以5种典型盐生植物——假盐生植物芦苇〔Phragmites australis （Cav.） Trin. ex Steud.〕和田菁〔Sesbania cannabina （Retz.） Pers.〕、泌盐盐生植物互花米草（Spartina alterniflora Loisel.）和柽柳（Tamarix chinensis Lour.）以及真盐生植物碱蓬〔Suaeda glauca （Bunge） Bunge〕为原材料，在限氧条件下以升温速率10 ℃·min^-1升温至500 ℃后滞留2 h制备生物炭。通过扫描电镜（SEM）和傅里叶变换红外光谱（FTIR）等技术表征其表面形貌和理化性质，筛选具有盐碱土壤改良潜力的生物炭，并利用苜蓿（Medicago sativa Linn.）盆栽实验验证改良效果。结果表明：碱蓬、柽柳和互花米草制备的生物炭的pH值（pH 9.40至pH 10.54）、电导率（3.51~7.59 mS·cm^-1）、灰分含量（19.55%~29.58%）和可溶性Na⁺含量（8.83~23.73 g·kg^-1）较高；表面附着大量颗粒物，比表面积较小（2.93~4.05 m²·g^-1），且以大孔为主（59.32%~73.45%）。芦苇和田菁制备的生物炭则表现出较低的电导率、灰分含量和可溶性Na⁺含量，以及较高的C含量和稳定性。其中，芦苇生物炭的特性尤为突出，pH值（pH 8.55）和电导率（0.78 mS·cm^-1）最低，比表面积最大（41.95 m²·g^-1），并具有多级孔隙结构（微孔、介孔和大孔共存）。盆栽实验结果表明：单一施用质量分数0.5%的芦苇生物炭可有效降低盐碱土壤容重和pH值，显著（p＜0.05）提高土壤速效钾含量和脲酶活性，并促进土壤碳封存。芦苇生物炭和复合肥联合施用对盐碱土壤中的苜蓿幼苗生长表现出显著的协同促进作用，使苜蓿幼苗的株高、根长和总干质量分别较对照增加28.82%、40.28%和86.84%。综上，芦苇生物炭具有优异的盐碱土改良潜力。

Taking five typical halophytes, namely pseudohalophytes Phragmites australis （Cav.） Trin. ex Steud. and Sesbania cannabina （Retz.） Pers., saltsecreting halophytes Spartina alterniflora Loisel. and Tamarix chinensis Lour., and euhalophyte Suaeda glauca （Bunge） Bunge, as raw materials, biochars were prepared under oxygen-limited pyrolysis at a heating rate of 10 ℃·min^-1 to 500 ℃ and holding for 2 h. Biochars with saline-alkali soil amelioration potential were screened by characterizing the surface morphology and physical and chemical properties via scanning electron microscopy （SEM） and Fourier transform. infrared spectroscopy （FTIR）, etc., and the ameliorative effect was verified by using a pot experiment with Medicago sativa Linn. The results show that pH value （pH 9.40 to pH 10.54）, electric conductivity （3.51-7.59 mS·cm^-1）, ash content （19.55%-29.58%）, and soluble Na⁺ content （8.83-23.73 g·kg^-1） of biochars derived from S. glauca, T. chinensis, and S. alterniflora are relatively high; their surfaces are attached with abundant particulate matter, showing relatively small specific surface areas （2.93-4.05 m²·g^-1）, and are mainly macropores （59.32%-73.45%）. Biochars derived from P. australis and S. cannabina exhibit relatively low electric conductivity, ash content, and soluble Na⁺ content, along with relatively high C content and stability. Among which, P. australis biochar exhibits the most outstanding characteristics: the pH value （pH 8.55） and electric conductivity （0.78 mS·cm^-1） are the lowest, the specific surface area （41.95 m²·g^-1） is the largest, and it has a hierarchical pore structure （coexistence of micropores, mesopores, and macropores）. The pot experiment result demonstrates that single application of P. australis biochar at mass fraction of 0.5% effectively reduces bulk density and pH value of saline-alkali soil, significantly （p＜0.05） increases available potassium content and urease activity of soil, and enhances soil carbon sequestration. Combined application of P. australis biochar and compound fertilizer shows an evident synergistic effect on promoting the growth of M. sativa seedlings in saline-alkali soil, with plant height, root length, and total dry mass increasing by 28.82%, 40.28%, and 86.84% respectively compared with the control. In conclusion, P. australis biochar shows excellent potential for saline-alkali soil amelioration.