氯氰菊酯对紫色土土著微生物数量及土壤酶活性的影响

通过3个水平上的土壤盆栽试验,研究了氯氰菊酯对紫色土土壤微生物数量及土壤酶活性的影响.试验表明,氯氰菊酯对紫色土细菌的影响表现为"促进-抑制-恢复":6～21d,LQ-L和LQ-M处理下的细菌数分别减少了53.1%,63.2%;11～21d,LQ-H处理下的细菌数减少了97.5%;26d后细菌数量基本恢复至对照水平.土壤真菌对氯氰菊酯极其敏感,处理后真菌数量显著降低,3周后恢复至对照水平.氯氰菊酯对紫色土过氧化氢酶和磷酸酶活性有促进作用,第1,11,16和21dLQ-M处理下的土壤磷酸酶活性分别较对照提高79.7%,67.7%,65.3%和26.9%.结果表明,真菌可作为指示紫色土环境污染的菌群;过氧化氢酶活性与残留态氯氰菊酯在土壤的降解有关;氯氰菊酯通过影响土壤微生物群落结构,可以间接增强土壤磷酸酶活性.

EffectofCypermethrinontheIndigenousMicroorganismQuantityandEnzymeActivityofthePurplishSoi

In a pot experiment,6-leaf maize plants were sprayed with cypermethrin solution at 2.50(LQ-L),5.0(LQ-M) and 10.0 mg/kg(LQ-H).Soil samples were collected from the next day after the treatment at 5-day intervals,designated as 1d,6d,11d,16d,21d and 26d,respectively,and used for microorganism quantity and enzyme activity determination.The experiment results showed that the influences of cypermethrin on bacteria of the purplish soil could be described as a "promotion-inhibition-recovery" pattern.From 6d to 21d,the bacteria number in treatments LQ-L and LQ-M decreased by 53.1% and 63.2%,respectively,and from 11d to 21d,it was reduced by 97.5% in LQ-H.As determined 26 days after the treatments,the number of bacteria recovered to the control level.The native fungi of the purplish soil were highly sensitive to cypermethrin,and the numbers of fungi were reduced significantly after the treatments and recovered to the control level after three weeks.Cypermethrin promoted the catalase and phosphatase activities of the purplish soil.In the treatment LQ-M,soil phosphatase activity increased by 79.7%,67.7%,65.3% and 26.9% compared with the control on the 1st,11th,16th and 21st day after the treatment,respectively.It is concluded from the above results that soil fungi can be used as an indicator of environmental pollution in the purplish soil;catalase activity is associated with degradation of the residual cypermethrin in the soil,and cypermethrin can indirectly enhance the phosphatase activity of the purplish soil through its influence on the microbial community structure in it.