连作障碍对党参根际土壤微环境的影响

Effects of Continuous Cropping on Nutrient and Enzyme Activity in Rhizosphere Soil of Codonopsis pilosula

目的:以连作党参根际土壤为研究对象,探索连作对党参根际土壤理化性质、养分含量及酶活性的影响。方法:通过对比轮作与连作茬党参根际土壤的pH值、有机质含量、土壤速效养分含量和土壤酶活性的变化动态,以明确连作对党参根际土壤微环境的影响。结果:连作和轮作茬的土壤pH值变化不明显;收获期连作茬土壤有机质含量较轮作茬低9.46%,连作土壤中的硝态氮、速效磷、速效钾含量分别较轮作茬低20.42%、17.63%和7.30%;收获期连作党参根际土壤中的过氧化氢酶、脲酶、碱性磷酸酶及蔗糖酶的活性也分别较轮作茬低9.79%、4.51%、13.79%和23.72%。结论:党参连作过度消耗了土壤养分,降低了土壤中有机质及速效养分的含量,打破了土壤养分间的平衡;连作降低了土壤酶活性,影响了土壤养分的转化,从而间接影响了党参对养分的吸收,导致了党参的生长障碍。

Objective:The effects of continuous cropping on physicochemical properties,nutrient content and enzyme activity of Codonopsis pilosula rhizosphere soil were studied.Methods:The dynamic changes of pH value,organic matter content,soil available nutrient content and soil enzyme activity of C.pilosula rhizosphere soil under rotation and continuous cropping were compared to determine the effect of continuous cropping on the microenvironment of C.pilosula rhizosphere soil.Results:The changes of soil pH value of continuous cropping and rotation cropping were not significant.The soil organic matter content in continuous cropping was 9.46% lower than that in rotation cropping,and the contents of nitrate nitrogen,available phosphorus and available potassium in continuous cropping soil were 20.42%,17.63% and7.30% lower than those in rotation cropping,respectively.The activities of catalase,urease,alkaline phosphatase and sucrase in the rhizosphere soil of continuous cropping C.pilosula in the harvest period were also 9.79%,4.51%,13.79% and 23.72% lower than those in the crop rotation,respectively.Conclusion:Continuous cropping of C.pilosula excessively consumes soil nutrients,reduces the content of organic matter and available nutrients in soil and breaks the balance between soil nutrients;Continuous cropping reduced soil enzyme activity and affected the transformation of soil nutrients,thereby indirectly affecting the absorption of nutrients by C.pilosula and leading to growth disturbance of C.pilosula.