Conclusions
Rice husks and non-valuable wood are regarded as
an agriculture waste product, but recently people
have used such solid wastes to sequester carbon by
processing them into biochar. This study compared
the agronomic properties of rice husk and wood
biochar, and investigated their effects on the growth
rate of water spinach. The field testing results with
water spinach showed that the application of rice
husk biochar improves biomass production. The wood
biochar added soil increased the plant weight of water
spinach by increasing the root size and leaf width; while
the rice husk biochar supplemented soil increased the
plant weight of water spinach by increasing the stem
size and lead length. In addition, the stem size of water