京津冀接壤区土壤表土层中碳酸钙的分布规律

通过对京津冀接壤区表层土壤进行网格化调查与采样,采用气量法测定样品碳酸钙含量,运用GIS软件进行Kriging插值,分析区域表土层中碳酸钙含量的空间分布特征,在与区域地貌类型、年均降水量、土壤类型进行空间叠加分析的基础上,揭示碳酸钙含量的分布规律及其成因.结果表明:研究区绝大部分表土层中碳酸钙含量在10～110 g/kg,其与气候相似的北美中东部区域土壤中碳酸钙含量相比明显偏高,将对土壤重金属产生一定的抑制作用;部分山地棕壤及淋溶褐土表土层中由于大气干沉降也存有极少量的碳酸钙.碳酸钙分布规律为:东南角子牙新河冲积平原上发育的滨海盐土、西北部怀来盆地及其山麓的石灰岩或风积黄土母质上发育的碳酸盐褐土和潮褐土中碳酸钙含量最多,北部燕山南麓区普通褐土和淋溶褐土、东南部永定河冲积平原上发育的潮土中碳酸钙含量次之,中部潮白河沉积平原上发育的潮土、西部太行山和东北部燕山中上部发育的山地棕壤和山地草甸土中碳酸钙含量最少.在3个相关因素中,地貌是控制表土层碳酸钙含量的主要因素.

Study on the CaCO_3 Content Characteristics in Conterminous Region of Beijing,Tianjin and Hebei

Based on grid(10 km×10 km) investigation and sampling on contiguous region of Beijing,Tianjin and Hebei Province,the contents of CaCO_3 in the topsoils were determined using the gas-volumetric method.The spatial distribution of CaCO_3 contents in the study area was analyzed by using the GIS Kriging interpolation,as well as overlaying with geomorphological type,average annual precipitation,and soil type maps.The results show: 1) The contents of CaCO3 in the topsoils in the study area range from 10 to 110 g/kg,and are distinctly higher than those of the northeastern region of the United States,which might restrain the activity of heavy metals.2) Very few CaCO_3 is partly found in the topsoils of mountain Brown soil and eluvial Cinnamon soils.3) The spatial distribution of CaCO_3 contents in the study area is as follows: the most CaCO_3 contents exist in the Seashore Saline Soils located on Ziya New River Alluvial Plain in the southeast of the study area,as well as the Carbanate Cinnamon soils and the Aquic Cinnamon soils evolved from mother materials of limestone and eolian loess located on the northwestern Huailai Basin and Piedmont; there are relatively less CaCO_3 contents in the Cinnamon soils and eluviated Cinnamon soils developed on the southern piedmont of northern Yan Mountain,as well as the Fluro-aquic soils developed on the alluvial plain of the southeastern Yongding River; the least CaCO_3 contents present in the Fluro-aquic soils developed on the central Chaobai River Alluvial Plain,together with the mountain Brown soils and Alpine meadow soils developed on the middle and upper place of the western Taihang Mountain and the northeastern Yan Mountain.4) The geomorphological type plays a primary role in controlling the distribution of CaCO_3 contents in the topsoils.Also,the human activities impact strongly on the CaCO_3 content in topsoils of the study area.