Igor Vyacheslavovich Danilin

Igor V. Danilin

Lomonosov Moscow State University

E-mail: danilin.i@mail.ru

About author Publications

1-st year Master's student of the Department of Soil Chemistry, Faculty of Soil Science

Extractable potassium compounds in the rhizosphere of Norway maple in podzolic soils
Moscow University Bulletin. Series 17. Soil science. 2019. 2. p.21-27

Igor V. Danilin Tatyana A. Sokolova Alexey V. Kiryushin Yulia G. Izosimova

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654
- The concentrations of potassium were measured in 1 М NH₄OAc, 2 M HCl, and hot 10% HCl extracts from samples of the rhizosphere of Norway maple ( Acer platanoides ) and of bulk soil taken in five replicates from the (AO)EL horizon of a podzolic soil. The rhizosphere soil was found to contain reliably more exchangeable potassium due to higher content of OM and more potassium compounds extractable with hot 10% HCl. According to the existing guidelines on growing the leaf-bearing trees the rhizosphere soil and the bulk soil can be referred to highly and moderately provided with available potassium respectively. The higher content of potassium soluble in hot 10% HCl in the rhizosphere soil can be explained by the dissolution of the finest poorly crystallized illite particles. These particles can be accumulated in the rhizosphere soil due to intensification of two processes: illitization and physical disintegration of illite particles enhanced by growing roots.
  
  Keywords: illitization; exchangeable potassium; non-exchangeable potassium; potassium buffering system
The mineral composition of clay subfractions in the rhizosphere of the norway maple (Acer platanoides L.) and in the soil of the inner-atmospheric space
Moscow University Bulletin. Series 17. Soil science. 2025. 1. p.8-15

Igor V. Danilin Inna I. Tolpeshta Yulia G. Izosimova

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- The fractionation of the clay fraction was carried out and the mineral composition of clay and its subfractions in the soil of the rhizosphere of the Norway maple (Acer platanoides L.) and in the bulk soil from the AELoa horizon of podzolic soil was studied. It was found that the clay fraction is dominated by a 1‒0.2 microns subfraction (56% in the rhizosphere of maple and 60% in the bulk soil) and contains 20% of 0.2‒0.06 microns subfraction in the rhizosphere and 27% of this fraction in the bulk soil. The content of 0.06‒0.02 and <0.02 microns subfractions did not exceed 10%. A significant increase was revealed in the proportion of 0.06‒0.02 microns subfraction and a decrease in the proportion of <0.02 microns subfraction in the rhizosphere compared with the bulk soil. The size fractions of clay both in the rhizosphere and in the bulk soil are differentiated by their mineral composition. The 1‒0.2 microns fraction is dominated by kaolinite; the proportion of micas increased and the proportion of kaolinite decreased in the 0.2‒0.02 microns fraction, while in the <0.02 microns fraction the proportion of labile minerals significantly increases. There was no significant difference in the mineral composition of the clay fraction and the 1‒0.2 microns subfraction. It was found that the 0.2‒0.02 microns subfraction in the rhizosphere contains significantly more labile minerals compared to the bulk one, which are a result of intensively occurring mica transformation processes into labile structures in the rhizosphere.
  
  Keywords: clay minerals; podzolic soils; X-ray diffractometry; soil organic matter; rhizospheric processes