�SEQ CHAPTER \h \r 1Land application of poultry litter provides essential nutrients for
crop production, but nitrogen (N) losses to the atmosphere can be detrimental
to the environment.� A multi-season study
was conducted to quantify ammonia (NH3) and nitrous
oxide (N2O)
volatilization rates from surface applied poultry litter under no-till (NT) and
paraplowed (PP) conservation tillage managements.� Litter was applied in the winter and summer
at rates of� 100 and 200 kg N ha-1,
respectively.� Evaluation of
volatilization rates were determined
using gas concentrations and the flux-gradient gas transport technique and the
momentum balance transport coefficient.�
Nitrous oxide fluxes ranged from 4.4 to 7.6% of total N applied.� Total N2O losses
were about 22% larger during the summer than winter study but a larger
percentage of applied N was lost during the winter.� Nitrous oxide losses during the winter were
8.1 and 7.2 kg ha-1 for the NT and PP treatments, respectively.� Total losses during the summer were 11.2 and
7.4 kg N2O ha-1 for the NT and PP treatments,
respectively.� The relatively large
losses during the winter indicate the importance of year-round measurements for
accurate N2O emission
estimates.� The losses found in this
study were substantially greater than the 1.25% emission factor used by the
Intergovernmental Panel on Climate Change to estimate global emissions and may
have been related to the reduced tillage management practices used in these
studies.� Ammonia fluxes ranged
from 3.3 to 24% of the total N applied during the winter and summer,
respectively.� Ammonia� volatilization was rapid immediately after
litter application and stopped within 7 to 8 days.� Precipitation of 17 mm essentially halted
volatilization, probably by transporting litter N into the soil matrix.� There was no differences in total NH3
volatilization between no-till and paraplowed treatments.