Biochar and hydrochar application influence soil ammonia volatilization and the dissolved organic matter in salt-affected soils

Yaxin Ma; Wenping Xie; Rongjiang Yao; Yanfang Feng; Xiangping Wang; Huifang Xie; Yuanyuan Feng; Jingsong Yang

doi:10.1016/j.scitotenv.2024.171845

Biochar and hydrochar application influence soil ammonia volatilization and the dissolved organic matter in salt-affected soils

Sci Total Environ. 2024 May 20:926:171845. doi: 10.1016/j.scitotenv.2024.171845. Epub 2024 Mar 21.

Authors

Yaxin Ma¹, Wenping Xie², Rongjiang Yao³, Yanfang Feng⁴, Xiangping Wang³, Huifang Xie¹, Yuanyuan Feng⁵, Jingsong Yang³

Affiliations

¹ Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
² State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, CAS, Nanjing 210008, China. Electronic address: wpxie@issas.ac.cn.
³ State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, CAS, Nanjing 210008, China.
⁴ Key Laboratory of Agro-Environment in Downstream of Yangtze Plain, Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
⁵ Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China.

PMID: 38521269
DOI: 10.1016/j.scitotenv.2024.171845

Abstract

Biochar, which including pyrochar (PBC) and hydrochar (HBC), has been tested as a soil enhancer to improve saline soils. However, the effects of PBC and HBC application on ammonia (NH₃) volatilization and dissolved organic matter (DOM) in saline paddy soils are poorly understood. In this research, marsh moss-derived PBC and HBC biochar types were applied to paddy saline soils at 0.5 % (w/w) and 1.5 % (w/w) rates to assess their impact on soil NH₃ volatilization and DOM using a soil column experiment. The results revealed that soil NH₃ volatilization significantly increased by 56.1 % in the treatment with 1.5 % (w/w) HBC compared to the control without PBC or HBC. Conversely, PBC and the lower application rate of HBC led to decrease in NH₃ volatilization ranging from 2.4 % to 12.1 %. Floodwater EC is a dominant factor in NH₃ emission. Furthermore, the fluorescence intensities of the four fractions (all humic substances) were found to be significantly higher in the 1.5 % (w/w) HBC treatment applied compared to the other treatments, as indicated by parallel factor analysis modeling. This study highlights the potential for soil NH₃ losses and DOM leaching in saline paddy soils due to the high application rate of HBC. These findings offer valuable insights into the effects of PBC and HBC on rice paddy saline soil ecosystems.

Keywords: Ammonia volatilization; Biochar; Dissolved organic matter (DOM); Hydrochar; Saline soils.