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我们对挪威南部山区石南荒地的小型源头集水区冬令时期土壤温度机制进行了操控实验,以研究土壤温度对径流中无机氮浓度和通量的可能影响。实验包括两个集水区土壤的隔热处理,以使土壤在整个冬季保持零上温度;另两个集水区的去除积雪处理,以促使土壤冻结。冬季土壤温度升高增加了春季径流中铵氮(NH_4)和硝酸盐(NO_3)的浓度和通量。相反,去除积雪覆盖,土壤显著冻结,则对无机氮浓度和通量没有系统的影响。我们的实验结果表明,暖冬较高的土壤温度或者较厚的积雪覆盖意味着这一地区无机氮淋溶的风险更大,而雪盖减少导致的土壤冻结事件,造成的无机氮淋溶增加的风险则不大。
We conducted a pilot experiment on the soil temperature regime during the winter months in the small source catchments in the heathland of southern Heisland, Norway, to study the possible effects of soil temperature on inorganic nitrogen concentrations and fluxes in runoff. The experiment consisted of adiabatic treatment of the soil in the two catchment areas to keep the soil at zero temperature throughout the winter, and the other two catchments were de-aerated to cool the soil. Winter soil temperature increased the spring runoff ammonium nitrogen (NH 4) and nitrate (NO 3) concentration and flux. In contrast, removal of snow cover and significant soil freezing have no systematic effect on inorganic nitrogen concentration and flux. Our experimental results show that the higher soil temperature or thicker snow cover in warm winters implies a greater risk of inorganic nitrogen leaching in this area and a decrease in snow cover leading to soil freezing events resulting in an increase in inorganic nitrogen leaching The risk is not big.