# Progress and Prospect of Saline-Alkaline Soil Management Technology: A Review
## 3 Advanced Technology of Saline-Alkaline Soil Management
### Emerging Chemical Treatments  
#### 3.2.1 Biochar Technology  
Biochar, a stable carbon-rich by-product synthesized through the pyrolysis of plant and animal biomass [81], has emerged as a promising tool for improving saline-alkaline soils. Biochar is notably one of the most used soil conditioners in saline-alkaline soil. Its distinctive characteristics, featuring an extensive surface area and strong absorption capabilities, enable it to regulate soil nutrients directly or indirectly. Biochar enhances soil organic matter content, reduces nitrogen and phosphorus loss under salt-alkali stress, and promotes the formation of soil aggregate. These properties contribute to soil improvement, enhanced water retention, and increased crop resistance to salt-alkali stress. Moreover, when returned to the field, biochar increases the soil carbon pool, demonstrating superior carbon sequestration and emission reduction potential compared to other agricultural practices [82]. Biochar's high adsorption capacity and well-developed porous structure play a key role in managing saline-alkaline soils by reducing nutrient leaching and minimizing underground runoff. This helps improve the retention of essential nutrients in these challenging environments. Additionally, biochar can adsorb organic molecules, facilitating the formation of organic matter through continuous polymerization, which is vital for enhancing soil quality in saline-alkaline conditions. Its stable carbon structure enhances resists microbial degradation, allowing it to persist longer in the soil and stabilize unstable carbon. This process promotes the creation of more stable organic matter, thus increasing soil organic carbon. Furthermore, biochar's ability to enhance soil aggregate stability helps reinforce the overall stability of soil organic carbon in saline-alkaline soils, making it an effective long-term amendment for improving soil structure and fertility. Therefore, biochar presents great potential for advancing the management of saline-alkaline soils [83]. In addition to enhancing soil structure, the addition of biochar helps to replace excess exchangeable sodium in saline-alkaline soils. It also does so by increasing the levels of organic carbon and cations which, in turn, reduces both the electrical conductivity and salt content of the soil [84]. The application of biochar-based fertilizers or composite materials in saline-alkaline land improvement can delay fertilizer release, prolong soil fertility, and enhance crop adaptability to saline-alkaline conditions. Studies such as that of [PERSON] et al. [85] have shown that an increase in labile carbon (LOC) content signals a higher carbon turnover rate, which boosts the input of carbon from plants and microbes into soil organic matter. This process promotes sustained carbon storage and aids in the restoration of salt affected soils. Similarly, research by [PERSON] et al. [86] demonstrated the potential of cotton stalk biochar in alkaline soils, while [PERSON] et al. [87] examined the impact of altered biochar on rehabilitating salt-affected soils and enhancing crop growth. The results showed that treated biochar notably enhanced soil drainage and lowered acidity and salinity levels while improving soil productivity and water-holding capacity. The application of biochar in saline-alkaline land remediation underscores its potential not only as soil amendment, but also as a key factor in promoting agricultural sustainability and environmental stewardship. By leveraging its exceptional adsorption capacity, biochar effectively regulates soil chemistry, sequestering harmful substances and mitigating their adverse effects on crop health [88,89]. Biochar also affects physical processes in the soil,such as reducing water evaporation at low application rates and improving water retention at higher rates, ultimately reducing surface salinity and sodium adsorption [90]. Additionally, the incorporation of bioactive biochar can significantly enhance microbial activity and biodiversity within the soil.