Pedosphere 26(1): 120--129, 2016
ISSN 1002-0160/CN 32-1315/P
©2016 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Influence of long-term fertilization on selenium accumulation in soil and uptake by crops |
WANG Qing-Yun1, ZHANG Jia-Bao1 , ZHAO Bing-Zi1, XIN Xiu-Li1, DENG Xi-Hai1 and Hai-Lin ZHANG2 |
1State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)
2Plant and Soil Sciences Department, Oklahoma State University, Stillwater, OK 74078 (USA) |
| ABSTRACT |
| 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 4 replications 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 fertilizer (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. |
| Key Words: agricultural soil, essential nutrient, fertilizer practices, Se deficiency, Se fractions |
| Citation: Wang, Q. Y., Zhang, J. B., Zhao, B. Z., Xin, X. L., Deng, X. H. and Lin, Z. 2016. Influence of long-term fertilization on selenium accumulation in soil and uptake by crops. Pedosphere. 26(1): 120-129. |
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