Korean J. Soil Sci. Fert. Vol.51, No.4, pp.317-326, 2018 Korean Journal of Soil Science and Fertilizer Short communication https://doi.org/10.7745/kjssf.2018.51.4.317 pissn : 0367-6315 eissn : 2288-2162 Development of Soil Organic Carbon Reference for Advancing National Greenhouse Gas Inventory Seong-Jin Park*, Chang-Hoon Lee, Myung-Sook Kim, and Seok-Cheol Kim Soil & Fertilizer Division, National Institute of Agricultural Sciences, RDA, Wanju 55365, Korea *Corresponding author: archha98@korea.kr A B S T R A C T Received: September 10, 2018 Revised: October 31, 2018 Accepted: November 2, 2018 Soil Organic Carbon (SOC) plays an important role in the global carbon cycle and climate change. The carbon stored in soil is estimated to be 2-3 times of the atmosphere s carbon. In this study, we estimated SOC storage at national scale and generated country specific factor related Soil Organic Carbon reference (SOCref) alternative IPCC s default value. The soil data was collected about 5,052 pedons and 21,170 layers by Korean Rural Development Adminstration (RDA) from 1970 to 1999. Because of lacking of bulk density (BD), we generated BD using Adam s equation (1999) and used to equal-area smoothing spline depth function for calculating carbon density. The analytical results showed that the total amount of soil organic carbon in South Korea was about 395 megaton, and that the average carbon density was about 45.7 ton C ha -1. The average and confidence interval of carbon density according to IPCC classification s 4 categories ; Sandy, Low Activity Clay (LAC), High Activity Clay (HAC), and Volcanic soil type were 19.7±4.5 Mg C ha -1, 37.6±2.1, 39.1±16.2, and 127.8±16.4 respectively. We also compared the SOCref to 2006 IPCC Guideline s default value. The results showed SOCref of Sandy, LAC soil type and HAC was lower, and Volcanic soil type was higher than IPCC s default value. This study presents basic data and an analysis method for carbon stock and storage study and also provides scientific support for policy making efforts to control CO 2 emission in South Korea. Keywords: Soil Organic Carbon, Carbon storage, SOC reference Soil Organic Carbon reference (SOCref) of South Korea according to IPCC s soil type classification Soil Type No. of soil series Mean (SOCref) SD Min Max CI (95%) Sandy 30 19.7 12.6 3.8 49.5 4.5 34 LAC (Low Activity Clay) 321 37.6 19.6 4.6 135.2 2.1 63 HAC (High Activity Clay) 7 39.1 21.9 9.5 78.9 16.2 88 Volcanic 45 127.8 56.1 9.8 224.2 16.4 80 IPCC default C The Korean Society of Soil Science and Fertilizer. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non- Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
318 Korean Journal of Soil Science and Fertilizer Vol. 51, No. 4, 2018 Introduction 토양속유기탄소는동식물의유체가섞여들어간생명활동의산물로써흙을부드럽게하고흙속동식물의영양분을공급하는역할을한다. 토양은이러한유기탄소를토양에저장함으로써기후변화의원인이되는이산화탄소를가두어두는저장고의역할을한다. 따라서기후변화완화를위해얼마나많은탄소가토양에축적되어있으며얼마나더많은탄소를저장할수있을지에대한연구가최근활발히이루어지고있다. Batjes (1995) 는전지구의토양의 2 m, 1 m, 30 cm 깊이에각각 2,157-2,293 Pg (10 15 g), 1,462-1,548, 684-724의탄소가저장돼있다고하였고, Eswaran et al. (1995) 은 1 m 깊이에 1,576 Pg의탄소가저장돼있다고한바있다. 이는대기중탄소량인 750 Pg C (IPCC, 2003) 의 2-3배에해당하는양이다. 자연상태의토양에서탄소의함량을좌우하는주요요인으로는온도, 강수량, 증발산량및모재등이있다. 온도의상승과적절한습도는토양미생물의활동을좋게하고유기물의분해를촉진해대기중으로토양탄소배출량을증가시키고, 모재는자연적으로토양이가진탄소의함량을결정한다. 이러한조건외에도토지이용이나토지관리방법에따라서도토양내탄소의함량이달라진다. 우리나라토양의모재는대부분이화강편마암으로유기물함량이적은무기질토양으로구성되어있다. 무기질토양은광질토양이라고도하며암석이기계적풍화작용에의해형성된파편이나화학적풍화과정에서형성된 2차광물로일반적으로유기탄소의함량이 12% 미만이다. 2015년파리협정 ( 제 21차유엔기후변화협약 ) 에따라모든국가는 2030년까지온실가스감축목표를설정하고목표를달성하기위한노력을기울이도록약속한바있다. 그중 LULUCF (Land Use, Land Use Change and Forestry) 분야는토양탄소축적량변화에의한이산화탄소배출량산정 보고하고있다 (NIR, 2017). IPCC (Intergovernmental Panel on Climate Change) 는 2003 GPG (Good Practice Guidance) 와 IPCC 2006 가이드라인에서토양탄소축적변화량산정을위한방법론을제공하고있는데토양탄소축적변화량산정은기후대에따른토양종류별기본탄소값 (Soil Organic Carbon reference, SOCref) 에면적을곱하여산정하는방식이다. 산정방법에따라 IPCC의기본탄소값 (default) 을사용할경우 Tier 1, 자국의환경에맞는탄소값을개발해적용할경우 Tier 2로수준을구분한다. 현재우리나라는개발된국가고유계수가없어 Tier 1 수준으로온실가스배출량을산정하고있다. 반면 Annex 1 국가에포함되어있는일본은자국의토양분류체계에따라 7가지의토양목 (order) 별고유계수를개발해적용하고있으며국토면적이상대적으로큰호주는표본조사를통해 1 km 1 km 격자단위의평균탄소함량을고유계수로사용하고있다. 우리나라도토양탄소축적계수개발을통해토지지용변화에따른온실가스변화량산정방법의고도화노력이필요하며, 국가탄소저장량의정확한산정을통해기후변화에적극적으로대응하고국가온실가스감축목표달성에동참할수있다. 그러나국가전체를대표할수있을만큼의시료지점수확보가어렵고용적밀도와자갈함량데이터의부재와깊이별로함량을보유하고있는데이터의부재로인해지금까지연구가미흡하였다. 따라서본연구에서는시군별정밀토양조사자료를활용하여기본토양탄소축적계수 (SOCref) 에대한국가고유계수를개발하고국가단위의탄소저장량산정을하고자하였다. Materials and Methods Database (DB) 전국을대표할수있는토양 DB를활용하기위해시군별정밀토양조사사업 ( 약 70-99, 농촌진흥청 ) 의 5,052 지점 (pedon), 21,170 층위 (layer) 를이용하였다 (Table 1). 토양 DB에는유기탄소축적량산정에필요
Development of Soil Organic Carbon Reference for Advancing National Greenhouse Gas Inventory 319 한모래, 미사, 점토비율, 자갈함량, 유기물함량, 토양통구분, 토성및기타이화학성 (ph, CEC, 양이온등 ) 을포함하고있다. Table 1. Descriptive statistics of using soil database. No. of layers unit Mean SD Min Max ph 20,923 5.71 0.81 0.02 9.90 Organic matter 20,915 % 1.55 1.74 0.01 67.23 Sand 21,170 % 42.71 23.88 0.00 99.60 Silt 21,160 % 38.02 16.73 0.00 89.70 Clay 21,162 % 19.25 10.77 0.00 74.70 Gravel 13,805 % 13.12 14.44 0.00 88.30 SD : Standard deviation. 토양층위표준화토양통별로조사된데이터는깊이가상이하여층위별표준화를위해 Equal-area spline profile function을이용하였다 (Bishop et al., 1999). Spline function은측정된층위별데이터를곡선으로이어용적밀도와유기물함량을 1 cm 간격의층위별데이터로변환할수있다. 본연구에서는 IPCC의고유계수산정을위해토양깊이를 0-30 cm로표준화하였다. 이를위해 R software의 ithir 패키지에있는 es-spline Tool을이용하였고최적화를위한 lambda (smoothing parameter) 값은 0.1을적용하였다 (Malone et al., 2009). 용적밀도추정시군별정밀토양조사자료에는용적밀도를포함하고있지않기때문에 Hong (2010) 등의선행연구에서이뤄진 Mineral bulk density 산정식과 Adams (1973) 의식을이용하여용적밀도를계산하였다 (Eq. 1, Eq. 1-1). 또한용적밀도가낮고유기물함량이많을것으로예상되는화산회토의경우 Tempel (1996) 과 Hong et al. (2013) 의산정식에따라구분하여산정하였다 (Eq. 2). Eq. 1. Equation of predicting Bulk Density (BDmin) Eq. 1-1. Equation of predicting Mineral Bulk Density BD min =1.017+0.0032*sand+0.054*log(depth)
320 Korean Journal of Soil Science and Fertilizer Vol. 51, No. 4, 2018 Eq. 2. Equation of predicting volcanic soil s Bulk Density (BDmin) log 토양통별 carbon density, SOC storage 토양통별로 0-30 cm 깊이의탄소함량을추정하기위하여 IPCC 지침이참조하고있는 Batjes (1996) 식을이용하여계산하였다. 이때 carbon concentration은유기물 (Organic matter) 의함량에전환계수 1.724를곱하여구하였고, 깊이는각층위의평균깊이를적용하였다. 전국토양통별분포면적은토양도 (Korean soil map) 을이용하여산출하고우리나라전체면적대비국가탄소저장량을구하였다 (Eq. 3, Eq. 3-1). Eq. 3. Equation of calculating SOC density Where, Bi is the Bulk density (g cm -3 ) Ci is Carbon concentration (g kg -1 ) Di is the thickness (cm) Gi is the gravel and stone content (%) Eq. 3-1. Calculation of total SOC storage Where, SOCdi is SOC density (ton C ha -1 ) Ai, is area of south korea 10-3 is conversion factor. 토양분류및고유계수 IPCC에서는기본토양유기탄소축적계수 (SOCref) 를기후대에따라 6가지로토양형 (HAC, LAC, SANDY, VOLCANIC, WETLAND, SPODIC) 으로구분하여제공하고있다 (Table 2). 국가고유계수개발을위한방법중신뢰도를높일수있는가장좋은방법은 IPCC의분류체계에따라토양형을구분하는것이다. 이번연구에서도시군별정밀토양조사자료를이용한토양형구분을위해 IPCC 기준을적용하였다 (Table 3). Sandy형은모래함량이 70% 이상, 점토함량이 8% 미만인토양으로가장먼저분류한후 WRB 분류의 Andosol과 USDA의 Andisol로분류된토양을 Volcanic 토양으로구분하였다. 마지막으로 HAC와 LAC형토양의구분은 CEC 24를기준으로이상인것은 HAC에포함하고미만인것은 LAC로분류하여각토양형별로 carbon density의평균과오차범위 (95%) 를적용해국가고유계수를산정하였다.
Development of Soil Organic Carbon Reference for Advancing National Greenhouse Gas Inventory 321 Table 2. IPCC s default reference value of SOC for mineral soils. Unit: C ton ha -1 (0-30cm depth) Climate region HAC 1) LAC 2) Sandy 3) Spodic 4) Volcanic 5) wetland 6) Boreal 68 NA 10 # 117 20 146 Cold temperate, dry 50 33 34 NA 20 Cold temperate, moist 95 85 71 115 130 87 Warm temperate, dry 38 24 19 NA 70 Warm temperate, moist 88 63 34 NA 80 88 Tropical, dry 38 35 31 NA 50 Tropical, moist 65 47 39 NA 70 Tropical, wet 44 60 66 NA 130 86 Tropical montane 88 63 34 NA 80 NA denotes not applicable because these soils do not normally occur in some climate zones. Table 3. Methodology of classification according to IPCC guideline. 4 categories IPCC s methodology Applied methodology Sandy Volcanics HAC LAC Sand >70% and Clay <8% (WRB) Arenosols (USDA) Psamments (Suborder) (WRB) Andosols (USDA) Andisols(Order) (WRB) Leptosols, Vertisols, Kastanozems, Chernozems, Chernozems, Phaeozems, Luvisols, Alisols, Albeluvisols, Solonetz, Calcisols, Cypsisols, Umbrisols, Cambisols, Regosols (USDA) Mollisols, Vertisols, based-alfisols, Aridisols, Inceptisols (WRB) Acrisols, Lixisols, Nitisols, Ferralsols, Durisols (USDA) Ultisols, Oxisols, acidic Alfisols Sand >70% and Clay <8% Andisols CEC: 24 cmol/kg CEC: <24 cmol/kg Results and Discussion 토양층위표준화 (Spline depth method) Fig. 1에서보는바와같이시군별정밀토양조사자료의조사층위가통별로상이하다. 1(a) 는 5개층위에서유기물함량이조사된반면, 1(b) 에서는 4개층위, 1(c) 에서는 3개층위만자료가존재하므로 0 에서 30 cm 까지 1 cm 간격의데이터를얻기위해 Spline depth function을이용하였다. 결과적으로 1) Soils with high activity clay (HAC) minerals are lightly to moderately weathered soils, which are dominated by 2:1 silicate clay minerals (in the World Reference Base for Soil Resources (WRB) classification these include Leptosols, Vertisols, Kastanozems, Chernozems, Phaeozems, Luvisols, Alisols, Albeluvisols, Solonetz, Calcisols, Gypsisols, Umbrisols, Cambisols, Regosols; in USDA classification includes Mollisols, Vertisols, high-base status Alfisols, Aridisols, Inceptisols). 2) Soils with low activity clay (LAC) minerals are highly weathered soils, dominated by 1:1 clay minerals and amorphous iron and aluminium oxides (in WRB classification includes Acrisols, Lixisols, Nitisols, Ferralsols, Durisols; in USDA classification includes Ultisols, Oxisols, acidic Alfisols). 3) Includes all soils (regardless of taxonomic classification) having > 70% sand and < 8% clay, based on standard textural analyses (in WRB classification includes Arenosols; in USDA classification includes Psamments). 4) Soils exhibiting strong podzolization (in WRB classification includes Podzols; in USDA classification Spodosols) 5) Soils derived from volcanic ash with allophanic mineralogy (in WRB classification Andosols; in USDA classification Andisols) 6) Soils with restricted drainage leading to periodic flooding and anaerobic conditions (in WRB classification Gleysols; in USDA classification Aquic suborders).
322 Korean Journal of Soil Science and Fertilizer Vol. 51, No. 4, 2018 1(a) 와같이대부분잘적용이되었으나몇몇토양데이터는 1(b) 와같이상위표층과하위층과의함량차가많아비정상적으로감소 (30-35 cm) 하는부분이발생하였다. 또한유기물함량이매우낮을경우추세선이음수가되어결국전체깊이에서의함량이과소평가되는결과를가져오게되는데이런경우음수는삭제하고 0으로보정하였다. 비록몇몇토양통들에서이런문제가나타났지만대부분의토양통에서 Spline depth function은층위별데이터를생산해내는데유용하였다. (a) (b) (c) Fig. 1. Performance of spline depth function fitted the OM concentration. Bulk density, carbon density 405개토양통에서 0-30 cm 깊이의표준화된데이터를이용하여용적밀도와 carbon density를산정하고그평균값을 Table 4에나타내었다. 용적밀도의평균은 1.15였고중앙값은 1.16으로일반적으로알려진용적밀도함량인 1.3 보다낮았다. 이는낮은용적밀도를갖는 Volcanic형토양이많이포함되었기때문인것으로판단된다. 용적밀도의최솟값은 Andisol 계열의 PYEONGDAE 통이었고, 최댓값은사질계열의 Entisols 토양인 INSANG 통이었다. Carbon density는평균 45.7 t C ha -1, 중앙값은 35.1 t C ha -1 이었으며, 최솟값과최댓값의범위가 4.8에서 224.2였다. Carbon density는사질계열인 INSANG 통에서가장낮은함량을보였고 Andisol에속하는 TOPYEONG 통이가장높은함량을가진것으로조사되었다. Table 4. Bulk density and Carbon density splined data. Soil series (n = 405) Unit Mean Mid Min Max BD g cm -3 1.15 1.16 Carbon density t C ha -1 45.7 35.1 0.56 PYEONGDAE series 3.8 INSANG series 1.46 INSANG series 224.2 TOPYEONG series Soil type 분류국내의토양분류체계는미국농무성 (USDA) 의분류기준인 Soil taxonomy를따르고토양통 (Soil series) 을기본단위로상위분류항목인토양목 (order) 과아목 (suborder) 으로구분되어있다. Table 2에는토양형별자연식생하에서의기후대별기본토양유기탄소의축적량인 SORref 인용값을나타내고있다. 강우량과증발산량을기준으로우리나라는난온대습윤 (Warm temperate, moist) 의기후대에속하며이때적용가능한인용값을보여준다.
Development of Soil Organic Carbon Reference for Advancing National Greenhouse Gas Inventory 323 IPCC 가이드라인은토양분류를위해세계토양분류체계 (WRB) 와 Soil taxonomy 에속하는토양목, 아목의예시를보여주는데우리나라의토양목을 IPCC 분류체계에직접적용하면다음과같이몇가지문제가발생한다. 첫째, HAC 토양을구분하기위한 high-base status Alfisol과둘째, LAC 분류를위한 Acid-Alfisol이분류되어있지않고, 셋째, Volcanic 토양구분은 WRB 의 Andosol 과 USDA의 Andisol 의분류가일치하지않는다. 따라서 IPCC 분류기준 (Table 3) 을통해투명성을확보하고자하였고그결과, 우리나라의모든토양통 (405 개 ) 을 IPCC 토양형에맞추어 4가지토양형 (Soil Type) 으로재분류하였다. 분류결과아곡통, 봉산통등 324개의토양통이 LAC에포함되었으며, 안덕통, 우도통등 45개가 Volcanic 통에속하였다. Sandy 형은백수통, 인상통, 하곡통등 30개의토양통이포함되고모산통, 정자통등 7개의토양통이 HAC로분류되었다 (Table 5). 무기질토양외의유기질토양으로구분되는이호통과, 용호통은그외의토양분류로표시하였다. 토양도 (Soil map) 를이용하여각토양형이차지하는면적비율을살펴보면 LAC (9634944 ha, 96%) > Sandy (161586 ha, 1.6%) > Volcanic (135491 ha, 1.35%) > HAC (80291 ha, 0.88%) 형순이었다. 우리나라전체면적의 0.003% 에해당되는유기질토양 (Histosols) 은용호통과이호통두개의토양통으로구분되었고분류방법상 HAC 토양에포함되었다. 4개토양형의국내분포는 Fig. 2와같다. LAC형분포는전국의대부분을차지하며 Sandy형토양은전국에널리불규칙하게분포되어있다. 반면 Volcanic형토양은제주도와울릉도부분에밀집되어있으며 HAC 형토양은강원도일대에주로분포하는것으로나타났다 (Fig. 2). SOC reference, SOC storage Table 4의평균값과중앙값은조사지점에대한평균값으로, 토양분류와분포면적에대한고려가없었기때문에우리나라전체의단위면적 (ha) 당평균함량이라고할수는없다. 국가고유계수를위해 IPCC 분류기준에따라토양형을분류하여우리나라토양형별탄소 SOCref를계산한결과는 Table 6과같다. 우리나라에존재하는 4가지토양형인 Sandy, LAC, HAC, Volcanic 형토양들의 carbon density는각각 19.7±4.5 t C ha -1, 37.6±2.1, 39.1±16.2, 127.8±18.1로분석되었다. 우리나라의평균기온, 강수량등을고려하면난온대 / 습윤기후대에속하게되는데이때 IPCC가제공하는기본값은 Sandy, LAC, HAC, Volcanic 형에서각각 34, 63, 88, 80 이다. 즉, Fig. 2. Spatial distribution of soil type by IPCC in South Korea.
324 Korean Journal of Soil Science and Fertilizer Vol. 51, No. 4, 2018 Table 5. The result of classification by IPCC soil type. Classification Sandy (30 series) (161586 ha) Volcanics (45 series) (135491 ha) HAC (7 series) (80291 ha) LAC (321 series) (9634944 ha) Extra (2 series, 0.003%) Soil series BAEGSU, BICHEON, CHUNCHEON, DAEBON, DAEHEUL, DAIN, DEOGGYE, DOSAN, GAPA, GWACHEON, HAERI, HAGGOG, HASA, HONGCHEON, HWABONG, HWANGRYONG, IBSEOG, JANGCHEON, MYEONGJI, NAGCHEON, NAGDONG, NOEGOG, ONPYEONG, SADONG, SADU, SINDAB, TOGYE, YEOMPO, DOAM, INSANG ANDEOG, ARA, BYEONGAG, EUIGUI, GAMSAN, GUJWA, GUNSAN, HAENGWEON, HANGYEONG, HANRIM, HEUGAG INSEONG, JEOGAG JEONGBANG, JUNGEOM, JUNGMUN, MIAG, MINAG, NAMWEON, NOGSAN, NONGO, NORO, PYEONGDAE, PYOSEON, SEONGIN, SINEOM, SONGAG, SONGDANG, TOPYEONG, TOSAN, UDO, ULREUNG, WEOLSAN, WUIMI, BONGSEONG, GEUMAG, GIMYEONG, HAMO, HOESU, ALBONG, ANDEOG, HONGMUN, NARI, SANBANG, WEOLRYEONG JEONGJA, JUGAM, MAESAN, MITAN, MOSAN, DOKDO, INOG ABGOG, AEWEOL, AGOG, AGYANG, ANGYE, ANMI, ANRYONG, ASAN, BAEGGU, BAEGRYEONG, BAEGSAN, BANCHEON, BANGGI, BANGGOG, BANGOG, BANHO, BANSAN, BEOMPYEONG, BIGOG, BOGCHEON, BOGNAE, BONGGOG, BONGGYE, BONGNAM, BONGRIM, BONGSAN, BONRYANG, BUGOG, BUGPYEONG, BUYEO, BUYONG, CHAHANG, CHANGGOG, CHANGPYEONG, CHEOLWEON, CHEONBU, CHEONGGYE, CHEONGOG, CHEONGPUNG, CHEONGRYONG, CHEONGSAN, CHEONGSIM, CHEONGWEON, CHEONPYEONG, CHILGOG, CHILWEON, CHOBONG, CHOGYE, CHOJEONG, CHUGYE, CHUNDO, CHUNPO, CHUSAN, DAEGOG, DAEGU, DAEHEUNG, DAEJEONG, DAEPYEONG, DAESAN, DAEWEON, DALCHEON, DALDONG, DANBUG, DANSEONG, DAPYEONG, DEOGCHEON, DEOGGOG, DEOGHA, DEOGPYEONG, DEOGSAN, DEUNGGU, DOCHEON, DODONG, DOGOG, DOGYE, DOJEON, DONGAM, DONGGUI, DONGHO, DONGHONG, DONGSONG, EUISEONG, EUMSEONG, EUNGOG, GACHEON, GAGHWA, GAGOG, GALGOG, GALJEON, GAMCHEON, GAMGOG, GANGDONG, GANGJEONG, GANGJIN, GANGREUNG, GANGSEO, GAPO, GEUMCHEON, GEUMGOG, GEUMJI, GEUMJIN, GEUMSEO, GEUNSAN, GIMHAE, GIMJE, GOCHEON, GOESAN, GOHEUNG, GONGDEOG, GONGSAN, GONGSEONG, GOPYEONG, GORYEONG, GOSAN, GUEOM, GUGOG, GUISAN, GUPO, GWANAG, GWANGHWAL, GWANGJU, GWANGPO, GWANGSAN, GWARIM, GYEONGSAN, GYORAE, GYUAM, HABIN, HAEAN, HAECHEOG, HAENGGOG, HAENGSAN, HAGPO, HAGSAN, HAGSEONG, HAJEONG, HAMCHANG, HAMPYEONG, HAWEON, HEUGSEOG, HEUNGPYEONG, HOEGOG, HOGYE, HONAM, HWADONG, HWASAN, HWASU, HWASUN, HYANGHO, HYANGMOG, HYOCHEON, ICHEON, IDO, IHYEON, ILPYEONG, IMDONG, IMGOG, IMJA, IMOG, IMSAN, INJE, ISAN, IWEON, JANGGYE, JANGHO, JANGPA, JANGSAN, JANGSEONG, JANGWEON, JANGYU, JECHEON, JEJU, JEODONG, JEOMGOG, JEONBUG, JEONGDONG, JEONGEUB, JEONNAM, JIGOG, JINCHEON, JINDO, JINGOG, JINMOG, JISAN, JOCHEON, JONGGOG, JUCHEON, JUGGOG, JUGOG, JUNGDONG, MAEBONG, MAEGOG, MAGOG, MAJI, MANGSIL, MANGYEONG, MANSEONG, MARYEONG, MASAN, MISAN, MIWEON, MUDEUNG, MUI, MULGEUM, MUNGYEONG, MUNPO, MUREUNG, NAGSAN, NAGSEO, NAMGOG,NAMGYE,NAMPYEONG,NAMSAN,NASAN,NOGJEON,NONSAN,OCHEON,ODAE,OESAN,OGCHEON,OGDONG,OGGYE,OPYEONG,ORA,OSAN,PAJU,PANGOG,PODU,POGOG, PORI, POSEUNG, PUNGCHEON, PYEONGAN, PYEONGCHANG, PYEONGHAE, PYEONGJEON, PYEONGTAEG, RYUCHEON, SACHON, SAMAM, SAMGAG, SANCHEONG, SANGJU, SANGYE, SARA, SEOGCHEON, SEOGGYE, SEOGTO, SEONGSAN, SEOTAN, SEUNGJU, SIMCHEON, SINBUL, SINGI, SINHEUNG, SINHYEON, SINJEONG, SINPYEONG, SIRYE, SONGJEONG, SONGSAN, SUAM, SUBUG, SUGYE, TAEAN, TAEHWA, TAESAN, TEUGGOG, TONGCHEON, UGOG, UJI, ULSAN, UNBONG, UNGOG, UNGYO, UPYEONG, WANGSAN, WANSAN, WEOLGOG, WEOLJEONG, WEOLPYEONG, WEONGOG, WEONJI, YANGGOG, YECHEON, YEGOG, YEONCHEON, YEONDAE, YEONGDONG, YEONGIL, YEONGOG, YEONGRAG, YEONGSAN, YEONGWEOL, YEOSU, YESAN, YONGDANG, YONGGANG, YONGGOG, YONGGYE, YONGHEUNG, YONGJI, YONGSU, YUGA, YUGOG, YUGYE, YUHA, YUHYEON, YULGOG, YULPO, YUWEON, INCHANG, INDONG, INGA, INGOG, INGWAN, INJI, INSAENG, INWOL, SUSAN, GEUGRAG, NAMYANG IHO, YONGHO
Development of Soil Organic Carbon Reference for Advancing National Greenhouse Gas Inventory 325 Table 6. SOCref of South korea compared with IPCC default (0-30 cm). Soil type (IPCC) No. of soil series Mean SD Min Max CI (95%) Sandy 30 19.7 12.6 3.8 49.5 4.5 34 LAC (Low Activity Clay) 321 37.6 19.6 4.6 135.2 2.1 63 HAC (High Activity Clay) 7 39.1 21.9 9.5 78.9 16.2 88 Volcanic 45 127.8 56.1 9.8 224.2 16.4 80 IPCC default Table 7. Total Soil Organic Carbon storage in South Korea. Soil type (IPCC) Area (ha) SOCref C (Mg) SUM Sandy 161586 19.7 3,183,244 385,912,267 LAC (Low Activity Clay) 9634944 37.6 362,273,894 Mg C HAC (High Activity Clay) 80291 39.1 3,139,378 ( 386 megaton) Volcanic 135491 127.8 17,315,749 IPCC 기본값과비교할때 Sandy 형과 LAC 형은낮은값을보여주었고, HAC형토양은비슷하였다. 그러나 Volcanic soil은 IPCC와비교하여상당히높은값을보였는데이값은 IPCC가제공하는열대다습기후의화산회토인용값과비슷하였다. HAC 형의 95% 신뢰수준이가장컸는데이는두개의유기질토양을포함함으로써최솟값과의편차가커졌고분류된토양통개수가 13개불과했기때문인것으로사료된다. 국가고유계수를적용하여우리나라면적에비례한탄소저장량을산정하면약 395 Mt (Megaton) 이되는것을알수있다 (Table 7). Hong (2010) 등은우리나라토양 1 m 깊이의탄소저장량을산림, 논, 밭, 초지별로각각 249 Gg, 102, 56, 16 이라하였고총양은 423 Gg 이라고하였는데이러한선행연구와비교하여본연구의결과값이적은이유는적용된토양데이터의깊이가다르고자갈함량추정방식에차이가있었기때문인것으로판단된다. Conclusions IPCC가제시하는 4가지토양분류기준을적용하여산정한우리나라 SOCref 값은 Sandy, LAC, HAC, Volcanic 형으로그값은각각 19.7±4.5, 37.6±2.1, 39.1±16.2, 127.8±18.1 t C ha -1 이었다. IPCC의기본값과비교했을때 Sandy, LAC 형은현저히낮았고 HAC 형은비슷한반면, Volcanic 형토양은높은값을나타냈다. 여기에면적을적용해 LULUCF 상에서의온실가스배출량을계산하면토양탄소축적변화량에따른이산화탄소배출량이감소할것으로예상된다. 토양도를기준으로우리나라전체면적 (1001만 ha) 에존재하는토양유기탄소는약 386 Mt (Megaton) 으로계산되었고, ha 당평균함량은 45 Mg C ha -1 이었다. 이들의평균인 1,300 Pg (10 15 ) 을적용하였을때우리나라가가지고있는토양탄소의함량은약 0.03% 에해당된다. 우리나라의전체면적은 1001만 ha로전지구육지면적의 0.065% 를차지하므로우리나라의탄소함량은이전연구에서예측한전세계평균함량에조금못미치는것을알수있다. 본연구에서산정된국내토양종류에따른탄소함량및국가탄소저장량산정에는몇가지한계가존재한다. 먼저, 시군별로조사된자료이므로조사자의견해및실험실의분석오차로인해데이터의일관성이부족할수있다. 또한
326 Korean Journal of Soil Science and Fertilizer Vol. 51, No. 4, 2018 토양층위별용적밀도와자갈함량의추정에따른오차, 기후조건과토지이용등을고려하지않았다는점은추후의연구에서보완해야할점으로보인다. 그럼에도불구하고많은샘플링수의토양프로파일데이터를활용하여층위별로표준화하였고토양형분류를통해토양종류별 carbon density와국가탄소저장량을산정한결과는추후토양탄소량산정및변화량연구에기초가될것으로기대한다. Acknowledgement This study was supported by research project of National Institute of Agricultural Science (PJ00934801), Rural Development Administration, Republic of Korea. References Adams, W.A. 1973. The effect of organic matter on the bulk and true densities of some uncultivated podzolic soil. J. Soil Sci. 24:10-17. Batjes, N.H. 1996. Total carbon and nitrogen in the soils of the world. Eur. J. Soil Sci. 47(2): 151-163. Bishop, T.F.A., A.B. Mcbratnet, and G.M. Laslett. 1999. Modelling soil attribute depth functions with equal- area quadratic smoothing splines. Geoderma. 91:27-45. Eswaran, H., E. Vandenberg, and P. Reich. 1993. Organic-carbon in soils of the world. Soil Sci. Soc. Am. J. 57(1): 192-194. Hong, S.Y., Y.S. Zhang, Y.H. Kim, and M.S. Kim. 2010. A study on estimating soil carbon storage in asian countries and Korea. Korean J. Soil Sci. Fert. 42(4):148-149. IPCC. 1996. IPCC guidelines for national greenhouse gas inventories. IPCC. 2000. Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories. Penman J., Kruger D., Galbally I., Hiraishi T., Nyenzi B., Emmanual S., Buendia L., Hoppaus R., Martinsen T., Meijer J., Miwa K., Tanabe K. (Eds). IPCC/OECD/IEA/IGES. Hayama, Japan. IPCC. 2003. Good Practice Guidance for Land Use, Land-Use Change and Forestry. Penman J., Gytarsky M., Hiraishi T., Krug T., Kruger D., Pipatti R., Buendia L., Miwa K., Ngara T., Tanabe K., Wagner F. (Eds). IPCC/IGES, Hayama, Japan. IPCC. 2006. IPCC guidelines for national greenhouse gas inventories. Korean Statistical Information Service. 2016. Investigation of agricultural area of Korea (1970-2014). http://kosis.kr/ Malone, B.P., A.B. McBratney, B. Minasny, and G.M. Laslett. 2009. Mapping continuous depth functions of soil carbon storage and available water capacity. Geoderma. 154:135-152. Ministry of Environment Greenhouse Gas Inventory and Research Center (GIR), 2017. National Greenhouse Gas Inventory Report of Korea (NIR). National Academy of Agricultural Sciences. 2011. Taxonomical classification of Korean soils. RDA, Suwon, Korea. Rawls, W.J. 1983. Estimating soil bulk density from particle size analysis and organic matter content. Soil Sci. 135: 123-125. Tempel, P., N.G. Batjes, and V.W.P. van Engelen. 1996. IGDP-DIS soil data set for pedotransfer function development. Wageningen.