N₂O emissions from spring barley production as influenced by fertilizer nitrogen rate

Abstract

(1 N when fertilizer N rate was increased from 0 to 75 kg N ha(1 and from 75 to 150 kg N ha (1 , respectively, indicating increased N 2 O emissions when fertilizer is applied at above optimal rates. N 2 O emissions increased linearly with nitrate intensity, the summation of daily NO 3 -N concentrations for 0-to 15-cm depth. This suggests that the non-linearity in the relationship between fertilizer N rate and N 2 O emissions can be explained by the decreasing efficiency in crop NO 3 -N uptake at high fertilizer N rates. Les auteurs attribuent les fortes e´missions de N 2 O observe´es a`ce moment a`une plus grande disponibilite´du carbone conse´cutivement a`l'humidification du sol sec. Il se pourrait donc que l'incidence de la fertilisation azote´e sur les de´gagements de N 2 O ne se fasse pas sentir imme´diatement apre`s l'application. Ceci montre bien qu'il importe de mesurer les e´missions de N 2 O en dehors de la pe´riode ve´ge´tative. Les e´missions cumulatives de N 2 O induites par l'engrais s'e´tablissaient en moyenne a`0,011 et a`0,021 kg de N par kg de N quand le taux d'application de l'engrais azote´passe de 0 a`75 kg de N par hectare ou de 75 a`150 kg de N par hectare, respectivement, ce qui signifie que les de´gagements de N 2 O augmentent quand on applique plus d'engrais que le taux optimal. Les e´missions de N 2 O progressent line´airement avec la charge nitrique, soit la somme des concentrations quotidiennes de N-NO 3 a`une profondeur de 0 a`15 cm. Ces re´sultats laissent croire que la non-line´arite´de la relation entre le taux d'application des engrais N et les e´missions de N 2 O s'explique par l'efficacite´de´croissante de la plante a`absorber le N-NO 3 aux taux d'application plus e´leve´s.

High N2O variations induced by agricultural practices in integrated weed management systems

“…In our study, the application of fertilizers in April 2012 in systems S1, S2, and S3 did not immediately cause N 2 O emission peaks, a phenomenon also reported by Zebarth et al (2008). However, no significant correlation was established between soil N dynamics and the N 2 O emissions observed later.…”

“…Seasonal patterns were accurately reproduced by the model, especially the high proportion of N 2 O emissions during spring and the low N 2 O emissions (Table 2). Despite the fact that no significant correlation was observed between measured N 2 O emissions and soil inorganic N dynamics, as is usually observed in fertilized soils (Zebarth et al 2008), simulated N 2 O emissions from systems S1, S2, and S3 appeared to be highly correlated with the response factors for soil nitrate content obtained using the nonlinear Fn function (Table 2). N 2 O emissions from system S5 simulated by NOE were determined more by the response factor for water contents (Table 2).…”

Nutrient Management in Support of Environmental and Agricultural Sustainability

“…This has been reported under maize [17,18] and spring barley [19]. Under these conditions, and when conditions are also conducive to denitrification, splitting fertilizer N applications could reduce N 2 O losses.…”

“…Under these conditions, and when conditions are also conducive to denitrification, splitting fertilizer N applications could reduce N 2 O losses. Data presented by Zebarth et al [19] suggest that lack of crop N uptake accounts for the relative increase in the proportion of mineral N that is emitted as N 2 O at high rates of N application. Dalal et al [20] state that NO 3 -usually inhibits full denitrification of N 2 O to N 2 , increasing the N 2 O:N 2 ratio.…”

Spatial and temporal variability of nitrous oxide emissions in a mixed farming landscape of Denmark

“…By contrast, high fluxes in late April and May 2008 were observed after re-wetting of the soil by 32 mm of rainfall to reach a positive soil water balance. When soil is re-wetted after a dry period, a pulse of N 2 O has been observed by several authors due to increased nutrient availability for microbes (Mummey et al, 1994;Zebarth et al, 2008;Chirinda et al, 2010). Soil water content influences N 2 O emission from all types of soil.…”