Enhancing the efficacy of biochar derived from crop residues on rice (Oryza sativa L.) dry matter, yield accumulation and soil organic carbon in Central Vietnam.

Biochar from crop residues plays an important role in reclamation of degraded rice soil due to imbalance fertilizer application and soil carbon sequestration. The objective of this study aimed to evaluate the best type and rate of biochar application for rice dry matter and soil organic carbon improvement. Therefore, pot experiments were carried out in two seasons of spring and summer 2023 at the University of Agriculture and Forestry, Hue University. Twelve treatments including 2 types of biochar (rice husk and peanut shell) and 6 application rates (0, 1, 2, 3, 4, 5%) were used and arranged in a randomized block design with three replications. Research results showed that the shoot dry matter was higher 9.5-27.0% (spring season) and 19.1-26.9% (summer season) at a rate of 5% application in both types of biochar than control. Rice husk biochar application had higher shoot dry matter than peanut shell biochar application in the same application rate from 0.30-0.46 g/plant in both seasons. Similarly, organic carbon was found the highest content (2.15-2.21%) when the application of biochar from crop residues at a rate of 5%. Biochar from crop residues is considered as a good amendment for increasing crop dry matter and soil organic carbon. [ABSTRACT FROM AUTHOR]