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International Agrophysics |
wydawca: | Instytut Agrofizyki
im. B. Dobrzańskiego
PAN
w Lublinie |
ISSN: |
0236-8722 |
vol. 16, nr. 3 (2002)
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poprzedni artykuł wróć do listy artykułów następny artykuł |
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Structural and Zn-binding features of ortho- and pyrophosphate modified soil metal-humus sorbents (Features of P-modified humus sorbents) |
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Kudeyarova A.Yu. |
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Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, 142290 Pushchino Moscow Region, Russia |
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vol. 16 (2002), nr. 3,
pp. 197-202
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streszczenie
The results of the experiments showed that the P treatment considerably enhanced the Zn-binding capability of acid soil. The contribution of ortho- and pyro-P to Zn binding was that they changed the structure of humus ligands in the sorbing metal-humus complexes. This was clearly demonstrated with the Fe-HA complex as a simulator of soil sorbent. New double carbon- carbon and phosphorus-oxygen bonds were discovered in the P-modified humic ligand of the Fe-HA complex. Their accumu- lation provided an explanation for the enhancement of Zn binding by P-treated soil. In addition to P=O bonds, the C=C bonds should also be considered as functional groups capable of metal ion bin- ding. Because of the greater number of electron-donor groups in the pyro-P-modified humus ligand, the pyro-P-treated soil bound Zn more firmly than the ortho-P-treated one. The dissimilar struc- ture of the control and ortho-, pyro-P-modified humus ligands had a direct relationship with the capability of microflora to adapt to the rising Zn pollution of soil. As compared with control, toxic action of Zn compounds was even enhanced by ortho-P although its addition to soil promoted the Zn binding. On the contrary, pyro-P addition to soil reduced the toxic action of Zn compounds. Con- sequently, the capability of soil to bind external Zn into inert and nontoxic compounds depends on the structural features of humus ligands in surface metal-humus complexes which are of a great importance as sorption barriers.
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słowa kluczowe
humus ligand structure, phosphate fertilizers, zinc binding
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