- 學位論文
六龜森林土壤碳循環有關酵素活性之研究
The activities of enzymes related to carbon cycle in Liu-Kuei forest soils
摘要
本研究目的為探究六龜森林土壤與碳循環有關之酵素活性及其與土壤性質特別是土壤有機碳含量之關係，並分析土壤有機碳與酵素活性之季節性的變化。本研究在農委會林業試驗所六龜研究中心之試驗林選取台灣杉人工林(N 23˚00΄13˝ E 120˚42΄25˝)與天然闊葉林(N 22˚59΄57˝ E 120˚42΄33˝)，闊葉林以樟科和殼斗科為主，進行其土壤分層(每層20 cm)採樣，並測定與碳循環有關的三種土壤酵素活性(β-配醣酶、β-胺基葡萄糖苷酶及纖維素酶)、微生物生質量、有機碳和其他土壤性質。結果顯示六龜森林土壤與碳循環有關的酵素活性:(1) 土壤β-配醣酶活性，在台灣杉人工林與天然闊葉林分別為1.20-3.06 (平均2.03 ± 0.79)及3.54-5.49 (平均4.18 ± 0.73) μmol p-nitrophenol g-1soil h-1 ，(2) 土壤β-胺基葡萄醣苷酶活性在台灣杉人工林與天然闊葉林分別為1.50-1.86 (平均1.67 ± 0.13)及1.95-4.37 (平均3.00 ± 0.93) μmol p-nitrophenol g-1soil h-1，(3) 土壤纖維素酶活性在台灣杉人工林與天然闊葉林分別為0.0945-0.332 (平均0.23 ± 0.08)及0.399-0.821 (平均0.62 ± 0.15) μmol glucose g-1soil 24 h-1。森林土壤有機碳總量和此三種土壤酵素活性均無顯著之季節性變化但均隨著土壤深度之增加而減少(P < 0.05)。簡單相關分析結果顯示：土壤β-配醣酶、β-胺基葡萄糖苷酶、纖維素酶活性彼此間且均與微生物生質碳、生質氮、全氮及有機碳間呈極顯著之正相關(P < 0.001)，土壤β-胺基葡萄糖苷酶、纖維素酶活性、生質碳、生質氮則均與土壤水分間呈顯著正相關(P < 0.05)。土壤有機碳總量占其森林碳匯池之比重: 台灣杉人工林估計為 61 %，天然闊葉林估計為 47 %。
並列摘要
A Taiwania plantation (N 23˚00΄13˝ E 120˚42΄25˝) and a native hardwood forest, mainly Lauraceae and Fagaceae (N 22˚59΄57˝ E 120˚42΄33˝) in Liu-Kuei, Taiwan were selected to measure the activities of soil enzymes related to carbon cycle and to examine the relations between the enzyme activities and soil properties, especially soil organic carbon, and the seasonal changes in soil organic carbon content and the enzyme activities. The results showed that soil β-glucosidase activities in the Taiwania plantation and native hardwood forests were 1.20-3.06 (average: 2.03 ± 0.79) and 3.54-5.49 (average: 4.18 ± 0.73) μmol p-nitrophenol g-1soil h-1, respectively; soil β-glucosaminidase activities in the Taiwania plantation and native hardwood forests were 1.50-1.86 (average: 1.67 ± 0.13) and 1.95-4.37 (average: 3.00 ± 0.93) μmol p-nitrophenol g-1soil h-1, respectively; and soil cellulase activities in the Taiwania plantation and native hardwood forests were 0.0945-0.332 (average: 0.24 ± 0.08) and 0.399-0.821 (average: 0.62 ± 0.15) μmol glucose g-1soil 24 h-1, respectively. There were no significant seasonal changes in the soil carbon content and the above soil enzyme activities, but all of them significantly decreased with soil depth increased (P < 0.05). The results of simple regression analysis indicated that soil β-glucosidase, β-glucosaminidase, and cellulase activities significantly correlated with microbial biomass C, microbial biomass N, total nitrogen and soil organic carbon (P < 0.001). Soil β-glucosaminidase, cellulose activities, microbial biomass C and N significantly correlated with soil moisture (P < 0.05). The estimated percentages of the total soil organic carbon amounts to the forest carbon sinks were 61 % and 47 % for the Taiwania plantation and native hardwood forests in Liu-Kuei, respectively.