南仁山低地雨林三種生育地凋落物及土壤有機碳貯存量之估算

Estimation of Litterfall and Soil Organic Carbon Storage un-der Three Habitat Types in Nanjenshan Lowland Rain Forest

郭家和(Chia-Ho Kuo)

指導教授 ： 陳朝圳 ； 張焜標

國立屏東科技大學/農學院/森林系所/碩士(2012年)

https://doi.org/10.6346/NPUST.2012.00063

摘要

全球土壤碳庫中有機碳及無機碳化合物總合是大氣中碳含量的二倍左右，其中有69%是貯存在森林土壤及枯枝落葉層中。本研究針對南仁山地區三種不同生育地，採集地表上枯枝落葉及土壤深度0-50 cm內之土壤，並將土壤分成0-10 cm、10-30 cm及30-50 cm之土壤層次。分析枯枝落葉層之生物量及有機碳含量，以及不同土壤層次中土壤有機碳含量、總體密度及含石量等，利用結果估算南仁山地區三種不同生育地枯枝落葉層及0-50 cm以內土壤中的碳貯存量。此外收集南仁山1999-2010年間共10年之凋落物，分析不同生育地凋落物量及組成之長期性變化，並測定凋落物碳養分含量，以了解不同生育地凋落物碳養分回歸量，在各凋落物收集網旁設置枯枝落葉袋測定不同生育地凋落物分解速率及碳養分留存率。結果顯示，南仁山地區10年間平均凋落物量為4.91±1.85 t ha-1 yr-1，因受颱風連續性干擾而導致南仁山凋落物量目前有持續的下降之情況。凋落物組成以葉所佔比例最高(67%)，其次為枝條(20%)，最後為花果(13%)。不同生育地類型亦會影響凋落物量，其中溪谷地形之凋落物量最高約6.00±1.72 t ha-1 yr-1，背風坡面約5.04±0.73 t ha-1 yr-1，迎風坡面最低約4.80±0.94 t ha-1 yr-1。每年凋落物碳養分輸入量介於2.44-2.96 t ha-1 yr-1間，在凋落物分解方面以溪谷分解率最高為(k=1.7±1.0 yr-1)、其次為背風坡(k=1.4±0.5 yr-1)、迎風坡(k=1.2±0.6 yr-1)。南仁山不同生育地枯枝落葉層及土壤碳貯存量皆有所差異。在枯枝落葉層碳貯存量方面以迎風坡最高(1.04±0.14 t ha-1)、其次為背風坡(0.87±0.15 t ha-1)、溪谷則為最低(0.64±0.17 t ha-1)。在深度0-50cm土壤碳貯存量方面在不同生育地間也有所差異，以溪谷碳貯存量最高(306.3 t ha-1);其次為背風坡(209.3 t ha-1)及迎風坡(128.6 t ha-1)。利用地理資訊系統分析南仁山不同生育地面積大小，南仁山有57.43%地區坡度在30∘以上，42%坡向多位於東北向，即為南仁山之迎風坡面，其餘58%則屬背風坡地形及溪谷地形。將各生育地面積乘上各生育地土壤碳貯存量，南仁山地區土壤0-50 cm有機碳貯存量分別為向風坡421.28 Kt、背風坡269.57 Kt 及溪谷123.94 Kt，南仁山整體土壤有機碳貯存量為814.79 Kt。

關鍵字

南仁山 ； 碳循環 ； 土壤有機碳 ； 凋落物

並列摘要

The combined organic and inorganic carbonate in global soil carbon pool is about twice the amount contained in the atmosphere, and 69% of it is re-served in forest soil and litter layers. In this study, soil in litter layer and ground less than 50cm in depth in three different habitats in Nanjen Mountain was collected and divided, according to the depth of collection, into three categories: 0-10cm, 10-30cm and 30-50cm. Litter layer’s biomass and organic carbon content, and the organic carbon content, overall density and stone content of the soil collected from different ground depths were analyzed to calculate the carbon reserves of the litter layers and ground less than 50cm in depth in the three different habitats in Nanjen Mountain. In addition, litterfall during the 10-year period between 1999 and 2010 was also gathered to ana-lyze the long-term changes in the litterfall amount and composition in differ-ent habitats. Also, litterfall’s carbon nutrient content was analyzed to under-stand the carbon return amount of the leaf litter in different habitats. Further-more, bags were installed beside litterfall-collecting nets to find out the de-composition rates and carbon nutrient retention rates of the leaf litter in the three different sites. The results showed that the average amount of the plant litter in Nanjen region over the above-mentioned 10-year period was 4.91±1.85 t ha-1yr-1, and had been declining due to the influence of typhoons. Plant litter was mostly composed of leaves (67%), followed by twigs (20%), and flowers and fruits (13%). The amount of leaf litter varied with terrains, of which valley had the high litterfall amount (about 6.00±1.72 t ha-1 yr-1), fol-lowed by leeward slope (about 5.04±0.73 t ha-1 yr-1) and windward slope (about 4.80±0.94 t ha-1 yr-1). The carbon return amount ranged between 2.45 and 2.96 t ha-1 yr-1. It was found that valley had the highest litterfall decom-position rate of 1.7±1.0 yr-1, followed by leeward slope of 1.4±0.5 yr-1, and windward slope of 1.2±0.6 yr-1. The carbon amount contained in the litter layer and soil in Nanjen Mountain varied from habitat to habitat. In terms of litter layer’s carbon content, windward slope was the highest (1.04±0.14 t ha-1), followed by leeward slope (0.87±0.15 t ha-1) and valley (0.64±0.17 t ha-1). Similarly, the carbon content of the soil collected from ground 0-50cm in depth also varied from site to site, with valley being the highest (306.3 t ha-1), followed by leeward slope (209.3 t ha-1) and windward slope (128.6 t ha-1). The analysis of the areas of different habitats in Nanjen Mountain using geographic information system found that about 57.43% of the region had an inclination of 30∘or above, 42% of the region inclined toward northeast, which happened to be Nanjen Mountain’s windward slope, and the rest 58% were made up of leeward slopes and valleys. The carbon reserve of each habitat can be calculated by multiplying the area of a habitat by its soil carbon content. The carbon pool of the soil collected from ground 0-50cm in depth with valley being the highest (421.28 Kt), followed by leeward slope (269.57 t ) and windward slope (123.94 Kt).Consequently,the overall carbon reserve in the soil in Nanjen Mountain region is estimated at 814.79 Kt.

並列關鍵字

Nanjenshan ； Carbon cycle ； Soil carbon ； Litterfall

參考文獻

金絜之 (2008) 南仁山低地雨林凋落物之時空變化研究。國立屏東科技大學森林系碩士論文，92頁。

楊淑瀚 (2007) 溪頭天然闊葉林枯落物及其落葉氮、磷濃度之動態變化。國立台灣大學森林環境暨資源學系碩士論文，83頁。

胡庭恩 (2006) 台灣北部地區主要人工林土壤碳貯存量之估算。國立台灣大學農業化學研究所碩士論文，98頁。

蕭怡茹 (2005) 烏來地區次生林、柳杉林、桂竹林三種林分枯落物量之動態變化。國立台灣大學森林環境暨資源學系碩士論文，44頁。

蔡呈奇、胡庭恩、林國銓、陳尊賢 (2009) 台灣北部地區人工林土壤碳存量的估算。台灣林業科學24(2)：103-115。