Earth Science Frontiers ›› 2008, Vol. 15 ›› Issue (5): 23-35.
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School of Earth Sciences and Resources, China University of Geosciences(Beijing), Beijing 100083, China
Online:
Published:
Abstract:
Chengdu economic region is selected as an example for ecogeochemical assessment
of agroecosystem for Cd 58 samples of dry and wet atmospheric deposition, 86 of chemical
fertilizers, 121 of irrigation water and 276 of plants were collected Concentrations of Cd
and other elements in those samples were analyzed and fluxes of input and output for the
agroecosystem were calculated The results indicated that Cd was more concentrated in the
surface soil than in the deep one and Cd concentrations in some rice samples exceeded the
standards for the pollution free agricultural products The flux of Cd inputting to the
agroecosystem is averaged to 1776 g/(hm2·a), accounting for 8520% of the total input
flux Water Downward infiltrating (234 g/(hm2·a)) and crop harvesting (187 g/(hm2·a))
are the two maximal Cd outputs The average increasing rate of Cd content in soil resulted
from sources outside of the agroecosystem is 0006 mg/(kg·a) It was forecasted that the
area of the third class soil would increase by 23 times under the condition of constant
input and output fluxes of Cd The rate of acidification is 0106 a-1 and the contribution
of chemical fertilization for soil acidification is 8962%, preponderating over that of
acid rain The study of ecogeochemical alarming indicated that though 95% of rice
production was safe at present, however, 70% of safe soil would degenerate to ecumenical
one, and the area of soil in alarm would increase from 4% to 27%
Key words: Key words: ecogeochemical assessment; agroecosystem; Cd; Chengdu economic region
Key words: ecogeochemical assessment; agroecosystem; Cd; Chengdu economic region
CLC Number:
X142
P595
YANG Zhong-Fang HOU Jing-Xie TU Chao CHEN Jia-Wei JIA Hua-Ji HUANG Yong LI Kuo. An example of ecogeochemical assessment for agroecosystems: a study of Cd in Chengdu economic region[J]. Earth Science Frontiers, 2008, 15(5): 23-35.
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