烯酰吗啉对土壤呼吸及微生物多样性的影响

Effects of dimethomorph on soil respiration and microbial diversity

【目的】研究烯酰吗啉对土壤呼吸强度和微生物多样性的影响,为烯酰吗啉的正确合理应用提供指导和科学依据。【方法】称取2kg供试土壤,在土壤中施用不同含量的烯酰吗啉水溶液,使土壤中烯酰吗啉的初始含量分别为5,10和25mg/kg,以不施用烯酰吗啉处理为空白组(CK),采用CO_2直接吸收法测定土壤呼吸强度,采用BIOLOG ECO法测定土壤微生物群落多样性和碳源利用率(AWCD);最后采用主成分分析法分析不同含量烯酰吗啉对31种碳源的利用情况。【结果】与CK相比,烯酰吗啉对土壤呼吸强度总体有明显的抑制作用,随着烯酰吗啉含量和施用次数的增加,土壤呼吸强度受抑制程度越大。前两次施用5,10mg/kg烯酰吗啉后对土壤微生物多样性指标影响不显著;第3次施用5,10mg/kg烯酰吗啉后,随着土壤中烯酰吗啉的积累,Shannon物种丰富度指数和McIntosh指数与CK相比总体显著降低,而Simpson优势度指数无显著变化。施用1~3次,与CK相比,25mg/kg的烯酰吗啉处理土壤Shannon物种丰富度指数、Simpson优势度指数及McIntosh指数总体显著降低。在第1次施用后,低含量(5,10mg/kg)烯酰吗啉污染对土壤AWCD值影响较小,高含量(25mg/kg)烯酰吗啉对土壤AWCD值影响明显,对土壤微生物的代谢活性有明显抑制作用;在第2次和第3次施用后,与CK相比,无论是低含量还是高含量,烯酰吗啉处理土壤AWCD值总体显著减小,烯酰吗啉对土壤微生物代谢活性的抑制作用增强。施用烯酰吗啉影响了土壤微生物碳源利用方式和土壤微生物群落结构。【结论】与低含量烯酰吗啉相比,高含量烯酰吗啉对土壤呼吸的抑制作用增大,明显改变了土壤微生物群落多样性。土壤微生物对碳水化合物类碳源利用率明显增大。

【Objective】The study investigated the effects of dimethomorph on soil respiration intensity and microbial diversity to provide guidance and scientific basis for reasonable application of dimethomorph.【Method】Two kg tested soil was collected and dimethomorph at different contents was applied to have initial concentrations of 5,10 and 25 mg/kg,respectively.No application of dimethomorph was used as blank（CK）.Soil respiration intensity was measured using CO_2 absorption spectrometry,soil microbial community diversity and carbon source utilization（AWCD）were determined by BIOLOG ECO method.Finally principal component analysis（PCA）was used to analyze the utilization of 31 carbon sources by dimethomorph with different contents.【Result】Compared with CK,dimethomorph had significant inhibitory effect on soil respiration intensity.As the increase of dimethomorph content and number of application,the inhibition of soil respiration intensity increased.The first two application at concentrations of 5 and 10 mg/kg dimethomorph had no significant effects on soil microbial diversity index.After the third application,Shan-non index and McIntosh index significantly reduced while Simpson dominance index had no significant change.Compared with CK,the 25 mg/kg treatment deceased soil species Shannon richness index,Simpson dominance index and McIntosh index overall after 1-3 applications.After the first application,low contents of（5 and 10 mg/kg）dimethomorph had less impact on soil AWCD,while high content（25 mg/kg）dimethomorph had significant effect on soil AWCD and the metabolic activity of soil microorganisms was inhibited.After the second and third applications,soil AWCD decreased greatly in all treatments and inhibition of soil microbial metabolic activity enhanced.Application of dimethomorph affected soil microbial carbon source utilization and soil microbial community structure.【Conclusion】Compared with low dimethomorph levels,high dimethomorph levels had higher inhibitory effect on soil respiration,changed the soil microbial community diversity,and increased the utilization rate of carbohydrates carbon sources.