三江平原不同群落小叶章枯落物的季节变化及养分累积特征

Seasonal variations and nutrient accumulation of Deyeuxia angustifolia litter in Sanjiang Plain wetlands,northeastern China

为确定典型湿地植物枯落物养分累积特征及其对植物养分利用的生态学意义,以三江平原不同群落小叶章为研究对象,采用定位采集与监测的方法研究小叶章植物枯落物量、养分含量和累积量的季节动态。结果表明:1)草甸湿地小叶章群落(XCD)和沼泽湿地小叶章群落(XZZ)枯落物量随时间的变化均符合指数增长模型;XCD和XZZ枯落物有机碳含量随时间的变化均符合二次函数模型,有机碳含量呈先减小后增加的变化趋势。2)不同群落小叶章枯落物碳累积量随时间的变化均符合指数增长模型,同一时期的XCD枯落物碳累积量均高于XZZ枯落物的碳累积量。3)XCD和XZZ枯落物氮、磷含量随时间的变化均符合一阶指数衰减模型,XZZ枯落物氮、磷含量随时间变化的波动性较XCD大。4)XCD和XZZ枯落物氮、磷累积量随时间的变化均符合指数增长模型,XCD枯落物氮、磷累积量均高于XZZ枯落物的累积量。5)XCD的群落环境适宜植物养分的吸收利用和归还,有利于小叶章植物的生长。6)磷是XZZ植物适应其群落环境的首要限制性养分,反映了XZZ的淹水环境不适宜小叶章植物的生长。

In order to investigate nutrient accumulation of litter and nutrient utilization efficiencies by wetland plants,we studied the seasonal dynamics of litter production,nutrient content and accumulation in two communities of Deyeuxia angustifolia in the Sanjiang plain of northeastern China. The results show that litter production of D. angustifolia with time could satisfactorily be fitted as an exponential model both in meadow（XCD） and in marsh communities（XZZ）,while organic carbon content in litter of the two communities were fitted quite well with a quadratic model which showed an initial decrease and then an increase over time. Organic carbon accumulation in the litter of the two communities fitted the monotonically increasing exponential model;the accumulation of organic carbon in XCD was higher than that in XZZ. Nitrogen and phosphorus content in the litter of the two communities both fitted the exponential decay model. The contents of nitrogen and phosphorus in XZZ fluctuated more than those in XCD. Nitrogen and phosphorus accumulation in the litter of the two communities fitted the increasing exponential model;the accumulation of nitrogen and phosphorus in XCD were higher than those in XZZ. The results indicate that D. angustifolia in meadows could adapt to absorption,utilization and return of nutrients,which in turn is favorable to plant growth. Phosphorus content is the primary nutrient factor for the adaption of D. angustifolia to the marsh,but excessively high water conditions are not appropriate for the growth of D. angustifolia.