Study On Carbon Sinks Of Soil Phyt Oc In Important Bamboo Plants In Zhejiang Province

Phytoliths are silicified features resulting from the deposition of microscopic Si in the intra-and extra-cellular structures in living plant tissues.During the formation of phytoliths in the plant,a portion of the plant’s organic carbon（0.1-6%）will be incorporated into the phytolith.This part of organiccarbon is called as phytolith-occluded organic carbon（Phyt OC）and is one of the most important mechanisms of carbon sequestration in terrestrial ecosystems on the scale of millennia or even ten thousand years.It plays an important role in regulating the global carbon cycle and mitigating the trend of global warming.Bamboo forest ecosystem is an important part of terrestrial ecosystem.Current studies showed that bamboo forest ecosystem has important scientific significance in carbon sinks,especially for Phyt OC in the plants.Carbon fixation of bamboo forest ecosystem has become a new research hotspot.The carbon content of phytolith is greatly higher than that of other forest trees,so bamboo forest plays an important role in slowing down the greenhouse effect.In the past,the accumulation amount of Phyt OC were calculated from the biomass of the aboveground part of bamboo stands,thus the carbon sink capacity of the bamboo forest ecosystem was greatly underestimate.Since the Phyt OC formed in the plants may be lost,ruptured,and stable change when it enters into the soil,so it is necessary to determine the Phyt OC content in the soils.In this study,the soil samples of bamboo forest in Zhejiang Province were collected by grid method to study the spatial variation characteristics of Phyt OC contents in the soils under bamboo plantation.Moreover,8 kinds of representative bamboo species（Phyllostachys pubescens,Pleioblastus amarus（Keng）Keng f,Phyllostac hys glauca,Phyllostachys prominens,Pseudosasa amabi Lis（Mc Clure）Keng f.,Dianthuschinensis,Cyperus alternifolius,Indocalamus tessellatus（Munro）Keng f）were selected to compared the differences of Phyt OC for 8 kinds of bamboo species and estimate their Phyt OC sinks.The phytolith in the soil samples was extracted through a microwave digestion method and the Phyt OC contents in the samples were determined by a Elementar Vario MAX CN Analyser.The findings of study are as follows:1.Ninty soil samples of bamboo plants in Zhejiang Province were collected to study the carbon spatial distribution of soil silicon.The high Phyt OC contents in the soils was mainly distributed in the southwest and southeast areas in the Zhejiang province,but the low Phyt OC contents in the soils was mainly distributed in the middle part.The Phyt OC contents in the soils were significantly affected by the phytolith contents in the plants,but there was no correlation between Phyt OC contents and nitrogen,phosphorus or potassium in the soils.2 Eight representative bamboo species from the bamboo species of Zhejiang Province were selected to compare the differences of soil Phyt OC.The average Phyt OC contents of the eight species of scattered bamboo were 0.06±0.02-0.97±0.75 g·kg^-1.In 10 cm soil layer,the highest soil Phyt OC content was obtained from Dianthuschinensis stand,whereas the lowest soil Phyt OC content was obtained from Phyllostachys prominens and Pleioblastus amarus（Keng）Keng f satnds.In 10-30 cm soil layer,the highest Phyt OC content was obtained from Dianthuschinensis stand,whereas the lowest Phyt OC content was obtained from Pleioblastus amarus（Keng）Keng f satnd.In 0-100 cm soil layers,Phyt OC content in the soils under 6 bamboo species decreased with soil depth except Pleioblastus amarus（Keng）Keng f and Pseudosasa amabi Lis stands.The total soil Phyt OC storage(5024 kg·ha^-1)of Dianthuschinensis stand was significantly higher than that of other bamboo species(677～2304kg·ha^-1).The total soil Phyt OC storage for 8 scattered bamboo stands in China was 5.46×10⁶t C,among which total soil Phyt OC storage of Phyllostachys pubescens accounted for 98.3%of total soil Phyt OC storage of 8 scattered bamboo stands in China...