Rice Husk Bio-ash Impacts Redox Status and Rice Growth in a Flooded Soil from Southwestern China

This paper reports a soil-based bioassay of rice husk bio-ash impacts on redox properties and rice production. Bio-ash was produced during the pyrolytic process of rice husk as a boiler fuel, after which it was applied as an amendment to a flooded soil. Bio-ash was amended before rice transplanting at different mass rates including 0%, 0.1%, 1% and 5%, which was defined as T1, T2, T3, and T4 respectively. Results show that rice husk bio-ash in flooded soil could increase soil Eh value, pH value and organic matter content (OM), and also reduce reductant amount and activity. The numbers of rice white roots of T2 and T3 increased by 30% and 8% compared to that of T1 in the tillering stage. Increased grain yields due to bio-ash amendments at the rate of 0.1% and 1% were 3.43% and 11.8% higher than that of T1.