纳帕海湿地区表土有机碳及其活性组分的空间分异

基于网格均匀布点,在纳帕海湿地区采集141个表土(0~20 cm)样品,采用地统计学等方法研究表土有机碳(SOC-Soil Organic Carbon)、易氧化有机碳(EOC-Easily Oxidized C)、溶解有机碳(DOC-Dissolved OC)及有机碳活性水平的空间变异和分异特征。结果表明:1.表土SOC、EOC、DOC、EOC/SOC(%)、DOC/SOC(%)均值分别为51.596 g/kg、4.950 g/kg、155.360 mg/kg、10.388%、0.403%,空间变异水平分别为强、强、中、中、中;2.表土有机碳和活性组分之间为极显著正相关,EOC/SOC(%)和SOC、EOC分别为显著负相关、负相关(不显著),DOC/SOC(%)和SOC、DOC分别为极显著负相关、负相关(不显著);3.表土DOC/SOC(%)空间变异具有强空间相关性,其他为中等空间相关性;4.湿地区不同类型土壤表土活性组分含量(均值)和相对值(均值)为一定程度负相关,水分可能是最重要的决定因子,而表土有机碳活性组分的相对值能更好地反映环境和人为干扰对土壤有机碳库空间分异的影响。     

中亚热带山区土地利用变化对土壤有机碳储量和质量的影响

Land use/cover change (LUCC) is widely recognized as one of the most important driving forces of global carbon cycles. The influence of converting native forest into plantations, secondary forest, orchard and arable land on stores and quality of soil organic carbon (SOC) was investigated in mid-subtropical mountainous area of southern China. The results showed that LUCC had led to great decreases in SOC stocks and quality. Considerable SOC and light-fraction organic carbon (LFOC) had been stored in the native forest (142.2 t hm⁻² and 14.8 t hm⁻² respectively). When the native forest was converted to plantations, secondary forest, orchard and arable land, the SOC stocks decreased by 25.6%, 28.7%, 38.0%, 31.8% and 51.2%, respectively. The LFOC stocks decreased by 52.2% to 57.2% when the native forest was converted to woodland plantations and secondary forest, and by 82.1% to 84.2% when converted to economic plantation, orchard and arable land. After the conversion, the ratios of LFOC to SOC (0–60 cm) decreased from 13.3% to about 3.0% to 10.7%. The SOC and LFOC stored at the upper 20 cm were more sensitive to LUCC when compared to the subsurface soil layer. Also, the decline in carbon storage induced by LUCC was greater than the global average level, it could be explained by the vulnerable natural environment and special human management practices. Thus, it is wise to enhance soil carbon sequestration, mitigate elevated atmospheric CO₂ and develop ecological services by protecting vulnerable environment, restoring vegetation coverage, and afforesting in mountainous area in mid-subtropics. Foundation: Supported by the Key Project of Ministry of Education of China, No.JA04166 Author: Yang Yusheng (1964–), Professor, specialized in carbon and nitrogen cycles of forest.     

念青唐古拉山东南坡高寒草原生态系统表层土壤有机碳分布特征及影响因素

对念青唐古拉山东南坡高寒草原生态系统表层(0~20 cm)土壤有机碳分布特征进行研究,结果表明:有机碳密度平均为5.002 8±1.103 7 kg/m2,变异系数21.96%;在拔4421~4598 m内,随海拔升高表现增加→减少→增加的分布特征;与地上及10~20 cm土层生物量、20~30 cm含水量、土壤有机质、速效N、全N和全P含量呈显著正相关,与20~40 cm容重呈显著负相关。影响其的第1因子是植被盖度、地上生物量、20~30 cm地下生物量和20~30 cm含水量,第2因子是0~20 cm和20~40 cm容重及全P量,第3因子是有机质含量和速效N含量,第4因子是0~10 cm地下生物量,累计贡献率92.83%。     

艾比湖湿地土壤活性有机碳及其对厌氧条件下碳分解的影响

揭示土壤活性有机碳的特征及其与碳释放的关系对研究全球气候变化具有重要意义.本研究对艾比湖湿地不同生境土壤活性有机碳及厌氧条件下碳分解过程进行测定与分析.研究结果表明：1）不同生境土壤DOC、MBC和EOC含量分别为43.41～151.30 mg.kg-1、8.23～417.83 mg.kg-1、69.63～2376.0...     

艾比湖湿地土壤活性有机碳及其对厌氧条件下碳分解的影响

揭示土壤活性有机碳的特征及其与碳释放的关系对研究全球气候变化具有重要意义.本研究对艾比湖湿地不同生境土壤活性有机碳及厌氧条件下碳分解过程进行测定与分析.研究结果表明:1)不同生境土壤DOC、MBC和EOC含量分别为43.41～151.30 mg.kg-1、8.23～417.83 mg.kg-1、69.63～2376.08 mg.kg-1,平均含量分别为81.18 mg.kg-1、112.20mg.kg-1、768.59 mg.kg-1,变异系数为40.8%、91.9%和88.0%;2)不同组分土壤活性有机碳之间呈现出极显著正相关(P<0.01);3)土壤氮含量和黏粒含量是影响DOC、MBC和EOC的重要因子;4)土壤EOC是指示不同生境土壤厌氧条件下碳分解潜力的主要碳源.     

科尔沁沙地生态系统典型土壤养分空间分布特征

通过对位于科尔沁沙地中南部的奈曼旗中部沙地灌溉农田、旱作农田和流动沙丘土壤有机C和全N含量空间分布特征的分析发现:由灌溉农田、旱作农田到流动沙丘,土壤10cm深度内有机C和全N的含量与相对高度的变化密切相关。随着相对高度的增加,上述土壤的有机C和全N的含量逐渐减少,而且全N含量比有机C含量与相对高度的相关性更为显著。从旱作农田到流动沙丘有机C和全N的含量随着相对高度的减小而减少。如果不考虑灌溉农田和流动沙地土壤,旱作农田土壤有机C和全N含量与相对高度的相关性显著程度更高。科尔沁沙地中部沙质灌溉农田土壤全N和有机C含量的垂直分布呈锯齿状,表现为明显的多'峰谷'性,这种变化与土壤的粘土层/有机质层和沙层交错分布的特点有关。尽管研究区的土壤发生了明显的空间变化,但是土壤的全N含量和有机C含量之间依然存在着显著的相关性     

黄河口滨岸潮滩湿地土壤碳、氮的空间分异特征

2009年5月,运用地统计学方法研究了黄河口滨岸潮滩湿地土壤碳、氮的空间分布格局。结果表明,潮滩湿地土壤的TC、TN和C/N含量具有明显的水平变异性,自表层向下均呈显著降低趋势,总体表现为TN>C/N>TC。潮滩湿地土壤不同土层TN和C/N含量的水平分布空间结构明显,分别符合不同的变异函数理论模型,且具有强烈/中等程度的空间相关性,其空间变异性均以向低潮滩延伸且受潮汐涨落影响较大的方向为最大,自然结构因素在引起TN和C/N空间异质性中的贡献占优,随机因素的影响相对较小。潮滩湿地土壤不同土层TN和C/N具有明显的空间分布格局,表层土壤的TN含量向低潮滩延伸方向形成明显斑块低值区,边缘则形成斑块高值区,而不同土层的C/N以及亚表层的TN则与之相反。研究发现,微地貌特征和潮汐微域物理扰动强度是导致空间异质性的重要随机因素,而水盐条件、土壤类型和潮汐物理扰动是重要结构因素。湿地有机质来源以陆源为主,且越靠近海的方向,潮滩湿地土壤中的有机质受陆源的影响越大。     

武夷山沿海拔梯度土壤活性有机碳库的变化(英文)

土壤活性有机碳(LOC)是一组活跃的化学物质,由于其较短的周转时间和对环境变化的敏感性在全球碳循环中发挥着重要的作用。但是,对活性有机碳在亚热带森林沿海拔梯度的空间变异还缺乏了解。在本研究中,我们测定了福建武夷山自然保护区不同海拔高度具有代表性的中亚热带常绿阔叶林(500 m)、针叶林(1150 m)、亚高山矮林(1750 m)以及高山草甸(2150 m)土壤不同土层(0-10,10-25和25-40 cm)中微生物可利用碳(MAC)、微生物量碳(MBC)、易氧化碳(ROC)、水溶性碳(WSOC)和轻组碳(LFC),并观测了相应的植物凋落物质量(LM),土壤温度和湿度。结果表明:沿海拔梯度的植被变化和土层深度变化对土壤活性有机碳有显著的影响。微生物可利用碳、微生物量碳、易氧化碳和水溶性碳在不同土层均沿海拔高度的增加而显著增加;而低海拔的常绿阔叶林和针叶林中轻组碳的含量高于亚高山矮林和高山草甸的轻组碳的含量。各土壤活性有机碳库均随土层的加深而减小。除轻组碳外,各碳库间存在着极显著的正相关(p0.001)。轻组碳分别在低海拔(常绿阔叶林和针叶林)和高海拔(亚高山矮林和高山草甸)与各碳库显著相关。     

神农架大九湖表层泥炭碳、氮、磷含量的空间分布特征及其控制因素

为了解亚热带泥炭地碳氮磷含量的空间分布模式及其影响因素,在神农架大九湖泥炭地采集147份表层泥炭样品进行总有机碳含量(TOC)、总磷含量(TP)和总氮含量(TN)测试和理化参数分析,探究表层泥炭碳氮磷的空间分布特征及其控制因素。结果表明:大九湖表层泥炭TOC含量变化范围为3.51%~37.93%,TP含量变化范围为0.37~2.75 mg/g,TN含量变化范围为0.59~1.6mg/g。相关性分析表明:TOC含量与含水率(r=0.45,P<0.01)和TP含量(r=0.27,P<0.05)呈显著正相关,TP含量与干容重呈显著正相关(r=0.32,P<0.05),TN含量与各种理化参数的相关性均不显著。通过对比亚热带、热带、北方泥炭地的碳氮磷含量,发现相对于热带和北方泥炭地,亚热带泥炭地的TOC含量和TN含量更低,而TP含量更高。本研究为亚热带泥炭地的生态保护提供了关键的基础数据和参考。     

安徽省土壤有机碳空间差异及影响因素

区域土壤碳储量和碳固定潜力及影响因素分析是全球变化中碳循环研究的重要前沿问题。本文采用第二次土壤普查资料,研究了安徽省不同类型土壤的有机碳密度和碳库,分析了影响土壤有机碳分布的自然和人为因素。结果表明,安徽土壤有机碳库为0.71Pg,表层土壤有机碳库为0.28Pg;土壤平均有机碳密度达117.54 t/hm²,碳密度的空间分布为:皖南山区>皖西大别山区>沿长江平原>江淮丘陵区>淮北平原区;气候和植被控制着表层土壤有机碳的省域分布,降水与土壤有机碳含量呈正相关。地形和母质影响土壤亚类间有机碳的差异;土壤总氮与土壤有机碳呈极显著相关,平原区土壤粘粒含量与表层土壤有机碳固定有较大关系。     

Salinity effects on soil organic carbon and its labile fractions, and nematode communities in irrigated farmlands in an arid region, northwestern China

The effects of salinity on soil organic carbon(SOC) and its labile fractions including microbial biomass carbon(MBC) and easily oxidation organic carbon(EOC),basal soil respiration,and soil nematode community in the Fluvents,an oasis in an arid region of northwestern China were investigated.Five sites were selected which had a salinity gradient with different groundwater table from 1.0 m to 4.0 m.Soils were sampled at the 0–20 cm plough layer from 25 irrigated fields of five sites and electrical conductivity was measured in the saturation paste extracts(ECe).Soils were categorized into five salinity levels:(1) non-saline,(2) very slightly saline,(3) slightly saline,(4) moderately saline,and(5) strongly saline according to the values of ECe.The results show that SOC and total nitrogen concentration,cation exchange capacity(CEC),and the concentrations of labile organic fractions(MBC,EOC),and basal soil respiration decreased significantly with increasing ECe.The relationships between ECe and MBC,EOC and basal soil respiration were best described by power functions.Slight and moderate salinity had no significant impact on soil nematode abundance,but excessive salt accumulation led to a marked decline in soil nematode community diversity and abundance.Soil salinity changed soil nematode trophic groups and bacterivores were the most abundant trophic groups in salt-affected soils.Further study is necessary to identify the response of soil microbial processes and nematode community dynamics to soil salinity.     

秦巴山区马尾松林和油松林的空间分布及亚热带与暖温带界线划分

秦岭不仅是中国南北的地理分界线,也是中国亚热带和暖温带的气候分界线,在中国地理生态格局中占有重要的地位和作用。由于过渡带的复杂性、过渡性和异质性以及划分指标、研究目的的不同,学术界关于这一南北地理—生态分界线的具体位置一直有争论。为了进一步揭示秦巴山区过渡带的特征,明确中国南北地理—生态分界线的位置,本文选择马尾松(Pinus massoniana)林和油松(Pinus tabulaeformis)林这两类分别代表中国南方亚热带针叶林和北方温带针叶林的植被,结合研究区SRTM地形数据、气温和降水数据等,以年降水、最冷月(1月)气温、最热月(7月)气温和年均温为气候指标,详细分析了这两类植被在秦巴山区的空间分布及二者分界线处的气候条件。结果表明:①马尾松林和油松林的分界线及相应位置的气候指标可以作为亚热带与暖温带界线划分的植被—气候指标之一。秦巴山区亚热带针叶林(马尾松林)与温带针叶林(油松林)的分界线位于伏牛山南坡至汉中盆地北缘一线(秦岭南坡)海拔1000～1200 m处;分界线处气候指标稳定:年降水750～1000 mm,年均温12～14℃,最冷月气温0～4℃,最热月气温22～26℃...     

重庆市主城区休闲设施空间格局变化及其解释

休闲设施作为城市休闲空间的物质形态载体,为城市居民提供多种休闲娱乐功能。依托城市的不断发展,休闲设施也随之呈现出空间结构异质性。基于POI大数据,运用GIS平台及地理探测器,对重庆主城区休闲设施空间格局进行探析,结果表明：（1）在数量特征上,研究区内休闲设施总量呈上升趋势,随距离变化表现出明显空间尺度依赖,各类设施在不同空间尺度下的分布数量存在差异。（2）休闲设施总体空间分布呈显著集聚特征,由于设施总量逐年增加,各类休闲设施空间集聚程度逐渐降低。（3）休闲设施整体为“大聚集,小分散”的多中心分布态势,并逐步由集聚中心向城市外围区域扩张。康娱游憩类演化特征与总体近似,文化休闲类设施集中分布于沙坪坝东南部与渝中区两江交汇处,休闲旅游类表现为“大分散,小集聚”的空间特征,专项休闲类呈带状连片分布态势。（4）常住人口密度、道路密度、距离市中心距离、旅游收入等是重庆市主城区休闲设施空间格局变化的重要影响因素,各影响因子在三个时间节点解释程度有所不同。对于休闲设施格局变化的研究旨在为休闲设施经营者投资选址提供参考,为政府决策者合理布局休闲空间提供依据。     

Spatial patterns of Pinus tabulaeformis and Pinus massoniana forests in Qinling-Daba Mountains and the boundary of subtropical and warm temperate zones

The Qinling Mountains is not only the geographical boundary between North and South China,but also the boundary between subtropical and warm temperate zones.It plays an important role in the geo-ecological pattern of China.However,there is controversy about the specific location of this geographical boundary in academic community due to the complexity,transition and heterogeneity of the transitional zone,as well as the differences in the delimitation indicators and research purposes.To further reveal the characteristics of the North-South transitional zone and clarify the specific location of the geo-ecological boundary between North and South China,combined with SRTM topographic data,temperature and precipitation data,Pinus massoniana forest and Pinus tabulaeformis forest,which represent subtropical coniferous forest in South China and temperate coniferous forest in North China respectively,were chosen to analyze their spatial distributions in the Qinling-Daba Mountains and the climatic conditions at their boundary with the climatic indexes of annual precipitation,the coldest month(January) average temperature,the warmest month(July) average temperature and the annual average temperature.The results show that:(1) Pinus massoniana and Pinus tabulaeformis forests and the climate indicators of their boundary can be used as one of the vegetation-climate indexes for the delimitation of subtropical and warm temperate zones.The boundary between the subtropical coniferous forest(Pinus massoniana forest) and temperate coniferous forest(Pinus tabulaeformis forest) is located along the south slope of Funiu Mountain to the north edge of Hanzhong Basin(the south slope of Qinling Mountains) at an altitude of 1000–1200 m,where the climatic indictors are stable:the annual precipitation is about 750–1000 mm,the annual average temperature is about 12–14℃,the coldest monthly average temperature is 0–4℃,and the warmest monthly average temperature is about 22–26℃.(2) It can be more scientifically to delimitate the boundary of subtropical and warm temperate zones in China by comprehensively considering the vegetation-climate indicators.Additionally,the boundary between subtropical and warm temperate zones in Qinling-Daba Mountains should be a transitional zone consisting of the boundaries of coniferous forests,broad-leaved forests and shrubs between subtropical and warm temperate zones.The results provide a scientific basis for the selection of delimitation index of subtropical and warm temperate zones.     

基于多光谱和地理加权回归模型的石嘴山城市土壤有机碳空间分布研究

城市土壤有机碳(SOC)分布受城市建设、工业发展等人为因素的影响表现出明显的空间差异。为揭示石嘴山市SOC受城市化、工业化等人类活动的影响,分别利用普通克里格法(OK)、多元线性回归克里格法(RK)、遥感反演方法(RS)和遥感-地理加权回归克里格法(RGWRK)预测石嘴山市SOC空间分布。结果表明:石嘴山市SOC含量在1.31～66.92 g·kg^-1之间变化,其平均值为17.61 g·kg^-1。石嘴山市不同功能区SOC含量存在显著差异(p<0.05),具体表现为工业区>医疗区>商业区>道路>住宅区>公园>农田>科教区;SOC含量变异系数为66.27%,呈中等程度变异;其最佳拟合模型为高斯模型,C₀/(C₀+C)为0.02,属于强空间自相关。SOC与遥感影像波段DN值的差值(B1-B7、B3-B7、B4-B7)和地形因子(高程、坡度、起伏度)之间存在着极显著的相关性(p<0.01);通过对4种方法的结果进行对比可知以各波段DN值差值与地形因子为输...     

Detecting the storage and change on topsoil organic carbon in grasslands of Inner Mongolia from 1980s to 2010s

Soil carbon sequestration and potential has been a focal issue in global carbon research. Under the background of global change, the estimation of the size as well as its change of soil organic carbon（SOC） storage is of great importance. Based on soil data from the second national soil survey and field survey during 2011–2012, by using the regression method between sampling soil data and remote sensing data, this paper aimed to investigate spatial distribution and changes of topsoil（0–20 cm） organic carbon storage in grasslands of Inner Mongolia between the 1980 s and 2010 s. The results showed that：（1） the SOC storage in grasslands of Inner Mongolia between the 1980 s and 2010 s was estimated to be 2.05 and 2.17 Pg C, with an average density of 3.48 and 3.69 kg C·m–2, respectively. The SOC storage was mainly distributed in the typical steppe and meadow steppe, which accounted for over 98% of the total SOC storage. The spatial distribution showed a decreased trend from the meadow steppe, typical steppe to the desert steppe, corresponding to the temperature and precipitation gradient.（2） SOC changes during 1982–2012 were estimated to be 0.12 Pg C, at 7.00 g C·m–2·yr–1, which didn＇t show a significant change, indicating that SOC storage in grasslands of Inner Mongolia remained relatively stable over this period. However, topsoil organic carbon showed different trends of carbon source/sink during the past three decades. Meadow steppe and typical steppe had sequestered 0.15 and 0.03 Pg C, respectively, served as a carbon sink; while desert steppe lost 0.06 Pg C, served as a carbon source. It appears that SOC storage in grassland ecosystem may respond differently to climate change, related to vegetation type, regional climate type and grazing intensity. These results might give advice to decision makers on adopting suitable countermeasures for sustainable grassland utilization and protection.     

Effects of afforestation on soil carbon turnover in China’s subtropical region

Afforestation in China’s subtropics plays an important role in sequestering CO2 from the atmosphere and in storage of soil carbon (C). Compared with natural forests, plantation forests have lower soil organic carbon (SOC) content and great potential to store more C. To better evaluate the effects of afforestation on soil C turnover, we investigated SOC and its stable C isotope (δ13C) composition in three planted forests at Qianyanzhou Ecological Experimental Station in southern China. Litter and soil samples were collected and analyzed for total organic C, δ13C and total nitrogen. Similarly to the vertical distribution of SOC in natural forests, SOC concentrations decrease exponentially with depth. The land cover type (grassland) before plantation had a significant influence on the vertical distribution of SOC. The SOC δ13C composition of the upper soil layer of two plantation forests has been mainly affected by the grass biomass 13C composition. Soil profiles with a change in photosynthetic pathway had a more complex 13C isotope composition distribution. During the 20 years after plantation establishment, the soil organic matter sources influenced both the δ13C distribution with depth, and C replacement. The upper soil layer SOC turnover in masson pine (a mean 34% of replacement in the 10 cm after 20 years) was more than twice as fast as that of slash pine (16% of replacement) under subtropical conditions. The results demonstrate that masson pine and slash pine plantations cannot rapidly sequester SOC into long-term storage pools in subtropical China.     

北京市高尔夫旅游资源空间分布特征及影响因素

高尔夫旅游不仅是中国旅游资源体系中的重要组成部分,也是旅游产业从观光型向休闲度假型调整的重要支撑点。选取北京市作为研究区域,对18洞及以上共51处标准高尔夫旅游资源空间分布特征及影响因素进行研究,得出以下结论:①在区域经济发展水平的影响下,北京市高尔夫旅游资源发展可分为两个阶段:1985-2000年缓慢发展阶段,2001-2011年蓬勃发展阶段。②北京市高尔夫旅游资源的空间分布形态已经出现多中心特征,由空间点状集聚分布转向扩散化并形成线状网络体系。③从球场面积的空间容量分布来看,北京市高尔夫旅游资源呈现出空间不均衡的集聚特征格局。中心城区球场密度大,但空间容量规模低;外围新兴区域球场密度相对较低,但开发强度高,空间容量规模大。总体上看,区域地形特征、重要水系分布、交通区位条件、配套服务设施、关联产业开发、土地价格、规划及政策引导等各种要素,通过综合作用机制共同影响北京市高尔夫旅游资源空间分布特征。     

林分密度对华北土石山区油松人工林土壤有机碳及养分特征的影响

 以木兰围场国有林场管理局实施间伐后6种保留密度下（540、650、1 084、1 104、1 408和1 860 株 / hm2）油松人工林为研究对象,研究各土层的土壤有机碳和N、P、K等养分元素含量及其相关关系。研究结果显示：(1) 土壤有机碳含量和碳密度垂直递减特征明显,均随土壤深度的增加而显著减小,当林分密度由540 株 / hm2增加到1 860 株 / hm2时,土壤有机碳含量及碳密度变化规律不尽一致,其分布区间分别为10.56~21.21 g / kg,与5.48~11.70 kg / m2;(2) 林分密度对土壤有机碳及碳密度有显著的影响,1 408 株 / hm2油松林下土壤有机碳含量及碳密度分别与650 株 / hm2和1 860 株 / hm2油松林下土壤有机碳含量及碳密度呈显著性差异,而其它林分密度间无显著差异。当林分密度为1 104 株 / hm2时,各土层土壤全N和P、K的有效量及全量均保持在一个相对较高的水平,在0~60 cm深度土壤全N、全P、全K、有效P和速效K含量均值均达到最高,分别为1.38 g/kg、0.34 g/kg、32.75 g/kg、33.10 mg/kg和118.85 mg/kg;(3) 不同林分密度、不同土层土壤有机碳含量、碳密度与土壤全N及P、K的全量和有效量的相关显著性有差异,对整个土壤剖面而言,土壤有机碳含量及碳密度与土壤全N、全P、速效K均呈显著或极显著正相关;(4) 在本研究林分密度范围内,从林地土壤固碳的角度,建议将油松人工林的林分密度控制在1 104 株 / hm2。