Soil fertility Effect of Active Si on Phosphate State in Sod-Podzolic Soils

Samples of the upper horizon of sod-podzolic virgin and arable soil were incubated with lime or superphosphate, then amorphous silicon dioxide was introduced in doses from 50 to 5000 kg/ha and incubated again for 2 weeks. The content of water-soluble and acid-soluble forms of silicon in soils was determined and the fractional composition of phosphorus compounds was analyzed. It is shown that an increase in the concentration of monosilicon acid in the soil solution of sod-podzolic soil initiated the processes of transformation of phosphorus compounds, leading to a decrease in the proportion of insoluble forms of phosphorus and an increase in the phosphorus content available to plants. The introduction of lime or phosphorus fertilizer contributed to the strengthening of these transformational processes, which is important for the development of recommendations for the practical application of silicon fertilizers and the reduction of doses of phosphorus fertilizers.