REFERENCES
- Arnall , D. B. , Raun , W. R. , Solie , J. B. , Stone , M. L. , Johnson , G. V. , Girma , K. , Freeman , K. W. , Teal , R. K. and Martin , K. L. 2006 . Relationship between coefficient of variation measured by spectral reflectance and plant density at early growth stages . Journal of Plant Nutrition , 29 : 1983 – 1997 .
- Hodgen , P. J. , Raun , W. R. , Johnson , G. V. , Teal , R. K. , Freeman , K. W. , Brixey , K. B. , Martin , K. L. , Solie , J. B. and Stone , M. L. 2005 . Relationship between response indices measured in-season and at harvest in winter wheat . Journal of Plant Nutrition , 28 : 221 – 235 .
- Johnson , G. V. and Raun , W. R. 2003 . Nitrogen response index as a guide to fertilizer management . Journal of Plant Nutrition , 26 : 249 – 262 .
- Large , E. C. 1954 . Growth stages in cereals illustration of the Feekes Scale . Journal of Plant Pathology , 3 : 128 – 129 .
- Lukina , E. V. , Freeman , K. W. , Wynn , K. J. , Thomason , W. E. , Mullen , R. W. , Stone , M. L. , Solie , J. B. , Klatt , A. R. , Johnson , G. V. , Elliott , R. L. and Raun , W. R. 2001 . Nitrogen fertilization optimization algorithm based on in-season estimates of yield and plant nitrogen uptake . Journal of Plant Nutrition , 24 : 885 – 898 .
- Lukina , E. V. , Raun , W. R. , Stone , M. L. , Solie , J. B. , Johnson , G. V. , Lees , H. L. , LaRuffa , J. M. and Phillips , S. B. 2000 . Effect of row spacing, growth stage, and nitrogen rate on spectral irradiance in winter wheat . Journal of Plant Nutrition , 23 : 103 – 122 .
- Morris , K. B. , Martin , K. L. , Freeman , K. W. , Teal , R. K. , Girma , K. , Arnall , D. B. , Hodgen , P. J. , Mosali , J. , Raun , W. R. and Solie , J. B. 2006 . Mid-season recovery from nitrogen stress in winter wheat . Journal of Plant Nutrition , 29 : 727 – 745 .
- Mullen , R. W. , Freeman , K. W. , Raun , W. R. , Johnson , G. V. , Stone , M. L. and Solie , J. B. 2003 . Identifying an in-season response index and the potential to increase wheat yield with nitrogen . Agronomy Journal , 95 : 347 – 351 .
- Nielsen , R. L. 2001 . “ Stand Establishing Variability in Corn ” . West Lafayette , IN : Purdue University Department of Agronomy . #AGRY-91-01
- Raun , W. R. , Solie , J. B. , Johnson , G. V. , Stone , M. L. , Lukina , E. V. , Thomason , W. E. and Schepers , J. S. 2001 . In-season prediction of potential grain yield in winter wheat using canopy reflectance . Agronomy Journal , 93 : 131 – 138 .
- Raun , W. R. , Solie , J. B. , Johnson , G. V. , Stone , M. L. , Mullen , R. W. , Freeman , K. W. , Thomason , W. E. and Lukina , E. V. 2002 . Improving nitrogen use efficiency in cereal grain production with optical sensing and variable rate application . Agronomy Journal , 94 : 815 – 820 .
- Raun , W. R. , Solie , J. B. , Stone , M. L. , Martin , K. L. , Freeman , K. W. , Mullen , R. W. , Zhang , H. , Schepers , J. S. and Johnson , G. V. 2005 . Optical sensor-based algorithm for crop nitrogen fertilization . Communications of Soil Science and Plant Analysis , 36 : 2759 – 2781 .
- Schepers , J. S. , Francis , D. D. and Thompson , M. T. 1989 . Simultaneous determination of total C, total N, and 15N on soil and plant material . Communications of Soil Science and Plant Analysis , 20 : 949 – 959. .
- Teal , R. K. , Tubana , B. , Girma , K. , Freeman , K. W. , Arnall , D. B. , Walsh , O. and Raun , W. R. 2006 . In-season prediction of corn grain yield potential using normalized difference vegetation index . Agronomy Journal , 98 : 1488 – 1494 .
- Washmon , C. N. , Solie , J. B. , Raun , W. R. and Itenfisu , D. D. 2002 . Within field variability in wheat grain yields over nine years in Oklahoma . Journal of Plant Nutrition , 25 : 2655 – 2662 .
- Weisz , R. , Weisz , R. , Crozier , C. R. and Heiniger , R. W. 2001 . Optimizing nitrogen application timing in no-till soft red winter wheat . Agronomy Journal , 93 : 435 – 442 .