In this study, the biochar treatments did not result
in significant improvements in soil properties that
affect nutrient retention. None of the macro- or micronutrients
measured in the biochar treatments were any
higher than the control at the end of the experiment.
Furthermore, there was no change in CEC as a result
of the biochars being added at the rates used in this
study. This is contrary to the findings of Dempster et
al. (2012), who showed that biochar reduced ammonium
and nitrate leaching in soil columns when applied
at 25 t ha−1
. Currently, clay is applied commercially
to sands to ameliorate water repellence. Added
clay has been shown to increase nutrient retention in
sands through increased CEC and organic C (Hall
et al., 2010) and reduced leaching of nutrients including
ammonium, nitrate (Dempster et al., 2012) and
P (Mokhtari et al., 2014).