三江平原小叶章湿地土壤中硝态氮和铵态氮含量的季节变化特征

选择三江平原典型小叶章湿地不同水分带上的两种土壤类型（草甸沼泽土和腐殖质沼泽土）为研究对象，对比研究了二者硝态氮和铵态氮含量的季节变化特征。结果表明，二者不同土层硝态氮含量的季节变化特征差异较大，缺乏相似性，而铵态氮含量的季节变化特征尽管差异较大，但存在一定相似性；二者不同土层硝态氮和铵态氮含量季节变化特征的差异主要与不同生长期植物吸收作用、融雪补给、大气氮沉降、冻层深度、土壤结构和水分条件的差异有关；不同土层硝态氮淋失、对铵态氮的吸附以及不同时期有机氮矿化和硝化一反硝化作用等进行的程度对其也有重要影响；尽管硝态氮和铵态氮含量的季节变化特征在两种土壤不同土层间差别较大，但均可用四次多项式进行模拟，模拟效果比较理想．基本反映了二者硝态氮和铵态氮含量的季节变化特征。图2，表2，参14。

Seasonal Change Characteristics of Nitrate Nitrogen and Ammonium Nitrogen in Typical Calamagrostis angustifolia Wetland Soils of Sanjiang Plain

Two typical soils （ meadow marsh soil and humus marsh soil） , located in zones different in moisture regime in Calamagrostis angustifolia wetland of Sanjiang Plain, were selected as the study objects, and the seasonal change characteristics of nitrate nitrogen （ NO3-N） and ammonia nitrogen （ NH4＋ -N） contents in them were contrastively studied. Results showed that the seasonal change char- acteristics of NO3 -N contents in different layers of the two typical soils were significantly different, with lacked similarity. Comparatively, although the seasonal change characteristics of NH4 -N contents in the two typical soils had differences, some similarities also could be found between them. In general, the differences of seasonal change characteristics of NO3-N and NHf -N contents in different layers of the two typical soils mainly con＇elated with plant absorption in different growth periods, thaw supplement, atmospheric nitrogen （N） deposition, frozen soil depth, soil structure and water conditions. In addition, the NO3 -N leaching, NH4 -N adsorption,organic N min- eralization and nitrification-denitrification in different soil layers also had significant effect on the seasonal change characteristics of NO3 -N and NHf-N contents. Although the seasonal change characteristics of NO3- -N and NHf -N contents in different layers of the two typical soils had significant differences, they all could be fitted by four-order polynomial, and these models gave a good fit, reflecting the seasonal change characteristics of NO3 -N and NH4＋ -N contents in the two typical soils.