Absorption of 15N Enriched Ammonia by Winter Wheat at Different Growth Stages

Background

Loss of gaseous reactive nitrogen in the form of aerosols may impact human health, and its deposition leads to eutrophication and acidification of natural ecosystems. In order to reduce ammonia (NH₃) emissions, which are a main pathway of nitrogen loss to the environment, accurate monitoring and understanding of the factors involved is required.

Aims

As information on the absorption of NH₃ by wheat plants in central Europe is scarce, we conducted a field experiment to quantify NH₃ absorption by a winter wheat canopy in May and June with each two emission scenarios (5 and 12 kg NH₃-N ha⁻¹).

Methods

To induce NH₃ emissions, a ¹⁵N enriched ammonium sulfate solution (pH 9) was applied in trays between the wheat rows.

Results

Absorption of the volatilized NH₃ of the aboveground plant biomass ranged between 23 and 181 mg NH₃-N m⁻² (corresponding to 14.8% and 20.0% of the emitted NH₃) and was significantly higher during the first sampling in May, when compared to the second sampling in June. A higher emission led to a higher absolute amount absorbed.

Conclusions

The results indicate that wheat will indeed absorb significant amounts of NH₃ emitted at ground level. They will be useful for further improving NH₃ emission factors and the understanding of the NH₃ emission pathway.