Research relating to the use of organic
amendments on soils has focused largely on agricultural
soils, and there is a lack of information worldwide on their
efficacy as amendments for urban soil management, especially
in tropical urban environments. A pot experiment
was conducted to assess the influence of biochar and
organic compost on urban soil properties and on tree
growth performance in Singapore. Biochar and compost
were mixed with topsoil in different proportions, and two
urban tree species commonly grown in Singapore (
Samanea
saman
and
Suregada multiflora
) were used. There were
significant additional height increments for both the tree
species following application of biochar.
S. saman exhibited
greater stem elongation compared with
S. multiflora in
response to organic amendments. A significantly higher
foliar N content was found in both tree species in biochar–amended
treatments along with significant increases in P
and K. Increases in soil nutrient concentrations were also
observed in combined biochar–compost treatments for both
species. Combined compost and biochar had the strongest
effects on soils and growth of the two urban tree species
examined and applications containing biochar resulted in
the most significant soil improvements.
