Neutral rice husk biochar amendment effectively mitigates ammonia emissions and improves Chinese Cabbage yield in different nitrogen rates condition

Abstract

Abstract Current agricultural practices are increasingly favoring the use of biochar to sequester carbon, enhance crop growth, and mitigate various environmental pollutants resulting from nitrogen (N) loss. However, since biochar’s characteristics can vary depending on pyrolysis conditions, it is essential to determine the optimal pyrolysis conditions, as they can have different effects on soil health. In this study, we categorized rice husk biochars based on their pH values and investigated the role of each rice husk biochar in reducing ammonia (NH3) emissions and promoting the growth of Chinese cabbage in urea-fertilized fields. The findings of this study revealed that the pH of rice husk biochars influenced the NH3 emissions and crop growth by regulating soil properties such as pH, organic matter, and nutrient contents. Neutral rice husk biochar effectively reduced the NH3 volatilization compared to acidic and basic rice husk biochar, particularly in the presence of high urea application rates. Chinese cabbage yield was highest in the basic rice husk biochar amendment along with high N rates. Therefore, neutral rice husk biochar can effectively mitigate the NH3 emissions from urea-treated fields, while basic rice husk biochar amendments achieved the highest agronomic performance and yield of Chinese cabbage.