不同利用方式下红壤微生物生物量及代谢功能多样性的变化

研究了不同农林利用方式下红壤微生物生物量和代谢功能多样性等土壤质量指标的变化.结果表明:不同利用方式对土壤质量各指标造成了显著的影响;稻田的微生物生物量碳、氮最高,林地和草地微生物生物量次之,旱地的微生物生物量碳、氮最低(分别是稻田利用方式的4.3% 和 13.7%);稻田的微生物代谢功能多样性最高,旱地、林地和草地的细菌代谢功能多样性较低,旱地的真菌代谢功能多样性最低;微生物生物量和代谢功能多样性可以作为反映土壤质量变化的早期敏感的指标,用来衡量管理措施的改变对土壤质量造成的影响.     

The influence of different types of urban land use on soil microbial biomass and functional diversity in Beijing,China

Soil microbes in urban ecosystems are affected by a variety of abiotic and biotic factors resulting from changes in land use. However, the influence of different types of land use on soil microbial properties and soil quality in urban areas remains largely unknown. Here, by comparing five types of land use: natural forest, park, agriculture, street green and roadside trees, we examined the effects of different land uses on soil microbial biomass and microbial functional diversity in Beijing, China. We found that soil properties varied with land uses in urban environments. Compared to natural forest, soil nutrients under the other four types of urban land use were markedly depleted, and accumulation of Cu, Zn, Pb and Cd was apparent. Importantly, under these four types of land use, there was less microbial biomass, but it had greater functional diversity, particularly in the roadside‐tree soils. Furthermore, there were significant correlations between the microbial characteristics and physicochemical properties, such as organic matter, total nitrogen and total phosphorus (P < 0.05), suggesting that lack of nutrients was the major reason for the decrease in microbial biomass. In addition, the larger C/N ratio, Ni concentration and pool of organic matter together with a higher pH contributed to the increase in microbial functional diversity in urban soils. We concluded that different land uses have indirect effects on soil microbial biomass and microbial community functional diversity through their influence on soil physicochemical properties, especially nutrient availability and heavy metal content.     

福建省不同耕地土壤和土地利用类型对“碳源/汇”的贡献差异研究

农田生态系统无论作为全球温室气体的“源”还是“汇”,均对大气CO2浓度的年际变化产生重要影响.以我国亚热带地区——福建省不同地理位置的闽侯县、浦城县、同安县和永定县为典型研究区,利用这4个县1982年23 869个样点和2008年12 521个样点实测数据建立的1∶5万土壤类型-土地利用方式数据库,分析了近30年来福建省不同土类、亚类、土属和土地利用方式耕地有机碳密度变化,并利用尺度上推的方法估算了全省两期耕地土壤有机碳储量.结果表明,近30年来福建省耕地总体上表现为弱的“碳汇”,土壤有机碳密度和储量分别上升了0.24 kg m-2和4.26 Tg,但不同土壤类型和土地利用方式在“碳汇/源”中的贡献程度差异很大.从土壤类型来看,紫色土、酸性紫色土和石灰泥田分别在土类、亚类和土属级别中的“碳汇”贡献最大,有机碳密度分别提高了0.63、0.63和1.25 kg m-2;而滨海盐土、滨海盐土和黄泥砂土则分别在土类、亚类和土属级别中的“碳源”贡献最大,有机碳密度分别下降了0.59、0.59和1.08 kg m-2.从土地利用方式来看,灌溉水田是全省最主要的“碳汇”,有机碳密度提高了0.27 kg m-2,而水浇地是全省最主要的“碳源”,有机碳密度下降了0.36 kg m-2.因此,在今后的福建省农田土壤有机碳管理政策中应重点考虑有机碳密度下降、面积较大的土壤类型及土地利用方式的有效管理.     

不同土壤类型和农业用地方式对土壤微生物量碳的影响

通过野外调查与室内分析,研究了山东桓台县3种土壤类型(潮土、褐土和砂姜黑土)与农业用地方式(林地、菜地和粮田)对土壤表层(0—10.cm)微生物量碳的影响。结果表明,不同农业用地方式对微生物量碳的影响较大,3种利用方式的微生物量碳含量差异显著,依次为:粮田>菜地>林地;土壤类型不同,土壤微生物量碳含量也不相同。任何一种土壤,菜地的N、P、K含量都高于粮田和林地;有机质含量粮田>菜地>林地;pH值林地>粮田>菜地。全N、有机质与土壤微生物量碳呈极显著正相关,有效P与微生物量碳呈弱负相关,速效K、pH值和微生物量碳不相关。不同用地方式下土壤养分与微生物量碳的相关程度不同。秸秆还田和施用有机肥有利于提高土壤中微生物量碳水平,施用化肥在一定程度上能够增加微生物量碳。     

东北黑土区不同土地利用方式下农田土壤微生物多样性

为探究黑龙江省黑土区不同土地利用方式下土壤微生物多样性,该研究主要采用Biolog Eco微平板法,以荒地为对照,研究了黑龙江省中部和西南部黑土区玉米、水稻、大豆及土豆4种不同土地利用方式下土壤微生物多样性的变化。结果表明：1）可培养细菌的数量从大到小依次为土豆、水稻、大豆、玉米、荒地,但群落Shannon-Wiener多样性指数从高到低依次为：荒地（2.18）、玉米（2.11）、土豆（2.00）、水稻（1.73）、大豆（1.49）;2）不同利用方式下黑土区微生物碳源利用程度大致随培养时间的延长而升高,并且氨基酸、糖类以及聚合物类是黑土微生物代谢的最主要碳源;玉米地土壤微生物的Shannon-Wiener指数（3.18）、McIntosh指数（5.96）、丰富度指数（24.89）、及Simpson指数（0.95）比其他土地利用方式土壤微生物的多样性指数高,而水稻田土壤微生物的多样性指数最低,土豆、大豆与荒地土壤微生物的多样性指数间无显著差别;3）不同土地利用方式显著影响了土壤微生物群落碳源代谢多样性,并且对土壤微生物群落代谢特征起分异作用的主要碳源类型为糖类、氨基酸类和羧酸类,其中糖类尤为突出。该研究将有助于了解黑土区土壤微生物多样性与土地利用方式之间的关系,为黑土区农业的可持续发展提供一定的科学依据。     

Soil respiration and carbon balance of gray forest soils as affected by land use

 Soil respiration was measured by closed chamber and gradient methods in soils under forest, sown meadow and crops. Annual total soil respiration determined with the closed chamber method ranged from 180 to 642 g CO₂-C m^–2 year^–1 and from 145 to 382 g CO₂-C m^–2 year^–1 determined with the CO₂ profile method. Soil respiration increased in the order: cropland<sown meadow<forest. The C balance calculated as the difference between net primary production (sink) and respiration of heterotrophs (source) suggested an equilibrium between the input and output of C in the cropland, and sequestration of 135 and 387 g CO₂-C m^–2 year^–1 in the forest and meadow, respectively. Received: 1 December 1997     

基于土地利用结构特征的土壤侵蚀强度预测研究——以四川省为例

研究计算四川省土地利用结构特征指数和土壤侵蚀强度指数结果表明,该省土地利用结构特征指数与土壤侵蚀强度指数的变化具有同步性,用土地利用结构特征指数预测其土壤侵蚀强度变化是合理可行的。     

Effect of vegetation manipulation of abandoned arable land on soil microbial properties

 The effect of vegetation composition on various soil microbial properties in abandoned arable land was investigated 2 years after agricultural practice had terminated. Microbial numbers and processes were determined in five replicate plots of each of the following treatments: continued agricultural practice (monoculture of buckwheat in 1997), natural colonization by the pioneer community (arable weeds), and manipulated colonization from low (four species, three functional groups: grasses, forbs and legumes) or high diversity (15 species, three functional groups) seed mixtures from plant species that are characteristic of abandoned fields in later successional stages. The results indicated that differences in above-ground plant biomass, plant species composition and plant species diversity had no significant effect on soil microbial processes (net N mineralization, short-term nitrification, respiration and Arg ammonification), microbial biomass C and N (fumigation-incubation) or colony-forming units of the major microbial groups. Hence, there were no indications that soil microbial processes responded differently within 2 years of colonization of abandoned arable land by later successional plants as compared to that by plants from the natural pioneer weed community. Therefore, it seems that during the first few years after arable field abandonment, plants are more dependent on the prevailing soil microbiological conditions than vice versa. Received: 8 April 1999     

河北省生态系统服务价值变化研究

本研究分析了1993～2000年河北省土地利用和生态系统服务价值变化。结果表明,河北省耕地、水域、湿地和未利用土地面积在减少,而园地、林地、牧草地和建设用地面积在增加,因水域和湿地单位面积生态系统服务价值较高,7年间河北省区域生态系统服务价值显著减少,河北省生态系统服务价值从1993年的157.3116亿美元减少到2000年的152.3503亿美元,减少率为3.15%,净减少值4.9613亿美元。     

Native carbon mineralization of an acid organic soil after use of the chloroform-fumigation method to estimate microbial biomass

Summary Two experiments were carried out on a dysmoder humus sampled from a depth of 2–5 cm from a mixed hardwood forest. In acid soil, the chloroform fumigation-incubation method failed to estimate the microbial biomass, not because bacterial growth was inhibited after fumigation but because a labile C source was taken up which differed from the killed biomass C.     

土地定量化模型在土地利用系统的应用

运用验证后的土地定量化模型(PS123)对曲周地区土地利用系统部分因素如冬小麦适播期、灌溉措施及光温生产潜力研究分析表明,该区冬小麦适播期为9月底～10月底,并宜选用早熟品种,总灌水量为180～240mm,平水年宜灌水3次左右,应重视冬小麦拔节后罐水,中后期灌水宜采用75～90mm较大定额。运用PS123模型计算该区冬小麦光温生产潜力为1.101万kg/hm~2左右。     

Fluxes of methane and carbon dioxide from soil under forest, grazing land, irrigated rice and rainfed field crops in a watershed of Nepal

Field evolution of CH₄ and CO₂ from soils under four dominant land uses in the Mardi watershed, western Nepal, were monitored at 15-day intervals for 1 year using closed chamber techniques. The CH₄ oxidation rate (mean±SE, g CH₄ m^–2 h^–1) in the forest (22.8±6) was significantly higher than under grazing land (14±2) and an upland rainfed maize and millet system (Bari) (2.6±0.9). Irrigated rice fields (Khet) showed an oxidation rate of 6±0.8 g CH₄ m^–2 h^–1 in the dry season (December–May) but emitted a mean rate of 131 g CH₄ m^–2 h^–1 in the rainy season and autumn (June–October). The evolution of CO₂ ranged from 10 mg CO₂ m^–2 h^–1 in the Bari in January to 1,610 mg CO₂ m^–2 h^–1 in the forest in July. Higher evolution of CO₂ (mean±SE, mg CO₂ m^–2 h^–1) was observed in the Bari (399±39) and forest (357±36) compared to Khet (246±25) and grazing (206±20) lands. The annual emission of CO₂ evolution varied from 86.6 to 1,836 g CO₂ m^–2 year^–1. The activation energy for CH₄ and CO₂ varied between 16–283 and 80–117 kJ mol^–1, respectively. The estimated temperature coefficient for CO₂ emission varied from 2.5 to 5.0. Temperature explained 46–51% of the variation in CO₂ evolution, whereas it explained only 4–36% of the variation in CH₄ evolution.     

土壤氮素内循环对生态覆被变化响应的研究进展

随着人口增长对粮食需求的不断提高,人类对自然生态系统扰动频繁,生态覆被/土地利用变化伴随着土壤活性氮库、氮形态组分及氮素内循环过程的改变,直接影响生态系统的持续与稳定,进而引起全球气候变暖,生物多样性减少等诸多生态环境问题。生态覆被/土地利用变化是全球生态系统变化的重要内容。本综述探讨了活性氮的基本概念及其引发的环境效应,国内外自然生态系统中森林与草地间转换、自然生态系统开垦为农田、弃耕撂荒或退耕还林还草、城市化发展等生态覆被/土地利用变化对土壤氮库消长、氮矿化产物形态变化以及影响氮循环的关键土壤微生物影响等,并探讨了制约氮循环的土壤微生物研究进展。指出农业开垦或农田弃耕撂荒会导致土壤全氮大幅度下降,同时引起土壤硝态氮(NO3--N)增加,造成环境活性氮增加的风险;退耕还林修复生态覆被过程中氮库完全恢复需要漫长的时间;运用现代微生物分子生态学的前沿技术是研究土壤氮循环对生态覆被/土地利用变化响应机理的关键。本综述为自然生态系统的保护与开发利用、退化生态系统的修复与重建以及人工生态系统的科学规划等提供了理论依据。     

Positive relationship between herbaceous layer diversity and the performance of soil biota in a temperate forest

The current decline in biodiversity is particularly pronounced in the herbaceous layer of forest ecosystems. We explored the relationship between a naturally occurring plant diversity gradient in the understory vegetation of a deciduous forest and several above-and belowground ecosystem processes. We show that particularly soil microbial parameters and microarthropod densities are positively correlated with plant species richness. These results confirm recent findings in grassland ecosystems and highlight the intimate interconnectance between the diversity and functioning of above-and belowground compartments. We conclude that irrespective of a potential causal relationship between plant species richness and belowground processes, it is essential to consider the performance of soil biota in order to understand the relationship between herbaceous layer composition and ecosystem function.     

2000——2013年衡阳市土地利用格局转变对生态系统服务的影响

将生态系统服务评估利用到区域生态保护决策中的重要途径之一是生态系统服务制图.本研究对衡阳市多期遥感影像进行解译,采用当量因子法估算其生态系统服务价值(ESV)及由土地利用格局转变而引起的价值损益;并在ArcGIS 10.0软件支持下,利用空间自相关、高低聚类及重心分析等空间统计方法,对衡阳市ESV的时空变化进行制图模拟,以期为衡阳市的生态保护规划与管理提供决策辅助.研究结果表明:1)2000—2013年衡阳市的ESV略有降低,由2000年的2410亿元降至2013年的2394亿元;转移矩阵分析发现林地及耕地转为建设用地,以及林地转为耕地是引起衡阳市ESV降低的最主要原因.2)衡阳市的ESV高值区对低值区呈包围态势;2000—2013年ESV损失区主要分布于市区及其东部区域,而增值区主要分布于市区西部区域.3)衡阳市ESV的空间自相关与高低值聚集现象明显,其程度趋于增强;ESV重心向西偏北9°方向迁移了245.73 m.可考虑通过限制林地及耕地向建设用地的转变、实施"存量"或"减量"用地政策、维护和强化区域整体生态系统格局的连续性等措施来提高研究区的生态系统服务价值.     

科尔沁沙地土地利用变化对大型土壤节肢动物群落影响

土地利用类型是地球表层系统最突出的景观标志,不仅可以客观地展示地球表面特征空间格局的活动,还反映着地球表面景观的时空动态过程[1-2].由于土地利用变化与人类活动和全球气候变化密切相关,对生物多样性消长、生态环境演变、生态安全水平以及人类可持续性发展有着重要影响,因而其研究已成为当今全球变化研究的前沿和热点课题[1,3].     

土地利用生态系统分析及服务价值估算——以北京市平谷区白各庄村为例

本研究以北京市平谷区白各庄村为例,详细分析了2002年土地利用生态系统的类型和特点,并进行生态系统服务价值核算,包括物质生产、吸收CO2、释放O2、水供给、废物处理和休闲娱乐,其总价值为1706.62万元,与农村经济总收入基本相等,其中吸收CO2的服务价值最大(72.57%),其次为释放O2价值(15.30%),物质生产服务价值仅占总价值的12.77%,水供给和休闲娱乐服务价值很小,而废物处理服务价值为负值。     

Impacts of land use change on soil aggregation and aggregate stabilizing compounds as dependent on time

Land use change is known to strongly affect soil aggregation and aggregate stabilizing compounds. In this study we wanted to gain insight into the temporal and spatial dimension of this process. Therefore, we studied water-stable aggregates, total organic carbon (TOC), carbohydrates and glomalin-related soil protein (GRSP) in a 110-year chronosequence of Stagnosols, which have been converted from pasture to cropland at different times in history. To describe the temporal dimension, the measured concentrations were approximated by an exponential decay function. The spatial dimension was assessed by analyzing the distribution of TOC, carbohydrates, GRSP, and ¹⁴C among the different aggregate-size fractions over the course of 110 years of cropland use. It was found that the TOC concentration decreased monoexponentially (R² = 0.92) from 195.2 t ha⁻¹ to 45.13 t ha⁻¹ in the first depth interval (0-20 cm) during the first 110 years after the conversion, and reached a new equilibrium 23 (±5) years after land use change. Carbohydrates and GRSP obtained a new equilibrium after 14 (±6) and 56 (±5) years in the same depth interval. The mean-weight diameter (MWD) of the water-stable aggregates reached a new equilibrium 33 (±2) years after the land use conversion. With respect to the spatial dimension we found that TOC, carbohydrates, and GRSP showed higher concentrations in the macroaggregates than in the microaggregates. The ratios of the distribution of TOC, carbohydrates and GRSP among macro- and microaggregates did not change significantly during the 110 years of arable use of the soils. The average age of the organic carbon in the different aggregate-size fractions analyzed by its ¹⁴C concentration showed of a wide range from 65 (±25) to 251 (±30) years, and did not change significantly during the cultivation of the sites. Thus, we conclude that water-stable aggregates and the concentrations of TOC, carbohydrates and GRSP reacted towards land use change at different speeds and reached a new equilibrium between 14 (±6) and 56 (±5) years after the conversion of land use. Secondly, we found, that the spatial distribution of aggregate stabilizing compounds was not significantly changed during the first 110 years of cultivation.     

Influence of land use change on soil nutrients in an intensive agricultural region of North China

The pressures of development and major shifts in land use have increased the need to assess the impact of land use change on soil nutrients. This study was conducted in an area with intensive agricultural land use in north China to assess effects of land use change on soil organic carbon (SOC), total nitrogen (TN), available phosphorus (AP) and available potassium (AK). Soil samples were collected from rainfed land, irrigated land, virgin grassland and vegetable land in 1980 and 1999. SOC, TN and AP were higher in 1999 than in 1980, and the increases followed the following order: vegetable land > irrigated land > rainfed land, except for AK. Soil nutrient contents were increased when land uses underwent the following changes (except for AK): virgin grassland → rainfed land → irrigated farmland → vegetable land. The SOC, TN and AP fluxes (rate of change in C, N, P and K as kg(ha y)⁻¹) in the transition systems from rainfed land to vegetable land were 518.46, 69 and 3.9 kg(ha y)⁻¹, respectively, which were considerably higher than the transition systems from rainfed land to irrigated land. The SOC, TN and AP fluxes in the transition systems from virgin grassland to irrigated land were 297.83, 56.3, 2.1 kg(ha y)⁻¹, respectively, which were higher than the transition systems from virgin grassland to rainfed land. The study shows that land use intensification can increase soil nutrient contents if accompanied by increased fertilizer application.