Solid pig manure (240 g kg1 DM) and
solid cattle manure (150-180 g kg1 DM)
were stored in an
open storage facility during spring-summer and
autumn conditions for periods of 9-14 weeks during
1994 and 1995. Concentrations of C, N, P and K were determined
prior to and after storage, corrected
for dry matter losses and distance from the surface.
Temperature and, in experiments with pig
manure, gas phase composition inside the manure heap were
monitored during storage. Nitrogen
losses as ammonia volatilization, nitrous oxide emission
and leaching were measured, while total
denitrification was estimated from mass balance calculations.
For both cattle and pig manure there
was little difference between seasons with respect to the
pattern of decomposition, as reflected in
temperature dynamics and C/N turnover. In contrast,
there was a distinct difference between manure
types. Pig manure was characterized by maximum temperatures
of 60-70°C, although the
concentrations of oxygen and methane clearly demonstrated
that anaerobic conditions dominated the
interior parts of the heap for several weeks. Losses of
C and N from pig manure both amounted to
c. 50%. In contrast, the temperature of cattle
manure remained close to the air temperature
throughout the storage period and cattle manure had lower,
not significant losses of C and N.
Leaching losses of N constituted 1-4% with both
manure types. Ammonia volatilization from cattle
manure constituted 4-5% of total N, and from pig
manure 23-24%. In pig manure a similar amount
of N (23-33%) could not be accounted for after
storage, a loss that was attributed to denitrification.
Nitrous oxide emissions amounted to <2% of estimated
denitrification losses.
Assessing Seasonal Methane and Nitrous Oxide Emissions from Furrow-Irrigated Rice with Cover Crops
