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Effect of nitrogen fertilization on nitrogen dynamics in oilseed rape using 15 N‐labeling field experiment
Author(s) -
Gombert Julie,
Le Dily Frédérik,
Lothier Jérémy,
Etienne Philippe,
Rossato Laurence,
Allirand JeanMichel,
Jullien Alexandra,
Savin Alexandre,
Ourry Alain
Publication year - 2010
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.200800270
Subject(s) - nitrogen , human fertilization , brassica , point of delivery , nitrogen fertilizer , horticulture , field experiment , chemistry , agronomy , elongation , biology , botany , materials science , organic chemistry , ultimate tensile strength , metallurgy
In order to optimize nitrogen (N) fertilization and to reduce the environmental impact of oilseed rape without decreasing yield, a clearer understanding of N dynamics inside the plant is crucial. The present investigation therefore aimed to study the effects of different N‐application rates on the dynamics of N uptake, partitioning, and remobilization. The experiment was conducted on winter oilseed rape ( Brassica napus L. cv. Capitol) under three levels of N input (0, 100, and 200 kg N ha –1 ) from stem elongation to maturity using 15 N‐labeling technique to distinguish between N uptake and N retranslocation in the plant. Nitrogen fertilization affected the time‐course of N uptake and also the allocation of N taken up from flowering to maturity. Most pod N came from N remobilization, and leaves accounted for the largest source of remobilized N regardless the N‐application rate. However, the contribution of leaves to the remobilized N pool increased with the N dose whereas the one of taproot decreased. Stems were the main sink for remobilized N from stem elongation to flowering. Leaves remained longer on N200 than on N0 and N100 plants, and N concentration in fallen leaves increased with the N treatment and in N100 plants along an axial gradient from the basal to the upper leaves. Overall, these results show that the timing of N supply is more crucial than the N amount to attain a high N efficiency.