黄河三角洲典型潮滩湿地土壤硝态氮和铵态氮的空间分布特征

Spatial Distribution Patterns of Nitrate Nitrogen and Ammonia Nitrogen in Typical Tidal Marsh Soils of Yellow River Delta

运用地统计学方法研究了黄河口滨岸潮滩湿地土壤中硝态氮和铵态氮的空间分布格局。结果表明,潮滩湿地土壤NO3--N和NH4+-N的水平变异性在不同土层差异较大,较高的水平变异性主要与其在潮滩湿地良好水分条件下较为活跃的物理运移特性有关;潮滩湿地表层土壤NO3--N的水平分布具有明显的空间结构,符合高斯模型,并具有中等程度的空间相关性;自然结构因素在引起NO3--N空间异质性中的贡献占优,随机因素的影响相对较小;表层土壤NO3--N的空间变异性以向低潮滩延伸且受潮汐涨落影响较大的方向最大;潮滩湿地表层土壤的NO3--N具有明显的空间分布格局,表现出向低潮滩延伸方向形成明显斑块低值区,边缘则形成斑块高值区的特征。微地貌特征和潮汐微域物理扰动强度是导致空间异质性的两个重要随机因素,而水盐条件、土壤类型和潮汐物理扰动是3个重要结构因素。

Spatial distribution patterns of nitrate nitrogen and ammonia nitrogen were studied in the tidal marsh soils of the Yellow River Delta by geo-statistical methods.The results showed that the NO-3—N and NH＋4—N contents had significant horizontal variability in different soil layers,which was mainly correlated with their active physical transport characteristics caused by the better water conditions in the tidal marsh.The horizontal distribution of NO-3—N in topsoil displayed significant spatial structure,which can be best fitted with Gaussian model and had moderate spatial correlation.The natural structure factors had significant effects on the spatial variability,while the effects of random factors were relatively low.The maximum spatial variability of NO-3—N in topsoil was observed in the direction extending towards the low tidal marsh,showing a great effect by the ebbs and flows of tide.The spatial distribution patterns of NO-3—N in topsoil were significant.The low NO-3—N contents in topsoil were generally observed on the sites close to low tidal marshes,while the high values appeared on the edges of the study area.This study indicated that micro-physiognomy characteristics and tidal micro-domain physical disturbance were the two most important random factors inducing spatial heterogeneity,while water and salinity conditions,soil types and tidal circulation were three important structure factors.