Purpose

This study investigated the chemical and physical mechanisms associated with the movement of water and salt in saline-alkali soil amended with different types of biochar.

Materials and methods

Four types of biochar were selected: ordinary laboratory-prepared biochar (BC), acidified biochar (HBC), particle size modified biochar (NBC), and composite modified biochar (HNBC). The physical and chemical properties of the biochar treatments were characterized. Vertical infiltration simulation tests were conducted to analyze the effects of modification on the adsorption and distribution of salt ions on biochar, and the soil water-stable macro-aggregates in saline-alkali soil.

Results and discussion

The porous structure, specific surface area (SSA), micropore volume (VMIC), and H/C value were increased by acidification, particle size modification, and composite modification. Compared with BC, HBC and HNBC enhanced the O/C and (O+N)/C values, thereby increasing the hydrophilicity. The vertical infiltration tests showed that the depth of the soil wetting peak and cumulative infiltration were both higher than in the control (CK) after adding biochar, where HBC had the greatest water retention capacity. The modified biochar reduced the salt content and water-soluble Na⁺ content of the soil profile by increasing the soil water content and adsorbing Na⁺. The modified biochar promoted the formation and stabilization of soil water-stable macro-aggregates. Amending soil with HBC showed the greatest reduction in salt content and increased water-stable macro-aggregation.

Conclusions

HBC improved the water retention and Na⁺ adsorption capacity of biochar. This enhanced the formation of soil water-stable macro-aggregates and improved the effects of biochar on saline-alkali soil by altering soil physical and chemical properties.

中文翻译：

---

改性生物炭对盐碱土中水盐分布及水稳性大团聚体的影响

目的

这项研究调查了用不同类型的生物炭改良的盐碱土壤中与水和盐分运动有关的化学和物理机制。

材料和方法

选择了四种类型的生物炭：普通的实验室制备的生物炭（BC），酸化的生物炭（HBC），粒度改性的生物炭（NBC）和复合改性的生物炭（HNBC）。表征了生物炭处理的物理和化学性质。进行了垂直入渗模拟试验，以分析改性对盐离子在生物炭和盐碱土中水稳性大团聚体上的吸附和分布的影响。

结果与讨论

通过酸化，粒径改性和复合改性，提高了多孔结构，比表面积（SSA），微孔体积（VMIC）和H / C值。与BC相比，HBC和HNBC增强了O / C和（O + N）/ C值，从而增加了亲水性。垂直入渗试验表明，添加生物炭后，土壤湿润峰的深度和累积入渗量均高于对照（CK），其中HBC具有最大的保水能力。改性生物炭通过增加土壤水分和吸附Na ^+来降低土壤剖面中的盐含量和水溶性Na ⁺含量。。改性生物炭促进了土壤水稳性大团聚体的形成和稳定。用六溴代二苯改良土壤后，盐分减少最大，水稳性宏观团聚增加。

结论

HBC改善了生物炭的保水率和Na ⁺吸附能力。通过改变土壤的物理和化学特性，这增强了土壤水稳定性大团聚体的形成，并改善了生物炭对盐碱土壤的影响。