-194. https://doi.org/10.1007/s10705-023-10283-z.Sugarcane green harvest management influencing soil phosphorus fractions-(Peer Reviewed Journal) Luiz Correia, B., Kovar, J.L., Thompson, M.L., Pavinato, P.S., Ferracciú Alleoni, L.R. 2023. Sugarcane green harvest management influencing soil phosphorus fractions. Soil & Tillage Research. 231. Article 105713. https://doi.org/10.1016/j.still.2023.105713.Thirteen-year stover harvest and tillage effects on corn agroecosystem sustainability in Iowa-(Database / Dataset) Karlen, D.L., Phillips, C.L., O'Brien, P.L., Obrycki, J.N., Tekeste, M.Z., Ebrahimi, E., Cambardella, C.A., Kovar, J.L., Birrell, S.J. 2022. Thirteen-year stover harvest and tillage effects on corn agroecosystem sustainability in Iowa. Ag Data Commons. https://doi.org/10.15482/USDA.ADC/1528303.Nitrate losses in subsurface drainage and nitrous oxide emissions from a winter camelina relay cropping system reveal challenges to sustainable intensification-(Peer Reviewed Journal) Emmett, B.D., O'Brien, P.L., Malone, R.W., Rogovska, N.P., Kovar, J.L., Kohler, K., Kaspar, T.C., Moorman, T.B., Jaynes, D.B., Parkin, T.B. 2022. Nitrate losses in subsurface drainage and nitrous oxide emissions from a winter camelina relay cropping system reveal challenges to sustainable intensification. Agriculture, Ecosystems and Environment. 339. Article 108136. https://doi.org/10.1016/j.agee.2022.108136.Nitrate losses and nitrous oxide emissions under contrasting tillage and cover crop management-(Peer Reviewed Journal) O'Brien, P.L., Emmett, B.D., Malone, R.W., Nunes, M.R., Kovar, J.L., Kaspar, T.C., Moorman, T.B., Jaynes, D.B., Parkin, T.B. 2022. Nitrate losses and nitrous oxide emissions under contrasting tillage and cover crop management. Journal of Environmental Quality. 51:683-695. https://doi.org/10.1002/jeq2.20361.P-FLUX: A phosphorus budget dataset spanning diverse agricultural production systems in the United States and Canada-(Peer Reviewed Journal) Williams, M.R., Welikhe, P., Bos, J.H., King, K.W., Akland, M., Augustine, D.J., Baffaut, C., Beck, G., Bierer, A.M., Bosch, D.D., Boughton, E., Brandani, C., Brooks, E., Buda, A.R., Cavigelli, M.A., Faulkner, J., Feyereisen, G.W., Fortuna, A., Gamble, J.D., Hanrahan, B.R., Hussain, M., Kohmann, M., Kovar, J.L., Lee, B., Leytem, A.B., Liebig, M.A., Line, D., Macrae, M., Moorman, T.B., Moriasi, D.N., Nelson, N., Ortega-Pieck, A., Osmond, D., Pisani, O., Ragosta, J., Reba, M.L., Saha, A., Sanchez, J., Silveira, M., Smith, D.R., Spiegal, S.A., Swain, H., Unrine, J., Webb, P., White, K.E., Wilson, H., Witthaus, L.M. 2022. P-FLUX: A phosphorus budget dataset spanning diverse agricultural production systems in the United States and Canada. Journal of Environmental Quality. 51:451–461. https://doi.org/10.1002/jeq2.20351.Crop production response to conservation practices and sustainable intensification in a corn-soybean cropping system-(Abstract Only) O'Brien, P.L., Emmett, B.D., Kovar, J.L., Malone, R.W., Cambardella, C.A., Jaynes, D.B., Kaspar, T.C., Kohler, K.A., Moorman, T.B., Parkin, T.B. 2021. Crop production response to conservation practices and sustainable intensification in a corn-soybean cropping system [abstract]. ASA-CSSA-SSSA Annual Meeting. Paper no. 138076.LTAR Phosphorus Budget Dataset-(Other) Williams, M.R., Weilkhe, P., Bos, J.H., King, K.W., Akland, M., Augustine, D.J., Baffaut, C., Beck, G., Bierer, A.M., Bosch, D.D., Boughton, E., Brandani, C., Brooks, E., Buda, A.R., Cavigelli, M.A., Faulkner, J., Feyereisen, G.W., Fortuna, A., Gamble, J.D., Hanrahan, B.R., Hussain, M., Kohmann, M., Kovar, J.L., Lee, B., Leytem, A.B., Liebig, M.A., Line, D., Macrae, M., Moorman, T.B., Moriasi, D.N., Nelson, N., Ortega-Pieck, A., Osmond, D., Pisani, O., Ragosta, J., Reba, M.L., Saha, A., Sanchez, J., Silveira, M., Smith, D.R., Spiegal, S.A., Swain, H., Unrine, J., Webb, P., White, K.E., Wilson, H., Witthaus, L.M. 2022. LTAR Phosphorus Budget Dataset. Ag Data Commons. https://doi.org/10.15482/USDA.ADC/1523365.Potassium bioavailability in a tropical kaolinitic soil-(Peer Reviewed Journal) Volf, M.R., Crusciol, C.A.C., De Azevedo, A.C., Thompson, M.L., Kovar, J.L., Rosolem, C.A. 2021. Potassium bioavailability in a tropical kaolinitic soil. Agronomy. 11(10). https://doi.org/10.3390/agronomy11102016.Nitrogen losses in response to conservation practices and sustainable intensification of corn-soybean cropping systems in the Upper Midwest-(Abstract Only) Emmett, B.D., O'Brien, P.L., Malone, R.W., Kovar, J.L., Cambardella, C.A., Jaynes, D.B., Kaspar, T.C., Kohler, K.A., Moorman, T.B., Parkin, T.B. 2021. Nitrogen losses in response to conservation practices and sustainable intensification of corn-soybean cropping systems in the Upper Midwest [abstract]. Soil and Water Conservation Society Proceedings.Contribution of streambanks to phosphorus export from Iowa-(Peer Reviewed Journal) Schilling, K.E., Isenhart, T.M., Kovar, J.L. 2021. Contribution of streambanks to phosphorus export from Iowa. Journal of Soil and Water Conservation. 77(2):103-112. https://doi.org/10.2489/jswc.2022.00036.Science-based maize stover removal can be sustainable-(Peer Reviewed Journal) Nunes, M.R., De, M., Mcdaniel, M.D., Kovar, J.L., Birrell, S.J., Karlen, D.L. 2021. Science-based maize stover removal can be sustainable. Agronomy Journal. https://doi.org/10.1002/agj2.20724.Maize response to sulfur fertilizer in three Iowa soils-(Peer Reviewed Journal) Kovar, J.L. 2021. Maize response to sulfur fertilizer in three Iowa soils. Communications in Soil Science and Plant Analysis. 52(8):905-915. https://doi.org/10.1080/00103624.2020.1869773.Riparian land-use, stream morphology and streambank erosion within grazed pastures in southern Iowa, USA: A catchment-wide perspective-(Peer Reviewed Journal) Tufekcioglu, M., Schultz, R.C., Isenhart, T.M., Kovar, J.L., Russell, J.R. 2020. Riparian land-use, stream morphology and streambank erosion within grazed pastures in southern Iowa, USA: A catchment-wide perspective. Sustainability. 12(16). https://doi.org/10.3390/su12166461.The LTAR croplands common experiment: long-term research for improved agricultural sustainability-(Abstract Only) Liebig, M.A., Robertson, P., Archer, D.W., Awada, T., Baker, J.M., Cavigelli, M.A., Collins, H.P., Dell, C.J., Huggins, D.R., Jaradat, A.A., Johnson, J.M., King, K.W., Kleinman, P.J., Kovar, J.L., Locke, M.A., Maul, J.E., Mccarty, G.W., Mirsky, S.B., Moorman, T.B., Pisani, O., Smith, D.R., Starks, P.J., Strickland, T.C., Sudduth, K.A., Veum, K.S., Wienhold, B.J. 2019. The LTAR croplands common experiment: long-term research for improved agricultural sustainability. Meeting Abstract. 1.Use of a micro-capillary system to evaluate nutrient dynamics in rhizosphere soil solution of maize and soybean-(Abstract Only) Kovar, J.L., Sitzmann, T.J., Mcdaniel, M.D. 2019. Use of a micro-capillary system to evaluate nutrient dynamics in rhizosphere soil solution of maize and soybean [abstract]. Rhizosphere 5. p. 161.Malachite green method for determining Phosphorus concentration in diverse matrices-(Peer Reviewed Journal) Rahutomo, S., Kovar, J.L., Thompson, M.L. 2019. Malachite green method for determining Phosphorus concentration in diverse matrices. Communications in Soil Science and Plant Analysis. https://doi.org/10.1080/00103624.2019.1635140.Phosphorus and soil health management practices-(Peer Reviewed Journal) Duncan, E.W., Osmond, D.L., Shober, A.L., Starr, L., Tomlinson, P., Kovar, J.L., Moorman, T.B., Peterson, H., Fiorellino, N.M., Reid, K. 2019. Phosphorus and soil health management practices. Agricultural and Environmental Letters. 4(1):190014.Measuring crop available phosphorus-(Review Article) Kovar, J.L., Cantarella, H. 2019. Measuring crop available phosphorus. Better Crops. Available: http://www.ipni.net/publication/bettercrops.nsf/0/4C2F131ED7125B5F852583B7004F2DBC/$FILE/BC-2019-1%20p13.pdf.Varying redox potential affects P release from stream bank sediments-(Peer Reviewed Journal) Rahutomo, S., Kovar, J.L., Thompson, M.L. 2018. Varying redox potential affects P release from stream bank sediments. PLoS One. 13(12). https://doi.org/10.1371/journal.pone.0209208.Phosphorus transformations in stream bank sediments in Iowa, USA, at varying redox potentials-(Peer Reviewed Journal) Rahutomo, S., Kovar, J.L., Thompson, M.L. 2018. Phosphorus transformations in stream bank sediments in Iowa, USA, at varying redox potentials. Journal of Soils and Sediments. 19:1029-1039. https://doi.org/10.1007/s11368-018-2139-4.Ten-year assessment encourages no-till for corn grain and stover harvest-(Peer Reviewed Journal) Obrycki, J.F., Kovar, J.L., Karlen, D.L., Birrell, S.J. 2018. Ten-year assessment encourages no-till for corn grain and stover harvest. Agricultural and Environmental Letters. 3:1800034. https://doi.org/10.2134/ael2018.06.0034.Subsoil potassium in central Iowa soils: Status and future challenges-(Peer Reviewed Journal) Obrycki, J.F., Kovar, J.L., Karlen, D.L. 2018. Subsoil potassium in central Iowa soils: Status and future challenges. Agrosystems, Geosciences & Environment. https://doi.org/10.2134/age2018.07.0018.Corn stover harvest, tillage, and cover crop effects on soil health indicators-(Peer Reviewed Journal) Obrycki, J.F., Karlen, D.L., Cambardella, C.A., Kovar, J.L., Birrell, S.J. 2018. Corn stover harvest, tillage, and cover crop effects on soil health indicators. Soil Science Society of America Journal. 82(4):910-918. https://doi.org/10.2136/sssaj2017.12.0415.Inorganic and organic phosphorus in sediments in the Walnut Creek Watershed of central Iowa, USA-(Peer Reviewed Journal) Rahutomo, S., Kovar, J.L., Thompson, M.L. 2018. Inorganic and organic phosphorus in sediments in the Walnut Creek Watershed of central Iowa, USA. Water, Air, and Soil Pollution. 229:72. https://doi.org/10.1007/s11270-018-3721-5.Distribution and mass balance of groundwater orthophosphorus in an agricultural watershed-(Peer Reviewed Journal) Shilling, K.E., Streeter, M.T., Isenhart, T.M., Beck, W.J., Tomer, M.D., Cole, K.J., Kovar, J.L. 2018. Distribution and mass balance of groundwater orthophosphorus in an agricultural watershed. Science of the Total Environment. 625:1330-1340.Distribution and mass of groundwater orthophosphorus in an agricultural watershed-(Peer Reviewed Journal) Schilling, K.E., Streeter, M.T., Isenhart, T.M., Beck, W.J., Tomer, M.D., Cole, K.J., Kovar, J.L. 2018. Distribution and mass of groundwater orthophosphorus in an agricultural watershed. Science of the Total Environment. 625:1330-1340. https://doi.org/10.1016/j.scitotenv.2018.01.035.Phosphorus source – sink relationships of stream sediments in the Rathbun Lake watershed of southern Iowa, USA-(Peer Reviewed Journal) Hongthanat, N., Kovar, J.L., Thompson, M.L., Russell, J.R., Isenhart, T.M. 2016. Phosphorus source – sink relationships of stream sediments in the Rathbun Lake watershed of southern Iowa, USA. Environmental Monitoring and Assessment. 188(8):453. doi: 10.1007/s10661-016-5437-6.Eleven years of runoff and phosphorus losses from two fields with and without manure application, Iowa, USA-(Peer Reviewed Journal) Tomer, M.D., Moorman, T.B., Kovar, J.L., Cole, K.J., Nichols, D.J. 2016. Eleven years of runoff and phosphorus losses from two fields with and without manure application, Iowa, USA. Agricultural Water Management. 168:104-111.Phosphorus runoff from Coastal Plain forest soil in Louisiana-(Peer Reviewed Journal) Felicien, W.L., Wight, J.P., Gaston, L.A., Blazier, M.A., Kovar, J.L. 2016. Phosphorus runoff from Coastal Plain forest soil in Louisiana. Communications in Soil Science and Plant Analysis. 47(10):1283-1295.Corn stover nutrient removal estimates for Central Iowa, U.S.A.-(Peer Reviewed Journal) Karlen, D.L., Kovar, J.L., Birrell, S.J. 2015. Corn stover nutrient removal estimates for Central Iowa, U.S.A.. Sustainability. 7:8621-8634.Mobility of poultry litter phosphorus in a Coastal Plain forest soil-(Peer Reviewed Journal) Wight, J.P., Waldron, G.J., Gatson, L.A., Blazier, M.A., Kovar, J.L. 2015. Mobility of poultry litter phosphorus in a Coastal Plain forest soil. Soil Science. 180(3):124-133.Nutrient depletion from rhizosphere solution by maize grown in soil with long-term compost amendment-(Abstract Only) Bortolon, L., Kovar, J.L., Thompson, M.L., Gianello, C. 2015. Nutrient depletion from rhizosphere solution by maize grown in soil with long-term compost amendment. Rhizosphere 4 Proceedings. In: van Veen, H. Rhizophhere 4 Proceedings. June 21,25, 2015, Maastrict, The Netherlands. Available: http://www.rhizo4.org/sites/default/files/ALL%20ABSTRACTS_0.pdf.Riparian land-use and stream bank erosion within grazed pastures in southern Iowa, USA-(Proceedings) Tufekcioglu, M., Isenhart, T.M., Schultz, R.C., Kovar, J.L., Russell, J. 2015. Riparian land-use and stream bank erosion within grazed pastures in southern Iowa, USA. Frontiers in Environmental and Water Management Proceedings. In: Zaimes, G.N, editor. New Frontiers in Environmental and Water Management; March 19-21, 2015, Kavala, Greece.What are the unique attributes of potassium that challenge existing nutrient uptake models?-(Research Technical Update) Kovar, J.L., Brouder, S.M. 2015. What are the unique attributes of potassium that challenge existing nutrient uptake models? In: Murrell, T.S., editors. Frontiers in Potassium Science Workshop Proceedings. ISSPA, January 26-30, 2015, Kona, HI. Available: https://www.ipni.net/ipniweb/portal.nsf/0/D2C87A2DB34DD45385257E3100521A87/$FILE/K%20Frontiers%20Summary.pdf.Profile distribution of available potassium in Des Moines Lobe soils-(Proceedings)Phytoremediation of high phosphorus soil by annual ryegrass and common bermudagrass harvest-(Peer Reviewed Journal) Gaston, L.A., Kovar, J.L. 2015. Phytoremediation of high phosphorus soil by annual ryegrass and common bermudagrass harvest. Communications in Soil Science and Plant Analysis. 46:736-752.Corn stover nutrient removal estimates for central Iowa-(Other) Karlen, D.L., Kovar, J.L., Birrell, S.J. 2015. Corn stover nutrient removal estimates for central Iowa. Scientific and Technical Review. 7:8621-8634. DOI:10.3390/su7078621.Stream bank erosion in grazed pasture stream reaches of southern Iowa, USA-(Proceedings) Stream bank erosion in grazed pasture stream reaches of southern Iowa, USA. International Caucascian Forestry Symposium Meeting Proceedings. 529-535. Available at: https://ekonferans.artvin.edu.tr/index.php/ICFS/ICFS/paper/viewFile/192/20.Fluid fertilizer's role in sustaining soils used for bio-energy feedstock production-(Proceedings) Kovar, J.L., Karlen, D.L. 2013. Fluid fertilizer's role in sustaining soils used for bio-energy feedstock production. In: Leikman, D.F., editor. Fluid Fertilizer Foundation Symposium Proceedings, February 18-20, 2013, Scottsdale, Arizona. Available: http://www.fluidfertilizer.com/Forum%.20Presentations/2013/Proceedings/Kovar%202013%20Proceedings.pdf.Tillage and crop rotation effects on soil quality in two Iowa fields-(Peer Reviewed Journal) Karlen, D.L., Cambardella, C.A., Kovar, J.L., Colvin, T.S. 2013. Tillage and crop rotation effects on soil quality in two Iowa fields. Soil & Tillage Research. 133:54-64.Thirty-year tillage effects on crop yield and soil fertility indicators-(Peer Reviewed Journal) Karlen, D.L., Kovar, J.L., Cambardella, C.A., Colvin, T.S. 2013. Thirty-year tillage effects on crop yield and soil fertility indicators. Soil & Tillage Research. 130:24-41.Value of fluid fertilizer in bio-energy production-(Trade Journal) Kovar, J.L., Karlen, D.L. 2012. Value of fluid fertilizer in bio-energy production. Fluid Journal. 20:6-9.Modeling phosphorus capture by plants growing in a multi-species riparian buffer-(Peer Reviewed Journal) Kelly, J., Kovar, J.L. 2012. Modeling phosphorus capture by plants growing in a multi-species riparian buffer. Applied and Environmental Soil Science. DOI:10.1155/2012/838254.Fluid fertilizer's role in sustaining soils used for bio-energy feedstock production-(Proceedings) Kovar, J.L., Karlen, D.L. 2012. Fluid fertilizer's role in sustaining soils used for bio-energy feedstock production. In: Leikam, D.F., editor. Proceedings of the Fluid Fertilizer Foundation Symposium, February 19-21, 2012, Scottsdale, AZ. 29:1-9. Available: http://www.fluidfertilizer.com/fertilizer_forum_proceedings2012.html.Stream bank erosion as a source of sediment and phosphorus in grazed pastures of the Rathbun Lake Watershed in southern Iowa, USA-(Peer Reviewed Journal) Tufekcioglu, M., Isenhart, T.M., Schultz, R.C., Bear, D.A., Kovar, J.L., Russell, J.R. 2012. Stream bank erosion as a source of sediment and phosphorus in grazed pastures of the Rathbun Lake Watershed in southern Iowa, USA. Journal of Soil and Water Conservation. 67(6):545-555.Don't overlook sulfur in crop management-(Trade Journal) Grant, C.A., Kovar, J.L. 2012. Don't overlook sulfur in crop management. Fluid Journal. 20(2). Available: http://www.fluidjournalonline.com/?iid=59118.Stocking rate and riparian vegetation effects on physical characteristics of riparian zones of midwestern pastures-(Peer Reviewed Journal) Bear, D.A., Russell, J.R., Tufekcioglu, M., Isenhart, T.M., Morrical, D.G., Kovar, J.L. 2011. Stocking rate and riparian vegetation effects on physical characteristics of riparian zones of midwestern pastures. Rangeland Ecology and Management. 65:119-128.Nitrogen, phosphorus, and potassium requirements to support a multi-billion gallon biofuel industry-(Book / Chapter) Murrell, T., Fixen, P.E., Huang, W., Kovar, J.L., White Jr, P.M. 2011. Nitrogen, phosphorus, and potassium requirements to support a multi-billion gallon biofuel industry. In: Braun, R., Karlen, D., and Johnson D., (ed.). Sustainable Alternative Fuel Feedstock Opportunities, Challenges and Roadmaps for Six U.S. Regions. Ankeny, IA: Soil and Water Conservation Society. p. 160-176. Available: http://www.swcs.org/documents/resources/Chapter_10__Murrell__Billion_Ton_Re_8B308171BD289.pdf.Grazing management effects on sediment, phosphorus, and pathogen loading of streams in cool-season grass pastures-(Peer Reviewed Journal) Schwarte, K.A., Russell, J.R., Kovar, J.L., Morrical, D.G., Ensley, S.M., Yoon, K., Cornick, N.A., Cho, Y. 2011. Grazing management effects on sediment, phosphorus, and pathogen loading of streams in cool-season grass pastures. Journal of Environmental Quality. 40:1303-1313.Fluid fertilizer's role in sustaining soils used for bio-energy feedstock production-(Proceedings) Kovar, J.L., Karlen, D.L. 2011. Fluid fertilizer's role in sustaining soils used for bio-energy feedstock production. In: Leikam, D.F. (ed). Fluid Fertilizer Foundation Symposium Proceedings. Fluid Fertilizer Forum, Feb. 20-22, 2011, Scottsdale, AZ. Volume 28. Available: http://www.fluidfertilizer.com/fertilizer_forum_proceedings2011.html.Nutrient cyling in soils: Sulfur-(Book / Chapter) Kovar, J.L., Grant, C.A. 2011. Nutrient cyling in soils: Sulfur. In: Hatfield, J.L., Sauer, T.J., editors. Soil Management: Building a Stable Base for Agriculture. Madison, WI: American Society of Agronomy and Soil Science Society of America. p. 103-115.Grazing management effects on sediment, phosphorus, and pathogen loading of pasture streams-(Experiment Station) Schwarte, K.A., Russell, J.R., Kovar, J.L., Morrical, D.G., Ensley, S.M., Yoon, K., Cornick, N.A., Cho, Y. 2011. Grazing management effects on sediment, phosphorus, and pathogen loading of pasture streams. Iowa State University Animal Industry Report. Report R2614.Grazing management effects on stream bank erosion and phosphorus delivery to a pasture stream-(Peer Reviewed Journal) Nellesen, S.L., Kovar, J.L., Haan, M.M., Russell, J.R. 2011. Grazing management effects on stream bank erosion and phosphorus delivery to a pasture stream. Canadian Journal of Soil Science. 91:385-395.Sorption indices to estimate risk of soil phosphorus loss in the Rathbun Lake Watershed, Iowa-(Peer Reviewed Journal) Hongthanat, N., Kovar, J.L., Thompson, M.L. 2011. Sorption indices to estimate risk of soil phosphorus loss in the Rathbun Lake watershed, Iowa. Soil Science. 176:237-244.How does fertilizer/manure placement affect P and K availability in the root zone?-(Proceedings) Kovar, J.L. 2010. How does fertilizer/manure placement affect P and K availability in the root zone? In: Vyn, T. (ed.). Indiana Certified Crop Advisors Conference Proc., December 14-15, 2010, Indianapolis, IN. CDROM.Swine manure injection with a low-disturbance applicator and cover crops reduce phosphorus losses in runoff-(Peer Reviewed Journal) Kovar, J.L., Moorman, T.B., Singer, J.W., Cambardella, C.A., Tomer, M.D. 2011. Swine manure injection with a low-disturbance applicator and cover crops reduce phosphorus losses in runoff. Journal of Environmental Quality. 40:329-336.Optimizing Nutrient Management for Sustainable Bio-energy Feedstock Production-(Trade Journal) Kovar, J.L., Karlen, D.L. 2010. Optimizing Nutrient Management for Sustainable Bio-energy Feedstock Production. Fluid Journal. 18(3). Available: http://fluidjournal.org/1gsdgfs-S10/S10-A2.pdfSoil Phosphorus Distribution in a Crop Production System with Long-term Compost Amendment-(Proceedings) Bortolon, L., Kovar, J.L., Cambardella, C.A., Singer, J.W., Gianello, C. 2010. Soil Phosphorus Distribution in a Crop Production System with Long-term Compost Amendment. In: Gilkes, R.J. and Prakongkep, N. (ed). Proceedings of the 19th World Congress Soil Science, August 1-6, 2010, Brisbane, Australia. ISBN 978-0-646-53783-2. DVD.Is Sulfur Limiting Maize Grown on Eroded Midwestern U.S. Soils?-(Proceedings) Kovar, J.L., Karlen, D.L. 2010. Is Sulfur Limiting Maize Grown on Eroded Midwestern U.S. Soils? In: Gilkes, R.J. and Prakongkep, N. (ed). Proceedings of the 19th World Congress Soil Science, August 1-6, 2010, Brisbane, Australia. ISBN 978-0-646-53783-2. DVD.Fluid Fertilizer's Role in Sustaining Soils Used for Bio-fuels Production-(Proceedings) Kovar, J.L., Karlen, D.L. 2010. Fluid Fertilizer's Role in Sustaining Soils Used for Bio-fuels Production. In: Fluid Fertilizer Foundation Symposium Proceedings. Fluid Fertilizer Forum, Feb. 14-16, 2010, Scottsdale, AZ. 2010 CD-ROM, Volume 27.Potassium Uptake Efficiency and Dynamics in the Rhizosphere of Maize, Wheat, and Sugar Beet Evaluated with a Mechanistic Model-(Peer Reviewed Journal) Samal, D., Kovar, J.L., Steingrobe, B., Sadana, U.S., Bhadoria, P.S., Claassen, N. 2010. Potassium Uptake Efficiency and Dynamics in the Rhizosphere of Maize, Wheat, and Sugar Beet Evaluated with a Mechanistic Model. Plant and Soil Journal. 332:105-121.Phosphorus availability to corn and soybean evaluated by three soil test methods for southern Brazilian soils-(Peer Reviewed Journal) Bortolon, L., Gianello, C., Kovar, J.L. 2011. Phosphorus availability to corn and soybean evaluated by three soil test methods for southern Brazilian soils. Communications in Soil Science and Plant Analysis. 42:39-49.Inorganic and Organic Phosphorus in Soil Affected by Compost, Tillage and Cropping System-(Abstract Only) Bortolon, L., Kovar, J.L., Cambardella, C.A., Singer, J.W., Gianello, C. 2009. Inorganic and Organic Phosphorus in Soil Affected by Compost, Tillage and Cropping System [CD-ROM]. In: ASA-CSSA-SSSA Annual Meeting Abstracts, Nov. 1-5, 2009, Pittsburgh, PA. Paper No. 352-11.Coupling Cover Crops with Alternative Swine Manure Application Strategies: Manure-15N Tracer Studies-(Abstract Only) Cambardella, C.A., Moorman, T.B., Singer, J.W., Tomer, M.D., Kovar, J.L., Kerr, B.J. 2009. Coupling Cover Crops with Alternative Swine Manure Application Strategies: Manure-15N Tracer Studies [abstract]. In: ASA-CSSA-SSSA Annual Meeting Abstracts, Nov. 1-5, 2009, Pittsburgh, PA. Paper No. 555-77.Phosphorus in Soil and Runoff Following Swine Manure Injection with a Low-Disturbance Applicator-(Abstract Only) Kovar, J.L., Moorman, T.B., Cambardella, C.A., Singer, J.W., Tomer, M.D. 2009. Phosphorus in Soil and Runoff Following Swine Manure Injection with a Low-Disturbance Applicator [CD-ROM]. In: ASA-CSSA-SSSA Annual Meeting Abstracts,  Nov. 1-5, 2009, Pittsburgh, PA. Paper No. 270-7.Livestock Grazing and Vegetative Filter Strip Buffer Effects on Runoff Sediment, Nitrate, and Phosphorus Losses-(Peer Reviewed Journal) Webber, D.F., Mickelson, S.K., Ahmed, S.I., Russell, J.R., Powers, W.J., Schultz, R.C., Kovar, J.L. 2010. Livestock Grazing and Vegetative Filter Strip Buffer Effects on Runoff Sediment, Nitrate, and Phosphorus Losses. Journal of Soil and Water Conservation. 65:34-41.Sediment and Phosphorus Losses from Stream Banks in Grazed Riparian Pastures-(Proceedings) Kovar, J.L., Russell, J.R., Nellesen, S.L., Haan, M.M. 2009. Sediment and Phosphorus Losses from Stream Banks in Grazed Riparian Pastures. 2009 SERA-17 Annual Meeting, July 28-31, 2009, Windsor, Ontario, Canada. In: Great Lakes Phosphorus Forum Proceedings. Available: http://www.sera17.ext.vt.edu/Meetings/greatlakespforum/poster.shtmlDistribution of Phosphorus and Potassium Following Surface Banding of Fertilizer in Conservation Tillage Systems-(Proceedings) Kovar, J.L., Bortolon, L., Karlen, D.L. 2009. Distribution of Phosphorus and Potassium Following Surface Banding of Fertilizer in Conservation Tillage Systems. Plant Nutrition Colloquium Proceedings. Available: http://escholarship.org/uc/item/8j0224dqPhosphorus Depletion From Rhizosphere Solution by Maize Grown in Compost-amended Soil-(Proceedings) Bortolon, L., Kovar, J.L., Gianello, C. 2009. Phosphorus Depletion From Rhizosphere Solution by Maize Grown in Compost-amended Soil. Plant Nutrition Colloquium Proceedings. Available: http://escholarship.org/uc/item/1cc397f1Methods of Phosphorus Analysis for Soils, Sediments, Residuals, and Waters-Revised Edition-(Book / Chapter) Kovar, J.L., Pierzynski, G.M. 2009. Methods of Phosphorus Analysis for Soils, Sediments, Residuals, and Waters-Revised Edition. Southern Cooperative Series Bulletin. Available: http://www.sera17.ext.vt.edu/Documents/P_Methods2ndEdition2009.pdfBook Review: "The Rhizosphere: Biochemistry and Organic Substances at the Soil-Plant Interface, Second Edition"-(Other) Kovar, J.L. 2009. Book Review: "The Rhizosphere: Biochemistry and Organic Substances at the Soil-Plant Interface, Second Edition". Journal of Environmental Quality. 38(4):1977.Plant Growth and Phosphorus Uptake of Three Riparian Grass Species-(Peer Reviewed Journal) Kovar, J.L., Claassen, N. 2009. Plant Growth and Phosphorus Uptake of Three Riparian Grass Species. Agronomy Journal. 101:1060-1067.Fluid Fertilizer’s Role in Sustaining Soils Used for Bio-fuel Feedstock Production-(Proceedings) Kovar, J.L., Karlen, D.L. 2009. Fluid Fertilizer’s Role in Sustaining Soils Used for Bio-fuel Feedstock Production. In: Fluid Fertilizer Foundation Symposium Proceedings. Fluid Fertilizer Forum, Feb. 15-17, 2009, Scottsdale, AZ 2009 CDROM.Streambank Erosion from Grazed Pastures, Grass Filters and Forest Buffers Over a Six-Year Period-(Abstract Only) Tufekcioglu, M., Schultz, R.C., Zaimes, G.N., Isenhart, T.M., Kovar, J.L., Russell, J.R. 2008. Streambank Erosion from Grazed Pastures, Grass Filters and Forest Buffers Over a Six-Year Period [CD-ROM]. In: ASA-CSSA-SSSA Annual Meeting Abstracts, Oct. 5-9, 2008, Houston, TX.Assessment of Watershed and Site-specific Characteristics in Relation to Streambank Erosion-(Abstract Only) Tufekcioglu, M., Isenhart, T.M., Russell, J.R., Kovar, J.L., Schultz, R.C. 2008. Assessment of Watershed and Site-specific Characteristics in Relation to Streambank Erosion [CD-ROM]. In: ASA-CSSA-SSSA Annual Meeting Abstracts, Oct. 5-9, 2008, Houston, TX.Use of Ground-Based LiDAR to Assess Potential Sediment Loss from Stream Banks in Grazed Pastures.-(Abstract Only) Kovar, J.L., Russell, J.R. 2008. Use of Ground-Based LiDAR to Assess Potential Sediment Loss from Stream Banks in Grazed Pastures [CD-ROM]. In: ASA-CSSA-SSSA Annual Meeting Abstracts, Oct. 5-9, 2008, Houston, TX.Will Sulfur Limit Bioenergy Feedstock Production?-(Abstract Only) Kovar, J.L., Karlen, D.L. 2008. Will Sulfur Limit Bioenergy Feedstock Production? [CD-ROM]. In: ASA-CSSA-SSSA Annual Meeting Abstracts, Oct. 5-9, 2008, Houston, TX.Guide to Managing Pasture Water: Streamside Buffers-(Experiment Station) Isenhart, T.M., Kovar, J.L. 2008. Guide to Managing Pasture Water: Streamside Buffers. Iowa State University Extension. Publication No. IBC08.04. Available: http://www.extension.iastate.edu/Publications/IBC08-4.pdf.Fluid Fertilizer's Role in Sustainng Soils Used for Bio-Fuels Production-(Proceedings) Kovar, J.L., Karlen, D.L. 2008. Fluid Fertilizer's Role in Sustainng Soils Used for Bio-Fuels Production. In: Fluid Fertilizer Foundation Symposium Proceedings. Fluid Fertilizer Forum, February 17-19, 2008, Scottsdale, AZ. 2008 CDROM.Will Sulfur Limit Bio-fuel Corn Production?-(Abstract Only) Kovar, J.L., Karlen, D.L. 2007. Will Sulfur Limit Bio-fuel Corn Production? [CD-ROM]. In: ASA-CSSA-SSSA Annual Meeting Abstracts, Nov. 4-8, 2007, New Orleans, LA.Patterns of sediment and phosphorus accumulation in a riparian buffer-(Abstract Only) Tomer, M.D., Moorman, T.B., Kovar, J.L., James, D.E., Burkart, M.R 2007. Patterns of sediment and phosphorus accumulation in a riparian buffer [CD-ROM]. In: ASA-CSSA-SSSA Annual Meeting Abstracts, November 4-8, 2007, New Orleans, LA.Comparison of the Phosphorus Sorption Characteristics of a Conservation Reserve Buffer and an Adjacent Crop Field-(Peer Reviewed Journal) Schroeder, P.D., Kovar, J.L. 2008. Comparison of the Phosphorus Sorption Characteristics of a Conservation Reserve Buffer and an Adjacent Crop Field. Communications in Soil Science and Plant Analysis. 39(19&20):2961-2970.Effects of grazing management on stream bank erosion-(Abstract Only) Haan, M.M., Russell, J.R., Kovar, J.L., Nellesen, S.L. 2007. Effects of grazing management on stream bank erosion [abstract]. American Forage and Grassland Council Conference Proceedings. 16:18.Fractionation of Soil Phosphorus-(Book / Chapter)Spatial Patterns of Sediment and Phosphorus in a Riparian Buffer, Western Iowa-(Peer Reviewed Journal) Tomer, M.D., Moorman, T.B., Kovar, J.L., James, D.E., Burkart, M. 2007. Spatial Patterns of Sediment and Phosphorus in a Riparian Buffer, Western Iowa. Journal of Soil and Water Conservation. 62(5):329-338.SELECTION OF A WATER EXTRACTABLE PHOSPHORUS TEST FOR MANURES AND BIOSOLIDS AS AN INDICATOR OF RUNOFF LOSS POTENTIAL-(Peer Reviewed Journal) Kleinman, P.J., Sullivan, D., Wolf, A., Brandt, R., Dou, Z., Elliott, H., Kovar, J.L., Leytem, A.B., Maguire, R., Moore Jr, P.A., Sharpley, A.N., Shober, A., Sims, T., Toth, J., Toor, G., Zhang, H., Zhang, T., Saporito, L.S. 2007. Selection of a Water-Extractable Phosphorus Test for Manures and Biosolids as an Indicator of Runoff Loss Potential. Journal of Environmental Quality. 36(5):1357-1367.EFFECTS OF FORAGE MANAGEMENT ON PASTURE PRODUCTIVITY AND PHOSPHORUS CONTENT-(Peer Reviewed Journal) Haan, M.M., Russell, J.R., Powers, W.J., Kovar, J.L., Benning, J.L. 2007. Effects of forage management on pasture productivity and phosphorus content. Rangeland Ecology and Management. 60:311-318.Phosphorus Uptake During Four Years by Different Vegetative Cover Types in a Riparian Buffer-(Peer Reviewed Journal) Kelly, J.M., Kovar, J.L., Sokolowsky, R., Moorman, T.B. 2007. Phosphorus Uptake During Four Years by Different Vegetative Cover Types in a Riparian Buffer. Nutrient Cycling in Agroecosystems. 78:239-251.Grazing Management Effects on Potential Sediment and Phosphorus Loss from Streambanks-(Abstract Only) Moeller, S.L., Kovar, J.L., Russell, J.R., Haan, M.M. 2006. Grazing Management Effects on Potential Sediment and Phosphorus Loss from Streambanks. In: ASA-CSSA-SSSA Annual Meeting Abstracts. ASA-CSSA-SSSA Annual Meeting, Indianapolis, Indiana, November 12-16, 2006. 2006 CD-ROM.Fall Surface-Applied Fluid P Movement Into Soil Limits Potential Loss to Erosion-(Trade Journal) Kovar, J.L. 2006. Fall Surface-Applied Fluid P Movement Into Soil Limits Potential Loss to Erosion. Fluid Journal. 14:14-16.STANDARDIZING THE WATER-SOLUBLE PHOSPHORUS TEST FOR MANURES AND BIOSOLIDS-(Abstract Only) Sullivan, D., Kleinman, P.J., Wolf, A., Brandt, R., Dou, Z., Elliott, H., Kovar, J.L., Leytem, A.B., Maguire, R., Moore Jr, P.A., Sharpley, A.N., Shober, A., Sims, J.T., Toor, G., Zhang, H., Zhang, T. 2006. Standardizing the water-soluble phosphorus test for manures and biosolids. ASA-CSSA-SSSA Annual Meeting Abstracts.EFFECTS OF GRAZING MANAGEMENT ON PASTURE CHARACTERISTICS AFFECTING SEDIMENT AND NUTRIENT LOADS IN SURFACE WATERS-(Abstract Only)GRAZING MANAGEMENT EFFECTS ON SEDIMENT AND PHOSPHORUS IN SURFACE RUNOFF-(Peer Reviewed Journal) Haan, M.M., Russell, J.R., Powers, W.J., Kovar, J.L., Benning, J.L. 2006. Grazing management effects on sediment and phosphorus in surface runoff. Rangeland Ecology and Management. 59:607-615.IS POTASSIUM LIMITING NO-TILL CORN YIELDS?-(Proceedings) Karlen, D.L., Kovar, J.L. 2006. Is potassium limiting no-till corn yields? Proceedings of Great Plains Soil Fertility Conference. 11:206-211.POSITIONAL AVAILABILITY OF PHOSPHORUS FROM FALL-APPLIED SURFACE BANDS-(Proceedings) Kovar, J.L. 2006. Positional availability of phosphorus from fall-applied surface bands. In: Fluid Fertilizer Foundation Symposium Proceedings, February 12-14, 2006, Scottsdale, AZ. 2006 CDROM.NO-TILL CORN RESPONSE TO BANDED K ON DES MOINES LOBE SOILS-(Proceedings) Karlen, D.L., Kovar, J.L. 2006. No-till corn response to banded K on Des Moines lobe soils. In: Fluid Fertilizer Foundation Symposium Proceedings. Fluid Feritlizer Forum 2006, February 12-14, 2006, Scottsdale, AZ. 2006 CD-ROMPHOSPHORUS MANAGEMENT AND WATER QUALITY PROTECTION-(Other) Wortmann, C., Helmers, M., Mallarino, A., Barton, C., Devlin, D., Pierzynski, G., Lory, J., Massey, R., Holz, J., Shapiro, C., Kovar, J.L. 2006. Phosphorus management and water quality protection. Heartland Water Quality Workgroup, Regional Workgroup Bulletin. In: The Midwest (RP187) Lincoln; University of Nebraska Press. p.23.PLANT GROWTH AND PHOSPHORUS UPTAKE KINETICS OF THREE RIPARIAN GRASS SPECIES-(Abstract Only) Kovar, J.L., Claassen, N. 2005. Plant growth and phosphorus uptake kinetics of three riparian grass species [abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts. ASA-CSSA-SSSA Annual Meeting. Nov. 6-10, 2005, Salt Lake City, UT.POTENTIAL PHOSPHORUS LOSSES FROM STREAMBANKS IN GRAZING LANDS-(Abstract Only) Moeller, S.L., Kovar, J.L., Russell, J.R. 2005. Potential phosphorus losses from streambanks in grazing lands [CD-ROM]. In: ASA-CSSA-SSSA Annual Meeting Abstracts, Nov. 6-10, 2005, Salt Lake City, UT.COMPARISON OF PHOSPHORUS SORPTION AND DESORPTION FROM AN ESTABLISHED BUFFER AND ADJACENT PRODUCTION FIELD-(Abstract Only) Schroeder, P.D., Kovar, J.L. 2005. Comparison of phosphorus sorption and desorption from an established buffer and adjacent production field [CD-ROM]. In: ASA-CSSA-SSSA Annual Meeting Abstracts, Nov. 6-10, 2005, Salt Lake City, UT.WHAT LIMITS PHOSPHORUS FERTILIZER EFFICIENCY?-(Abstract Only) Kovar, J.L. 2005. What limits phosphorus fertilizer efficiency [CD-ROM]? In: ASA-CSSA-SSSA Annual Meeting Abstracts, Nov. 6-10, 2005, Salt Lake City, UT.EVALUATING THE INFLUENCE OF STORAGE TIME, SAMPLE HANDLING METHOD, AND FILTER PAPER ON THE MEASUREMENT OF WATER EXTRACTABLE PHOSPHORUS IN ANIMAL MANURES-(Peer Reviewed Journal) Baum, K., Pierzynski, G., Kleinman, P.J., Kovar, J.L., Maguire, R., Moore Jr, P.A., Zhang, T. 2006. Evaluating the influence of storage time, sample handling method, and filter paper on the measurement of water extractable phosphorus in animal manures. Communications in Soil Science and Plant Analysis. 37:451-463.IS K THE CINDERELLA NUTRIENT FOR REDUCED-TILL SYSTEMS?-(Trade Journal) Karlen, D.L., Kovar, J.L. 2005. Is K the Cinderella nutrient for reduced-till systems? Fluid Journal. 13(4):8-11.COMPARISON OF ORGANIC AND INORGANIC PHOSPHORUS FRACTIONS IN AN ESTABLISHED BUFFER AND ADJACENT PRODUCTION FIELD-(Peer Reviewed Journal) Schroeder, P.D., Kovar, J.L. 2006. Comparison of organic and inorganic phosphorus fractions in an established buffer and adjacent production field. Communications in Soil Science and Plant Analysis. 37:1219-1232.STREAM BANK EROSION UNDER DIFFERENT RIPARIAN LAND-USE PRACTICES IN NORTHEAST IOWA-(Proceedings) Zaimes, G.N., Schultz, R.C., Isenhart, T.M., Mickelson, S.K., Kovar, J.L., Russell, J.R., Powers, W.J. 2005. Stream bank erosion under different riparian land-use practices in northeast Iowa. In: Proceedings of the North American Agroforestry Conference. 9th North American Agroforestry Conference, June 12-15, 2005, Rochester, MN. 2005 CD-ROM.EVALUATING THE INFLUENCE OF STORAGE TIME, SAMPLE HANDLING METHOD AND FILTER PAPER ON THE MEASUREMENT OF WATER EXTRACTABLE PHOSPHORUS IN ANIMAL MANURES-(Peer Reviewed Journal) Baum, K., Pierzynski, G., Kleinman, P.J., Kovar, J.L., Maguire, R., Moore Jr, P.A., Zhang, T. Evaluating the Influence of Storage Time, Sample-handling Method, and Filter Paper on the Measurement of Water-Extractable Phosphorus in Animal Manures. Communications in Soil Science and Plant Analysis. 37(3-4):451-463.IS K THE CINDERELLA NUTRIENT FOR REDUCED TILLAGE SYSTEMS?-(Proceedings) Karlen, D.L., Kovar, J.L. 2005. Is K the Cinderella nutrient for reduced tillage systems? [CD-ROM] In: Fluid Fertilizer Foundation Symposium Proceedings, Feb. 13-15, 2005, Scottsdale, Arizona.INFLUENCE OF LAND-USE PRACTICES ON STREAM BANK EROSION IN IOWA-(Abstract Only) Zaimes, G.N., Schultz, R.C., Isenhart, T.M., Mickelson, S.K., Kovar, J.L., Russell, J.R., Powers, W.P. 2004. Influence of Land-use Practices on Stream Bank Erosion in Iowa [CD-ROM]. In: ASA-CSSA-SSSA Annual Meeting Abstracts, Oct. 31-Nov. 4, 2004, Seattle, WA.PHOSPHORUS UPTAKE IN A LOESS HILLS MIXED SPECIES RIPARIAN BUFFER-(Abstract Only) Kelly, J.M., Kovar, J.L., Moorman, T.B., Sokolowsky, R. 2004. Phosphorus Uptake in a Loess Hills Mixed Species Riparian Buffer [CD-ROM]. ASA-CSSA-SSSA Annual Meeting Abstracts. Madison, Wisconsin.IN-SITU DYNAMICS OF FOUR MACRONUTRIENTS IN THE RHIZOSPHERE SOIL SOLUTION OF MAIZE, SWITCHGRASS, AND COTTONWOOD-(Abstract Only) Kovar, J.L., Kelly, J.M., Schroeder, P.D., Wang, Z.Y. 2005. In-situ dynamics of four macronutrients in the rhizosphere soil solution of maize, switchgrass, and cottonwood. In: Hartmann, A., Schmid, M., Wenzel, W., and Hinsinger, P., editors. 2004 Rhizosphere, Perspectives and Challenges - A Tribute to Lorez Hiltner, September 12-17, 2004, Neuherberg, Germany. p. 192.USE OF ANION EXCHANGE MEMBRANES TO CHARACTERIZE POSITIONAL AVAILABILITY OF SOIL PHOSPHORUS-(Abstract Only)SOIL-ROOT INTERACTIONS AND PHOSPHORUS NUTRITION OF PLANTS-(Book / Chapter) Kovar, J.L., Claassen, N. 2005. Soil-root interactions and phosphorus nutrition of plants. Book Chapter. In: Sims, J.T. and Sharpley, A.N., editors. Phosphorus: Agriculture and the Environment. Madison, WI: ASA-CSSA-SSSA. p 379-414.RHIZOSPHERE SOLUTION CHEMISTRY AND THE NUTRIENT STATUS OF JUVENILE CORN, COTTONWOOD, AND SWITCHGRASS PLANTS-(Peer Reviewed Journal) Wang, Z., Kelly, J.M., Kovar, J.L. 2005. Rhizosphere solution chemistry and the nutrient status of juvenile corn, cottonwood, and switchgrass plants. Plant and Soil Journal. 270:213-221.POSITIONAL AVAILABILITY OF PHOSPHORUS FROM SURFACE FERTILIZER BANDS-(Proceedings) Kovar, J.L., Schroeder, P.D., Washburn, Jr., K.L. 2004. Positional availability of phosphorus from surface fertilizer bands. In: A.J. Schlegel (ed.). Proceedings of Great Plains Soil Fertility Conference. March 2-3, 2004, Kansas State University, Manhattan, KS. p. 271-276.STARTER COMPOSITION AND HYBRID SELECTION AFFECT EARLY GROWTH AND YIELD OF CORN-(Proceedings) KOVAR, J.L. STARTER COMPOSITION AND HYBRID SELECTION AFFECT EARLY GROWTH AND YIELD OF CORN. FLUID FERTILIZER FOUNDATION SYMPOSIUM PROCEEDINGS. 2004. V. 21. P. 131-141.IN SITU DYNAMICS OF PHOSPHORUS IN THE RHIZOSPHERE SOLUTION OF FIVE SPECIES-(Peer Reviewed Journal) Wang, Z., Kelly, J.M., Kovar, J.L. 2004. In situ dynamics of phosphorus in the rhizosphere solution of five species. Journal of Environmental Quality. 33:1387-1392.EVALUATING STARTER FERTILIZER PLACEMENT OPTIONS FOR CORN-(Abstract Only) Kovar, J.L. 2003. Evaluating starter fertilizer placement options for corn [CD-ROM]. Indiana Crop Advisor Conference Abstracts. Purdue University. West Lafayette, IN.IMPACTS OF CATTLE GRAZING MANAGEMENT ON SEDIMENT AND PHOSPHORUS LOADS IN SURFACE WATERS-(Proceedings)RECOMMENDED METHODS OF MANURE ANALYSIS-(Abstract Only) PETERS, J., COMBS, S., HOSKINS, B., JARMAN, J., KOVAR, J.L., WATSON, M., WOLF, A., WOLF, N. RECOMMEDED METHODS OF MANURE ANALYSIS. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2003. CD-ROM. MADISON, WI.EFFICIENT USE OF NUTRIENTS - ARE WE IGNORING THE HIDDEN HALF OF THE CROP?-(Abstract Only) KOVAR, J.L. EFFICIENT USE OF NUTRIENTS - ARE WE IGNORING THE HIDDEN HALF OF THE CROP?. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2003. CD-ROM. MADISON, WI.PREDICTING PHOSPHORUS LOSS IN RUNOFF USING A DISPLACEMENT TECHNIQUE-(Abstract Only) GASTON, L.A., KOVAR, J.L., SAUER, T.J. PREDICTING PHOSPHORUS LOSS IN RUNOFF USING A DISPLACEMENT TECHNIQUE. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2003. CD-ROM. MADISON, WI.GROWTH AND PHOSPHORUS ACCUMULATION OF BROMEGRASS FOLLOWING PHOSPHONATE APPLICATION-(Abstract Only) Boehm, J.L., Kovar, J.L., Allan, D.L. 2003. Growth and phosphorus accumulation of bromegrass following phosphonate application. ASA-CSSA-SSSA Annual Meeting Abstracts. CD-ROM. Madison, WI.LAND-USE PRACTICE IMPACTS ON STREAM BANK EROSION WITH AN EMPHASIS ON GRAZING PRACTICES-(Abstract Only) ZAIMES, G.N., SCHULTZ, R.C., ISENHART, T.M., MICKELSON, S.K., KOVAR, J.L., RUSSELL, J.R., POWERS, W.P. LAND-USE PRACTICE IMPACTS ON STREAM BANK EROSION WITH AN EMPHASIS ON GRAZING PRACTICES. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2003. CD-ROM. MADISON, WI.EARLY GROWTH AND NUTRIENT UPTAKE OF TRANSGENIC AND NON-TRANSGENIC CORN HYBRIDS-(Abstract Only) KOVAR, J.L., DOERGE, T.A. EARLY GROWTH AND NUTRIENT UPTAKE OF TRANSGENIC AND NON-TRANSGENIC CORN HYBRIDS. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2003. CD-ROM. MADISON, WI.EFFECTS OF GRAZING MANAGEMENT ON SEDIMENT AND PHOSPHORUS IN RUNOFF-(Proceedings) Haan, M.M., Russell, J.R., Powers, W.J., Mickelson, S.K., Ahmed, S.I., Kovar, J.L., Schultz, R.C. 2003. Effects of grazing management on sediment and phosphorus in runoff. In: Prosser, Jr., P.J. (ed.). Proceedings Ninth International Symposium on Animal, Agricultural, and Food Processing Wastes, October 12-15, 2003. Raleigh, NC. p. 318-386.METHODS OF DETERMINATION OF P, K, CA, MG, AND TRACE ELEMENTS-(Book / Chapter) KOVAR, J.L. METHODS OF DETERMINATION OF P, K, CA, MG, AND TRACE ELEMENTS. BOOK CHAPTER. 2003. AVAILABLE FROM: WWW.UWEX.EDU/CES/PUBS/PDF/A3769.PDF. UW EXTENSION.EFFECTIVE STARTER FERTILIZERS FOR CORN IN CONSERVATION TILLAGE SYSTEMS-(Proceedings) KOVAR, J.L. EFFECTIVE STARTER FERTILIZERS FOR CORN IN CONSERVATION TILLAGE SYSTEMS. FLUID FERTILIZER FOUNDATION SYMPOSIUM PROCEEDINGS. 2003. V. 20. P. 230-240.RUNOFF PHOSPHORUS RELATED TO SOIL PHOSPHORUS IN LOUISIANA COASTAL PLAIN    SOILS AMENDED WITH POULTRY LITTER-(Peer Reviewed Journal) DRAPCHO, C.M., GASTON, L.A., TAPADOR, S., KOVAR, J.L. RUNOFF PHOSPHORUS RELATED TO SOIL PHOSPHORUS IN LOUISIANA COASTAL PLAIN SOILS AMENDED WITH POULTRY LITTER. JOURNAL OF ENVIRONMENTAL QUALITY. 2003. V. 32. P. 1422-1429.TURKEY LITTER AS A PHOSPHORUS SOURCE FOR CORN-(Abstract Only) KOVAR, J.L., SAUER, T.J., MOORMAN, T.B. TURKEY LITTER AS A PHOSPHORUS SOURCE FOR CORN. AMERICAN SOCIETY OF AGRONOMY MEETINGS. 2002. CD-ROM. MADISON, WI.AN ECONOMICALLY SUSTAINABLE RIPARIAN BUFFER TO PROMOTE BANK STABILITY AND REDUCE PHOSPHORUS LOSS IN THE LOESS HILLS-(Abstract Only) KELLY, J.M., BURKART, M.R., KOVAR, J.L., MOORMAN, T.B., LOGSDON, S.D. AN ECONOMICALLY SUSTAINABLE RIPARIAN BUFFER TO PROMOTE BANK STABILITY AND REDUCE PHOSPHORUS LOSS IN THE LOESS HILLS. AMERICAN SOCIETY OF AGRONOMY. 2002. CD-ROM. MADISON, WI.REDUCING SOIL PHOSPHOROUS BY HAY HARVEST-(Abstract Only) GASTON, L., COOPER, D., KOVAR, J.L., BELL, P. REDUCING SOIL PHOSPHOROUS BY HAY HARVEST. AGRONOMY ABSTRACTS. 2002. CD-ROM. MADISON, WI.DEFINING COTTONWOOD UPTAKE OF PHOSPHORUS USING RHIZOSPHERE SOLUTION PHASE MESUREMENTS-(Abstract Only) WANG, Z., KELLY, M.J., KOVAR, J.L. DEFINING COTTONWOOD UPTAKE OF PHOSPHORUS USING RHIZOSPHERE SOLUTION PHASE MESUREMENTS. AGRONOMY ABSTRACTS. 2002. CD-ROM. MADISON, WI.GRAZING MANAGEMENT SYSTEMS TO MINIMIZE PHOPHORUS LOSSES FROM UPLAND PASTURES-(Abstract Only) BOEHM, J.L., KOVAR, J.L., RUSSELL, J.R., HAAN, M.M., POWERS, W.J., MICKELSON, S.K., SCHULTZ, R.C. GRAZING MANAGEMENT SYSTEMS TO MINIMIZE PHOPHORUS LOSSES FROM UPLAND PASTURES. AGRONOMY ABSTRACTS. 2002. CD-ROM. MADISON, WI.WHAT ARE THE BEST P AND K PLACEMENT OPTIONS FOR CORN-(Abstract Only) KOVAR, J.L. WHAT ARE THE BEST P AND K PLACEMENT OPTIONS FOR CORN. SOIL SCIENCE SOCIETY OF AMERICA ANNUAL MEETING. 2002. CD-ROM. MADISON, WI.AGRONOMIC PRINCIPLES OF FERTILIZER PLACEMENT-(Review Article) KOVAR, J.L. AGRONOMIC PRINCIPLES OF FERTILIZER PLACEMENT. PROSSER, P.J. EDITOR. ANNUAL FERTILIZER INDUSTRY ROUND TABLE. 2002. CD-ROM. FOREST HILL, MD.SEARCHING FOR MORE EFFECTIVE CORN STARTERS IN CONSERVATION-TILLAGE SYSTEMS-(Trade Journal) KOVAR, J.L. SEARCHING FOR MORE EFFECTIVE CORN STARTERS IN CONSERVATION-TILLAGE SYSTEMS. FLUID JOURNAL. 2003. V. 11(2). P. 8-11.GREENHOUSE AND FIELD STUDIES ON HAY HARVEST TO REMEDIATE HIGH PHOSPHORUS SOIL-(Peer Reviewed Journal) GASTON, L.A., EILERS, T.L., KOVAR, J.L., COOPER, D., ROBINSON, D.L. GREENHOUSE AND FIELD STUDIES ON HAY HARVEST TO REMEDIATE HIGH PHOSPHORUS SOIL. COMMUNICATION IN SOIL SCIENCE PLANT ANALYSIS. 2003. V. 34. p. 2085-2097.IMPACT OF DIFFERENT GRAZING SYSTEMS AND VEGETATIVE FILTER STRIPS ON SEDIMENT AND NUTRIENT LOSSES WITH SURFACE RUNOFF-(Proceedings) AHMED, S., MICKELSON, S.K., RUSSELL, J.R., POWERS, W.J., SCHULTZ, R.C., KOVAR, J.L. IMPACT OF DIFFERENT GRAZING SYSTEMS AND VEGETATIVE FILTER STRIPS ON SEDIMENT AND NUTRIENT LOSSES WITH SURFACE RUNOFF. AGRICULTURAL ENGINEERING INTERNATIONAL CONFERENCE PROCEEDINGS. 2002. PAPER NO. 022141.EFFECTS OF GRAZING MANAGEMENT ON SEDIMENT AND PHOSPHORUS RUNOFF-(Proceedings) HAAN, M.M., RUSSELL, J.R., POWERS, W.J., MICKELSON, S.K., KOVAR, J.L., SCHULTZ, R.C. EFFECTS OF GRAZING MANAGEMENT ON SEDIMENT AND PHOSPHORUS RUNOFF. AMERICAN FORAGE AND GRASSLAND COUNCIL PROCEEDINGS. 2002. V. 11. P. 292-296.GYPSUM AND COMPOST EFFECTS ON SUGARCANE ROOT GROWTH, YIELD, AND PLANT      NUTRIENTS-(Peer Reviewed Journal) VIATOR, R., KOVAR, J.L., HALLMARK, W. GYPSUM AND COMPOST EFFECTS ON SUGARCANE ROOT GROWTH, YIELD, AND PLANT NUTRIENTS. AGRONOMY JOURNAL. 2002. V. 94(6). P. 1332-1336.GRAZING SYSTEMS TO MAXIMIZE FORAGE AND MINIMIZE P, N, AND SEDIMENT POLLUTION OF STREAMS-(Proceedings) POWERS, W., RUSSELL, J., HAAN, M., SCHULTZ, R., STAUFFER, E., ZAIMES, G., HUNKINS, B., KOVAR, J.L., BOEHM, J., MICKELSON, S. GRAZING SYSTEMS TO MAXIMIZE FORAGE AND MINIMIZE P, N, AND SEDIMENT POLLUTION OF STREAMS. AGRICULTURAL AND ENVIRONMENT CONFERENCE PROCEEDINGS. 2003. P. 23-35.FACTORS AFFECTING N AND P NEEDS IN STARTERS: FORMULATIONS AND PLACEMENT FOR REDUCED-TILLAGE CORN-(Proceedings) KOVAR, J.L. FACTORS AFFECTING N AND P NEEDS IN STARTERS: FORMULATIONS AND PLACEMENT FOR REDUCED-TILLAGE CORN. FLUID FERTILIZER FOUNDATION SYMPOSIUM PROCEEDINGS. 2002. V. 19. P. 12-20.CHANGES IN PLANT-AVAILABLE NITROGEN AND PHOSPHORUS IN SOILS TREATED WITH   ANIMAL MANURES AND COMMERCIAL FERTILZER-(Abstract Only)EFFECTS OF POULTRY LITTER ON THE QUALITY OF A COASTAL PLAIN SOIL AND       RUNOFF WATER-(Abstract Only) WIGHT, J., GASTON, L.A., KOVAR, J.L., COOPER, D.C., ROBBINS, M.L., CLASON, T.R., ROBINSON, D.L. EFFECTS OF POULTRY LITTER ON THE QUALITY OF A COASTAL PLAIN SOIL AND RUNOFF WATER. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2001. CD-ROM. MADISON, WI.DEVELOPMENT OF A MANURE TESTING MANUAL BY A MULTI-REGIONAL COMMITTEE-(Abstract Only) PETERS, J., BEEGLE, D., COMBS, S., HOSKINS, B., KOVAR, J.L., WATSON, M., WOLF, A., WOLF, N. DEVELOPMENT OF A MANURE TESTING MANUAL BY A MULTI-REGIONAL COMMITTEE. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2001. CD-ROM. MADISON, WI.CHANGES IN PHOSPHORUS AVAILABILITY IN MANURE- AND FERTILIZER-AMENDED       SOILS.-(Abstract Only)RELATION OF SOIL P TO SURFACE RUNOFF P FOR FOUR SOILS AMENDED WITH         POULTRY LITTER-(Abstract Only) KOVAR, J.L., GASTON, L., DRAPCHO, C., TAPADAR, S. RELATION OF SOIL P TO SURFACE RUNOFF P FOR FOUR SOILS AMENDED WITH POULTRY LITTER. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2001. CD-ROM. MADISON, WI.PHOSPHORUS INDEXING IN CROPLAND: THE IOWA P INDEX-(Abstract Only) MALLARINO, A.P., STEWART, B.M., BAKER, J.L., DOWNING, J.A., FENTON, T.E., SAWYER, J.E., MILLER, G.A., KOVAR, J.L., SAUER, T.J., VOSS, R.D. PHOSPHORUS INDEXING IN CROPLAND: THE IOWA P INDEX. MEETING ABSTRACT. 2001.MEASURED AND PREDICTED PHOSPHORUS TRANSPORT FROM ANIMAL MANURE IN A        MIDWESTERN U.S. WATERSHED-(Abstract Only)THE ROLE OF ROOTS IN MAXIMUM SOIL PRODUCTIVITY-(Review Article) KOVAR, J.L. THE ROLE OF ROOTS IN MAXIMUM SOIL PRODUCTIVITY. FLUID JOURNAL. 2001. V. 9(2). P. 18-21.STARTER FERTILIZER FORMULATIONS AND PLACEMENT FOR REDUCED TILLAGE CORN-(Proceedings) KOVAR, J.L., MALLARINO, A.P. STARTER FERTILIZER FORMULATIONS AND PLACEMENT FOR REDUCED TILLAGE CORN. FLUID FERTILIZER FOUNDATION SYMPOSIUM PROCEEDINGS. 2001. V. 18. P. 188-194.ROOTS IN PLANT NUTRITION RESEARCH:  AN OVERVIEW-(Abstract Only) KOVAR, J.L. ROOTS IN PLANT NUTRITION RESEARCH:  AN OVERVIEW. FLUID FERTILIZER FOUNDATION SYMPOSIUM PROCEEDINGS. 2001. V. 18. P. 25.ON-FARM TRIALS TO ASSESS THE ACCURACY OF P AND K RECOMMENDATIONS FOR       AGRONOMIC CROPS IN LOUISIANA-(Abstract Only)SOIL BIOAVAILABLE P AFFECTS P IN SURFACE RUNOFF FROM FOUR SOILS AMENDED    WITH POULTRY LITTER-(Abstract Only)DEVELOPMENT OF A PHOSPHORUS ASSESSMENT TOOL FOR IOWA-(Abstract Only) MALLARINO, A.P., BAKER, J.L., DOWNING, J.A., FENTON, T.E., MILLER, G.A., SAWYER, J.E., STEWART, B.M., KOVAR, J.L. DEVELOPMENT OF A PHOSPHORUS ASSESSMENT TOOL FOR IOWA. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2000. CD-ROM. MADISON, WI.SOIL ARSENIC EFFECTS ON CANOLA SEEDLING GROWTH AND ION UPTAKE-(Peer Reviewed Journal)  ProjectsManaging Nutrient, Carbon, and Water Fluxes to Provide Sustainable and Resilient Cropping Systems for Midwestern LandscapesIn-House Appropriated (D)Accession Number:443545Watershed-scale Phosphorus Inputs from StreambanksNon-Funded Cooperative Agreement (N)Accession Number:437529Water and Light Use Efficiency of Native Grasses in a Silvopasture SystemNon-Assistance Cooperative Agreement (S)Accession Number:443530  ARS News ArticlesNo news articles listed for this employee.


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