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1.
Safe and economical disposal of paper mill sludge is a key consideration for forest products industry. A study was conducted to examine the effects of amendments of sludge and nutrients on soil surface CO2 flux (Rs) in northern hardwood forests and to quantify the relat among R5, soil temperature, and moisture in these stands. The experiment was a randomized complete block design that included sludge-amended, fertilized, and control treatments in sugar maple (Acer saccharum Marsh) dominated hardwood forests in the Upper Peninsula of Michigan, USA. Results showed that Rs was positively correlated to soil temperature (R2=0.80, p<0.001), but was poorly correlated to soil moisture. Soil moisture positively affected the Rs only in the sludge-amended treatment. The Rs was significantly greater in the sludge-amended treatment than in the fertilized (p=0.033) and the control (p=0.048) treatments. The maximum Rs in the sludge-amended treatment was 8.8 μmol CO2·m−2·s−1, 91% and 126% greater than those in the fertilized (4.6 μmol CO2·m−2·s−1) and control (3.9 μmol CO2·m−2·s−1) treatments, respectively. The Rs did not differ significantly between the fertilized and control treatments. The difference in Rs between sludge-amended and the other treatments decreased with time following treatment. Foundation item: The research was funded by a NCASI grant to S.T. Gower. Wang CK was supported by Innovated Talent Program of Northeast Forestry University (2004–07) Biography: WANG Chuan-kuan (1963-), male, Professor in the Ecology Program, College of Forestry, Northeast Forestry University, Harbin 150040, China. Responsible editor: Chai Ruihai  相似文献   

2.
采用静态箱/气相色谱分析技术对中国科学院鹤山丘陵综合开放试验站尾叶桉纯林(Eucalyptus urophylla,EUp)、厚荚相思纯林(Acacia crassicarpa,ACp)、10个树种混交林(Tp)和30个树种混交林(THp)4种林型的土壤CO2和CH4排放通量进行了原位测定,研究纯林和混交林对土壤温室气体排放的影响。结果表明:4种林型土壤都是CO2的源,但对CH4而言,可能是源,也可能是汇。CO2和CH4排放通量季节波动幅度较大;4种林型土壤CO2和CH4通量在湿季均维持较高水平;峰值均出现在湿季,旱季则趋于降低,且相对稳定。由于EUp和ACp纯林土壤微生物碳(Microbial Biomass Carbon,MBC)比混交林高,导致Eup(130.67 mg.m-2.h-1)和Acp(134.65 mg.m-2.h-1)土壤CO2通量显著高于Tp(111.39 mg.m-2.h-1)和THp(108.53 mg.m-2.h-1)。在4种林型中,尾叶桉和厚荚相思对土壤NO3-N和NH4-N快速吸收,土壤CH4排放通量较低。土壤温度、湿度、MBC、NO3-N和NH4-N都是影响土壤CO2和CH4...  相似文献   

3.
研究了2003 年夏季长白赤松和红松土壤微生物活性对高浓度CO2的响应规律。结果表明,长白赤松和红松土壤细菌数量受高浓度CO2影响显著(p < 0.05)减少;与对照箱(350 μmol ·mol-1 CO2)和裸地(350 μmol ·mol-1 CO2)相比,红松土壤淀粉酶和转化酶活性降低,而长白赤松土壤淀粉酶和转化酶活性却表现为增加;同时发现受700 μmol ·mol-1 CO2处理的红松和长白赤松土壤微生物生物量碳均表现为显著降低。DGGE 结果表明:受高浓度CO2 的影响,长白赤松和红松土壤细菌群落结构发生了明显的变化。研究结果表明土壤微生物对高浓度CO2的响应规律与所研究的的树种有关。图2 表2 参29。  相似文献   

4.
[目的 ]探明极端干旱事件对高原泥炭地二氧化碳(CO_2)通量的影响机制。[方法 ]以若尔盖高原泥炭地为研究对象,采用野外控制实验和静态箱法,利用快速温室气体分析仪测定极端干旱下高原泥炭地CO_2通量变化,并结合环境因子及土壤酶活性的测定,分析其变化机制。[结果 ](1)极端干旱显著降低了若尔盖高原泥炭地生态系统的净生态系统CO_2交换(NEE)、生态系统呼吸(Re)和总初级生产力(GPP)(P0.05)。(2)高原泥炭地生态系统Re对于空气温度和土壤温度的相关性在极端干旱的影响下增强。(3)NEE与β-葡萄糖苷酶(BG)、α-葡萄糖苷酶(AG)显著相关(P0.05),Re与木糖苷酶(XYL)、纤维素外切酶(CB)显著相关(P0.05),GPP与BG显著相关(P0.05)。[结论 ]高原泥炭地生态系统CO_2通量在极端干旱的影响下将显著降低,其对环境因子的相关性也有所增强; NEE和Re变化分别受到不同土壤酶活性的影响,随着土壤深度的增加,与不同深度土壤温度相关性表现出相反的变化趋势。  相似文献   

5.
3年生白桦同时接受3种外源糖溶液(蔗糖、果糖、葡萄糖)和3种高浓度CO2(700、1400、2100μLL-1CO2)处理。处理1个月后,测定了叶片的总糖、蔗糖、果糖和蛋白质含量。结果表明:在700μLL-1和1400μLL-1 CO2下,外源糖溶液增加了叶片的可溶性糖和蛋白质含量,其中外源蔗糖的效果最好;外源糖溶液与2100μLL-1CO2结合,会抑制叶片积累总糖和蛋白质;在700μLL-1和1400μLL-1CO2下,喷施葡萄糖、果糖的叶片在蛋白质含量上没有明显差别;;同700、1400μLL-1CO2相比,除喷施果糖植株外,2100μLL-1CO2明显增加了叶片的总糖、蔗糖、果糖和蛋白质含量;;在喷施同种外源糖溶液的情况下,叶片的糖含量与CO2浓度呈正相关性。图6参7。  相似文献   

6.
以位于长江三峡库区的重庆缙云山针阔混交林为研究对象,利用美国LI-COR公司生产的LI-8100开路式土壤碳通量测量系统对林地有凋落物和无凋落物两种土壤呼吸速率进行了观测。结果表明:(1)有无凋落物对土壤温度、土壤含水量均无影响;(2)有凋落物和无凋落物土壤呼吸的昼夜变化都呈现为单峰曲线,下午14:00左右达到峰值,并且无凋落物土壤呼吸速率小于有凋落物土壤呼吸速率;(3)有凋落物和无凋落物土壤呼吸季节变化趋势都表现为双峰型,峰值分别出现在7月和9月;(4)针阔混交林通过土壤呼吸释放的CO2量达到24.05 t/hm2,其中由凋落物释放的CO2达到5.09 t/hm2,占总CO2释放量的21.16%,说明凋落物对土壤呼吸影响显著。  相似文献   

7.
通过对1995-2004年西辽河流域气候变化的分析,运用DNDC模型模拟出土壤表面CO2的排放量,从而分析空气中CO2浓度的增加对土壤表面CO2排放量的影响,同时采用曲线对比分析法,研究CO2浓度变化对该地区的农业总产值及农、林、牧、渔业各产值的影响。结果表明,CO2浓度增加使土壤表面CO2排放量增大,气温升高、降水量减少使土壤表面CO2排放量增加,CO2浓度增加利于农业各产值升高。  相似文献   

8.
以开顶箱的方式研究了长白山两年生红松、长白赤松、水曲柳幼苗,经过从1999年9月到2001年9月两个生长季高浓度CO2处理后,在700、500 L·L-1高浓度CO2和大气CO2条件下的净光合、暗呼吸速率,RuBP羧化酶活性及叶绿素含量变化。结果表明:红松、长白赤松和水曲柳幼苗在高浓度CO2下RuBP羧化酶活性增加;除500 L·L-1 CO2下的长白赤松幼苗外,高浓度CO2促进净光合速率;700 L·L-1 CO2使红松和长白赤松的暗呼吸速率升高,而水曲柳的暗呼吸在700、500 L·L-1CO2下降低。高浓度使水曲柳幼苗的叶绿素含量降低。  相似文献   

9.
CO2和其它温室气体浓度的增加,使全球气候发生了急剧变化,影响到森林生态系统的结构和功能。在总结国内外已有研究成果的基础上,就气候变化及CO2浓度的升高对森林植被地理分布和组成结构、森林生产力和碳氮循环,以及极端灾害事件(病虫害和森林火灾)产生的影响进行了阐述,对气候变化与森林生态系统相互作用关系进行了分析与探讨,对今后的研究方向及研究重点进行了展望,以期为气候变化的科学研究和森林生态系统的管理提供借鉴与帮助。  相似文献   

10.
为探究配方施肥对云南松松针养分含量和土壤理化性质的影响,为云南松幼林抚育提供科学依据,以8年生云南松为试材,采用U*15(157)均匀设计开展复合肥、氮肥、磷肥、镁肥和硼肥配施的试验。处理组合的针叶长、烘干含水率、针叶全氮、全磷和全钾分别为23.90~27.34 cm、55.47%~60.88%、0.17%~0.57%、0.13%~0.33%和0.17%~0.82%,对照的则为24.14 cm、60.75%、0.35%、0.17%和0.29%。其中,全磷和全钾具有显著的差异。处理组合的土壤pH、烘干含水率、速效氮、速效磷、速效钾和胸径增长率分别为4.08~4.69、17.27%~34.59%、22.77~41.91、7.70~11.80、66.44~174.67 mg/kg和23.5%~50.3%,对照的则为4.42、17.27%、23.70、8.23、81.11 mg/kg和22.4%,处理组合间速效磷、速效钾和胸径增长率具有极显著的差异。土壤理化性质与因素具有复杂的相关性,硼肥与胸径增长率呈现显著的正相关;配施复合肥1.6 kg/3 cm、氮肥0.10 kg/3 cm、磷肥0.2 kg/3 cm,镁肥7.5 g/3 cm和硼肥1.5 g/3 cm可改善土壤理化性质,促进云南松幼树胸径生长。  相似文献   

11.
Soil surface CO2 flux (Sflux) is the second largest terrestrial ecosystem carbon flux, and may be affected by forest harvest. The effects of clearcutting on Sflux have been studied, but little is known about the effect of alternative harvesting methods such as selective tree harvest on Sflux. We measured Sflux before and after (i) the creation of forest canopy gaps (simulating group tree selection harvests) and (ii) mechanized winter harvest but no tree removal (simulating ground disturbance associated with logging). The experiment was carried out in a sugar maple dominated forest in the Flambeau River State Forest, Wisconsin. Pre-treatment measurements of soil moisture, temperature and Sflux were measured throughout the growing season of 2006. In January–February 2007, a harvester created the canopy gaps (200–380 m2). The mechanization treatment consisted of the harvester traveling through the plots for a similar amount of time as the gap plots, but no trees were cut. Soil moisture and temperature and Sflux were measured throughout the growing season for 1 year prior to harvest and for 2 years after harvest. Soil moisture and temperature were significantly greater in the gap than mechanized and control treatments. Instantaneous Sflux was positively correlated to soil moisture and soil temperature at 2 and 10 cm, but temperature at 10 cm was the single best predictor. Annual Sflux was not significantly different among treatments prior to winter 2007 harvest, and was not significantly different among treatments after harvest. Annual (+1 std. err.) Sflux averaged 967 + 72, 1011 + 72, and 1012 + 72 g C m−2 year−1 in the control, mechanized and gap treatments, respectively, for the 2-year post-treatment period. The results from this study suggest selective group tree harvest significantly increases soil moisture and temperature but does not significantly influence Sflux.  相似文献   

12.
In September, 1988, a paper mill sludge from Georgia-Pacific Corporation's wastewater treatment facility in Port Edwards, WI., was applied to a 4- and 6-year-old red pine (Pinus resinosa Ait.) plantation. Sludge was applied using industrial spreaders at rates of 0, 10, 20 and 40 Mg ha-1. Twenty-one months following treatment, above-ground biomass production of sedge (Carex spp.), the predominant understory component, was increased by as much as 85% from the 40 Mg ha-1 rate relative to the control. The increase in dry matter production coincided with significant increases in above- and below-ground levels of N, P and K. Weed control performed in August, 1989, resulted in reduced levels of woody and herbaceous vegetation, without a concomitant effect on red pine performance. Possible reasons for this lack of response are discussed within this paper.  相似文献   

13.
应用简化生物圈模式(SiB2)模拟通榆地气通量研究   总被引:3,自引:0,他引:3  
主要通过对比观测与SiB2模拟的吉林通榆农田和草地样地的感热通量、潜热通量、CO2通量和气温来检测独立版简化生物圈模式的数值模拟能力。在模拟中,农田和草地代表半干旱区2种典型的地表覆盖类型,它们的全年冠层高度和叶面积指数都处于变化当中,在非生长季地表裸露,而在生长季,冠层高度农田可达2m,草地可达0.8m,对应的叶面积指数分别可达4.2和2.4。SiB2模型模拟用观测值为初始场,以半小时气象观测为驱动场。对2003年的模拟和观测的比对研究表明:在生长季模式具有很好的模拟小时时间尺度的潜热、感热和CO2通量及地表气温的能力;(2)模式模拟土壤热通量可能偏大;(3)模拟的逐日潜热、感热和CO2通量及地表气温可用合理地反映全年的季节变化。图11表3参23。  相似文献   

14.
Wetlands contribute significant amounts of greenhouse gases to the atmosphere, yet little is known about what variables control gas emissions from these ecosystems. There is particular uncertainty about forested riparian wetlands, which have high variation in plant and soil properties due to their location at the interface between land and water. We investigated the fluxes of carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) and associated understory vegetation and soil parameters at five northern hardwood riparian sites in the Adirondack Park, NY, USA. Gas fluxes were measured in field chambers 4 times throughout the summer of 2008. CO2 flux rates ranged from 0.01 to 0.10 g C m−2 h−1, N2O fluxes ranged from −0.27 to 0.65 ng N cm−2 h−1 and CH4 flux rates ranged from −1.44 to 3.64 mg CH4 m−2 d−1. Because we observed both production and consumption of N2O and CH4, it was difficult to discern relationships between flux and environmental parameters such as soil moisture and pH. However, there were strong relationships between ecosystem-scale variables and flux. For example, CO2 and N2O flux rates were most strongly related to percent plant cover, i.e., the site with the lowest vegetation cover had the lowest CO2 and highest N2O emissions. These ecosystem-scale predictive relationships suggest that there may be prospects for scaling information on trace gas fluxes up to landscape and regional scales using information on the distribution of ecosystem or soil types from remote sensing or geographic information system data.  相似文献   

15.
We monitored two Pinus taeda L. genotypes, planted in 170 L lysimeters, subjected to different combinations of fertilization and logging residue (LR) incorporation for 1 year. The objectives were to elucidate how soil amendments modified soil biological properties and belowground C cycling, and secondly, to determine if planting of contrasting genotypes have a detectable impact on total soil CO2 efflux (FS). LR incorporation resulted in decreased bulk density, increased total soil porosity, and increased total soil C and N contained within the fine-soil fraction. For most of the experiment we found no consistent differences between genotypes; however, on the final two sampling dates a pattern emerged of one clone showing greater FS. If this pattern continues or becomes stronger with increased occupation of soil by roots it may have an influence on total site net C exchange. Increased C loss by way of FS and soil leaching made up approximately 7% of total C incorporated as LR. Conservative estimates using a constant rate of decomposition showed that it would take a minimum of 15 years to fully decompose the incorporated LR. Our data suggest that moderate rates of LR incorporation following harvesting over multiple rotations could increase SOM without negatively impacting plant growth, which could increase soil C sequestration.  相似文献   

16.
Fluxes of CO2, CH4 and N2O were measured during two to three years at four sites, located within an area of 9 km2 in southern Sweden, using dark static chamber techniques. Three of the sites were drained coniferous forests on moist organic soils that differed in forest productivity and tree species. The fourth site was an undrained tall sedge mire. Although the drained sites were all moist, with average groundwater levels between 17 and 27 cm below the soil surface, the mean annual dark forest floor CO2 release rate was significantly higher at the drained sites, (0.9–1.9 kg m−2 y−1) than at the undrained mire site (0.8 to 1.2 kg m−2 y−1). CH4 emissions were significantly lower from the drained sites than from the undrained mire (0.0 to 1.6 g m−2 y−1, compared to 10.6 to 12.2 g m−2 y−1), while N2O emissions were significantly lower from the undrained site than from the drained sites (20 to 30 mg m−2 y−1, compared to 30 to 90 mg m−2 y−1). There were no clear effects of site productivity or tree species on the soil fluxes of any of the gases. The annual net primary production of the forests was modeled. All drained sites were net sinks, while the undrained mire was a net source of greenhouse gases. The estimated net greenhouse gas exchange of the drained sites was correlated with productivity: the most productive site was the largest net sink and the least productive the smallest net sink for greenhouse gases. The results indicate that, to mitigate the increase of atmospheric greenhouse gases, drained forest sites, which have been unsuccessfully drained or rewetted due to subsidence, should be managed in a way that keeps the groundwater level at a steady state.  相似文献   

17.
Large areas of northern coniferous forests once naturally maintained by stand-replacing wildfires have shifted to an anthropogenic disturbance regime of clearcut harvesting followed by natural or artificial regeneration, with unknown consequences for soil biogeochemical processes. We used a comparative approach to investigate the effects of whole-tree harvesting (WTH) vs. stand-replacing wildfire (WF) on soil C and nutrient availability, and nutrition and growth of the succeeding stand, in jack pine (Pinus banksiana) forests of northern Lower Michigan. We compared total carbon (C), total nitrogen (N), potential N mineralization, and extractable phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) among stands regenerated via WTH or WF in two age classes (4–7 years and 12–18 years). We also measured jack pine foliar nutrition and height growth in these same stands, as well as estimating the contribution of legacy dead wood to ecosystem nutrient capital in young stands. We found some evidence in support of our hypothesis that WTH would leave behind greater pools of soil C and N, but lower pools of P and base cations. However, the differences we observed were confined entirely to surface organic horizons, with the two disturbance regimes indistinguishable when viewed cumulatively to our maximum sampling depth of 30 cm. Estimates of nutrient pools in legacy wood inherited by young jack pine stands were also small in comparison to total soil pools (ranging from 1 to 9% depending on the element), suggesting that decomposition and nutrient release from this material is not likely to result in noticeable differences in soil fertility later in stand development. Similar levels of soil nutrients between WTH- and WF-origin stands were reflected in our measures of jack pine foliar nutrition and height growth, which were both unaffected by mode of stand origin. Results from this study suggest that soil nutrient levels following WTH fall within the natural range of variation produced by WF in these jack pine forests; however, comparison with a similar study on boreal jack pine suggests that latitudinal effects on O-horizon nutrient capital may influence the degree to which WTH matches the effects of WF on soil nutrient availability.  相似文献   

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