Research Soil Scientist
Merle F. Vigil
Research Leader/Soil Scientist
Nutrient Management
Phone: 970-345-0517
E-Mail: Merle.Vigil@ars.usda.gov
Education
1980 B.S. Agronomy, Colorado State University
1983 M.S. Soil Fertility, Colorado State University
1989 Ph.D. Soil Fertility/Soil Chemistry, Kansas State University
Research Interests
Mineralization-Immobilization of soil organic N and crop residue N
Nitrate leaching through soils
Crop residue management and nutrient cycling of animal manuresFertilizer use efficiency particularly with N fertilizers
The effect of soil water on N use efficiency
Management strategies to maximize fertilizer and water use efficiencies
Simulation modeling of the above processes
Management Practices for Long Term Productivity of Great Plains Agriculture In-House Appropriated (D) Accession Number:432311 Development of Sugar Beet Germplasm Enhanced for Resistance to Important and Emerging Plant Pathogens In-House Appropriated (D) Accession Number:434410 Development of Wheat Based Alternative Crop Production Systems for the Central Great Plains Non-Funded Cooperative Agreement (N) Accession Number:436941 Data Innovations Non-Assistance Cooperative Agreement (S) Accession Number:437134 USDA Agriculture and Forestry Greenhouse Gas Inventory and the Agricultural Collaborative Research Outcomes System (AgCROS)
Non-Assistance Cooperative Agreement (S) Accession Number:436740 Development of Long-term Best Management Practices to Adapt to a Changing Climate Non-Assistance Cooperative Agreement (S) Accession Number:436760
will take you to the publication reprint.)
Stewart, C.E., Jin, V.L., Liebig, M.A., Calderon, F.J., Vigil, M.F. 2020. What long-term research can tell us about agroecosystem C storage potential. Meeting Abstract.
Follett, R.F., Stewart, C.E., Bradford, J.A., Pruessner, E.G., Sims, P.L., Vigil, M.F. 2020. Stable C isotope data of southern mixed-grass prairie vegetation from Oklahoma, United States. Data in Brief. 32. https://doi.org/10.1016/j.dib.2020.106204.
Follett, R.F., Stewart, C.E., Bradford, J.A., Pruessner, E.G., Sims, P.L., Vigil, M.F. 2020. Long-term pasture management impacts on eolian sand soils in the southern mixed-grass prairie. International Union for Quaternary Research. https://doi.org//10.1016/j.quaint.2020.07.019.
Sudduth, K.A., Drummond, S.T., Long, D., Vigil, M.F. 2020. Automation of yield-based management decisions [abstract]. ASABE Annual International Virtual Meeting, July 13-15, 2020.
Del Grosso, S.J., Stewart, C.E., Delgado, J.A., Manter, D.K., Vigil, M.F. 2020. Observational and modeling methods to inform ecosystem service markets. Proceedings Great Plains Soil Fertility Conference. 18:1-265.
Gazave, E., Tassone, E.E., Baswggio, M., Cyder, M., Byrel, K., Oblath, E.A., Lueschow, S.R., Poss, D.J., Hardy, C.D., Wingerson, M., James, D.B., Abdel-Haleem, H.A., Grant, D.M., Hatfield, J.L., Isbell, T., Vigil, M.F., Dyer, J.M., Jenks, M.A., Brown, J., Gore, M.A., Pauli, D. 2020. Genome-wide association study identifies acyl-lipid metabolism candidate genes involved in the genetic control of natural variation for seed fatty acid traits in Brassica napus L. Industrial Crops and Products. 145. https://doi.org/10.1016/j.indcrop.2019.112080.
Olayemi, P., Kallenbach, C., Schneekloth, J., Calderon, F.J., Vigil, M.F., Wallenstein, M. 2020. Potential soil health benefits of lactobionate - a cheese production byproduct. Frontiers in Sustainable Food Systems. 3:127. https://doi.org/10.3389/fsufs.2019.00127.
Schlegel, A.J., Baumhardt, R.L., Vigil, M.F. 2019. Precipitation use efficiency of dryland cropping systems [abstract]. 2019 ASA-SSSA-CSSA Annual International Meeting - Special Session Symposium: Managing Limited Water Resources in a Changing Climate, November 10-13, 2019, San Antonio, Texas. Abstract No. 117-5.
Sherrod, L.A., Vigil, M.F., Stewart, C.E. 2019. Do fulvic, humic and humin c fractions represent meaningful biological, physical and chemical carbon pools? Journal of Environmental Quality. https://doi.org/10.2134/jeq2019.03.0104.
Gesch, R.W., Long, D.S., Palmquist, D.E., Allen, B.L., Archer, D.W., Brown, J., Davis, J.B., Hatfield, J.L., Jabro, J.D., Kiniry, J.R., Vigil, M.F., Oblath, E.A., Isbell, T. 2019. Agronomic performance of Brassicaceae oilseeds in multiple environments across the Western USA. BioEnergy Research. 12(3):509-523. https://doi.org/10.1007/s12155-019-09998-1.
Brewer, P., Calderon, F.J., Vigil, M.F., Von Fischer, J. 2018. Impacts of moisture, soil respiration, and agricultural practices on methanogenesis in upland soils as measured with stable isotope pool dilution. Soil Biology and Biochemistry. 127:239-251. https://www.sciencedirect.com/science/article/pii/S0038071718303092?via%3Dihub.
Nielsen, D.C., Vigil, M.F. 2018. Dry bean water use/yield production function to estimate yields in the Central Great Plains. Field Crops Research. 228:60-67. https://doi.org/10.1016/j.fcr.2018.08.016.
Nielsen, D.C., Vigil, M.F. 2018. Soil water extraction for several dryland crops. Agronomy Journal. 110:2447-2455. https://doi.org/10.2134/agronj2018.05.0335.
Nielsen, D.C., Vigil, M.F., Henry, B.W. 2018. Effect of skip row planting configuration on grain sorghum water use. Field Crops Research. 223:67-74. https://doi.org/10.1016/j.fcr.2018.04.003.
-(Peer Reviewed Journal)
Nielsen, D.C., Vigil, M.F. 2018. Probabilities of having minimum amounts of available soil water at wheat planting. Field Crops Research. 221:32-37. doi:10.1016/j.fcr.2018.02.008.
-(Peer Reviewed Journal)
Nielsen, D.C., Vigil, M.F. 2018. Wheat yield and yield stability of eight dryland crop rotations. Agronomy Journal. 110-594-601.doi:10.2134/agronj2017.07.0407.
-(Peer Reviewed Journal)
Nielsen, D.C., Vigil, M.F. 2017. Influence of water use and environmental parameters on proso millet yield. Field Crops Research. 212:34-44. doi:10.1016/j.fcr.2017.06.025.
-(Peer Reviewed Journal)
Wienhold, B.J., Vigil, M.F., Hendrickson, J.R., Derner, J.D. 2017. Vulnerability of crops and croplands in the U.S. Northern Plains to predicted climate change. Climatic Change. doi:10.1007/s10584-017-1989-x.
-(Peer Reviewed Journal)
Hunter, K.M., Archer, D.W., Gesch, R.W., Vigil, M.F., Hatfield, J.L., Allen, B.L., Jabro, J.D., Kim, S., Meki, M.N., Kiniry, J.R. 2017. Degree days to 50% flowering for 12 cultivars of spring canola-like mustard. Journal of Agriculture and Ecology Research International. 11(4):1-8.
-(Peer Reviewed Journal)
Nielsen, D.C., Vigil, M.F. 2017. Defining a dryland grain sorghum production function for the Central Great Plains. Agronomy Journal. 109:1582-1590.
-(Peer Reviewed Journal)
Mikha, M.M., Benjamin, J.G., Vigil, M.F., Poss, D.J. 2017. Manure and tillage use in remediation of eroded land and impacts on soil chemical properties. PLoS One. 12(4):1-25. doi:10.1371/journal.pone.0175533.
Nielsen, D.C., Vigil, M.F. 2017. Intensifying a semi-arid dryland crop rotation by replacing fallow with pea. Agricultural Water Management. 186:127-138.
Calderon, F.J., Vigil, M.F., Benjamin, J.G. 2018. Compost input effects on dryland wheat and forage yields and soil quality. Pedosphere. 28(3):451-462.
McMaster, G.S., Edmunds, D.A., Jones, S.M., Johnson, J.J., Vigil, M.F. 2016. Simulating the probability of grain sorghum maturity before the first frost in northeastern Colorado. Agronomy Journal. 6(4):44. doi:10.3390/agronomy6040044.
-(Peer Reviewed Journal)
Nielsen, D.C., Vigil, M.F., Hansen, N.C. 2016. Evaluating potential dryland cropping systems adapted to climate change in the Central Great Plains. Agronomy Journal. 108:2391-2405.
Latshaw, S., Vigil, M.F., Haley, S. 2016. Genotypic differences for nitrogen use efficiency and grain protein deviation in hard winter wheat. Agronomy Journal. 108:6/2201-2213. doi:10.2134/agronj2016.02.0070.
Nielsen, D.C., Vigil, M.F., Lyon, D.J., Higgins, R.K., Hergert, G.W., Holman, J.D. 2016. Cover crops can affect subsequent wheat yield in the central great plains. Crops and Soils. 49:51-54.
-(Peer Reviewed Journal)
Vigil, M.F., Poss, D.J. 2016. N response of no-till dryland winter triticale forage. Communications in Soil Science and Plant Analysis. 47(9):1117-1127.
Vigil, M.F., Poss, D.J., Benjamin, J.G., Mikha, M.M. 2016. Use of manure to remediate eroded hill top soils. Progressive Forage Grower. 3/33-34.
-(Peer Reviewed Journal)
Nielsen, D.C., Lyon, D.J., Higgins, R.K., Holman, J.D., Hergert, G.W., Vigil, M.F. 2015. Cover crop effect on subsequent wheat yield and water use efficiency in the central great plains. Agronomy Journal. 108:243-256.
-(Peer Reviewed Journal)
Calderon, F.J., Nielsen, D.C., Acosta Martinez, V., Vigil, M.F., Lyon, D. 2016. Cover crop and irrigation effects on soil microbial communities and enzymes in semiarid agroecosystems of the Central Great Plains of North America. Pedosphere. 26(2):192-205.
Johnson, J., Haley, S., Bosley, B., Meyer, R., Trujillo, W., Hain, J., Saure, S., Bartolo, M., Larson, K., Vigil, M.F., Stromberger, J., Byrne, P., Davis, J., Manmathan, H., Peairs, F., Jahn, C., Cokrell, D. 2015. Making Better Decisions: 2014 Colorado Winter Wheat Variety Performance trials. Agronomy Technical Report. 2015/1-59.
-(Peer Reviewed Journal)
Benjamin, J.G., Nielsen, D.C., Vigil, M.F., Mikha, M.M., Calderon, F.J. 2015. Cumulative deficit irrigation effects on corn (Zea mays, L.) biomass and grain yield. Agricultural Water Management. 159/107-114.
Nielsen, D.C., Lyon, D.J., Hergert, G.W., Higgins, R.K., Calderon, F.J., Vigil, M.F. 2015. Cover crop water use. CSA News. Available: http://www.crops.org/publications/CSA/pdfs/60/6/12.
-(Peer Reviewed Journal)
Gesch, R.W., Isbell, T., Oblath, E.A., Allen, B.L., Archer, D.W., Brown, J., Hatfield, J.L., Jabro, J.D., Kiniry, J.R., Long, D.S., Vigil, M.F. 2015. Comparison of several Brassica species in the north central U.S. for potential jet fuel feedstock. Industrial Crops and Products. 75(B):2-7.
-(Peer Reviewed Journal)
Calderon, F.J., Benjamin, J.G., Vigil, M.F. 2015. A comparison of corn residue and its biochar on soil C and plant growth. PLoS One. doi:10.1371/journal.pone.0121006.
-(Peer Reviewed Journal)
Nielsen, D.C., Lyon, D.J., Hergert, G.W., Higgins, R.K., Calderon, F.J., Vigil, M.F. 2015. Cover crops in mixtures do not use water differently than single-species plantings. Agronomy Journal. 107:1025-1038.
Sauer, S.M., Johnson, J.J., McMaster, G.S., Vigil, M.F. 2015. Argonomic practices of dryland grain sorghum maturity, yield, and test weight.. Extension Publications. 3(1):9-11.
Gesch, R.W., Allen, B.L., Archer, D.W., Banuelos, G.S., Behrman, K.D., Brown, J., Hatfield, J.L., Jabro, J.D., Kiniry, J.R., Long, D.S., Vigil, M.F. 2014. Agronomic comparison of several brassica species in the U.S. Corn Belt as feedstock for hydrotreated jet fuel [abstract]. In: Miller, T., Alexopoulou, E. and Berti, M.T., editors. International Conference in Industrial Crops and 26th Annual Meeting of the Association for the Advancement of Industrial Crops (AAIC). Program and Abstracts. September 13-19, 2014, Athens, Greece.
Sauer, S., Johnson, J., McMaster, G.S., Vigil, M.F. 2014. Agronomic factors affecting dryland grain sorghum maturity and production in northeast Colorado. Agronomy Journal. 106(6):2001-2012.
-(Peer Reviewed Journal)
Benjamin, J.G., Nielsen, D.C., Vigil, M.F., Mikha, M.M., Calderon, F.J. 2014. Water deficit stress effects on corn (Zea mays, L.) root: shoot ratio. Open Journal of Soil Science 4:151-160.
-(Peer Reviewed Journal)
Allen, B.L., Vigil, M.F., Jabro, J.D. 2014. Camelina growing degree hour and base temperature requirements. Agronomy Journal. 106(3):940-944.
-(Peer Reviewed Journal)
Nielsen, D.C., Vigil, M.F. 2014. Searching for synergism in dryland cropping systems in the central Great Plains. Field Crops Research. 158:34-42. Doi:10.1016/j.fcr.2013.12.020.
Vigil, M.F. 2013. Standing crop residues and wind erosion. Southeast Area Extension Circular Farm and Ranch Newsletter. 1(3) 1-11.
-(Peer Reviewed Journal)
Mikha, M.M., Vigil, M.F., Benjamin, J.G. 2013. Long-term tillage impacts on soil aggregation and carbon dynamics under wheat-fallow in the central Great Plains. Soil Science Society of America Journal. 77:594-605.
-(Peer Reviewed Journal)
Benjamin, J.G., Nielsen, D.C., Vigil, M.F., Mikha, M.M., Calderon, F.J. 2013. A comparison of two models to evaluate soil physical property effects on corn (Zea mays, L.)root growth. Agronomy Journal. 105:713-720.
Van Pelt, R.S., Baddock, M.C., Zobeck, T.M., Schlegel, A.J., Vigil, M.F., Acosta Martinez, V. 2013. Field wind tunnel testing of two silt loam soils on the North American Central High Plains. Aeolian Research. 10(1):53-59.
Acosta Martinez, V., Mikha, M.M., Sistani, K.R., Stahlman, F., Benjamin, J.G., Vigil, M.F., Erickson, R. 2011. Multi-location study of soil enzyme activities as affected by different manure types, rates, and tillage application practices. Agriculture. 1(1): 4-21.
-(Peer Reviewed Journal)
Aguilar, J.P., Evans, R.G., Vigil, M.F., Daughtry, C.S. 2012. Spectral estimates of crop residue cover and density for standing and flat wheat stubble. Agronomy Journal. 104:271-279.
Van Pelt, R.S., Baddock, M., Zobeck, T.M., Schlegel, A., Vigil, M.F. 2011. Field Wind Tunnel Testing of Two Silt Loam Soils in the North American Central High Plains[abstract]. American Society of Agronomy, Crop Science Society of America,Soil Science Society of America Annual Meeting. October 16-19, 2011, San Antonio, Texas.
Acosta Martinez, V., Mikha, M.M., Sistani, K.R., Stahlman, P.W., Benjamin, J.G., Vigil, M.F., Erickson, R. 2011. Soil enzyme activities as affected by manure types, rates and tillage practices[abstract]. American Society of Agronomy, Crop Science Society of America, Soil Science Society of America Annual Meeting. October 16-19, 2011, San Antonio, Texas.
Van Pelt, R.S., Baddock, M., Zobeck, T.M., Acosta Martinez, V., Vigil, M.F., Schlegel, A. 2011. Field Wind Tunnel Testing of Two Silt Loam Soils on the North American Central High Plains[abstract]. International Symposium on Erosion and Landscape Evolution. September 18-21, 2011, Anchorage, Alaska.
Calderon, F.J., Vigil, M.F., Nielsen, D.C., Benjamin, J.G., Poss, D.J. 2012. Water use and yields of no-till managed dryland grasspea and yellow pea under different planting configurations. Field Crops Research. 125:179-185.
Calderon, F.J., Mikha, M.M., Vigil, M.F., Nielsen, D.C., Benjamin, J.G., Reeves III, J.B. 2012. Diffuse-reflectance mid-infrared spectral properties of soils under alternative crop rotations in a semiarid climate. Communications in Soil Science and Plant Analysis. 42:17, 2143-2159.
Nielsen, D.C., Vigil, M.F., Benjamin, J.G. 2011. Evaluating decision rules for dryland rotation crop selection. Field Crops Research. 120:254-261.
Calderon, F.J., Reeves III, J.B., Vigil, M.F. 2010. Mid-Infrared Spectroscopic Properties of Humic Acid and Fulvic Acid-Soil Mixtures.. Meeting Proceedings. 15th Annual Meeting of the International Humic Substances Society, June 27-July 2, 2010. Tenerife, Spain.
Saseendran, S.A., D.C. Nielsen, Liwang Ma, L.R. Ahuja, M.F. Vigil, 2010. Simulating Alternative Dryland Rotational Cropping Systems in the Central Great Plains with RZWQM2. Agronomy Journal. 102:1521-1534. doi:10.2134/agronj2010.0141.
Nielsen, D.C., Halvorson, A.D., Vigil, M.F. 2010. Critical Precipitation Period for Dryland Maize Production. Field Crops Research 118:259-263. doi:10.1016/j.fcr.2010.06.004
Calderon, F.J., Reeves Iii, J.B., Vigil, M.F. 2010. Mid-Infrared Spectroscopic Properties of Humic Acid and Fulvic Acid-Soil Mixtures. Meeting Abstract. Presented at the 15th International Humic Substances Society Meeting. June 27 to July 2, 2010. Pto. De la Cruz, Tenerife, Spain.
Humberto, B., Stone, L.R., Schlegel, A.J., Benjamin, J.G., Vigil, M.F., Stahlman, P.W. 2010. Continuous Cropping Systems Reduce Near-Surface Maximum Compaction in No-Till Soils. Agronomy Journal. 102:1217-1225. DOI:10.2134/agronj2010.0113.
Mikha, M.M., Benjamin, J.G., Vigil, M.F., Nielsen, D.C. 2010. Cropping Intensity Impacts on Soil Aggregation and Carbon Sequestration in the Central Great Plains. Soil Science Society of America Journal. 74(5):1712-1719. doi:10.2136/sssaj2009.0335.
Vigil, M.F., Poss, D.J., Nielsen, D.C., Benjamin, J.G. 2010. Rainfall probability and EONR for dryland corn in Colorado. [Agronomy Abstract]Presented at the annual ASA/CSSA/SSSA meetings. Oct. 31 thru Nov. 5, 2010. Long Beach, CA.
Nielsen, D.C., A.D. Halvorson, M.F. Vigil. 2010. Critical Precipitation Period for Dryland Corn Production. Agronomy Abstracts. Presented at the 2010 (ASA-CSSA-SSSA) meetings. Oct. 31 thru Nov. 3, 2010. Long Beach, CA.
Vigil, M.F., Poss, D.J., Halvorson, A.D. 2010. Nitrogen Rates for Dryland Triticale Hay. Great Plains Soil Fertility Conference. Pages 189-194. March 2-3, 2010. Denver, CO.
Mikha, M.M., Stahlman, P.W., Benjamin, J.G., Vigil, M.F., Geier, P.W., Poss, D.J. 2010. Remediation/Restoration of Degraded Soil to Improve Productivity In The Central Great Plains Region. Proceedings of the Great Plains Soil Fertility Conference. Pages 229-235. March 2-3, 2010. Denver, CO.
Nielsen, D.C., Vigil, M.F. 2010. Precipitation Storage Efficiency During Fallow in Wheat-Fallow Systems. Agronomy Journal. v.102(2)537-543.
Vigil, M.F., Nielsen, D.C., Benjamin, J.G., Calderon, F.J., Mikha, M.M. 2009. Alternative Dryland Cropping Systems to Wheat Fallow. Agronomy Abstracts. Presented at the ASA-CSSA-SSSA Annual meeting. Nov. 1-5, 2009. Pittsburg, PA.
Calderon, F.J., Reeves III, J.B., Vigil, M.F., Poss, D.J. 2009. Mid-Infrared and Near Infrared Calibrations for Nutritional Parameters of Triticale (Triticosecale) and Pea (Pisum sativum). Journal of Agriculture and Food Chemistry. 57:5136-5142. doi:10.1021/jf803936x.
Calderon, F.J., Schneekloth, J., Nielsen, D.C., Vigil, M.F. 2009. Sunflower Production in Skip Row Configurations for the Semi-Arid Central Plains. Meeting Proceedings. Presented at the National Sunflower Association Research Forum. Jan. 12-15, 2009. Fargo, ND. Pages 1-4.
Calderon, F.J., Hanson, L.E., Panella, L.W., Reeves III, J.B., Vigil, M.F. 2009. Mid-Infrared and Near-Infrared Spectroscopic Properties of Fusarium Isolates: Effects of Culture Conditions. Meeting proceedings poster presentation at the American Phytopathological Society Annual Meeting. Aug. 1-5, 2009. Portland, OR.
Calderon, F.J., Acosta Martinez, V., Douds, D.D., Reeves III, J.B., Vigil, M.F. 2009. Mid-Infrared and Near Infrared Spectral Properties of Mycorrhizal and Non-Mycorrhizal Root Cultures. Journal of Applied Spectroscopy. 63(5)494-500.
Blanco-Cangui, H., Mikha, M.M., Benjamin, J.G., Stone, L.R., Schlegel, A.J., Lyon, D.J., Vigil, M.F., Stahlman, P.W. 2009. Regional Study of No-Till Impacts on Near-Surface Aggregate Properties that Influence Soil Erodibility. Soil Science Society of America Journal 73:1361-1368.
Blanco, H., M.M. Mikha, J.G. Benjamin, L.R. Stone, A.J. Schlegel, D.J. Lyon, M.F. Vigil, and P.W. Stahlman. 2009. No-Till Management Effects on Soil Water and Wind Erodibility Parameters. 2009 Kansas Fertilizer Research Extension Report. Pages 100-105.
Nielsen, D.C., Vigil, M.F., Benjamin, J.G. 2009. Precipitation Storage Efficiency During Fallow in Wheat-Fallow Systems. Agronomy Abstracts. Presented at the ASA-CSSA-SSSA annual meetings. Nov. 1-5, 2009. Pittsburg, PA.
Mikha, M.M., Benjamin, J.G., Stahlman, P.W., Vigil, M.F. 2009. Restoration of Degraded/Eroded Soil under Different Management Practices in the Central Great Plains. Agronomy Abstracts. Presented at the ASA-CSSA-SSSA annual meetings. Nov. 1-5, 2009. Pittsburg, PA.
Lyon, D.J., Pavlista, A.D., Hergert, G.W., Klein, R.N., Shapiro, C.A., Knezevic, S., Mason, S.C., Nelson, L.A., Baltensperger, D.D., Elmore, R.W., Vigil, M.F., Schlegel, A.J., Olson, B.L., Aiken, R.M. 2009. Skip-row Planting Patterns Stabilize Corn Grain Yields in the Central Great Plains. Crop Management. doi:10.1094/CM-2009-0224-02-RS.
Nielsen, D.C., Vigil, M.F., Benjamin, J.G. 2008. The Variable Response of Dryland Corn Yield to Soil Water Content. Agricultural Water Management 96:330-336.
Plante, A.F., Magrini-Bair, K., Vigil, M.F., Eldor, P. 2008. Pyrolysis-Molecular Beam Mass Spectrometry to Characterize Soil Organic Matter Composition in Chemically Isolated Fractions from Differing Land Uses. Biogeochemistry. DOI 10.1007/s10533-008-9218-3.
Mikha, M.M., Vigil, M.F., Calderon, F.J. 2008. Gas Flux in Tillage Field That Have Been in No-Tillage for 12 Years. Agronomy Abstract. Presented at the International American Society of Agronomy meetings, Crop Science Society of America and Soil Science Society of America (ASA/CSSA/SSSA) annual meetings. Oct. 5-9, 2008. Houston, TX.
Francis, D.D., Vigil, M.F., Moiser, A.R. 2008. Gaseous Losses of Nitrogen Other Than Through Denitrification [abstract] . ASA-SCCA-SSSA Annual Meeting, October 5-9, 2008, Houston, Texas. 2008 CDROM. Abstract No. 749.5.
Lyon, D.J., Burgener, P.A., Deboer, K., Harveson, R.M., Hein, G.L., Hergert, G.W., Krall, J.M., Nielsen, D.C., Vigil, M.F. 2008. Producing and Marketing Proso Millet in the Great Plains. University of Nebraska Extension Circular #EC137. Lincoln, NE.
Vigil, M.F., Nielsen, D.C., Poss, D.J. 2008. Economic Optimum N Rates for Fertilizing Winter Wheat and Corn. Agronomy Abstract. Presented at the International American Society of Agronomy meetings, Crop Science Society of America and Soil Science Society of America (ASA/CSSA/SSSA) annual meetings. Oct. 5-9, 2008. Houston, TX.
Pikul Jr, J.L., Johnson, J.M., Schumacher, T., Vigil, M.F., Riedell, W.E. 2008. Change in Surface Soil Carbon Under Rotated Corn in Eastern South Dakota. Soil Science Society of America Journal. 72:1738-1744.
Nielsen, D.C., Henry, W.B., Vigil, M.F., Calderon, F.J., West, M.S. 2008. Proso Millet Yield and Residue Mass Following Direct Harvest with a Stripper-header. Agronomy Abstract. Presented at the International American Society of Agronomy meetings, Crop Science Society of America and Soil Science Society of America (ASA/CSSA/SSSA) annual meetings. Oct. 5-9, 2008. Houston, TX.
Vigil, M.F., Mikha, M.M., Nielsen, D.C., Benjamin, J.G., Calderon, F.J. 2008. Alternative Crop Rotations in the Semi-arid Central Great Plains Region: How Much Fallow? Evaluating the Economics. Meeting Proceedings. Presented at the XXI Congreso Argentino de la Ciencia Del Suelo. 13 al 16 de Mayo de 2008. Potrero de los Funes (San Luis) Argentina. Page 524.
Benjamin, J.G., Mikha, M.M., Vigil, M.F. 2008. Organic Carbon Effects on Soil Physical and Hydraulic Properties in a Semi-arid Climate. Soil Science Society of America Journal. 72:1357-1362. doi:10.2136/sssaj2007.0389.
Mikha, M.M., Benjamin, J.G., Vigil, M.F. 2008. Long-Term Tillage Affects on Soil Aggregation and Carbon Sequestration. Meeting Abstract. Presented at the Colorado Conservation Tillage meeting. Feb. 5-6, 2008. Greeley, Colo.
Vigil, M.F., Poss, D.J. 2008. Managing N Rates for Reduce-till Dryland Wheat. Meeting Proceedings. Proceedings of the 5th Annual Cover Your Acres Winter Conference. Pages 7-11. Oberlin, KS. January 22-23, 2008.
Mikha, M.M., Vigil, M.F., Benjamin, J.G., Poss, D.J., Calderon, F.J. 2008. Best Management Practices for Remediation/Restoration of Degraded Soils in the Central Great Plains Region. Meeting Proceedings of the 18th High Altitude Revegetation Workshop #18. Information Series #105. Pages 461-470. March 4-6, 2008. Fort Collins, Colo.
Vigil, M.F., Henry, W.B., Calderon, F.J., Poss, D.J., Nielsen, D.C., Benjamin, J.G., Klein, R. 2008. A use of Skip-row Planting as a Strategy for Drought Mitigation in the West Central Great Plains. Meeting Proceedings. Presented at the 2008 Great Plains Soil Fertility Conference. Denver, Colo. March 5, 2008. Vol. 12:101-106.
Henry, W.B., Nielsen, D.C., Vigil, M.F., Calderon, F.J., West, M.S. 2008. Proso millet yield and residue mass following direct harvest with a stripper-header. Agronomy Journal. 100:580-584.
Henry, W.B., Nielsen, D.C., Vigil, M.F., Calderon, F.J., West, M.S. 2008. Proso Millet Yield and Residue Mass following Direct Harvest with a Stripper-Header. Agronomy Journal 100:580-584.
Calderon, F.J., Vigil, M.F., Nielsen, D.C., Benjamin, J.G., Mikha, M.M. 2008. A comparison of Dryland Grasspea (lathyrus sativus l.) and Admiral Pea (pisum sativum l.) Grown Under Different Row Spacings. Meeting Proceedings. Presented at the 2008 Great Plains Soil Fertility Conference. Denver, Colo. March 5, 2008. Vol. 12:107-111.
Mikha, M.M., Benjamin, J.G., Vigil, M.F. 2007. Soil Aggregation and Carbon Sequestration as affected by Long-Term Tillage Practices. Agronomy Abstracts. Presented at the International American Society of Agronomy Meetings, Crop Science Society of America and Soil Science Society of America (ASA/CSSA/SSSA) annual meetings. Nov. 5-9, 2007. New Orleans, LA.
Calderon, F.J., Reeves III, J.B., Foster, J.G., Clapham, W.M., Fedders, J.M., Vigil, M.F., Henry, W.B. 2007. Comparison of Diffuse Reflectance Fourier Transform Mid-Infrared and Near-Infrared Spectroscopy with Grating-Based Near-Infrared for the Determination of Fatty Acids in Forages. Journal of Agricultural and Food Chemistry 55:8302-8309.
Vigil, M.F., Nielsen, D.C., Poss, D.J., Henry, W.B. 2007. Skip-row Corn and Sorghum in the West Central Great Plains. Agronomy Abstracts. Presented at the International American Society of Agronomy meetings, Crop Science Society of America and Soil Science Society of america (ASA/CSSA/SSSA) annual meetings. Nov. 5-9, 2007. New Orleans, LA.
Pikul Jr, J.L., Schumacher, T.E., Vigil, M.F., Riedell, W.E. Changes in Soil Organic Carbon of Crop Rotations in the Northern Corn Belt. In Annual Meetings Abstracts (CD-ROM). ASA, CSSA, SSSA, Madison, WI. 2007.
Cabrera, M., Molina, J.A., Vigil, M.F. 2008. Modeling of the N Cycle. Book Chapter In Nitrogen in Agricultural Systems. 18:695-730. American Society of Agronomy, Inc. Madison, WI.
Calderon, F.J., Reeves Iii, J.B., Foster, J.G., Clapham, W.M., Fedders, J.M., Vigil, M.F., Henry, W.B. 2007. Diffuse Reflectance Fourier Transform Mid-Infrared Spectral Properties of Forages with Varied Fatty Acid Content. Meeting Abstract. Presented at the 2007 National Federation of Analytical Chemistry and Spectroscopy Societies annual meeting. Oct. 14-18, 2007. Memphis, TN.
Nielsen, D.C., Vigil, M.F., Calderon, F.J., Schneekloth, J., Poss, D.J., Henry, W.B., Benjamin, J.G. 2007. Soil Water Extraction Patterns in Skip Row Corn, Sorghum, and Sunflower. Meeting Abstract. Presented at the National American Society of Agronomy Annual Meeting. Nov. 5-8, 2007. New Orleans, LA.
Vigil, M.F. 2007. Alternative No-till Rotations and Drought Mitigation Research in the Central Great Plains Region. Meeting Abstract. Annual Soil and Water Conservation Society Conference. July 24-26, 2007. Tampa, FL.
Nielsen, D.C., Greb, B.W., Vigil, M.F., Mickelsen, R.H. 2007. History of the Central Great Plains Research Station. Agricultural Research Service Publication. Pgs. 1-55.
Calderon, F.J., Reeves Iii, J.B., Foster, J.G., Clapham, W.M., Fedders, J.M., Vigil, M.F., Henry, W.B. 2007. Diffuse Reflectance Fourier Transform Mid-infrared Spectral Properties of Forages with Varied Fatty Acid Content. Meeting Abstract. Presented at the Federation of Analytical Chemistry and Spectroscopy Societies Conference. October 14-18, 2007. Memphis, TN.
Palic, D.B., Dunn, G.H., Vigil, M.F., Burgener, P.A. 2007. Fine Tuning Your Lease. No Till Farmer. Volume 36, No. 7, pp14-15, July 2007.
Acosta Martinez, V., Mikha, M.M., Vigil, M.F. 2007. Microbial communities and enzyme activities in soils under alternative crop rotations compared to wheat-fallow for the Central Great Plains. Applied Soil Ecology. 37:41-52.
Benjamin, J.G., Mikha, M.M., Nielsen, D.C., Vigil, M.F., Calderon, F.J., Henry, W.B. 2007. Cropping Intensity Effects on Physical Properties of a No-till Silt Loam Soil. Soil Science Society of America Journal 71:1160-1165.
Vigil, M.F. 2007. Optimal Nitrogen Fertilization of Dryland Wheat. Meeting Proceedings. Research Update 2007. Presented at the High Plains Ag Lab, Feb. 15, 2007. Sidney, Nebr. Pages 20-23.
Henry, W.B., Nielsen, D.C., Foster, J.G., Calderon, F.J., Vigil, M.F. 2007. Weed control possibilities and harvest strategies for the Omega-3 fatty acid producing crop common purslane (Portulacca oleracea var. sativa) [abstract]. Proceedings 2007 Weed Science Society of America Annual Meeting. p. 56.
Mikha, M.M., Acosta Martinez, V., Vigil, M.F. 2007. Soil Carbon and Enzyme Activities as affected by Cropping Intensity and Tillage. Meeting Abstract.
Vigil, M.F., Henry, W.B., Klein, B. 2007. Skip-row Planting: A Strategy for Stabilizing Dryland Corn/Sorghum Yields. Proceedings of the Colorado Conservation Tillage Association and National Sunflower Association 19th High Plains No-Till Conference. January 30-31, 2007. Island Grove Regional Park. Greeley, Colo. Pages
Mikha, M.M., Acosta Martinez, V., Vigil, M.F. 2006. Soil Aggregation and Enzyme Activities as affected by Management Practices. Agronomy Abstracts. Presented at the International American Society of Agronomy Meetings/Soil Science Society of America (ASA/CSSA/SSSA) Annual Meetings. November 12-16, 2006. Indianapolis, IN.
Vigil, M.F., Henry, W.B., Nielsen, D.C., Calderon, F.J., Benjamin, J.G., Klien, R. 2006. Skip-Row Planting as a Drought Avoidance Strategy in the West Central Great Plains. Agronomy Abstracts. Presented at the National American Society of Agronomy Meetings/Soil Science Society of America (ASA/SSSA)Annual Meetings. November 13-16, 2006. Indianapolis, IN.
Vigil, M.F., Henry, W.B., Poss, D.J., Nielsen, D.C., Calderon, F.J., Benjamin, J.G., Klein, R. 2006. Skip-row Planting in the CGPR as a Drought Mitigation Strategy. Meeting Abstract. Presented at the 18th World Congress of Soil Science in Phildelphia, PA July 9-13, 2006.
Nielsen, D.C., Vigil, M.F., Benjamin, J.G. 2006. Evaluating Decision Rules for Dryland Crop Selection. Agronomy Abstracts. Presented at the International American Society of Agronomy Meetings/Soil Science Society of America (ASA/CSSA/SSSA) Annual Meetings. November 12-16, 2006. Indianapolis, IN.
Nielsen, D.C., Vigil, M.F., Benjamin, J.G. 2006. Forage yield response to water use for dryland corn, millet, and triticale in the Central Great Plains. Agronomy Journal. 98:992-998.
Henry, W.B., Vigil, M.F., Nielsen, D.C. 2006. Proso Millet Harvest: A Comparison of Conventional Harvest and Direct Harvest with a Stripper Header. Conservation Tillage Fact Sheet.
Mikha, M.M., Acosta Martinez, V., Vigil, M.F. 2006. Cropping intensity and tillage affects on carbon sequestration and enzyme activities. Meeting of the 18th World Congress of Soil Science. July 9-15, 2006. Philadelphia, Pennsylvania.
Varvel, G.E., Riedell, W.E., Deibert, E., Mcconkey, B., Tanaka, D.L., Vigil, M.F., Schwartz, R.C. 2006. Great plains cropping system studies for soil quality assessment. Renewable Agriculture and Food System 21:3-14.
Mikha, M.M., Vigil, M.F., Benjamin, J.G., Nielsen, D.C., Henry, W.B., Calderon, F.J. 2005. Carbon sequestration and aggregate size distribution as affected by cropping intensity. Agronomy Abstract. Presented at the 2005 ASA, CSSA-SSSA International Annual Meeting. Nov. 6-10, 2005. Salt Lake City, UT.
Vigil, M.F., Nielsen, D.C., Henry, W.B., Benjamin, J.G., Mikha, M.M., Calderon, F.J. 2005. How much fallow: Evaluating the economics of alternative rotations at Akron, Colorado. Agronomy Abstract. Presented at the 2005 ASA,CSSA-SSSA International Annual Meeting. Nov. 6-10, 2005. Salt Lake City, UT
Nielsen, D.C., Vigil, M.F., Benjamin, J.G. 2005. The variable response of dryland corn yield to soil water at planting. Agronomy Abstracts. Presented at the 2005 ASA, CSSA-SSSA International Annual Meeting. Nov. 6-10, 2005. Salt Lake City, UT.
Mikha, M.M., Vigil, M.F., Liebig, M.A., Bowman, R.A., Mcconkey, B., Deibert, E., Pikul Jr, J.L. 2006. Cropping system influences on soil chemical properties and soil quality in the Great Plains. Renewable Agriculture and Food System. 21(1); 26-35. Online DOI:10.1079/RAF2005123.
Mikha, M.M., Vigil, M.F. 2005. Soil carbon and nitrogen in dryland cropping systems. Meeting Abstract. Third USDA Symposium on Greenhouse Gases & Carbon Sequestration in Agriculture and Forestry. March 21-24, 2005. Baltimore, Maryland. p. 175.
Saseendran, S.A., Nielsen, D.C., Ma, L., Ahuja, L.R., Vigil, M.F., Benjamin, J.G., Halvorson, A.D. 2005. Effectiveness of RZWQM for simulating alternative Great Plains cropping systems. Agronomy Journal 97:1183-1193.
Anapalli, S.A., Nielsen, D.C., Ma, L., Ahuja, L.R., Vigil, M.F., Benjamin, J.G., Halvorson, A.D. 2005. Effectiveness of RZWQM for simulating alternative great plains cropping systems. Proceedings from the 35th Biological Systems Simulation Conference. April 19-21, 2005. Phoenix, AZ. P. 37-38.
Vigil, M.F., Lamond, R., Meyer, R. 2005. Nutrient management. High Plains Sunflower Production Handbook. P. 4-6.
Lyon, D., Vigil, M.F., Nielsen, D.C. 2005. Crop rotations and residue management. High Plains Sunflower Production Handbook. P. 35-37.
Nielsen, D.C., Vigil, M.F. 2005. Legume green fallow effect on soil water content at wheat planting and wheat yield. Agronomy Journal. 97:684-689.
Vigil, M.F., Nielsen, D.C., Benjamin, J.G., Henry, W.B., Mikha, M.M., Calderon, F.J., Anderson, R.L., Bowman, R.A. 2005. Changes in soil after 14 years of no-till alternative crop rotation research. Proceedings of the 17th Annual Winter Conference, Colorado Conservation Tillage Association in cooperation with National Sunflower Association presents The High Plains No-Till Conference. Feb. 1-2. 2005. Island Grove Park, Greeley, CO. P. L1-L6.
Saseendran, S.A., Ma, L., Nielsen, D.C., Vigil, M.F., Ahuja, L.R. 2005. Simulating planting date effects on corn production using RZWQM and CERES-Maize Models. Agronomy Journal. 97:58-71 (2005).
Cabrera, M.L., Kissel, D.E., Vigil, M.F. 2005. Nitrogen mineralization from organic residues: research opportunities. Environmental Quality. v34:75-79.
Vigil, M.F., Nielsen, D.C., Henry, W.B., Benjamin, J.G., Mikha, M.M., Anderson, R.L. 2004. Evaluating the rotation effect in alternative rotations at Akron, Colorado. Agronomy Abstracts. Presented at the ASA-CSSA-SSSA 2004 Annual Meetings. Oct. 31-Nov. 4, 2004. Seattle, WA.
Henry, W.B., Nielsen, D.C., Vigil, M.F. 2004. The effect of alternative harvest strategies on residue in the central Great Plains. Agronomy Abstracts. Presented at the 2004 ASA-CSSA-SSSA International Annual Meeting. Oct. 31-Nov. 4, 2004. Seattle, WA
Benjamin, J.G., Nielsen, D.C., Vigil, M.F., Mikha, M.M., Henry, W.B. 2004. Crop rotation and tillage effects on soil hydraulic properties. Agronomy Abstracts. Presented at the International ASA-CSSA-SSSA Annual Meeting. Oct. 31-Nov. 4, 2004. Seattle, WA.
Nielsen, D.C., Halvorson, A.D., Vigil, M.F., Byrne, P.F. 2004. Predicting winter wheat yield from temperature and rainfall. Agronomy Abstracts. Presented at the 2004 ASA-CSSA-SSSA International Annual Meeting. Oct. 31-Nov. 4, 2004. Seattle, WA
Anapalli, S.S., Nielsen, D.C., Ma, L., Ahuja, L.R., Vigil, M.F., Benjamin, J.G. 2004. Modeling alternative cropping systems for central great plains using RZWQM. Proceedings of the International Workshop on Applications, Enhancements and Collaborations of ARS RZWQM and GPFARM Models. April 20-22, 2004. p.22-23.
Henry, W.B., Vigil, M.F., Nielsen, D.C., Benjamin, J.G., Anderson, R.L., Bowman, R.A. 2004. Cropping sequence in a long-term dryland rotation study. Meeting Abstract. Presented at the WSSA 2004 Annual Meeting, February 2004. Kansas City, MO.
Baltensperger, D.D., Frickel, G.E., Krall, J.M., Vigil, M.F., Hain, J., Johnson, J., Stymiest, C., Rickertsen, J.R. 2004. Registration of 'horizon' proso millet. Crop Science. v. 44 p. 688.
Mikha, M.M., Vigil, M.F., Liebig, M.A., Wienhold, B.J., Bowman, R.A., Mcconkey, B., Deibert, E., Pikul Jr, J.L. 2003. Great plains soil quality assessment project: soil chemical properties. Meeting Abstract. Presented at the Dynamic Cropping Systems Meeting Aug. 4-7, 2003. Bismarck, ND.
VARVEL, G.E., RIEDELL, W.E., TANAKA, D.L., VIGIL, M.F., SCHWARTZ, R.C., DEIBERT, E., MCCONKEY, B. 2003. GREAT PLAINS SOIL QUALITY ASSESSMENT PROJECT: LOCATIONS AND CROPPING SYSTEMS. AGRONOMY ABSTRACTS #872941.
Mikha, M.M., Vigil, M.F., Liebig, M.A., Wienhold, B.J., Bowman, R.A., Mcconkey, B., Deibert, E., Pikul Jr, J.L. 2004. Great plains soil quality assessment project: soil chemical properties. Agronomy Abstracts. Presented at the Annual American Society of Agronomy Meeting (ASA), November 2003. Denver, Colo.
Wienhold, B.J., Pikul Jr, J.L., Liebig, M.A., Vigil, M.F., Varvel, G.E., Doran, J.W., Andrews, S.S. 2003. Cropping system effects on soil quality in the Great Plains. Abstract 478851. ASA Abstracts. CDROM
Shanahan, J. F., Doerge, T.A., Johnson, J. J., and Vigil M.F. 2004. Feasibility of site-specific management of corn hybrids and plant densities in the Great Plains. Journal of Precision Agriculture 5:207-225.
WIENHOLD, B.J., PIKUL JR, J.L., LIEBIG, M.A., VIGIL, M.F., VARVEL, G.E., DORAN, J.W. CROPPING SYSTEM EFFECTS ON SOIL QUALITY IN THE GREAT PLAINS: SUMMARY FROM A REGIONAL PROJECT. Proceedings from Dynamic Cropping Systems: Prinicples, Processes, and Challenges. PP 215-219. 2003.
WESTFALL, D.G., VIGIL, M.F., PETERSON, G.A. MANAGING SOIL FERTILITY IN DIVERSE DRYLAND CROPPING SYSTEMS. Proceedings from Dynamic Cropping Systems: Prinicples, Processes, and Challenges. 2003. p. 29-36. Aug. 4-7, 2003, Bismarck, ND.
VARVEL, G.E., RIEDELL, W.E., DEIBERT, E., MCCONKEY, B., TANAKA, D.L., VIGIL, M.F., SCHWARTZ, R.C. ASSESSMENT OF CROPPING SYSTEM EFFECTS ON SOIL QUALITY IN THE GREAT PLAINS: INTRODUCTION. Proceedings from Dynamic Cropping Systems: Prinicples, Processes, and Challenges. pp. 197-204. 2003.
VIGIL, M.F., BENJAMIN, J.G. NITROGEN RESPONSE OF SUNFLOWERS IN A FOUR YEAR DRYLAND ROTATION. AGRONOMY ABSTRACTS. Presented at the National American Society of Agronomy Meeting, Oct. 2002. Indianapolis, IN.
DAVIS, J.G., VIGIL, M.F., JAKUBOWSKI, B.R., SMITH, G.M. IMPACT OF MANURE CHARACTERISTICS AND MANAGEMENT ON NITROGEN MINERALIZATION. WESTERN NUTRIENT MANAGEMENT CONFERENCE PROCEEDINGS. 2003. v. 5. p. 29-33.
Vigil, M.F. 2004. Fate and transformation of fertilizers in soils. Presented at the 15th Annual Winter Conference of the Colorado Conservation Tillage Association (The High Plains No-till Conference) Feb. 4-5, Greeley, Colorado. p. F1-F6.
NIELSEN, D.C., VIGIL, M.F. LEGUME GREEN FALLOW EFFECT ON SOIL WATER AT WHEAT PLANTING AND WHEAT YIELD. AGRONOMY ABSTRACTS. 2002.
DAVIS, J.G., IVERSEN, K.V., VIGIL, M.F. NUTRIENT VARIABILITY IN MANURES: IMPLICATIONS FOR SAMPLING AND REGIONAL DATABASE CREATION. JOURNAL OF SOIL AND WATER CONSERVATION. 2002. v. 57 p. 473-478.
VIGIL, M.F., EGHBALL, B., CABRERA, M.L., JAKUBOWSKI, B.R., DAVIS, J.G. ACCOUNTING FOR SEASONAL NITROGEN MINERALIZATION: A REVIEW. JOURNAL OF SOIL AND WATER CONSERVATION SOCIETY. 2002. v. 94. p. 464-469.
Shaffer, M.J., Bartling, P.N., Vigil, M.F., Mcmaster, G.S., Dunn, G.H., Ascough Ii, J.C., Ahuja, L.R. 2002. Gpfarm cycling of crop residues. American Society of Agronomy Meetings. Indianapolis, IN. November 10-14, 2002.
Francis, D.D., Vigil, M.F., Moiser, A.R. 2008. Gaseous losses of nitrogen other than through denitrification. In: J.S. Schepers and W.R. Raun, editors. Nitrogen in Agricultural Systems. Agronomy Monograph 49. Madison, WI: American Society of Agronomy. p. 255-279.
BENJAMIN, J.G., NIELSEN, D.C., VIGIL, M.F., BOWMAN, R.A. QUANTIFYING EFFECTS OF SOIL CONDITIONS ON PLANT GROWTH AND CROP PRODUCTION. GEODERMA. 2003. v. 116 p. 137-148.
NIELSEN, D.C., VIGIL, M.F., ANDERSON, R.L., BOWMAN, R.A., BENJAMIN, J.G., HALVORSON, A.D. INFLUENCE OF ROTATION ON PLANTING SOIL WATER CONTENT AND YIELD OF WINTER WHEAT. AGRONOMY JOURNAL. 2002. v. 94 p. 962-967.
BOWMAN, R.A., VIGIL, M.F. SOIL TESTING AND ANALYSES FOR DIFFERENT PHOSPHORUS POOLS. JOURNAL OF SOIL AND WATER CONSERVATION. 2002. v. 57. p. 479-485.
Pikul Jr, J.L., Schumacher, T.E., Vigil, M.F. 2002. Nitrogen use and carbon sequestered by corn rotations in the northern corn belt, usa. International Nitrogen Conference.
Pikul Jr, J.L., Schumacher, T.E., Vigil, M.F. 2002. Nitrogen use and carbon sequestered by corn rotations in the northern corn belt, U.S. Galloway, J., E. Cowling, J.W. Erisman, J. Wisniewski, C. Jordan. Editors. A.A. Balkema Publishers, Lisse, The Netherlands. Optimizing Nitrogen Management in Food and Energy Production and Environmental Protection, pp. 707-713.
Pikul Jr, J.L., Carpenter Boggs, L.A., Vigil, M.F., Schumacher, T.E., Lindstrom, M.J., Riedell, W.E. 2001. Crop yield and soil condition under ridge and chisel-plot tillage in the northern Corn Belt, USA. Soil & Tillage Research 60:21-33.