Biochar can play a key role in nutrient
cycling, potentially affecting nitrogen retention when
applied to soils. In this project, laboratory experiments
were conducted to investigate the adsorption properties
of bamboo charcoal (BC) and the influence of BC on
nitrogen retention at different soil depths using multilayered
soil columns. Results showed that BC could
adsorb ammonium ion predominantly by cation exchange.
Ammonium nitrogen (NH4
+-N) concentrations
in the leachate of the soil columns showed significant
differences at different depths after ammonium chloride
application to the columns depending on whether
BC had been added. Addition of 0.5% BC to the
surface soil layer retarded the downward transport of
NH4
+-N in the 70-day experiment, as indicated by
measurements made during the first 7 days at 10 cm,and later, in the experimental period at 20 cm. In
addition, application of BC reduced overall cumulative
losses of NH4
+-N via leaching at 20 cm by 15.2%.
Data appeared to suggest that BC could be used as a
potential nutrient-retaining additive in order to increase
the utilization efficiency of chemical fertilizers. Nonetheless,
the effect of BC addition on controlling soil
nitrogen losses through leaching needs to be further
assessed before large-scale applications to agricultural
fields are implemented.