Effects of carbonized rice hull and wood charcoal mixed with pyroligneous acid on the yield, and antioxidant and nutritional quality of rice

The effects of mixture of rice hull charcoal and pyroligneous acid (MRPA) and mixture of wood charcoal and pyroligneous acid (MWPA) with reduced rate of chemical fertilizer on the yield, and antioxidant and nutritional quality of rice were investigated. Results showed that RF (Recommended N-P-K fertilizer application = 110-55-48 kg ha(-1)) generally had higher agronomic and yield components than MWPA and MRPA treatments while MWPA was more effective in improving the yield of rice than MRPA. The total phenolic compounds and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical electron-donating ability were improved at higher application rate of MWPA while xanthine oxidase (XO) inhibition was improved at lower MWPA. In the case of nutritional quality of rice, total amylose content increased while lipid content decreased at lower MWPA. Fatty acid contents were generally high at the combined treatments of organic material and chemical fertilizer than at chemical fertilizer alone. Furthermore, the results revealed that MWPA was more appropriate to use than MRPA in increasing both the antioxidant property and nutritional quality of rice.