稻-渔共作农田一株优势真菌LW-1对土壤碱解氮、有效磷、土壤酶活性及镉生物有效性的影响

Effects of a dominant fungus LW⁃1 on soil available nitrogen,available phosphorus,soil enzyme activity and biological availability of cadmium in rice⁃fishery co⁃cropping field

为了探讨稻-鳅-蛙共作农田优势真菌对土壤碱解氮、有效磷、土壤酶活性及镉污染土壤镉生物有效性的影响,本研究分离、纯化及初步鉴定稻-鳅-蛙农田土壤中的优势真菌LW-1,并将其扩繁后制成1×10^(3)、1×10^(5)、1×10^(7)个/mL孢子3种浓度的菌液,最后将3种浓度的菌液和空白菌液分别添加至0、5、10、20 mg/kg镉污染的土壤中,每10天取土壤样本检测土壤有效磷、碱解氮、转化酶、过氧化氢酶、脲酶有效态镉含量。结果表明,随着菌液浓度的增加,土壤中碱解氮和有效磷的含量显著增加(P<0.05),土壤转化酶和脲酶活性均显著性提高(P<0.05),而有效态镉的含量显著降低(P<0.05)。这说明稻-鳅-蛙共作农田中的优势真菌可提高土壤肥力并降低镉污染土壤的生物有效性,研究结果为该模式在土壤改良和修复中的应用提供理论依据,也为理解稻-鳅-蛙共作农田土壤肥力高于常规稻田的机制提供了新的视角。

To investigate the effects of dominant fungi from rice⁃loach⁃frog co⁃culture farmland on soil available nitro⁃gen,available phosphorus,soil enzyme activities and cadmium bioavailability in cadmium⁃contaminated soil.this study isolated,purified and preliminarily identified the dominant fungus LW⁃1 from the soil of rice⁃loach⁃frog co⁃culture farm⁃land,and then prepared three concentrations of spore suspensions of 1×10^(3),1×10^(5),and 1×10^(7) spores/mL,which were added to soils contaminated with 0,5,10 and 20 mg/kg cadmium,respectively.Soil samples were collected every 10 days to measure soil available phosphorus,available nitrogen,invertase,catalase,urease and available cadmium con⁃tents.The results showed that with the increase of spore suspension concentration,the contents of available nitrogen and available phosphorus in soil increased significantly(P<0.05),the activities of soil invertase and urease increased signifi⁃cantly(P<0.05),and the content of available cadmium decreased significantly(P<0.05).This indicates that the domi⁃nant fungus from rice⁃loach⁃frog co⁃culture farmland can improve soil fertility and reduce the bioavailability of cadmium in cadmium⁃contaminated soil.The research results provide a theoretical basis for the application of this mode in soil im⁃provement and remediation,and also provide a new perspective for understanding the mechanism of soil fertility in rice⁃loach⁃frog co⁃cropping farmland higher than that in conventional paddy field.