黄河三角洲潮汐性和短暂性淹水湿地土壤硝态氮时空分布特征

Spatial and Temporal Distribution Characteristic of Nitrate Nitrogen in Soils of Tidal and Short-term Flooding Wetlands in Yellow River Delta

以黄河三角洲典型样带湿地为研究对象,对比研究了潮汐性淹水湿地（样带A）和短暂性淹水湿地（样带B）土壤硝态氮含量图谱的时空分布特征及其与土壤理化性质的关系.结果表明,样带A的硝态氮含量呈现春季低、夏季和秋季高的变化趋势,而样带B的变化趋势与之相反;两类湿地土壤硝态氮都富集在土壤表层,其含量由表层向下逐渐减少;硝态氮含量的变异系数都为中等变异水平,且其在0～20 cm土层的变异系数比在20～40 cm土层的大;样带B不同剖面土壤硝态氮含量都高于样带A,表明潮汐性淹水湿地不利于硝态氮在土壤中的积累;样带A土壤硝态氮含量的空间分布格局在8月和11月呈现一定的相似性,样带B土壤硝态氮含量的空间分布格局在11月和4月呈现一定的相似性;样带A的土壤硝态氮含量与土壤盐分之间存在显著的正相关关系,样带B的土壤硝态氮含量与土壤容重显著负相关,与有机质含量和全氮含量显著正相关.

Two typical sampling belts （Zones A and B）were chosen in the Yellow River Delta to compare the spatial and temporal distribution characteristic of nitrate nitrogen in the soils from both tidal and short-term flooding wetlands and to identify the relationship between nitrate nitrogen and other physical and chemical properties of the soils in both wetlands. The results showed that the contents of nitrate nitrogen in the soils of Zone A were lower in spring （April） whereas they were higher in both summer （August） and fall （November）, whereas an opposite tendency was observed in Zone B. Nitrate nitrogen mainly concentrated in surface soils and decreased gradually with depth along soil profiles. The coefficients of variation of nitrate nitrogen exhibit- ed moderate levels of variability, and the coefficient of variation for the 0-20 cm soil layer was higher than that for the 20-40 cm soil layer. Nitrate nitrogen contents in Zone B were higher at all soil layers than those in Zone A, demonstrating that tidal flooding could not improve the accumulation of nitrate nitrogen. The nitrate nitrogen in Zone A showed similar spatial and temporal distribution patterns in August and November, where- as the similar distribution patterns were observed in November and April in Zone B. Correlation analysis showed that there was significantly positive correlation between nitrate nitrogen content and salinity in Zone A, however, in Zone B, nitrate nitrogen content was significantly positively correlated with soil organic matter and total nitrogen contents, meanwhile, a remarkable negative correlation was observed between nitrate nitro- gen content and soil bulk density.