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

This Article Figures Only Full Text Full Text (PDF) 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 Google Scholar Articles by Ziadi, N. Articles by Tremblay, N. PubMed Articles by Ziadi, N. Articles by Tremblay, N. Agricola Articles by Ziadi, N. Articles by Tremblay, N. Related Collections Nitrogen Remote Sensing Nutrient Management

CORN

Leaf Nitrogen Concentration as an Indicator of Corn Nitrogen Status

^a Agriculture and Agri-Food Canada (AAFC), Soils and Crops Research and Development Centre, 2560 Hochelaga Blvd., Québec, QC, Canada G1V 2J3
^b AAFC, 430 Gouin Blvd., St-Jean-sur-Richelieu, QC, Canada J3B 3E6
^c INRA, Unité de Recherche Pluridisciplinaire Prairies et Plantes Fourragères, BP 6, 86600 Lusignan, France

^* Corresponding author (noura.ziadi{at}agr.gc.ca).

Plant-based measurements can be used to diagnose the in-season N status of corn (Zea mays L.). Our objective was to assess the relationship between the corn nitrogen nutrition index (NNI), an index based on whole plant N concentration, and leaf nitrogen concentration of the uppermost collared leaf expressed on the basis of dry matter (DM; N_L) or area (N_LA). Three to seven N fertilization treatments were used in this study conducted at eight site-years in Canada and two site-years in France. Leaf N concentrations were measured from the uppermost collared leaf on three to five sampling dates along with NNI determinations. At all sites and most sampling dates, N_L, N_LA, and NNI increased with increasing N rates. With data from all sampling dates, N_L and N_LA were related to NNI, but the intercept of the response curves varied with site-year. These site-specific relationships should be used with caution for the in-season evaluation of corn N status. At stage of development V12, however, N_L was strongly related to NNI (NNI = –0.035 + 0.028 N_L; R² = 0.82) and the response curve was not affected by site, year, nor cultural practice; N_LA was also related to NNI, but the intercept of the response curve varied with site-year. Determining N concentration (DM basis) of the uppermost collared leaf at, or near, the V12 stage of development is an alternate method for assessing NNI, hence eliminating the need to measure shoot biomass.

Abbreviations: DM, dry matter • N_c, critical nitrogen concentration • N_L, nitrogen concentration on a leaf dry matter basis • N_LA, nitrogen concentration on a leaf area basis • NNI, nitrogen nutrition index

All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Received for publication November 7, 2008.