Recently, the Innovation Team of Improvement and Amelioration of Soil Fertility at the Institute of Agricultural Resources and Regional Planning (IARRP) at the Chinese Academy of Agricultural Sciences (CAAS) made significant progress in their research on the mechanisms of biochar improves the soil hydrological function of coastal saline-alkali land. The findings were published in a top-tier journal, Agricultural Water Management (IF = 5.9), under the title "Biochar enhances soil hydrological function by improving the pore structure of saline soil."

The poor soil structure caused by salinization is a major factor affecting crop growth and soil structure will further affect hydrological function. Biochar is widely used to improve soil physical structure because of its special porous material. However, the mechanism of soil pore structure on hydrological function (e.g., soil saturated hydraulic conductivity, plant available water, least limiting water range) after biochar incorporation in saline soil remains unclear.

This study, based on a biochar amendment field experiment in coastal saline-alkali land, integrated methods such as micron-scale soil 3D structure measurement, soil water retention curve , and soil compaction curves to investigate the mechanism of biochar addition affects soil pore structure characteristics and hydrological functions. The results showed that biochar addition reduced the proportion of small soil pores (pore diameter < 50 µm) while increasing the proportion of large pores (pore diameter > 300 µm). Biochar amendment reduced the soil penetration resistance, with the soil saturated hydraulic conductivity, plant available water and the least limiting water range were measured 46%, 27% and 40% greater in rate of 30 t ha-1 biochar addition as compared with those of the CK, respectively. The soil saturated hydraulic conductivity was positively correlated with large pores (diameter >300 μm) and pore connectivity (p < 0.05). The improved pore connectivity and elongated pore structures were the key responsible for the reduced penetration resistance in biochar-amended soil, which subsequently increased the least limiting water range. These quantitative estimates highlight the positive effects of biochar amendment-induced soil pore structure alternations towards improving soil hydrological functionalities. These findings provide important theoretical support for the improvement and sustainable utilization of saline-alkali land.

Angyuan Jia, a doctoral student at the IARRP, is the first author of the paper. Researcher Xueping Wu from the IARRP and Professor Gang Wang from China Agricultural University are the corresponding authors. This research was supported by the National Key Laboratory of Efficient Utilization of Dryland and Semi-Arid Arable Land in Northern China, the National Key R&D Program, and the Science and Technology Innovation Project of the Chinese Academy of Agricultural Sciences.

Citation and Original Link:

Angyuan Jia, Xiaojun Song, Shengping Li, Zhipeng Liu, Xiaotong Liu, Zixuan Han, Huizhou Gao, Qiqi Gao, Yan Zha, Ying Liu, Xueping Wu*, Gang Wang*. 2024. Biochar enhances soil hydrological function by improving the pore structure of saline soil. Agricultural Water Management, 306, 109170.

Original link: 

https://doi.org/10.1016/j.agwat.2024.109170