P. A. Lawlor

发表

Impact of Fertilizer Application Timing on Drainage Nitrate Levels

M. Helmers, C. Pederson, R. Christianson, 2009 .

Nitrogen Application Rate Effect on Nitrate-Nitrogen Concentration and Loss in Subsurface Drainage for a Corn-Soybean Rotation

Matthew J. Helmers, James L. Baker, Stewart W. Melvin, 2008 .

Nitrogen Application Rate Effects on Corn Yield and Nitrate-Nitrogen Concentration and Loss in Subsurface Drainage

M. Helmers, J. Baker, S. Melvin, 2005 .

Nitrification Inhibitor and Nitrogen Application Timing Effects on Yields and Nitrate-Nitrogen Concentrations in Subsurface Drainage from a Corn-Soybean Rotation

M. Helmers, P. Lawlor, J. Baker, 2004 .

Comparison of Nitrate-Nitrogen in Subsurface Drainage from Continuous Corn and Corn-soybean Rotation

M. Helmers, P. A. Lawlor, 2007 .

Comparison of Liquid Swine Manure and Aqua-Ammonia Nitrogen Application Timing on Subsurface Drainage Water Quality in Iowa

Matthew J. Helmers, James L. Baker, Stewart W. Melvin, 2011 .

Temporal Subsurface Flow Patterns from Fifteen Years in North-Central Iowa

Matthew J. Helmers, James L. Baker, Stewart W. Melvin, 2005 .

Conservation Systems: Effects of Manure Application on Drainage Water Quality

M. Helmers, P. A. Lawlor, 2005 .