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Tesfahunegn, G.B. and C.S. Wortmann*. 2008. Tie-Ridge Tillage for High Altitude Pulse Production in Northern Ethiopia. Agron. J. 100(2):447-453. [Full Paper]

Garcia, J.P., C.S. Wortmann*, M. Mamo, R.A. Drijber, J.A. Quincke, and D. Tarkalson. 2007. One-time tillage of no-till: effects on nutrients, mycorrhizae, and phosphorus uptake. Agron. J. 99:1093-1103. [Full Paper]

Quincke, J.A., C.S. Wortmann*, M. Mamo, T. Franti, and R.A. Drijber. 2006. Occasional tillage of no-till systems: carbon dioxide flux and changes in total and labile soil organic carbon. Agron. J. 99:1158-1168. [Full Paper]

Quincke, J.A., C.S. Wortmann*, M. Mamo, T.G. Frani, R.A. Drijber, and J.P. Garcia. 2006. One-time tillage of no-till systems: soil physical properties, phosphorus runoff, and crop yield. Agron. J. 99:1104-1110. [Full Paper]

Brhane, G., C.S. Wortmann, M. Mamo, H. Gebrekidan, and A. Belay. 2006. Micro-basin tillage for grain sorghum production in semi-arid areas of northern Ethiopia. Agronomy Journal 98:124-128. [Full Paper]

Wortmann, C.S and S.C. Brubaker, 2004. Soil aggregation: a practical exercise for crop producer education. J. Extension 42(6) (http://www.joe.org/joe/2004december/tt7.shtml [Full Paper]).

Wilhelm, W. and C.S. Wortmann, 2004. Tillage and Rotation Interactions for Corn and Soybean Grain Yield as Affected by Precipitation and Air Temperature. Agronomy Journal 96:425-432. [Full Paper]

Charles A. Shapiro, David L. Holshouserb, William L. Kranzc, David P. Sheltonc, John F. Witkowskic, Keith J. Jarvic, Gerald W. Echtenkampa, Lisa A. Lunza, Robert D. Frerichsa, Ray L. Brentlingera, Mari A. Lubberstedta, Melinda McVey McCluskeyd and Walter W. Stroupe. Tillage and Management Alternatives for Returning Conservation Reserve Program Land to Crops. 2001. Agron J. 93:850-862 [Abstract]