烤烟根残体浸提液对土壤酶活性的影响

目的]为探讨烤烟根残体在烤烟连作障碍方面的作用和机理。方法]采用室内模拟试验和化学分析方法,研究根残体浸提液对土壤酶活性的影响。结果]烤烟根残体浸提液对土壤氧化还原酶活性有激活作用,培养25 d后以添加45%处理的作用最明显,但随着培养时间的延长过氧化氢酶和多酚氧化酶活性与对照无显著差异。根残体水浸提和培养时间均影响脲酶、蔗糖酶、磷酸酶活性。随着培养时间的延长,土壤脲酶活性明显增强,蔗糖酶活性呈下降趋势,3种磷酸酶活性均降低;随着根残体浸提液浓度的增加,脲酶活性增加越明显,土壤蔗糖酶活性降低越显著,土壤酸性磷酸酶活性抑制作用增强。结论]根残体影响土壤中主要酶活性,间接促进或降低土壤中养分含量的变化,从而影响烤烟的生长发育、产量与品质。

Effects of Extracts from Tobacco Root Remains on Activities of Soil Enzymes

Objective] The research aimed to explore the effects and the mechanism of the extracts from tobacco root remains in the role of continuous cropping obstacles of tobacco.Method] The method of laboratory simulation experiments and chemical analysis were carried out to study the influence of the extracts from tobacco root remains on the soil enzyme activities.Result] The water extracts from root remains increased the activities of oxide-reductase in soils.They reached the highest at 25 days after adding 45% extracts.However,the activities of catalase and polyphenol oxidase in soils varied little,compared to the treatment without extracts added as the culture period prolonged.Both the extracts of root remains and the culture time influenced the activities of urease,phosphatases and invertase in soils.As the culture time prolonged,the activities of urease increased in contrast to those of invertase and phosphatases(acidic,alkaline and neutral) which were declined.Along with the increment of extract concentration,the activities of urease were increased obviously,the activities of invertase and acid phosphatases were declined obviously.Conclusion] Tobacco root remains affected the soil enzyme activity,promoted or reduced indirectly a change in the soil nutrient content,which affected tobacco growth,yield and quality.