材料期刊网

采用盆栽实验方法,研究了膨润土钝化与不同水分灌溉联合处理对酸性稻田土Cd污染修复效应,以及对土壤脲酶活性和氮、磷有效性的影响及其机制.结果表明,与干湿灌溉相比,长期淹水和湿润灌溉可明显降低稻谷生物量.膨润土钝化修复与不同水分灌溉联合处理时稻谷和稻草生物量总体上虽略有增加,但与对照相比并无明显差异.于湿灌溉、湿润灌溉和长期淹水灌溉下,稻米Cd含量分别为0.29、0.38、0.18 mg·kg-1,其中与干湿灌溉相比,长期淹水可使稻米镉降低37.93％,而湿润灌溉则使稻米Cd含量增加31.03％.添加膨润土钝化修复后,与干湿灌溉联合处理相比,长期淹水灌溉可使稻米Cd降低45.29％,而湿润灌溉可使稻米Cd增加23.53％.与未钝化处理相比,膨润土钝化修复下,水稻根表Fe(Ⅱ)含量显著增加,但水稻根表Fe(Ⅲ)含量间无明显差异,水稻根表Cd含量显著降低.在未添加膨润土和添加膨润土钝化修复下,长期淹水灌溉处理时土壤脲酶活性比干湿灌溉处理分别降低21.05％和15.79％.在未添加膨润土钝化修复下,不同水分灌溉处理对土壤碱解氮含量无明显影响,但长期淹水灌溉处理比干湿灌溉处理土壤有效磷增加34.92％,而湿润灌溉下土壤有效磷则降低16.99％.不同水分灌溉处理下,膨润土钝化修复对土壤碱解氮和有效磷含量无明显影响.

Pot experiments were conducted to investigate the effects of bentonite and different water managements on remediation of Cd contaminated acid paddy soil,soil urease activity,and the contents of alkaline hydrolysis nitrogen and available phosphorus.The results showed that the biomass of rice grain was significantly decreased under the treatments of continuous flooding irrigation and humid irrigation in contrast to wet-dry cycles irrigation.Although there was no significant difference among the treatments of bentonite and water managements,the biomass of rice grain and straw was slightly increased.Under wet-dry cycle irrigation,humid irrigation and continuous flooding irrigation,the contents of Cd in brown rice were 0.29,0.38 and 0.18 mg· kg-1,respectively.When compared with wet-dry cycle irrigation,the concentration of Cd in brown rice under the continuous flooding irrigation was decreased by 37.93％,and while it was increased by 31.03％ under the humid irrigation.The content of Cd in brown rice was inhibited by 45.29％ for the combined treatments of bentonite and continuous flooding irrigation,and by 23.53％ for the combined treatments of bentonite and the humid irrigation,respectively,compared with wet-dry cycles irrigation.The content of Fe (Ⅱ) in the root surface of rice was significantly increased,but there was no obvious difference in the content of Fe(Ⅲ) between the treatments of bentonite and water managements,and meanwhile the contents of Cd in the root surface of rice were significantly decreased.The activity of urease under continuous flooding irrigation experienced a 21.05％ and 15.79％ reduction,respectively,compared with bentonite and non-bentonite treated soils.Under non-bentonite treated soil,there was no significant difference on the content of alkaline hydrolysis nitrogen in soils under different treatments of water management.The content of soil available phosphorus under the continuous flooding irrigation was 34.92％ higher than that of the wet-dry cycle irrigation,while it suffered 16.99％ reduction under the humid irrigation.Under different water managements,the treatments of bentonite had no remarkable difference on the concentrations of soil alkaline hydrolysis nitrogen and available phosphorus.