镁改性粪便污泥水热炭对土壤改良和小白菜生长的影响

Effects of Mg-Modified Fecal Sludge Hydrochar on Soil Amendment and Pak Choi Growth

摘要: 在无废城市背景下，对粪便污泥等有机废弃物进行资源化利用已成为农业与环境领域的重要课题。传统磷肥虽能为土壤补充养分，但其较高的淋溶风险易导致水体富营养化等环境问题。相比之下，镁改性粪便污泥水热炭表面富集了镁活性位点，其特殊的界面化学行为可高效固持磷素并阻控其淋溶迁移，进而延长土壤有效磷的供应周期，实现长效缓释供肥。为了探索镁改性粪便污泥水热炭对土壤改良以及植物生长的促进作用，文章采用水热炭化技术，以粪便污泥(FS)、粪便污泥水热炭(HC)及镁改性粪便污泥水热炭(MgHC)为研究对象，开展土壤培养试验以分析其特性变化，并通过小白菜种植试验验证镁改性水热炭对植物促生以及土壤的改良效果。结果表明，与对照组(CK)相比，土壤培养60 d时，5% MgHC处理组处理效果最佳，总氮、总磷、有机质及有效磷分别提高了51.7%、39.5%、19.1%和305.6%。植物种植60 d时，5% MgHC处理组的植物生长性状表现最好，与CK相比，小白菜株高、鲜重、叶面积、生物量分别增加了245.6%、183.4%、543.5%和250.7%。因此，5% MgHC添加比例是本探究添加下的最佳比例。研究证明了镁改性粪便污泥水热炭对土壤改良以及植物生长具有相对明显的促进作用，在农业领域有一定的应用前景。

Abstract: Under the zero-waste city initiative, the resource utilization of organic wastes such as fecal sludge has become a critical research topic in agriculture and environmental science. Although traditional phosphorus fertilizers can supplement soil nutrients, their high leaching risk tends to cause environmental problems such as water eutrophication. By comparison, magnesium-modified fecal sludge hydrochar is enriched with magnesium active sites on its surface; its distinctive interfacial chemistry enables efficient phosphorus immobilization and suppression of leaching losses, thereby prolonging the availability of soil phosphorus and achieving sustained slow-release fertilization. To investigate the promoting effects of magnesium-modified fecal sludge hydrochar on soil amendment and plant growth, this study employed hydrothermal carbonization technology, using fecal sludge (FS), fecal sludge hydrochar (HC), and Mg-modified fecal sludge hydrochar (MgHC) as research subjects. Soil incubation experiments were conducted to investigate changes in soil characteristics, and pak choi cultivation experiments were performed to verify the effects of Mg-modified hydrochar on plant growth promotion and soil amendment. The results showed that, compared with the control (CK), the 5% MgHC treatment exhibited the optimal performance after 60 days of soil incubation, with total nitrogen, total phosphorus, organic matter, and available phosphorus increasing by 51.7%, 39.5%, 19.1%, and 305.6%, respectively. After 60 days of plant cultivation, the 5% MgHC treatment group demonstrated the best plant growth traits; compared with CK, the plant height, fresh weight, leaf area, and biomass of pak choi increased by 245.6%, 183.4%, 543.5%, and 250.7%, respectively. Therefore, the 5% MgHC addition ratio is the optimal ratio under the conditions investigated in this study. Mg-modified fecal sludge hydrochar exerts significant positive effects on soil amendment and plant growth promotion, demonstrating broad application prospects in the agricultural sector.