Leaf Absorption of Atmospheric Ammonia Emitted from Pig Slurry Applied beneath the Canopy of Winter Wheat

Absorption of volatilized ammonia after application of slurry onto the soil surface (sand) between rows of a wheat crop was studied in two experiments. The slurry was labelled with 15N-NH4. During seven days the accumulated gaseous N loss from the slurry varied from 6.9 to 11.1 g N m−2. In April ammonia losses from slurry applied beneath a 5 cm high wheat crop were equal to losses from slurry applied to a fallow, but 2.2% of the lost atmospheric ammonia was taken up by the leaves. In May ammonia loss from slurry applied between the rows of a 43 cm high crop was reduced by 6% compared to the loss from fallow, because of a reduced transfer of ammonia from the slurry to the air. Of the emitted ammonia 3.3% was absorbed by the canopy.