Silicon in attapulgite is mainly present in the stable siloxane tetrahedral crystal structure, and the proportion that can be directly absorbed by crops is very low. The absorption process and mechanism of its silicon elements are as follows:
1.Slow natural release
The porous structure of attapulgite will gradually weather in the soil. The active silicon elements on the surface are dissolved out in the form of monosilicic acid (H₄SiO₄), which is the available silicon form that can be directly absorbed by crops. It enters the plant through the silicon transporters in crop roots.
2.Modification and activation to improve absorption efficiency
After modification treatments such as acid leaching and thermal activation, part of the crystal structure of attapulgite is destroyed. The silicon elements originally wrapped in the crystal lattice are largely released as available silicon, which greatly increases the concentration of soluble monosilicic acid in the soil and enables crop roots to absorb and utilize it more efficiently.
3.Carrier slow-release for synergistic effect
The inherent adsorption characteristics of attapulgite can adsorb the dissolved available silicon in its pores, preventing the silicon elements from being rapidly fixed by the soil. This achieves slow and continuous release, allowing crops to stably absorb silicon elements throughout the entire growth period. It promotes the formation of silicified cells in the stems and leaves of plants, and improves the resistance to lodging, diseases and pests.
According to relevant data from December 2024, when natural attapulgite is applied directly, the release amount of available silicon is limited. After being matched with activation modification processes, the crop absorption rate of silicon can be significantly improved.