喀斯特石漠化过程中土壤氮同位素组成及其空间分异特征

NITROGEN ISOTOPE COMPOSITIONS AND SPATIAL DISTRIBUTION CHARACTERISTICS OF SOIL IN THE PROCESS OF KARST ROCKY DESERTIFICATION

对喀斯特高原区贵州省清镇市王家寨峰丛洼地同一流域内不同类型石漠化、不同等级石漠化以及不同干扰方式石漠化表层土壤全氮的同位素组成及其空间分异特征进行了研究。结果表明:流域内黄壤区样地的表土全氮δ15N值主要分布在+0.35‰～+6.82‰之间,平均值为+4.50‰;黑色石灰土区样地的表土全氮δ15N值主要分布在+2.70‰～+6.50‰之间,平均值为+4.27‰;无论是黄壤区样地还是黑色石灰土区样地,其表土全氮δ15N值在各等级石漠化样地间、不同干扰方式环境下、甚至在不同坡位上都无显著性差异体现,两土壤类型间的总体差异也不显著(P≤0.05),这主要与喀斯特区高度的生境异质性有关。

Isotopic composition and spatial distribution characteristic of the total nitrogen of the surficial soil in karst rocky desertification area,including different types,different grades and different disturbed modes karst rocky desertification within the same small catchment,which belong to the Wangjiazhai peak-cluster depression basin and located in Qingzhen City,Guizhou Province were discussed in this study.Results showed that δ15N values of total nitrogen in top soil in yellow soil area were mainly between ＋0.35‰~＋6.82‰ with the average of ＋4.50‰,and between ＋2.70‰~＋6.50‰ in black calcareous with the average of ＋4.27‰.In both yellow soil area and black calcareous area,there were no significant difference in the δ15N values of total nitrogen on sample lands of rocky desertification at different levels,different ways of interruption and different slope positions,and no obvious difference on the whole（P≤0.05）,which is mainly due to the high habitat heterogeneity of karst area.