陕北黄土区微地形土壤有效水饱和度

摘要

为了明确不同微地形土壤有效水饱和度的特征以及与植被群落特征的关系,采用小波分析、回归分析和Mann-Kendall趋势检验等方法,分析了陕北黄土区阳向陡坡不同微地形0～60 cm土层深度的土壤有效水饱和度.结果表明:(1)在0～～60 cm土层深度范围内,不同微地形土壤有效水饱和度顺序为塌陷＜缓台＜原状坡＜切沟＜浅沟＜陡坎,其中切沟、塌陷和陡坎的土壤有效水饱和度呈现显著增加趋势,浅沟、缓台和原状坡的土壤有效水饱和度呈现下降趋势,但趋势不显著;(2)研究期间,不同微地形土壤有效水饱和度的变化周期不同,陡坎、塌陷和缓台的主周期相同,为22个月,浅沟、切沟和原状坡的主周期分别为23、21个月和28个月;(3)在不同微地形中,Nargalef丰富度指数、Shannon-Wiener多样性指数、Simpson多样性指数和Alatalo均匀度指数均与土壤有效水饱和度呈正相关关系,其中Shannon-Wiener多样性指数和土壤有效水饱和度的相关性最高.%The paper investigated the saturation of available soil water at soil depths of 0 ～ 60 cm for sunny,steep slope micro-topography in a loess area of north Shaanxi on the basis of wavelet analysis,regression analysis,and the Mann-Kendall trend test,aiming to clarify the characteristics of saturation of available soil water in different micro-to-pographies and its relationship with plant community characteristics.The following findings were made:(1) At soil depths of 0～ 60 cm,in terms of the saturation of available soil water,different landform units can be ranked in the following ascending order:collapse,platform,undisturbed slope,gully,shallow gully,and scarp.The sattwation of available soil water of the gully,collapse,and scarp increased significantly;the saturation of the available soil water of the shallow gully,platform,and undisturbed slope showed a downward trend,but the trend was not significant.(2) During the study period,the main cycles of different micro-topographies were different.Scarp,collapse,and platform had the same main cycle.The main cycles of the shallow gully,gully,and undisturbed slope were 23,21,and 28 months,respectively.(3) In different micro-topographies,the Margalef richness,Simpson diversity,Shannon-Wiener diversity,and Pielou evenness indices were positively correlated with the saturation of available soil water.The highest correlation was found between the Shannon-Wiener diversity index and the saturation of available soil water.