冻融作用对含有黑炭土壤中硝态氮淋失的影响

Effect of Freezing and Thawing on the Nitrate Nitrogen Leaching of Soil Contained Black Carbon

在对比分析添加和未添加黑炭以及冻融和未冻融处理土柱淋出液中硝态氮浓度差异基础上,考察研究了不同冻融条件(冻结温度、冻结时间和融化时间)和氮素形态与含有黑炭土壤中硝态氮淋出效果之间的关系。结果表明,黑炭提高了土壤固持硝态氮的能力,冻融降低土壤固持硝态氮的能力,促进了土柱中硝态氮的淋失。在添加KNO_3的土柱淋出液中硝态氮浓度最高,最大值达到96.80mg/L;而添加NH_4Cl的土柱淋出液中硝态氮浓度为最低。冻结温度为-5℃和-25℃处理土柱淋出液中硝态氮的浓度相近,而且均高于冻结温度为-15℃的硝态氮浓度。延长冻结时间和融化时间均会使淋出液中硝态氮的浓度增高。

In this paper, on the basis of contrastive analysis of the nitrate nitrogen concentrations from added or unadded black carbon and freeze thawing or unfrozen treated soil columns, the relationships between the freezing and thawing conditions （freezing temperature, freezing time and melting time） , nitrogen species and the concentrations of nitrate nitrogen in leachates from added black carbon soil nitrate were studied. The results showed that the black carbon improved ability of the soil to hold the nitrate nitrogen and frreezing and thawing reduced the ability of the soil to hold nitrate nitrogen and promoted the loss of nitrate nitrogen in the soil cohmm. The nitrate nitrogen concentration in the leachate from the added KNO3 soil column was the maximum value of 96.80 mg/L. However, that from the added NH4C1 soil column was the lowest. The concentralions of nitrate nitrogen in the leachate from the -5℃ and -25℃ treated soil columns were close and higher than that from the -15℃ treated soil column. Long freezing time and thawing time enhanced the concentrations of nitrate nitrogen in the leachate.