Occlusion of organic carbon in phytolith (phytOC) is a mechanism for long-term C sequestration.
PhytOC content and production in the above and belowground parts of steppe plants were determined.
PhytOC concentration was significantly higher in below than above ground plant parts.
PhytOC production was at least one order of magnitude greater from below than above ground parts.
Belowground part plays a dominant role in biogeochemical silica cycle and C sequestration.