青稞连作对根际土壤理化性质及酶活性的影响OA

[Objective]The present paper analyzed the changes in physico-chemical properties and enzyme activities in the rhizosphere soil of highland barley under different continuous cropping years,aiming to reveal the impact mechanism of continuous cropping on the rhizosphere soil micro-environment,explore scientific approaches to mitigate continuous cropping obstacles,and clarify the regulatory patterns of continu-ous cropping on the soil micro-environment.[Method]Three treatments were established including continuous cropping for 2 years(CCY02),5 years(CCY05)and 10 years(CCY10).Rhizosphere soil samples were collected to determine physio-chemical indicators and key enzyme activities.Correlation analysis and other methods were employed to examine the relationships among these parameters.[Result]With the ex-tension of continuous cropping years,the carbon and nitrogen nutrient contents in the rhizosphere soil of highland barley continued to decline.Specifically,compared with CCY02,the soil organic matter decreased by 76.77％,indicating a significant depletion of soil basic fertility.A-vailable potassium accumulated abnormally,suggesting a severe imbalance between nutrient input and crop uptake.Soil bulk density de-creased,leading to altered porosity,while electrical conductivity increased significantly,raising the risk of soluble salt accumulation.The soil pH remained neutral to slightly alkaline(ranging from 8.06 to 8.91)with no significant differences observed among different cropping years.Regarding ecological stoichiometry,the ratios of C/P,C/K,N/P and N/K decreased,whereas the C/N ratio increased,indicating a dis-ruption in the coordination of nutrients required for microbial metabolism.After 10 years of continuous cropping,the activities of catalase,phosphatase and invertase generally decreased.Notably,invertase activity significantly declined by 39.72％,suggesting that the functionality of the soil enzyme system was inhibited.Correlation analysis revealed a significant negative correlation between soil carbon and nitrogen nutri-ents and available potassium.Furthermore,invertase activity showed an extremely significant positive correlation with carbon and nitrogen con-tents,establishing it as a key biological indicator for reflecting nutrient changes in continuously cropped soil.[Conclusion]Long-term continu-ous cropping of highland barley leads to depletion of carbon and nitrogen,accumulation of potassium,fluctuation in phosphorus availability,and disruption of nutrient balances in the rhizosphere soil.It also significantly suppresses key soil enzyme activities.The coordinated deterio-ration of soil physio-chemical properties and enzyme activity is a critical mechanism underlying the formation of continuous cropping obstacles in highland barley.