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| 1 | Influence of Long-Term Fertilization on Selenium Accumulation in Soil and Uptake by Crops显示文摘Continuous applications of organic and inorganic fertilizers can affect soil and food quality with respect to selenium(Se) concentrations.A long-term(over 20 years) experimental field study,started in 1989,was conducted to investigate the changes in soil Se fractions and its uptake by crops,as affected by different fertilizer practices,in the North China Plain with an annual crop rotation of winter wheat and summer maize.The long-term experiment was arranged in a complete randomized block design consisting of 4replications with 7 fertilizer treatments:1) organic compost(OC),2) half organic compost plus half N-P-K chemical fertilizers(OC+ NPK),3) N-P-K fertilizers(NPK),4) N-P fertilizers(NP),5) P-K fertilizers(PK),6) N-K fertilizers(NK),and 7) an un-amended control.Soil samples from the surface(20 cm) were collected in 1989,1994,1999,2004 and 2009 to characterize Se and other soil properties.In 2009,the average soil Se concentrations in the treatments(149 ± 8 μg kg^(-1)) were higher than those in the soil samples collected in 1989 at the beginning of the experiment(112 ± 4 μg kg^(-1)),and decreased in the order of OC > OC + NPK > NPK≈NP > PK ≈NK > control.Sequential extraction showed the oxidizable fraction(50.06%± 3.94%) was the dominant form of Se in the soil,followed by the residual fraction(24.12%± 2.89%),exchangeable fraction(15.09%± 4.34%) and Fe-Mn oxides fraction(10.73%± 4.04%).With an increase of soil K,the exchangeable Se concentrations in the soil increased.The Se concentrations in the soil tillage layer(0-20 cm) were mainly related to soil organic carbon(SOC),although different contributions came from atmospheric deposition,irrigation and fertilizers.With the accumulation of SOC,the uptakes of soil Se by two crops were inhibited.For the OC and OC + NPK treatments,Se concentrations in wheat grains were lower than the critical standard of Se in stable food(100 μg kg^(-1)).Additionally,Se concentrations in grains were also decreased by the deficiencies of major soil nutrients,especially P. | WANG Qingyun ZHANG Jiabao ZHAO Bingzi XIN Xiuli DENG Xihai Hailin ZHANG | 2016 | Pedosphere2016，26，1： | 12 |
| 2 | Effect of Lanthanum Accumulation on Cation Exchange Capacity and Solution Composition of Red Soil显示文摘Pot and adsorption-exchange experiments were carried out by collecting the soil samples from the surface layer(0-15cm) of red soil at the Ecological Experiment Station of Red Soil,the Chinese Academy of Sciences,in Jiangxi Province of CHina.When concentration of the exogenous La^3+ exceeded 400mg kg^-1,there was less non-exchangeable La^3+ than exchangeable La^3+ in the soil.Cation exchagne capacity of the soil changed slightly with increasing concentration of the exogenous La^3+ in both experiments.However,in the adsorption-exchange experiment,when concentration of the exogenous La^3+ was higher than 300mg kg^-1,exchangeable basic cations decreased significantly,while exchangeable hydrogen and exchangeable aluminum increased significantly compared with the control treatments.The amounts of base cations(Ca^2+,Mg^2+,k^+and Na^+)exchanged by La^3+ in the supernatant solution increased with the concentration of the exogenous La^3+,especially when concentration of the exogenous La^3+ was higher than 50mg kg^-1. | XIE ZUBIN ZHU JIANGUO CHU HAIYAN CAO ZHIHONG and DENG XIHAI(Institute of Soil Science, the Chinese Academy of Sciences, P.O. Box 821, Naviing 210008 China) | 2000 | Pedosphere2000，10，2： | 6 |
| 3 | Comprehensive evaluation of heavy metal contamination of sediment in Lake Dianchi by using modified AHP method and ^(137)Cs dating显示文摘Through the use of general sampling and measurement by ^(137)Cs dating,problems regarding the absence of monitoring data can easily be resolved.Further,weighted values need to be determined while Environment Quality Comprehensive Index(EQCI)is commonly used as applied in environmental quality comprehensive evaluation.In order to overcome the subjectivity in determining weights,the modified Analytical Hierarchy Process(AHP)method was designed.The modified AHP method involved the following key procedures:First,the parameters y_(i1) and y_(i2) were calculated based on the monitoring data;second,the factors were put in order according to the symbol and value of y_(i1) and y_(i2);third,the continuous odd integers,which represented the importance of factors,were given to factors according to their seating order;and,fourth,the factor weights were determined from the pair-wise comparison matrix calculated by the ratio of the given odd integers.Therefore,the weights were completely based on the monitoring data.In the present study,the comprehensive quality of sediments in five sections of Lake Dianchi were evaluated and the results indicated that the current contamination of sediments in each lake section is much more serious than at any other time in history. | Yan ZHANG Xiang GAO Zhenyu ZHONG Xihai DENG Buzhuo PENG | 2008 | Frontiers of Environmental Science & Engineering2008，2，3： | 4 |
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