| dc.description.abstract | Six agro-organic wastes were evaluated for their
ability to reduce N losses from cattle manure during
storage. The materials were selected based on their
low pH, high C: N ratios or high cation exchange
capacity. They included; filter mud (FM), sawdust (SD),
a common by-product of the timber industry, maize
stover (MS), wood ash (WA), Ondiri peat (OP), and
coffee pulp (CP), a waste product from coffee factories.
Manure samples equivalent to 40 g (dry weight basis)
were combined with 20% of each of the amendments
and placed in 500 ml elernmeyer flasks. Volatilization of
ammonia was determined using a laboratory gas train
simulator and volatilized NH3 was collected in 100 ml
of 2% boric acid and determined by titration with 0.01
M H2SO4. Mixing organic amendments with manure
significantly reduced NH3 losses relative to nonamended
manure heaps with the exception where
wood ash was added. The total N content of the
untreated manure prior to incubation was 17.11 g N
kg-1 and after 51 days declined to 9.36 g N kg-1 which
translated to a 43% loss from the initial levels. The
cumulative NH3 losses ranged between 7.6% to 78.7%
of the initial N, depending on the type of amendment.
The N losses were positively correlated (r2=0.855) to
the initial pH of the amended manures. Addition of
sawdust, resulted in least mass and carbon loss and the
original mixture was unchanged showing that minimal
decomposition had occurred. | |
