不同秋眠类型紫花苜蓿根际与非根际土壤理化性质及化学计量特征

Physicochemical Properties and Stoichiometric Characteristics of Rhizosphere and Bulk Soils of Alfalfa of Different Fall Dormancy Types

为探究不同秋眠类型紫花苜蓿根际与非根际土壤理化性质,本研究调查了关中地区种植5年不同秋眠类型紫花苜蓿再生期和休眠期根际与非根际土壤有机碳(Soil organic carbon,SOC)、全氮(Total nitrogen,TN)、全磷(Total phosphorus,TP)及土壤酶活性。结果表明:根际SOC、TN、土壤酶活性及化学计量比显著高于非根际土壤(P<0.05);TP在根际与非根际土壤中无显著差异(P>0.05);休眠期土壤SOC、TN、TP含量整体变化趋势表现为随着秋眠级数递增,养分含量逐渐升高,即强秋眠(D)<半秋眠(SD)<非秋眠(ND),而再生期的表现趋势正好相反。根际与非根际SOC与TN、蔗糖酶活性呈正相关;根际土壤TN与蔗糖酶、蛋白酶活性呈正相关,与脲酶活性呈负相关;非根际土壤TN与蔗糖酶活性呈正相关,与蛋白酶活性呈负相关。本研究结果将有助于进一步探究不同秋眠类型紫花苜蓿土壤营养物质循环与生产力之间的关系及根际土壤的微生态。

To investigate the physicochemical properties and stoichiometric characteristics of rhizosphere and bulk soils of different fall dormant types of alfalfa,this study investigated the organic carbon(SOC),total nitrogen(TN),total phosphorus(TP)and soil enzyme activities of rhizosphere and bulk soil of different fall dormant alfalfa grown in Guanzhong area for five years during spring regrowth and winter dormancy.The results showed that rhizosphere SOC,TN,soil enzyme activities and stoichiometric ratios were significantly higher than those of bulk soil(P<0.05);TP was not significantly different between rhizosphere and bulk soils(P>0.05).During the winter dormancy period,the overall trend of SOC,TN and TP contents showed a gradual increase in nutrient contents with increasing fall dormancy levels(fall dormancy<semi-fall dormancy<non-fall dormancy),while the regrowth period showed the opposite trend.The SOC of rhizosphere and bulk soli was positively correlated with TN and sucrase activity;TN in rhizosphere soil was positively correlated with sucrase and protease activity,and negatively correlated with urease activity.TN in bulk soil was positively correlated with sucrase activity and negatively correlated with protease activity.The results of this study will help to further investigate the relationship between nutrient cycling and productivity of soils and the microecology of rhizosphere soils grown different fall dormancy alfalfa varieties.