磺胺嘧啶在玉米驯化根际土壤中的降解规律

Biodegradation of Sulfadiazine in Acclimated Corn Rhizospheric Soil

采用根际袋盆栽试验研究磺胺嘧啶在驯化和未驯化的玉米根际与非根际土壤中的降解规律。结果表明,磺胺嘧啶在土壤中的降解符合一级动力学反应模型,降解速率常数为0.015～0.043 d-1,半衰期为16.8～46.5 d。磺胺嘧啶添加量为2、5和10 mg.kg-1条件下,培养40 d时,其在未驯化根际与非根际土壤中的降解率分别为65.5%和43.9%、60.4%和40.2%、58.5%和34.2%,在驯化根际与非根际土壤中的降解率分别为77.7%和58.4%、71.3%和53.4%、66.1%和51.9%。磺胺嘧啶在根际土壤中的降解速率大于非根际土壤,在受磺胺嘧啶驯化土壤中的降解速率普遍大于未驯化土壤。适当的驯化及根系的协同作用可明显提高磺胺嘧啶在土壤中的降解速率。

A pot experiment using rhizospheric bags were carried out to investigate regularity of the degradation of sulfadiazine in acclimated and unacclimated corn rhizospheric soils and non-rhizospheric soils. Results show that the degradation tallies with the first order kinetic reaction model, with degradation rate constant varying in the range of 0. 015 -0. 043 d-1 and the half life in the range of 16. 8 - 46. 5 d. The degradation rate of sulfadiazine added at a rate of 2, 5 and 10 mg · kg-i , separately, reached 65.5% and 43.9%, 60. 4% and 40. 2% , and 58. 5% and 34. 2% , respectively, in unacclimated rhizospheric and non-rhizospheric soils after 40 days of incubation. The degradation date of sulfadiazine in acclimated rhizospheric and non-rhizospheric soils were 77. 7% and 58.4%, 71.3% and 53.4%, and 66. 1% and 51.9%, respectively. Obviously, the degradation rate was much higher in rhizospheric soils than in non-rhizospheric soils and in acclima- ted soils than in unacclimated soils. The synergy of the root system with appropriate acclimation may significantly improve degradation rate of sulfadiazine in soils.