农作物秸秆炭对土壤中镉和磷的影响

Effect of Crop Straw Biochar on Cadmium and Phosphorus in Soil

摘要: 本研究采用室内土壤培养实验分析了秸秆炭施加到土壤后对土壤pH、镉和磷的影响。进一步利用秸秆炭吸附实验和材料表征手段，分析了秸秆炭对土壤中镉和磷的作用机理。结果表明：在芦苇秸秆炭、棉花秸秆炭、辣椒秸秆炭和烟草秸秆炭中，烟草秸秆炭对镉和磷的吸附效果最佳，分别可以达到92.95%和14.13%。其施加到土壤后，可以显著提高土壤pH和磷含量，且随着施加比例和作用时间的延长，秸秆炭的影响越显著。相较于CK，0.5%，1%和3%烟草秸秆炭处理对镉的钝化作用分别可以达到79%，90%和96%。秸秆炭对镉和磷的吸附过程和材料表征表明，烟草秸秆炭对镉和磷的吸附主要是以化学吸附为主，其中炭表面的含氧官能团(O-H和C=O)是主要影响因素。此外，生物炭表面孔径也会影响其对镉和磷的吸附。

Abstract: In this study, the effects of straw biochar on soil pH, cadmium and phosphorus after application to soil were analyzed using indoor soil culture experiments. The mechanism of action of straw biochar on cadmium and phosphorus in soil was further analyzed using straw biochar adsorption experiments and material characterization. The results showed that among reed straw biochar, cotton straw biochar, pepper straw biochar and tobacco straw biochar, tobacco straw biochar had the best adsorption effect on cadmium and phosphorus, which could reach 92.95% and 14.13%, respectively. When applied to the soil, it could significantly increase the soil pH and phosphorus content, and the effect of straw charcoal was more significant with the extension of the application ratio and action time. Compared with CK, 0.5%, 1% and 3% tobacco straw biochar treatments could passivate cadmium by 79%, 90% and 96%, respectively. The adsorption process and FTIR characterization of cadmium and phosphorus by straw biochar showed that the adsorption of cadmium and phosphorus by tobacco straw biochar was mainly based on chemisorption, in which the oxygen-containing functional groups on the surface of the charcoal (O-H and C=O) were the main influencing factors. In addition, the surface aperture of biochar also affects the adsorption of cadmium and phosphorus.