三江平原小叶章湿地土壤中碱解氮和全氮含量的季节变化特征

Seasonal change characteristics of alkaline hydrolysis nitrogen and total nitrogen in typical Calamagrostis angustifolia wetland soils of Sanjiang Plain

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,对比研究了二者碱解氮(K-N)和全氮(TN)含量的季节变化特征。结果表明:二者不同土层K-N和TN含量的季节变化特征差异较大,前者0-50 cm土层K-N含量以及0-40 cm土层TN含量的变化最为显著,而后者K-N和TN含量的显著变化仅集中在0-20 cm土层;二者不同土层K-N和TN含量的季节变化与不同生长期植物吸收作用、水分条件、降水、有机氮矿化和硝化-反硝化作用等因素有关。TN含量的季节变化还取决于不同时期根际分泌物的产生量以及枯落物分解与有机氮的矿化平衡;尽管K-N和TN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,基本可反映二者K-N和TN含量的季节变化特征。

Two typical soils （meadow marsh soil and humus marsh soil）, located in different moisture zones in Calamagrostis angustifolia wetland of Sanjiang Plain, were selected as study objects, and the seasonal change characteristics of alkaline hydrolysis nitrogen （ K - N） and total nitrogen （TN） contents in them were contrastively studled. Results showed that the seasonal change characteristics of K - N and TN contents in different layers of the two typical soils were significantly different. The changes of K - N contents in 0 - 50cm layers and TN contents in 0 -40cm layers of meadow marsh soil were signiticant than those m other layers, while the significant changes of K- N and TN contents of humus marsh soil were only observed in 0 - 20era layers. In general, the seasonal changes of K -N and TN contents in different layers of the two typical soils were mainly correlated with plant absorption in different growth periods, water conditions, precipitation, organic nitrogen mineralization and nitrification - denitri- fication etc. In addition, the seasonal changes of TN contents also rested with the production amount of root scoretion in different periods, and the balance of litter decomposition and organic nitrogen mineralization. Although the seasonal change characteristics of K - N and TN contents in different layers of the two typical soils had significant differences, they all could be fitted by fourorder polynomial, and these models gave a good fit, which reflected the seasonal change characteristics of K -N and TN contents in the two typical soils.