Phytolith carbon sequestration in China's croplands

• A recent found persistent carbon sink is C occluded within plant phytoliths.
• The Chinese cropland phytolith C sink contributes 18% of world's croplands.
• The predominant phytolith producing crop species were rice, wheat and corn.
• The sink has doubled since 1978 due to fertilizer application and irrigation.
• Management practices may further enhance the cropland phytolith C sink.

A relatively recent found persistent component of the carbon (C) sink is C occluded within plant phytoliths. We constructed a silica–phytolith content transfer function and used crop production data to explore the phytolith C sink within China's croplands. The purposes of the study are to offer references for agricultural management and contribute to mitigating climate change. The Chinese cropland phytolith sink represented approximately 18% of world's croplands (24.39 ± 8.67 Tg yr−1) and sequestered 4.39 ± 1.56 Tg yr−1 of carbon dioxide (CO2); more than the USA or India. The predominant crop species were rice (Oryza sativa L., 40%), wheat (Triticum sp., 18%) and corn (Zea mays, 30%), while the main contributing areas were the midsouthern (28%) and eastern (26%) Chinese regions. The sink has doubled since 1978 owing to fertilizer application and irrigation. Therefore, fertilizer application and irrigation in conjunction with other management practices (such as crop pattern optimization) may further enhance the cropland phytolith C sink and thereby mitigate climate change.