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Relationship between P and N Concentrations in Corn
Author(s) -
Ziadi Noura,
Bélanger Gilles,
Cambouris Athy.,
Tremblay Nicolas,
Nolin Michel C.,
Claessens Annie
Publication year - 2007
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2006.0199
Subject(s) - shoot , biomass (ecology) , growing season , limiting , human fertilization , zoology , agronomy , crop , dry matter , zea mays , fertilizer , poaceae , chemistry , biology , mechanical engineering , engineering
Tools to diagnose P crop status are becoming increasingly important to minimize the risk of surface and groundwater contamination from excessive fertilization while still applying sufficient P to optimize crop yield. The objectives of this study were to establish the relationship between P and N concentrations of corn ( Zea mays L.) during the growing season and, in particular, to determine the critical P concentration required to diagnose P deficiency. Shoot biomass and P and N concentrations were determined weekly in an experiment with four to six N rates conducted over 2 yr (2004 and 2005) at three sites with adequate soil P for growth. The P and N concentrations decreased with time and increasing shoot biomass at all sites. The P concentration in relation to N under nonlimiting N conditions is described by a linear relationship ( P = 1.00 + 0.094 N, R 2 = 0.76, P < 0.001, n = 71) in which the concentrations are expressed in g kg −1 dry matter (DM). Under limiting N conditions, the relationship was different with greater P concentrations for a given N concentration. The present study establishes a predictive model for critical P concentration in corn shoots, as a function of the N concentration in the shoot biomass and the degree of N deficiency. This critical P concentration can then be used to quantify the degree of P deficiency during the current growing season.