Type of document: Journal Article
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More information on authors/freelancers connected to LBI :
Joachim G.C. Deru MSc.;
Nick J.M. van Eekeren Ph.D.;
Nyncke J. Hoekstra Ph.D.
Language of document: English
Title in English: Strategic timing of nitrogen fertilization to increase root biomass and nitrogen-use efficiency of Lolium perenne L.
Abstract / summary in English:
During the first days after harvest of Lolium perenne L., N remobilized from roots and stubble forms the main N source for regrowth. Low N uptake from the soil during this period may lead to N loss if N fertilizer is applied too soon. Furthermore, temporary N deprivation has been found to stimulate root growth. We therefore hypothesized that a strategic delay in N application after harvest may improve N-use efficiency of L. perenne grassland by increasing root biomass and reducing N loss.
In a laboratory and field experiment with L. perenne, we delayed N fertilizer application after harvest for 0, 3, 6, 9 and 12 days, repeated this for up to six harvest cycles, and determined effects on herbage yield, herbage N uptake and root biomass.
In both experiments, delaying N application for up to 12 days had no significant effect on root biomass or total herbage N uptake, but it significantly reduced total herbage yield in the laboratory experiment. Total yield tended to be highest when N application was delayed for 3 days. Two growth periods in the field experiment showed significantly higher N uptake when N application was delayed, possibly due to rainfall-induced N losses in the treatments with shorter delay.
Our results do not provide evidence that delaying N application improves N-use efficiency of L. perenne grassland by increasing root biomass. However, strategic timing of N fertilizer application based on rainfall forecasts could contribute to improve N-use efficiency by reducing N losses from leaching and denitrification.
Keywords in English: N fertilization, Delayed N application, Timing, Root biomass, N-use efficiency, Lolium perenne L.