振荡浸提时间对不同保存方式土壤NO_3-N和NH_4-N含量测定值的影响

Effect of Oscillation and Extraction Time on Measurement of Content of NO_3-N and NH_4-N in Soil Held by Different Saving Methods

[目的]研究振荡浸提时间对土壤NO3-N、NH4-N测定结果的影响,为土壤氮素研究提供分析测定的理论依据.[方法]采集高、中、低三种肥力灰漠土,2 mol/L KCl溶液作浸提剂,以不同振荡的时间浸提鲜土、冷藏土和冷冻土,用连续流动注射分析仪测定浸提液中NO3-N、NH4-N含量.[结果]不同肥力土壤以不同方式保存后,振荡浸提时间对土壤硝态氮、铵态氮测定结果有明显的影响,鲜土、冷冻土测定结果比冷藏土稳定.振荡浸提30 ～ 60 min时,NO3-N和NH4-N的测定值相对稳定.[结论]从经济、可靠的角度衡量,无论是新鲜土壤,还是冷藏或冷冻土壤,测定土壤矿质氮含量的振荡浸提时间为30 min即可.对于土壤矿质氮含量极高的土壤,振荡浸提时间应延长至60 min.

[Objective] The test aims to study the content of NO3-N and NH4-N in soil influenced by different oscillation and extraction times in order to provide theoretical foundation for analysis and measurement of soil nitrogen research.[Method] The test took high fertility,middle fertility,and low fertility,three gray desert soils as the research objects,2 mol/L KCl solution as the extract liquid and different oscillation times were set to extract the fresh,refrigeration,freezing soil,and continuous flow analyzer was used to detect the content of NO3-N and NH4-N in extract liquid.[Result] While different fertility soils were saved in different methods,oscillation and extraction time had distinct effect on the measurement values of NO3-N、NH4-N in soil,and measurement values of fresh and freezing soil were more steady than refrigeration soil.While oscillation and extraction time at 30 to 60 min,measurement values of NO3-N and NH4-N were stable relatively.[Conclusion] Whatever fresh,refrigeration,or freezing soil were,30 oscillation and extraction minutes time for measuring the content of mineral nitrogen in soil could be considered suitable from the economic and reliable perspective.But for the soil that had high content of mineral nitrogen,the oscillation and extraction time should be extended to 60 min.