Carbon Occlusion Potential of Rice Phytoliths: Implications for Global Carbon Cycle and Climate Change Mitigation

Abstract

Abstract. Phytoliths are silica bodies produced by plants through bio-mineralization process. During such process, occlusion of carbon (C) also takes place within the phytoliths called phytolith occluded C (PhytOC). The PhyOC is highly stable and may substantially contribute to long-term terrestrial C sequestration. The present study aimed to investigate the phytolith and PhytOC contents variability in rice cultivars and its potential for long-term terrestial C biosequestration.The results indicate that dry matter yield of rice cultivars varied from 15.52 to 28.82 g plant , the global annual potential sink rate of PhytOC in soils through rice phytoliths would approximately be 16.4 Tg-e-CO 2 . Therefore rice crop may play a significant role in long-term C sequestration through PhytOC.

Silicon Fertilizer Application Promotes Phytolith Accumulation in Rice Plants

“…There was a significant correlation between the Si content and the phytolith content of the crop materials, such as the phytolith contents of the rice leaves, stems and sheaths (Song et al, 2014a). The shape of the phytoliths in the different rice organs varied (e.g., double-peaked, bulliform, and parallel dumbbell phytoliths) (Prajapati et al, 2016). Prajapati et al (2016) reported that the phytolith content in the different rice organs (stem, sheath, leaf, and grain) ranged from 0.14 to 26.4 g kg -1 .…”

“…The shape of the phytoliths in the different rice organs varied (e.g., double-peaked, bulliform, and parallel dumbbell phytoliths) (Prajapati et al, 2016). Prajapati et al (2016) reported that the phytolith content in the different rice organs (stem, sheath, leaf, and grain) ranged from 0.14 to 26.4 g kg -1 . Similar results and trends were reported by other researchers (Li et al, 2013c; Guo et al, 2015).…”

“…The global rice cultivation area was approximately 1.64 × 10 8 ha in 2014 (Prajapati et al, 2016); when rice is harvested, the rice straw and husks are removed from the paddy field and used for other purposes, including animal feeding and firewood, or simply incinerated (Savant et al, 1996). Thus, most of the Si taken up by rice is removed from a field when the rice straw is removed, and the loss of SiO 2 is from 75 to 130 kg ha -1 every production season (Zhang et al, 2014).…”

“…Rice is a staple crop, with a global planting area of approximately 1.64 × 10 8 ha as of 2014 (Prajapati et al, 2016). When rice is harvested, the rice straw and husks are removed from the paddy field and used for other purposes, including animal feeding and firewood, or simply incinerated (Savant et al, 1996).…”

Straw phytolith for less hazardous open burning of paddy straw

“…Phytolith makes up from 1.6 to 14.4% of rice (stem, sheath, and leaf) 9,22 , thereby hundreds of million tonnes of phytolith are recycled annually if all world rice residues are returned to the soil instead of exported or used for other purposes. Phytoliths, including fresh phytolith (from straw residue incorporated into soil), ash phytolith (obtained from straw burning) and aged phytoliths (both fresh and ash phytoliths buried in soil), might co-exist in rice field.…”