基于扣除根系体积新方法的秦岭辛家山2种林分土壤有机碳密度特征
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摘要
【目的】比较秦岭辛家山林场云杉和红桦天然林土壤有机碳密度的估算结果,检验新方法通过扣除根系体积而提高的估算精度。【方法】分别估算矿质土层(表土层、心土层和底土层)和有机土层(凋落物的未/半分解层和完全分解层)的有机碳密度。在现有方法的基础上通过扣除林木根系体积含量来提高矿质土层有机碳密度的估算精度。各层林木根系体积含量的估算方法为:首先,使用前人提出的回归方程估算出单株林木根系生物量,乘以林木生长密度得到单位面积林地的根系总生物量;其次,通过采集部分根系样品测定其生物量和体积,并计算出根系样本的密度以代表整体根系的密度;然后,通过单位面积林地的根系总生物量除以根系的密度计算出单位面积林地的根系总体积;最后,利用前人研究得出的根系沿深度的分布规律,将单位面积根系总体积分配到各土层,计算出根系体积含量。对有机土层有机碳密度的估算,使用林木平均地径估算林木根基部所占面积,将有机土层中含有的林木体积扣除。此外,由于有机土层的各组分分布极不均匀,本研究依据来源器官和物理形态对凋落物(有机土层)中的不同成分进行了细致的分组,分别测定各组分的有机碳密度。【结果】云杉林表土层、心土层和底土层的厚度分别为19.10、14.20和31.03 cm,红桦林则分别为18.57、15.13和28.13 cm;云杉林表土层、心土层和底土层的有机碳含量分别为(44.56±3.72)、(25.63±1.77)和(10.79±2.28)g·kg~(-1),红桦林的分别为(34.11±5.46)、(19.06±4.95)和(11.02±3.86)g·kg~(-1); 2种林分有机土层各组分有机碳含量差异显著(P<0.05),凋落物中枝条、根系、云杉球果和苔藓的有机碳含量均大于600 g·kg~(-1),叶片次之,云杉林和红桦林分别为(458.90±46.81)和(420.72±55.66)g·kg~(-1),其余难以分辨的细颗粒含量最低均小于300 g·kg~(-1);在矿质土层,云杉林各层每公顷根系体积(及体积比例)分别为表土层66.81(3.5%)、心土层20.69(1.5%)以及底土层9.18(0.3%)m~3,红桦林则分别为50.57(2.7%)、31.75(2.1%)和17.22(0.6%)m~3;使用改进公式估算的云杉林矿质土层有机碳密度为16.58 kg·m~(-2),有机土层有机碳密度为4.26 kg·m~(-2),完全分解层和半分解层分别占84%和16%,矿质土层和有机土层有机碳密度分别较原方法降低2.13%和0.73%;使用改进公式估算的红桦林矿质土层有机碳密度为14.06 kg·m~(-2),有机土层碳密度为3.49 kg·m~(-2),分解层和半分解层分别占90%和10%,矿质土层和有机土层有机碳密度分别较原方法降低1.61%和0.48%。【结论】去除根系体积含量后,云杉林与红桦林的土壤总有机碳密度估算值分别降低1.85%和1.39%,这意味着目前预测的林地土壤碳储量可能普遍偏高。
【Objective】 Through the comparison among the estimated result of the soil organic carbon density in the spruce(Picea asperata) and red birch(Betula albosinensis) natural forests in the Xinjiashan Forest Farm in Qinling Mountains with different estimation method, we tested the improvement of the new method on estimation accuracy by subtracting the root volume.【Method】 The organic carbon densities of the mineral soil layers(top soil layer, core soil layer and subsoil layer) and organic soil layers(non/semi-decomposed layer namely L + F and fully decomposed layer of litter namely H) were estimated separately. For the estimation of the organic carbon density in the mineral soil layer, the estimation accuracy is improved by deducting the root volume of trees based on the existing method. The method for estimating the volume content of roots in each layer contains 4 steps as follow. Firstly, the root biomass of a single tree was estimated with the regression equations proposed by the previous study, which is multiplied by the growth density of the forest to obtain the total biomass of the roots per unit area of the forest land; secondly, by measuring the biomass and the volume of a partial sample of the root system,the density of the partial root sample is calculated to represent the density of the whole root system; then, the total root volume of the forest area per unit area is calculated by dividing the total biomass of the roots per unit area of the root system by the density of the root system; Finally, according to the distribution result of the root system along the depth obtained in previous studies, the total root volume per unit area is distributed to each soil layer and the content of root volume is calculated. For the estimation of the carbon density of the organic soil layer,the volume of the base of the trunk contained in the organic soil layer is subtracted, which is calculated with the mean ground diameter. In addition, due to the extremely uneven distribution of different components in the organic soil layer, the different components in the litter(organic soil layer) are carefully grouped according to the source organs and physical forms, and the organic carbon content of each component is determined.【Result】 Thicknesses of top soil layer(A), core soil layer(B) and subsoil layer(C) were 19.10, 14.20, 31.03 cm and 18.57, 15.13, 28.13 cm for the spruce and the red birch, respectively. The SOC contents in A, B and C horizons were(44.56±3.72) g·kg~(-1),(25.63±1.77) g·kg~(-1) and(10.79±2.28) g·kg~(-1) respectively for spruce;they were(34.11±5.46) g·kg~(-1),(19.06±4.95) g·kg~(-1) and(11.02±3.86) g·kg~(-1) respectively for red birch. The carbon contents of various components in organic soil layer of the two stands were significantly different(P < 0.05). The organic carbon contents of spruce cones, moss, tree branches and roots in litters were greater than 600 g·kg~(-1). Followed by the organic carbon contents of leaves, which were(458.90±46.81) g·kg~(-1) for spruce forest and(420.72±55.66) g·kg~(-1) for red birch forest. The organic carbon contents of other undistinguishable fine particles was the minimum which were less than 300 g·kg~(-1). The root volumes in A, B and C horizons were 66.81(3.5%), 20.69(1.5%) and 9.18(0.3%) m~3·hm~(-2) respectively for spruce, and they were 50.57(2.7%), 31.75(2.1%) and 17.22(0.6%) m~3·hm~(-1) respectively for red birch. The carbon density of organic soil layers was 4.26 kg·m~(-2) for spruce, less than that of the original method by 0.73%; H and L+F layers accounted for 84% and 16% respectively; the carbon density of mineral soil layers was 16.58 kg·m~(-2), less than that of the original method by 2.13%. The carbon density of organic soil layers was 3.49 kg·m~(-2) for red birch, less than that of the original method by 0.48%; H and L + F layers accounted for 90% and 10%; the carbon density of mineral soil layers was 14.06 kg·m~(-2) for red birch, less than that of the original method by 1.61%.【Conclusion】 The estimated total organic carbon densities of soil in spruce forest and red birch forest decreased by 1.85% and 1.39% respectively after deducting the content of root volume, which suggested that the currently-estimated forest soil carbon storage might be generally higher than the actual value.
【Objective】 Through the comparison among the estimated result of the soil organic carbon density in the spruce(Picea asperata) and red birch(Betula albosinensis) natural forests in the Xinjiashan Forest Farm in Qinling Mountains with different estimation method, we tested the improvement of the new method on estimation accuracy by subtracting the root volume.【Method】 The organic carbon densities of the mineral soil layers(top soil layer, core soil layer and subsoil layer) and organic soil layers(non/semi-decomposed layer namely L + F and fully decomposed layer of litter namely H) were estimated separately. For the estimation of the organic carbon density in the mineral soil layer, the estimation accuracy is improved by deducting the root volume of trees based on the existing method. The method for estimating the volume content of roots in each layer contains 4 steps as follow. Firstly, the root biomass of a single tree was estimated with the regression equations proposed by the previous study, which is multiplied by the growth density of the forest to obtain the total biomass of the roots per unit area of the forest land; secondly, by measuring the biomass and the volume of a partial sample of the root system,the density of the partial root sample is calculated to represent the density of the whole root system; then, the total root volume of the forest area per unit area is calculated by dividing the total biomass of the roots per unit area of the root system by the density of the root system; Finally, according to the distribution result of the root system along the depth obtained in previous studies, the total root volume per unit area is distributed to each soil layer and the content of root volume is calculated. For the estimation of the carbon density of the organic soil layer,the volume of the base of the trunk contained in the organic soil layer is subtracted, which is calculated with the mean ground diameter. In addition, due to the extremely uneven distribution of different components in the organic soil layer, the different components in the litter(organic soil layer) are carefully grouped according to the source organs and physical forms, and the organic carbon content of each component is determined.【Result】 Thicknesses of top soil layer(A), core soil layer(B) and subsoil layer(C) were 19.10, 14.20, 31.03 cm and 18.57, 15.13, 28.13 cm for the spruce and the red birch, respectively. The SOC contents in A, B and C horizons were(44.56±3.72) g·kg~(-1),(25.63±1.77) g·kg~(-1) and(10.79±2.28) g·kg~(-1) respectively for spruce;they were(34.11±5.46) g·kg~(-1),(19.06±4.95) g·kg~(-1) and(11.02±3.86) g·kg~(-1) respectively for red birch. The carbon contents of various components in organic soil layer of the two stands were significantly different(P < 0.05). The organic carbon contents of spruce cones, moss, tree branches and roots in litters were greater than 600 g·kg~(-1). Followed by the organic carbon contents of leaves, which were(458.90±46.81) g·kg~(-1) for spruce forest and(420.72±55.66) g·kg~(-1) for red birch forest. The organic carbon contents of other undistinguishable fine particles was the minimum which were less than 300 g·kg~(-1). The root volumes in A, B and C horizons were 66.81(3.5%), 20.69(1.5%) and 9.18(0.3%) m~3·hm~(-2) respectively for spruce, and they were 50.57(2.7%), 31.75(2.1%) and 17.22(0.6%) m~3·hm~(-1) respectively for red birch. The carbon density of organic soil layers was 4.26 kg·m~(-2) for spruce, less than that of the original method by 0.73%; H and L+F layers accounted for 84% and 16% respectively; the carbon density of mineral soil layers was 16.58 kg·m~(-2), less than that of the original method by 2.13%. The carbon density of organic soil layers was 3.49 kg·m~(-2) for red birch, less than that of the original method by 0.48%; H and L + F layers accounted for 90% and 10%; the carbon density of mineral soil layers was 14.06 kg·m~(-2) for red birch, less than that of the original method by 1.61%.【Conclusion】 The estimated total organic carbon densities of soil in spruce forest and red birch forest decreased by 1.85% and 1.39% respectively after deducting the content of root volume, which suggested that the currently-estimated forest soil carbon storage might be generally higher than the actual value.
引文
白龙龙,李银,侯琳,等.2016.秦岭山地主要森林凋落物化学组分.西北农林科技大学学报:自然科学版,44(5):89-96.(Bai L L,Li Y,Hou L,et al.2016.Chemical composition of litters from main forests in Qinling Mountains.Journal of Northwest A&F University:Natural Science Edition,44(5):89-96.[in Chinese])
鲍士旦.2000.土壤农化分析.3版.北京:中国农业出版社.(Bao S D.2000.Soil agro-chemistricalanalysis.3rd ed.Beijing:China Agriculture Press.[in Chinese])
陈存根,彭鸿.1996.秦岭火地塘林区主要森林类型的现存量和生产力.西北林学院学报,11(S1):92-102.(Chen C G,Peng H.1996.Standing crops and productivity of the major forest type at the Huoditang forest region of the Qinling Mountains.Journal of Northwest Forestry College,11(S1):92-102.[in Chinese])
邓仁菊,杨万勤,张健,等.2007.川西亚高山森林土壤有机层碳、氮、磷储量特征.应用与环境生物学报,13(4):492-496.(Deng R J,Yang W Q,Zhang J,et al.2007.Carbon,nitrogen and phosphorus storage in soil organic layer of the subalpine forests in western Sichuan.Chinese Journal of Applied and Environmental Biology,13(4):492-496.[in Chinese])
高甲荣,肖斌,陈海滨,等.2000.秦岭山地云杉林结构特征与更新动态的研究.林业科学,36 (S1):104-109.(Gao J R,Xiao B,Chen H B,et al.2000.Study on the structure characteristics and regeneration dynamics of Chinese spruce forests in Qinling Mountains.Scientia Silvae Sinicae,36(S1):104-109.[in Chinese])
韩其晟,任宏刚,刘建军,等.2012.秦岭主要森林凋落物中易分解和难分解植物残体含量及比值研究.西北林学院学报,27(5):6-10.(Han Q S,Ren H G,Liu J J,et al.2012.Contents and ratios of the decomposable and resistant plant material in the litters of the main trees in Qingling Mountains.Journal of Northwest Forestry College,27(5):6-10.[in Chinese])
季志平,苏印泉,贺亮,等.2006.秦岭北坡几种人工林根系及土壤有机碳剖面分布特征的研究.西北植物学报,26(10):2155-2158.(Ji Z P,Su Y Q,He L,et al.2006.Root system and organic carbon distributions in soil profiles of several plantations of northern slope of Qinling Mountains.Acta Botanica Boreali-Occidentalia Sinica,26(10):2155-2158.[in Chinese])
康博文,刘建军,党坤良,等.2006.秦岭火地塘林区油松林土壤碳循环研究.应用生态学报,17(5):759-764.(Kang B W,Liu J J,Dang K L,et al.2006.Soil carbon cycle of Pinus tabulaeformis forest in huoditang forest region of Qinling Mountains.Chinese Journal of Applied Ecology,17(5):759-764.[in Chinese])
刘兴良,马钦彦,杨冬生,等.2006.川西山地主要人工林种群根系生物量与生产力.生态学报,26(2):542-551.(Liu X L,Ma Y Q,Yang D S,et al.2006.Studies on root biomass and productivity in dominant plantation populations in the mountainous land in western Sichuan.Acta Ecologica Sinica,26(2):542-551.[in Chinese])
屈冉,李俊生,罗遵兰,等.2010.秦岭太白山土壤CO2的释放特征及温度的影响.华北农学报,25(2):188-193.(Qu R,Li J S,Luo Z L,et al.2010.Character of release of soil CO2 and the impact of temperature in the Taibai Mountain of Qinling.Acta Agriculturae Boreali-Sinica,25(2):188-193.[in Chinese])
王棣,耿增超,佘雕,等.2014.秦岭典型林分土壤活性有机碳及碳储量垂直分布特征.应用生态学报,25(6):1569-1577.(Wang D,Geng Z C,She D,et al.2014.Vertical Distribution of soil active carbon and soil organic carbon storage under different forest types in the Qinling Mountains.Chinese Journal of Applied Ecology,25(6):1569-1577.[in Chinese])
王金叶,车克钧,蒋志荣.2000.祁连山青海云杉林碳平衡研究.西北林学院学报,15(1):9-14.(Wang J Y,Che K J,Jiang Z R.2000.A study on carbon balance of Picea crassifolia in Qilian Mountains.Journal of Northwest Forestry College,15(1):9-14.[in Chinese])
王效科,冯宗炜,欧阳志云.2001.中国森林生态系统的植物碳储量和碳密度研究.应用生态学报,12(1):13-16.(Wang X K,Feng Z W,Ouyang Z Y.2001.Vegetation carbon storage and density of forest ecosystems in China.Chinese Journal of Applied Ecology,12(1):13-16.[in Chinese])
杨玉盛,陈光水,王义祥,等.2006.格氏栲人工林和杉木人工林碳库及分配.林业科学,42(10):43-47.(Yang Y S,Chen G S,Wang Y X,et al.2006.Carbon storage and allocation in Castanopsis kawakamii and Cunninghamia lanceolata plantations in subtropical China.Scientia Silvae Sinicae,42(10):43-47.[in Chinese])
周玉荣,于振良,赵士洞.2000.我国主要森林生态系统碳贮量和碳平衡.植物生态学报,24(5):518-522.(Zhou Y R,Yu Y L,Zhao S D.2000.Carbon storage and budget of major Chinese forest types.Chinese Journal of Plant Ecology,24(5):518-522.[in Chinese])
Batjes N H.1996.Total carbon and nitrogen in the soils of the world.European Journal of Soil Science,47(1):151-163.
De Vos B,Cools N,Ilvesniemi H,et al.2015.Benchmark values for forest soil carbon stocks in Europe:results from a large scale forest soil survey.Geoderma,251/252:33-46.
Labaz B,Galka B,Bogacz A,et al.2014.Factors influencing humus forms and forest litter properties in the mid-mountains under temperate climate of southwestern Poland.Geoderma,230/231:265-273.
Mcdaniel P A,Munn L C.1985.Effect of temperature on organic carbon-texture relationships in Mollisols and Aridisols.Soil Science Society of America Journal,49(6):1486-1489.
Smit A.1999.The impact of grazing on spatial variability of humus profile properties in a grass-encroached Scots pine ecosystem.Catena,36(1):85-98.
鲍士旦.2000.土壤农化分析.3版.北京:中国农业出版社.(Bao S D.2000.Soil agro-chemistricalanalysis.3rd ed.Beijing:China Agriculture Press.[in Chinese])
陈存根,彭鸿.1996.秦岭火地塘林区主要森林类型的现存量和生产力.西北林学院学报,11(S1):92-102.(Chen C G,Peng H.1996.Standing crops and productivity of the major forest type at the Huoditang forest region of the Qinling Mountains.Journal of Northwest Forestry College,11(S1):92-102.[in Chinese])
邓仁菊,杨万勤,张健,等.2007.川西亚高山森林土壤有机层碳、氮、磷储量特征.应用与环境生物学报,13(4):492-496.(Deng R J,Yang W Q,Zhang J,et al.2007.Carbon,nitrogen and phosphorus storage in soil organic layer of the subalpine forests in western Sichuan.Chinese Journal of Applied and Environmental Biology,13(4):492-496.[in Chinese])
高甲荣,肖斌,陈海滨,等.2000.秦岭山地云杉林结构特征与更新动态的研究.林业科学,36 (S1):104-109.(Gao J R,Xiao B,Chen H B,et al.2000.Study on the structure characteristics and regeneration dynamics of Chinese spruce forests in Qinling Mountains.Scientia Silvae Sinicae,36(S1):104-109.[in Chinese])
韩其晟,任宏刚,刘建军,等.2012.秦岭主要森林凋落物中易分解和难分解植物残体含量及比值研究.西北林学院学报,27(5):6-10.(Han Q S,Ren H G,Liu J J,et al.2012.Contents and ratios of the decomposable and resistant plant material in the litters of the main trees in Qingling Mountains.Journal of Northwest Forestry College,27(5):6-10.[in Chinese])
季志平,苏印泉,贺亮,等.2006.秦岭北坡几种人工林根系及土壤有机碳剖面分布特征的研究.西北植物学报,26(10):2155-2158.(Ji Z P,Su Y Q,He L,et al.2006.Root system and organic carbon distributions in soil profiles of several plantations of northern slope of Qinling Mountains.Acta Botanica Boreali-Occidentalia Sinica,26(10):2155-2158.[in Chinese])
康博文,刘建军,党坤良,等.2006.秦岭火地塘林区油松林土壤碳循环研究.应用生态学报,17(5):759-764.(Kang B W,Liu J J,Dang K L,et al.2006.Soil carbon cycle of Pinus tabulaeformis forest in huoditang forest region of Qinling Mountains.Chinese Journal of Applied Ecology,17(5):759-764.[in Chinese])
刘兴良,马钦彦,杨冬生,等.2006.川西山地主要人工林种群根系生物量与生产力.生态学报,26(2):542-551.(Liu X L,Ma Y Q,Yang D S,et al.2006.Studies on root biomass and productivity in dominant plantation populations in the mountainous land in western Sichuan.Acta Ecologica Sinica,26(2):542-551.[in Chinese])
屈冉,李俊生,罗遵兰,等.2010.秦岭太白山土壤CO2的释放特征及温度的影响.华北农学报,25(2):188-193.(Qu R,Li J S,Luo Z L,et al.2010.Character of release of soil CO2 and the impact of temperature in the Taibai Mountain of Qinling.Acta Agriculturae Boreali-Sinica,25(2):188-193.[in Chinese])
王棣,耿增超,佘雕,等.2014.秦岭典型林分土壤活性有机碳及碳储量垂直分布特征.应用生态学报,25(6):1569-1577.(Wang D,Geng Z C,She D,et al.2014.Vertical Distribution of soil active carbon and soil organic carbon storage under different forest types in the Qinling Mountains.Chinese Journal of Applied Ecology,25(6):1569-1577.[in Chinese])
王金叶,车克钧,蒋志荣.2000.祁连山青海云杉林碳平衡研究.西北林学院学报,15(1):9-14.(Wang J Y,Che K J,Jiang Z R.2000.A study on carbon balance of Picea crassifolia in Qilian Mountains.Journal of Northwest Forestry College,15(1):9-14.[in Chinese])
王效科,冯宗炜,欧阳志云.2001.中国森林生态系统的植物碳储量和碳密度研究.应用生态学报,12(1):13-16.(Wang X K,Feng Z W,Ouyang Z Y.2001.Vegetation carbon storage and density of forest ecosystems in China.Chinese Journal of Applied Ecology,12(1):13-16.[in Chinese])
杨玉盛,陈光水,王义祥,等.2006.格氏栲人工林和杉木人工林碳库及分配.林业科学,42(10):43-47.(Yang Y S,Chen G S,Wang Y X,et al.2006.Carbon storage and allocation in Castanopsis kawakamii and Cunninghamia lanceolata plantations in subtropical China.Scientia Silvae Sinicae,42(10):43-47.[in Chinese])
周玉荣,于振良,赵士洞.2000.我国主要森林生态系统碳贮量和碳平衡.植物生态学报,24(5):518-522.(Zhou Y R,Yu Y L,Zhao S D.2000.Carbon storage and budget of major Chinese forest types.Chinese Journal of Plant Ecology,24(5):518-522.[in Chinese])
Batjes N H.1996.Total carbon and nitrogen in the soils of the world.European Journal of Soil Science,47(1):151-163.
De Vos B,Cools N,Ilvesniemi H,et al.2015.Benchmark values for forest soil carbon stocks in Europe:results from a large scale forest soil survey.Geoderma,251/252:33-46.
Labaz B,Galka B,Bogacz A,et al.2014.Factors influencing humus forms and forest litter properties in the mid-mountains under temperate climate of southwestern Poland.Geoderma,230/231:265-273.
Mcdaniel P A,Munn L C.1985.Effect of temperature on organic carbon-texture relationships in Mollisols and Aridisols.Soil Science Society of America Journal,49(6):1486-1489.
Smit A.1999.The impact of grazing on spatial variability of humus profile properties in a grass-encroached Scots pine ecosystem.Catena,36(1):85-98.
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