HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Laboski, C. A. M. Articles by Andraski, T. W. Search for Related Content PubMed Articles by Laboski, C. A. M. Articles by Andraski, T. W. Agricola Articles by Laboski, C. A. M. Articles by Andraski, T. W. Related Collections Nitrogen Maize Nutrient Cycling Nutrient Management Soil Analysis Soil Fertility and Productivity

Evaluation of the Illinois Soil Nitrogen Test in the North Central Region of the United States

^a Dep. Soil Sci., Univ. of Wisconsin-Madison, 1525 Observatory Dr., Madison, WI 53706
^b Dep. of Agronomy, 2104 Agronomy Hall, Iowa State Univ., Ames, IA 50011
^c Dep. of Agronomy, Univ. of Nebraska, 261 Plant Sci. Building, Lincoln, NE 68583
^d Dep. of Crop Sci., Univ. of Illinois at Urbana-Champaign, 1102 S. Goodwin Ave., Urbana, IL 61801
^e Univ. of Minnesota, Southern Research and Outreach Center, 35838 120th St., Waseca, MN 56093

View larger version (26K): [in this window] [in a new window]   Fig. 1. Relationship between Illinois soil nitrogen test (ISNT) at the 0- to 15-cm depth and economic optimum nitrogen rate (EONR) and nitrogen fertilizer response (NFR) for 96 sites. ***Statistically significant at the 0.001 probability level. Not statistically significant at the 0.05 probability level.

View larger version (21K): [in this window] [in a new window]   Fig. 2. Evaluation of the Illinois soil nitrogen test (ISNT) critical level (230 mg kg–1) published by Khan et al. (2001) using the relationship between INST at the 0- to 30-cm depth and relative yield (RY). TYPE A failures = ISNT > 230 mg kg–1 and RY <90%. TYPE B failures = ISNT 230 mg kg–1 and RY 90%.

View larger version (19K): [in this window] [in a new window]   Fig. 3. Relationship between corn nitrogen fertilizer response (NFR) and relative nitrogen uptake (RUN) for 49 sites. ***Statistically significant at the 0.001 probability level.

View larger version (18K): [in this window] [in a new window]   Fig. 4. Relationship between relative nitrogen uptake (RUN) and Illinois soil nitorgen test (ISNT) for 49 sites. Not statistically significant at the 0.05 probability level.

View larger version (30K): [in this window] [in a new window]   Fig. 5. Relationship between Illinois soil nitrogen test (ISNT) and total soil nitrogen (TN) for 0- to 15-cm depth samples. NC-218 data are from the present study. Other data were published by Khan et al. (2001) and Klapwyk and Ketterings (2005). **Statistically significant at the 0.001 probability level.