Dynamics of Accumulation and Disappearance of Zirconium-95 in the Maize/Soil and Soybean/Soil Ecosystem
玉米-土壤和大豆-土壤体系中95 Zr的消长动态

The dynamics of accumulation and disappearance of 95Zr in two kinds crop-soil ecosystem was studied by using isotope-tracer techniques for simulated pollutants, and the fitting equation was confirmed by application of the closed tow-compartment model and nonlinear regression method. The results showed: 1. The Zirconium-95 absorbed from soil main retention in root of the maize and soybean, and the specific activity of 95Zr in root increased with time slowly, then tended dynamics balance gradually after a period of time. The specific activity of rest parts was lower, and biggish parts were background activity level, which indicated that the 95Zr absorbed by roots was difficult of transference and transportation in the maize and soybean. 2. The 95Zr in soil main retention in surface layer soil(0-8 cm), and the rate of it's activity and total activity > 97.5%, which indicated that the 95Zr absorbed by surface soil could not readily move downwards with percolating water. 3. The regression equation of accumulation and disappearance of 95Zr in the maize and soybean were Cm(t) = 3.2067(1 - e-0.1582t) and Cb(t) = 3.0925(1- e -0.1363t) by analyzing the experiment data with exponential regression method. The results of squared deviations analyzing indicated that each regression equation could describe the dynamics of accumulation and disappearance of 95Zr in the maize-soil and soybean-soil ecosystems preferably.