The silicon in attapulgite mainly exists in the stable siloxane tetrahedral crystal structure, and the proportion that can be directly absorbed by crops in its natural state is extremely 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 its surface dissolve out in the form of monosilicic acid (H₄SiO₄), which is the available silicon form that crops can directly absorb, and enter the plant body 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 significantly increases the concentration of soluble monosilicic acid in the soil, allowing crop roots to absorb and utilize them more efficiently.
3.Carrier slow-release 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, enabling crops to stably absorb silicon elements throughout the entire growth period, promoting the formation of silicified cells in plant stems and leaves, and improving the resistance to lodging, diseases and pests.
According to relevant data in December 2024, the release amount of available silicon is limited when natural attapulgite is applied directly. After being matched with activation modification processes, the crop absorption rate of silicon can be significantly improved.