The release behaviour observed with

The release behaviour observed with fertilizer composition
is not as uniform as that observed for drug-release
compositions. This may possibly be due to fluctuations in
the physical environment of the soil compared to the relatively
stable physical parameters present in a biological
system. Furthermore, in the presence of two different
types of nanosystems in the fertilizer composition, slowrelease
behaviour can be expected to occur in different
steps. Once the urea-modified HA nanoparticles are encapsulated
within the cavities present in the wood, these
cavities become reservoirs for storage of urea-modified
HA nanoparticles. When the encapsulated G. sepium
wood pieces come into contact with water in the soil,
urea localized in large vascular canals would be released early during the release process. Cells which are smaller
in volume can be expected to release urea at an intermediate
stage. Urea-encapsulated HA nanoparticles localized
within the smaller volumes of intercellular spaces
may release nitrogen at the final stages during slowrelease.