Is crop N demand more closely related to dry matter accumulation or leaf area expansion during vegetative growth?

Lemaire, Gilles, van Oosterom, Erik J., Sheehy, John, Jeuffroy, Marie H., Massignam Angelo and Rossato, Laurence (2007) Is crop N demand more closely related to dry matter accumulation or leaf area expansion during vegetative growth?. Field Crops Research, 100 1: 91-106. doi:10.1016/j.fcr.2006.05.009


Author Lemaire, Gilles
van Oosterom, Erik J.
Sheehy, John
Jeuffroy, Marie H.
Massignam Angelo
Rossato, Laurence
Title Is crop N demand more closely related to dry matter accumulation or leaf area expansion during vegetative growth?
Journal name Field Crops Research   Check publisher's open access policy
ISSN 0378-4290
Publication date 2007-01-04
Sub-type Article (original research)
DOI 10.1016/j.fcr.2006.05.009
Volume 100
Issue 1
Start page 91
End page 106
Total pages 16
Place of publication Amsterdam
Publisher Elsevier Science Bv
Collection year 2008
Language eng
Subject 300201 Plant Biochemistry and Physiology
C1
Abstract The critical crop nitrogen uptake is defined as the minimum nitrogen uptake necessary to achieve maximum biomass accumulation (W). Across a range of crops, the critical N uptake is related to W by a power function with a coefficient less than unity that suggests crop N uptake is coregulated by both soil N supply and biomass accumulation. However, crop N demand is also often linearly related to the expansion of the leaf area index (LAI) during the vegetative growth period. This suggests that crop N demand could be also linked with LAI extension. In this paper, we develop theory to combine these two concepts within a common framework. The aim of this paper is to determine whether generic relationships between N uptake, biomass accumulation, and LAI expansion could be identified that would be robust across both species and environment types. To that end, we used the framework to analyze data on a range of species, including C-3 and C-4 ones and mono- and di-cotyledonous crops. All crops were grown in either temperate or tropical and subtropical environments without limitations on N supply. The relationship between N uptake and biomass was more robust, across environment types, than the relationship of LAI with biomass. In general, C3 species had a higher N uptake per unit biomass than C4 species, whereas dicotyledonous species tended to have higher LAI per unit biomass than monocotyledonous ones. Species differences in N uptake per unit biomass were partly associated with differences in LAI and N-partitioning. Consequently the critical leaf-N uptake per unit LAI (specific leaf nitrogen, SLN) was relatively constant across species at 1.8-2.0 g m(-2), a value that was close to published data on the critical SLN of new leaves at the top of the canopy. Our results indicate that critical N uptake curves as a function of biomass accumulation may provide a robust platform for simulating N uptake of a species. However, if crop simulation models are to capture the genotypic and environmental control of crop N dynamics in a physiologically functional manner, plant growth has to be considered as the sum of a metabolic (e.g. leaves) and a structural (e.g. stems) compartment, each with its own demand for metabolic and structural N. (c) 2006 Elsevier B.V. All rights reserved.
Keyword Agronomy
biomass accumulation
critical N-uptake
LAI
N-demand
leaf area ratio
Specific Leaf Nitrogen
Radiation Use Efficiency
Nitrogen Dilution Curve
Winter Oilseed Rape
Medicago-sativa L
Pure Grass Stand
Indian Mustard
Grain Number
Tall Fescue
Canopy
Wheat
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Agriculture and Food Sciences
 
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Created: Mon, 18 Feb 2008, 16:05:56 EST