Plant and Soil

, Volume 216, Issue 1, pp 65–82

Relationships between dynamics of nitrogen uptake and dry matter accumulation in maize crops. Determination of critical N concentration


  • Daniel Plénet
    • Unité d'AgronomieINRA
  • Gilles Lemaire
    • UR Ecophysiologie et Horticulture, Domaine St PaulINRA

DOI: 10.1023/A:1004783431055

Cite this article as:
Plénet, D. & Lemaire, G. Plant and Soil (1999) 216: 65. doi:10.1023/A:1004783431055


The concept of critical nitrogen concentration(%Nc) has been proposed as the minimum%N in shoots required to produce the maximum aerial biomassat a given time. Several authors have shown that%Nc declines as a function of aerial biomassaccumulation (W) and the %NcW relationship has been proposed as a diagnostic tool of N statusin different crops, excluding maize. From data obtained in five nitrogenfertilisation experiments in irrigated maize crops, 26 critical data-pointswere selected with a precise statistical procedure. An allometric relationwas fitted and a critical %NW relationshipmodel is proposed in maize as:

If W < 1 t ha-1%Nc = 3.40

If 1 t ha-1W ≤ 22 t ha-1%Nc = 3.40(W)−0.37

The model is applicable to maize crop development between emergenceand silking + 25 days. The model was tested and validated with dataobtained in a network of 17 N fertilisation experiments conducted inFrance under contrasting pedoclimatic conditions. In only nineout of 280 data-points (3.2%), the plant N status was mispredictedwhen ±5% error around %Nc wasallowed. A critical N uptake model (Nuc, kg Nha-1) is proposed as

Nuc = 34 (W)0.63

A comparison between Nuc and N uptake observedin N treatments giving the maximal grain yields has shown that maizecrops assimilate at least 30 kg N ha-1 in a storage N poolat the silking stage. The significance of the critical%NW and Nu−W relationships is discussed in relation to theoretical models proposed inwhole plant ecophysiology. Different relationships calculated betweenleaf area index and aerial biomass accumulation, and between N uptakeand leaf area were consistent with previous results for other crops.This strengthens the interest of the critical%NW relationship for use as diagnostictool of nitrogen status in maize crops.

AllometryCritical nitrogen concentrationGrowthLeaf area indexN uptakeZea mays L

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© Kluwer Academic Publishers 1999