刈割對蘆葦生物量與土壤有機碳庫之影響

Effect of Mowing on Common Reed Biomass and Soil Organic Carbon Pool

陳昶璋(Chang-Chang Chen)

指導教授 ： 張新軒

共同指導教授 ： 楊棋明(Chi-Ming Yang)

國立臺灣大學/生物資源暨農學院/農藝學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.01490

摘要

土壤有機碳庫是全球碳循環的重要組成部分，也是CO2 減量的重要指標，並且直接影響全球的碳素平衡。蘆葦(Phragmites communis (L.) Trin)為禾本科多年生植物，為溼地主要植物族群，具有淨化水質、維持溼地生物多樣性、藥用、造紙纖維及生質能源作物等多功能。為達到CO2 減量與開發能源作物之目的，本研究以關渡地區河岸泥灘與休耕水田之蘆葦濕地為試驗區域，以連續刈割方式處理，探討刈割對蘆葦生物量與土壤有機碳庫之影響。一般生長之最大生物量，休耕水
田與河岸泥灘分別為16.8 與10.5 Mg ha-1 yr-1。刈割處理後，休耕水田再生蘆葦株高可至151-243 cm，作物生長速率為1.97-5.96 g m-2 day-1，累積生物量為11.3 Mg ha-1(2007 年7 月至2008 年5 月)；河岸泥灘地再生蘆葦株高可至99-125 cm，作物生長速率為1.20-3.78 g m-2 day-1，累積生物量為5.6 Mg ha-1(2007 年9 月至2008 年 5月)。最佳收穫方式是以每年7-8 月進行一次收穫，不但可獲得最大生物量，且不干擾棲地保育。蘆葦藉由根圈沉降能增加土壤有機碳含量，主要影響0-20 cm 深之土壤。刈割與否對土壤有機碳含量之影響未達顯著性差異，顯示連續刈割在短期內不會造成土壤有機碳減少。休耕水田與河岸泥灘在試驗期間表土20 cm 內之土壤有機碳分別增加8.1 與4.5 Mg ha-1，相當於29.6 與16.5 Mg CO2 ha-1，蘆葦草稈每年分別固定27.7 與17.3 Mg CO2 ha-1。在休耕水田與河岸泥灘栽培蘆葦，估計每年分別能固定57.3 與33.8 Mg CO2 ha-1，收穫之草稈可做為生質能源原料。明顯地在未來進行蘆葦栽培可達到多重功能，例如CO2 減量、生質能源生產，並可在經濟與環境保育之間找到平衡點。

關鍵字

蘆葦 ； 刈割 ； 生物量 ； 土壤有機碳(SOC) ； CO2固定

並列摘要

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.

並列關鍵字

common reed ； mowing ； soil organic carbon (SOC) ； CO2 sequestration

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