| Summary: | 碩士 === 國立臺灣大學 === 農藝學研究所 === 96 === Common reed (Phragmites communis (L.) Trin) is a perennial plant of Gramineae. It is an important marshy species and has multiple functions of wastewater treatment, maintain of wetland biodiversity, medicinal plant, pulp and bio-alcohol crop. Soil organic carbon (SOC) pool plays a main role of the global carbon cycle. It is an important indicator of CO2 reduction and directly affects the global carbon balance. The objective of this study is to investigate the effects of continuous mowing on common reed yield and SOC pool of fallow paddy and river stand in Guandu, Taipei, Taiwan. The maximum yields of fallow paddy and river strand are 16.8 and 10.5 Mg ha-1 year-1, respectively. In the fallow paddy, the plant height was 151-243 cm; crop growth rate was 1.96-5.96 g m-2 day-1; and the accumulative yield was 11.3 Mg ha-1 (from July, 2007 to May, 2008) with continuous mowing. In the river strand, the plant height was 99-125 cm; crop growth rate was 1.20-3.78 g m-2 day-1; and the accumulative yield was 5.6 Mg ha-1 (from September, 2007 to May, 2008) with mowing. Mowing once in the period between July and August is the best harvest practice to gain not only maximal biomass but also less interference of habitat conservation. Common reed enriched the SOC content by rhizodeposition and affected top 20 cm soil mainly. There is no significant difference between SOC contents with and without mowing in both experiment sites. It suggests that short term continuous mowing didn’t decrease SOC content. During experimental period, the total SOC in top 20 cm soil increased 8.1 and 4.5 Mg ha-1 in fallow paddy and river strand, respectively, equivalent to decrease in 29.6 and 16.5 Mg CO2 ha-1, respectively, and the CO2 sequestration of reed shoot were 27.7 and 17.3 Mg CO2 ha-1. Therefore, common reed cultivation is estimated to sequestrate 57.3 and 33.8 Mg CO2 ha-1 in fallow paddy and in river strand, respectively, and the mowed shoot can supply bioenergy production. In conclusion, cultivating common reed in the future could conduct multiple functions, such as the CO2 reduction, bioenergy production, and balance between economic and environment conservation.
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