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RESEARCH PRODUCT

Comment expliquer l’avantage compétitif des espèces adventices nitrophiles dans les systèmes de cultures conventionnels ?

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Plant nitrophily/oligotrophy provides information on the nitrogen richness of their natural habitat. It plays a key role in structuring weed communities. Based on an ecophysiological analysis of the ecological character of nitrophily, our main goal was to better understand the success of nitrophilic weed species and the decline of oligotrophic ones in conventional cropping systems which are characterized by an abundant use of nitrogen fertilizers. A greenhouse experiment was conducted using a range eleven weed and crop species contrasted for their nitrophily status and grown at two different soil-nitrogen concentrations. We show that, compared to an oligotrophic species, a nitrophilic species has a growth highly responsive to soil nitrogen. This is due to higher nitrogen uptake or use efficiency for nitrophilic species when soil-nitrogen availability is high. Our results provide ecophysiological clues to better understand weed community assembly. Applications to weed management in cropping systems are proposed.