Abstract:
Use of biomass fertilizers appears to be the most appropriate way of adding nutrients into the
soil which is environmental friendly and suitable for local conditions. Among the biomass
fertilizer sources, Gliricidia has been identified as the most suitable nitrogen fixing legume.
Some experiments that have been carried out showed that the Gliricidia with high N content
and low lignin level is more suitable as N source. An investigation has been carried out to
determine the nitrogen (N), phosphorous (P), and potassium (K) contents of different parts of
gliricidia plant and to develop a slow-release nitrogen biomass fertilizer systems using
gliricidia plant. Four types of gliricidia plants (Provenance Trail Series of Gliricidia sepium
17/84 Oxford Forestry Institute (OFI), Gliricidia sepium 25/84 OFI, Gliricidia sepium 25/84
OFI and Gliricidia sepium (Local species)) were obtained from Rathmalagara estate,
Madampe in Coconut Research Institute (CRI).
According to the experimental results the level of nitrogen in different parts of the gliricidia
plants varied from 0.43 % to 2.36 %.It was found that phosphorous and potassium content in
gliricidia plant varied from 892.2 mg kg-1 to 1258.2 mg kg-1 and from 208.6 mg kg-1 to
8678.5 mg kg-1 respectively. Biofertilizers were prepared from gliricidia bark chips after
treated with a saturated solution of urea (CH4N2O). The morphology and physiochemical
parameters of treated gliricidia bark chips was investigated. Eexperimental result indicated
that after gliricidia bark chips were treated with urea, total nitrogen content in the bark has
increased by more than 200%. The initial nitrogen content in the bark was 17878 mg kg-1.
This study also evaluated the release pattern of nitrogen from impregnated gliricidia
woodchips in a soil matrix and found that nitrogen was released in a slow-release pattern. The
above findings confirm and gave promising results to further develop urea incorporated
gliricidia bark particles as a slow-release new biomass fertilizer system.
