Effectiveness of rice husk biochar in controlling heavy metals at polluted paddy soil

Abstract

Polluted irrigation can degrade soil chemical properties and then decrease land productivity. This research aimed to compare the effectiveness of biochar against manure in reducing the concentration of some heavy metals(HM) in the polluted rice field. This pot trial was conducted at Glasshouse using two types of amelioration (biochar and manure). Biochar and manure were incubated with paddy soil under field capacity at the glasshouse for one month. The results showed that increasing the dosage of either biochar or manure applied decreased the availability of HM, especially Fe (r=-0.87, r=-0.89) and Mn (r=-0.82, r=-0.91), respectively. However, there was no effect of biochar (r=0.25) but increased by manure (r=0.95) application on Zn concentration. Furthermore, some other heavy metals concentration also decreased, such as Ag (r=-0.89), Pb (r=-0.54), Cu (r=-0.51), Cr (=- 0.50), and Ni (r=-0.64) by applying biochar but tended to increase by applying manure. Both biochar and manure could increase some plant nutrients, especially K (r=0.74, r=0.82), P (r=0.85, r=-0.44), Mg (r=0.98, r=0.91) and Ca (r=0.98, r=0.84), respectively.