Interaction of Changes in pH and Urease Activity Induced by Biochar Addition Affects Ammonia Volatilization on an Acid Paddy Soil Following Application of Urea

ABSTRACT

A pot experiment was conducted to test the hypothesis that the interaction of changes in pH and urease activity induced by biochar addition affects ammonia (NH₃) volatilization on acid soils following application of urea. The results showed that the difference in accumulative NH₃ volatilization between biochar addition rates of 20 and 0 Mg ha^–1 was not significant, while the biochar addition rate of 40 Mg ha^–1 had 42% higher accumulative NH₃ volatilization than the biochar addition rate of 0 Mg ha^–1. Soil pH significantly increased with increasing biochar addition rate. The soil urease activity was significantly reduced by biochar addition, but there was no significant difference between biochar addition rates of 20 and 40 Mg ha^–1. These results support our hypothesis and suggest that the biochar addition rate may need to be properly selected in order to minimize fertilizer-N loss through NH₃ volatilization on urea-fertilized acid paddy soils.

KEYWORDS:

• Acid soil
• ammonia volatilization
• biochar amendment
• urea application

Funding

This research received funding from the National Natural Science Foundation of China under grant agreement no. 31460332 and the Earmarked Fund for China Agriculture Research System under the grant agreement no. CARS-01.

Additional information

Funding

This research received funding from the National Natural Science Foundation of China under grant agreement no. 31460332 and the Earmarked Fund for China Agriculture Research System under the grant agreement no. CARS-01.