摘要
以河南省新乡市娘娘庙污灌区一块约328 m2的田块为研究区,采用均值、变异系数、半方差函数及分维数等相结合的方法,分析一次污水灌溉前后10 d内东西向剖面A、B、C和D(南北向每相距10.5 m设置1个剖面,由北至南依次编号为A、B、C和D)的土壤有效镉的垂向空间变异及其分布特征,为田块土壤中有效态镉分布与土壤植物修复相结合的研究思路提供基础性探讨。结果表明:灌水后,土壤有效镉含量在剖面A、B、C和D的均值分别减少0.06 mg·kg-1、0.11 mg·kg-1、0.14 mg·kg-1和0.23 mg·kg-1,呈现中等离散程度;在0.393~1.308 m变程范围内,块基比C0/(C0+C)〈25%,土壤有效镉剖面总体表现出由随机性引发的变异较小,空间相关性较强;剖面A、C和D土壤有效态镉的分维数降低,空间变异程度减弱。Kriging插值结果表明该区有效镉呈条带状分布格局,且在0~15 cm土层呈现累积现象;沿灌水方向,土壤有效镉含量剖面等值线分布由密集到稀疏。相关分析表明,土壤有效镉含量与土壤有机质含量呈正相关,与土壤含水率呈中等程度相关,与p H呈现强负相关,表现为土壤有机质含量越高土壤有效镉含量越大,p H越高土壤有效镉含量越小;污水灌溉对土壤有效镉、土壤含水率、土壤p H和土壤有机质的影响显著,同时会削弱有效镉与各影响因子间的相关关系。伴随着污水灌溉动态的有效镉分布和变异特征可以为应用植物吸附进行土壤重金属污染修复方面的研究提供基础数据。
There is limited development of agricultural economy in the north area of China that has been irrigated with sewage water for a long time, because of the uneven distribution of water resources and different levels of soil pollution. The main contaminants of sewage irrigation are heavy metals, which contamination area has been expanding over the years. A number of large-scale or multi-scale studies have been conducted on heavy metal pollution in surface soils in irrigated areas.However, studies have less focused on the vertical distribution of heavy metal, but mainly concentrated on the characteristics of migration and leaching of heavy metals in the soil. It is therefore necessary to focus on the vertical cross-sectional view of the spatial variability of soil heavy metals in sewage irrigated areas on a small scale. In this study, we investigated the spatial variability and distribution of available cadmium in the soil after once sewage irrigation. Using classical statistics and geo-statistical techniques, we measured the spatial variability and distribution in a 328 m2 field in the Niangniangmiao sewage irrigation area in Xinxiang, Henan Province. The classical statistical analysis suggested that the mean available cadmium in soil sections A, B, C and D(the south-north sections with 10.5 m away from each other and across the field from north to south)decreased, respectively, by 0.06 mg -kg -1, 0.11 mg -kg -1, 0.14 mg -kg -1 and 0.23 mg -kg -1 after sewage irrigation; suggesting amoderate degree of dispersion. The dispersion in soil section B increased by 4.32%, while it decreased in other sections by9.39%(A), 6.12%(C) and 10.98%(D), all of which were within the 28.31% - 45.16% range after sewage irrigation.Geo-statistical analysis showed that the overall variation in available cadmium in the soil sections was random, C0/(C0+C) 〈25%. Soil available cadmium had a strong spatial correlation within the 0.393 - 1.308 m range. The optimal empirical semi-variogarm models for simulating soil cadmium content for soil sections A, B, C and D were respectively spherical,spherical, Gaussian and exponential modles. Soil profile B had the highest(1.997) fractal dimension of available cadmium.The fractal dimension decreased after sewage irrigation suggesting a weakening spatial variability of soil available cadmium.Structural factors played a decisive role in the vertical spatial variability and distribution of available cadmium in the soil sections. Kriging interpolation suggested a banded distribution pattern. There was significant available cadmium accumulation in the 0-15 cm soil layer. The distribution contour of available cadmium in the soil sections varied from dense to sparse along irrigation direction. Correlation and variance analysis showed that available cadmium content was positively correlated with organic matter content, moderately correlated with soil moisture, strongly negatively correlated with p H. The effect of irrigation on each factor was significantly, moreover, irrigation could dampen the impact of the factors on available cadmium.The results on distribution and variation in soil available cadmium showed leaching and migration of soil available cadmium after sewage irrigation. This was more visible for the 0-15 cm top soil than the 30 -40 cm sub-soil. The spatial variability of soil available cadmium was mainly influenced by soil structural factors. The study provided the primary investigation for phytoremediation of heavy metal in polluted soils.
出处
《中国生态农业学报》
CAS
CSCD
北大核心
2016年第2期235-243,共9页
Chinese Journal of Eco-Agriculture
基金
国家高技术研究发展计划(863计划)课题(2012AA101404)资助~~
关键词
污水灌溉
土壤剖面
有效镉
空间变异性
土壤重金属
Sewage irrigation
Soil profile
Available cadmium
Spatial variability
Heavy metal