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1.
We evaluated carbon stocks in the above-ground biomass (AGB) of three dominant mangrove species (Sonneratia apetala, Avicennia alba and Excoecaria agallocha) in the Indian Sundarbans. We examined whether these carbon stocks vary with spatial locations (western region vs. central region) and with seasons (pre-monsoon, monsoon and post-monsoon). Among the three studied species, S. apetala showed the maximum above-ground carbon storage (t ha−1) followed by A. alba (t ha−1) and E. agallocha (t ha−1). The above-ground biomass (AGB) varied significantly with spatial locations (p < 0.05) but not with seasons (p < 0.05). The variation may be attributed to different environmental conditions to which these areas are exposed to such as higher siltation and salinity in central region compared to western region. The relatively higher salinity in central region caused subsequent lowering of biomass and stored carbon of the selected species.  相似文献   

2.
A mass balance for organic carbon in Hinchinbrook Channel was constructed to identify major sources, sinks, and the magnitude of organic matter available for export to the adjacent coastal zone. Total organic carbon input from the Herbert River and from net production of mangroves, phytoplankton, seagrasses, and benthic microalgae is 8.94 ×109M Corgyr–1 (moles organic carbon per year). Mangroves and river inputs are the largest carbon sources, accounting for 56% and 27% of the total annual input, respectively. Benthic respiration and burial in sediments are the major sinks, accounting for 46% and 41% respectively of total losses (3.09 ×109 M Corgyr–1). This mangrovedominated coastal ecosystem is net autotrophic, with 5.85×109M Corgyr–1 (65% of total Corg input) available for export to the adjacent nearshore zone. Total export of organic carbon from the region (adding carbon export from Missionary Bay mangroves on the northern end of Hinchinbrook Island) amounts to 82,800 metric tons of organic carbon per year. These results confirm earlier evidence indicating that much of the particulate sediment carbon in the adjacent coastal zone is of mangrove origin. This mass balance, although preliminary, demonstrates the importance of Hinchinbrook Channel as a source of organic matter for the Great Barrier Reef lagoon.  相似文献   

3.
岷江上游杂谷脑河流域不同土地利用类型土壤碳氮特征   总被引:1,自引:0,他引:1  
对杂谷脑河流域不同区段(上、中、下游)6种不同土地利用类型土壤有机碳和全氮进行测定。结果表明:该流域土壤有机碳含量为经济林地>农耕地>人工成熟林地>灌木林地>人工幼龄林地>天然次生林地;土壤全氮含量为农耕地>经济林地>天然次生林地>人工成熟林地>灌木林地>人工幼龄林地;C/N为人工幼龄林地>人工成熟林地>经济林地>灌木林地>农耕地>天然次生林地。同一土地利用类型在不同区段中,经济林土壤有机碳和全氮含量表现为中游>下游;农耕地土壤有机碳含量为中游>上游>下游;土壤全氮含量为下游>中游>上游;灌木林地土壤有机碳和全氮含量为中游>下游。同一区段不同土地利用类型中,流域下游土壤有机碳表现为经济林地>农耕地>灌木林地,全氮含量表现为农耕地>经济林地>灌木林地;流域中游土壤有机碳和全氮含量均表现为含量农耕地>经济林地>灌木林地;流域上游土壤有机碳含量表现为人工成熟林地最高>农耕地>人工幼龄林地>天然次生林地,全氮含量表现为天然次生林地>人工成熟林地>农耕地>人工幼龄林地。  相似文献   

4.
为探讨海拔梯度变化对表层土壤(0~20 cm)全量养分的影响,以西藏色季拉山西坡的高山灌丛(AS)、杜鹃林(RF)、急尖长苞冷杉林(AGSF1-6)和林芝云杉林(PLLF)为试验对象,研究了林地土壤有机碳(SOC)、全氮(TN)、微生物生物量碳(MBC)、微生物生物量氮(MBN)、易氧化态碳(ROC)和颗粒有机碳(POC)的变化特征.结果表明:在色季拉山西坡,高海拔植被类型具有较高的土壤活性有机碳含量和分配比例.表层土壤SOC随着海拔的升高而增大.SOC最大的是AS,为77.167 g·kg-1,PLLF最低为22.351 g·kg-1.表层土壤TN随着海拔的升高而增大.TN最大的是AS,为2.430g·kg-1,PLLF最低为0.830 g·kg-1.表层土壤C/N最大者为AGSF4,达到了43.57,最小者是PLLF为26.93.海拔和林分对土壤MBC和MBN含量具有显著的影响.随着海拔高度的降低,POC占TOC含量的比率从44.81%降至19.32%,ROC占TOC含量的比率从41.72%降至7.07%.不同林地POC和ROC含量与SOC含量具有正相关关系.土壤活性有机碳与土壤总有机碳显著相关,土壤易氧化有机碳与颗粒有机碳的相关性也比较显著(p<0.05).  相似文献   

5.
笔者分析了川西米亚罗林区典型低效林经不同强度的抚育间伐后,对5种处理的2个土层(0 cm~15 cm,15 cm~30 cm)的土壤总有机碳、微生物量碳含量的变化进行了动态监测,并分析了土壤总有机碳和微生物量碳含量的季节变化。结果表明,5种处理的土壤总有机碳和微生物量碳含量均是上层高于下层;在观测的4个季节内,上层、下层土壤总有机碳均是夏季春季冬季秋季,土壤总有机碳含量的上、下层均值是F3F2F1F4CK;土壤微生物量碳含量均是秋季冬季春季夏季;土壤微生物量碳含量的上、下层均值表现为F3F2F1CKF4,而且30%的间伐强度样地土壤总有机碳含量和微生物量碳含量均最高。  相似文献   

6.
不同海拔梯度川滇高山栎林土壤颗粒组成及养分含量   总被引:3,自引:0,他引:3  
分析卧龙自然保护区皮条河上游巴郎山3个海拔梯度川滇高山栎林的土壤颗粒组成、总有机碳含量和全氮含量.结果表明:巴郎山川滇高山栎林土壤颗粒组成以粉粒为主,属中质地土壤;3个海拔梯度表层土(0~15cm)土壤总有机碳和全氮含量均高于亚层土(15~30cm);在表层土壤中总有机碳含量随海拔增加呈现由低到高,再变低的趋势,亚层土则随海拔升高呈增加趋势;表层和亚层土壤全氮含量均随海拔降低而减少;巴郎山高山栎林土壤碳氮比值较小,平均为12.77;在2个土层中,总有机碳含量与全氮含量的相关性随海拔梯度递减由极显著正相关(P<0.01)到不相关;表层土壤中总有机碳和全氮含量在海拔3549m处与粗粉粒含量呈极显著正相关(P<0.01),与粘粒呈显著负相关(P<0.05),3091m处与粗粉粒含量正相关性显著(P<0.05),2551m处与细砂粒含量呈显著正相关(P<0.05);亚层土壤全氮含量只在海拔2551m处与细粉粒含量呈显著负相关(P<0.05).  相似文献   

7.
Mangroves offer a number of ecosystem goods and services, including carbon (C) storage. As a carbon pool, mangroves could be a source of CO2 emissions as a result of human activities such as deforestation and forest degradation. Conversely, mangroves may act as a CO2 sink through biomass accumulation. This study aimed to determine carbon stocks, harvest removals and productivity of mangrove forests of mainland Tanzania. Nine species were recorded in mainland Tanzania, among them Avicennia marina (Forssk.) Vierh., Rhizophora mucronata Lam. (31%) and Ceriops tagal (Perr.) C.B.Rob. (20%) were dominant. The aboveground, dead wood, belowground and total carbon were 33.5 ± 5.8 Mg C ha?1, 1.2 ± 1.1 (2% of total carbon), 30.0 ± 4.5 Mg C ha?1 (46% of total carbon) and 64.7 ± 8.4 Mg C ha?1 at 95% confidence level, respectively. Carbon harvest removals accounted for loss of about 4% of standing total carbon stocks annually. Results on the productivity of mangrove forests (using data from permanent sample plots monitored for four years [1995-1998]) showed an overall carbon increment of 5.6 Mg C ha?1 y?1 (aboveground carbon), 4.1 C ha?1 y?1 (belowground carbon) and 9.7 C ha?1 y?1 (total carbon) at 23%, 32% and 27% levels of uncertainty, respectively. Both natural death and tree cutting/harvest removals resulted in significant decline of annual carbon productivity. Findings from this study demonstrate that mangroves store large quantities of carbon and are more productive than other dominant forest formations in southern Africa. Both their deforestation and forest degradation, therefore, is likely to contribute to large quantities of emission and loss of carbon sink functionality. Therefore, mangroves need to be managed sustainably.  相似文献   

8.
Microbial biomass, organic carbon, total nitrogen, and microbial quotient (MBC/Corg) in soil were determined during the secondary forest succession in north Ziwulin region in the middle of Loess Plateau, China. The results showed that with secondary forest succession organic carbon (Corg), total nitrogen (TN), microbial biomass carbon (MBC) and N (MBN) in soil increased quickly, and tended to be the highest contents under SF17 (17-year secondary forest), after that they decreased and gradually remained at quite a constant level, suggesting that accumulations of organic C, total N, MBC and MBN in soil occurred mainly at the early succession stages (before SF17). Soil microbial biomass was markedly correlated with the organic carbon and total nitrogen content of soil (p < 0.01), Furthermore, microbial quotient showed significant correlation not only with MBC and organic C, but also with succession duration during the secondary forest succession. Therefore, the results suggested that changes in microbial biomass in soil were relative not only to the quantity, but also to the quality of soil organic matter during secondary forest succession, and that changes in aboveground plant species during succession were critical to improve degradation soil physical, chemical and microbial properties in north Ziwulin of Loess Plateau, China.  相似文献   

9.
在广东省东源县康禾自然保护区常绿阔叶林设置4 hm2样地,按<0.01 mm土粒的含量从小到大将土壤质地分为3个类型,依次为:轻壤土、中壤土、重壤土,通过实地采样统计分析了不同土壤质地表层土壤有机碳含量、全氮含量、碳氮比(C/N)的大小及其关系。结果表明:土壤表层有机碳含量及全氮含量大小依次为:重壤土>中壤土>轻壤土。样地内土壤表层有机碳含量和全氮含量的最大值分别为31.343 g?kg-1、1.882 g?kg-1,最小值分别为8.411 g?kg-1、0.621 g?kg-1。本研究表明保护区土壤中碳氮含量在空间上存在异质性且中壤土最能代表整个样地土壤表层碳氮含量的整体情况。此外,不同土壤质地有机碳含量及碳氮比(C/N)存在显著差异(P<0.05),而全氮含量差异不显著。土壤有机碳含量与土壤全氮含量之间呈极显著的正相关关系(P<0.001),相关系数为r=0.833 9,说明不同土壤质地土壤有机碳含量和全氮含量有极高的相关性。  相似文献   

10.
Agroforestry systems are widely practiced in tropical forests to recover degraded and deforested areas and also to balance the global carbon budget. However, our understanding of difference in soil respiration rates between agroforestry and natural forest systems is very limited. This study compared the seasonal variations in soil respiration rates in relation to fine root biomass, microbial biomass, and soil organic carbon between a secondary forest and two agroforestry systems dominated by Gmelina arborea and Dipterocarps in the Philippines during the dry and the wet seasons. The secondary forest had significantly higher (p < 0.05) soil respiration rate, fine root biomass and soil organic matter than the agroforestry systems in the dry season. However, in the wet season, soil respiration and soil organic matter in the G. arborea dominated agroforestry system were as high as in the secondary forest. Whereas soil respiration was generally higher in the wet than in the dry season, there were no differences in fine root biomass, microbial biomass and soil organic matter between the two seasons. Soil respiration rate correlated positively and significantly with fine root biomass, microbial biomass, and soil organic C in all three sites. The results of this study indicate, to some degree, that different land use management practices have different effects on fine root biomass, microbial biomass and soil organic C which may affect soil respiration as well. Therefore, when introducing agroforestry system, a proper choice of species and management techniques which are similar to natural forest is recommended.  相似文献   

11.
This work studied the effects of tree species composition on soil carbon storage in five mixed stands dominated by oriental beech and grown in the western Caspian region in Guilan province, called Astara, Asalem, Fuman, Chere and Shenrud. The thickness of the litter layer, soil characteristics, tree composition and percentage of canopy coverage were measured in each stand. Total soil organic carbon differed significantly by stand. Total (organic) carbon stores at Fuman, which had the lowest tree species richness with 2 species and least canopy coverage (75%), were significantly (p〈0.05) higher than at other locations. Carbon stor-age in topsoil (0-10 cm) was significantly lower in Shenrud, which had the highest tree species richness with 5 species and highest canopy cov-erage (95%). The high percentage of canopy coverage in Shenrud proba-bly limited the conversion of litter to humus. However, in the second soil layer (10-25 cm), Asalem, with high tree species richness and canopy coverage, had the highest carbon storage. This can be explained by the different rooting patterns of different tree species. In the Hyrcanian forest. According to the results, it can be concluded that not only tree composi-tion but also canopy coverage percentage should be taken under consid-eration to manage soil carbon retention and release.  相似文献   

12.
Studying contents and seasonal dynamics of active organic carbon in the soil is an important method for revealing the turnover and regulation mechanism of soil carbon pool. Through 3 years of field sampling and lab analysis, we studied the seasonal variations, content differences, and interrelationships of total organic carbon (TOC), light fraction organic carbon (LFOC), and particulate organic carbon (POC) of the soil in the forest areas burned with different fire intensities in the Daxing’anling Mountains. The mean TOC content in the low-intensity burned area was greater than that in the unburned area, moderate-intensity, and high-intensity burned areas in June and November (P < 0.05). LFOC and POC in the low-intensity burned area were greater than that in either moderate-intensity or high-intensity burned areas, with significant differences in LFOC in September and November (P < 0.05). A significant difference in LFOC between the unburned and burned areas was only found in July (P < 0.05). However, the differences in POC between the unburned and burned areas were not significant in all the whole seasons (P > 0.05). Soil LFOC and POC varied significantly with the seasons (P < 0.05) in the Daxing’anling Mountains. Significant linear relationships were observed between soil TOC, LFOC, and POC, which were positively correlated with soil nitrogen and negatively correlated with soil temperature in the Daxing’anling Mountains.  相似文献   

13.
柳杉人工林皆伐后初期土壤有机碳和微生物量碳动态   总被引:3,自引:0,他引:3  
本文研究了华西雨屏区柳杉人工林皆伐后1年内土壤有机碳和微生物量碳动态。结果表明:柳杉人工林皆伐林地土壤平均有机碳含量比对照(未皆伐林地)减小2.01 gC.kg-1,但差异不显著,而土壤平均有机碳储量及微生物量碳分别比对照减少20.97 tC.hm-2、6.68 mg.kg-1(P0.05);皆伐林地土壤有机碳含量及微生物量碳均随季节的变化而逐渐降低,但有机碳储量随季节的变化无明显减少趋势;皆伐林地土壤四季的有机碳含量、碳储量和微生物量碳差异不显著。皆伐对柳杉人工林土壤有机碳储量的影响主要表现在0~20 cm土层(P0.05);皆伐林地和对照在0~40 cm土层的微生物量碳和有机碳含量都表现出显著相关性(P0.05),但对照的相关性高于皆伐林地。总之,柳杉人工林转变为采伐迹地后,其初期土壤有机碳储量和微生物量碳都明显减少。  相似文献   

14.
[目的]量化长白山原始阔叶红松林和杨桦次生林土壤颗粒有机碳和黑碳含量及分布特征,为研究东北森林土壤有机碳分布和积累提供依据。[方法]采用粒径分组方法测定原始阔叶红松林和杨桦次生林土壤表层(A_(11))和亚表层(A_(12))颗粒有机碳(POC)和黑碳(BC)含量,分析其与土壤基本性质(有机质、含水量、p H值、粘粒和团聚体等)的关系。[结果]表明:(1)两种森林类型土壤A_(11)和A_(12)POC含量分别为31.89 88.00、5.25 19.45 g·kg~(-1),BC含量分别为8.43 22.40、3.39 12.10 g·kg~(-1),二者随土壤深度增加而显著下降(p0.01)。(2)森林类型显著影响土壤POC和BC,表现为杨桦次生林原始阔叶红松林。(3)两种森林类型土壤POC与土壤有机质、含水量、水稳性团聚体均显著相关,与p H值、粘粒相关性不显著;BC与土壤p H值、粘粒和团聚体相关性均不显著,与含水量显著相关,与有机质仅在A_(11)显著相关。(4)土壤POC和BC显著相关(p0.01)。[结论]在长白山地区森林类型显著影响土壤POC和BC含量,杨桦次生林土壤POC和BC显著高于原始阔叶红松林,很大程度上与森林的采伐和火烧有关。两种森林类型土壤POC和BC分布格局是土壤物理化学性质综合作用的结果。  相似文献   

15.
[目的]通过实地采样对黑碳进行量化研究。[方法]利用相对密度分组方法探讨了长白山典型森林土壤黑碳含量及在不同有机碳组分中的分布特征。[结果]表明:黑碳(BC)含量在表层(A11)、亚表层(A12)分别为6.39~16.55 g·kg-1、1.44~6.16 g·kg-1,随土壤深度的增加而显著下降(p﹤0.01)。在A11、A12层中,轻组有机碳(LFOC)平均含量分别为66.66 g·kg-1、6.65 g·kg-1,轻组黑碳(LFBC)平均含量分别为5.63 g·kg-1、1.21 g·kg-1,同时,LFBC/LFOC在A12层(10.02%~34.89%)显著高于A11层(6.99%~14.45%)(p﹤0.01);A11、A12层重组有机碳(HFOC)平均含量分别为49.16 g·kg-1、36.55 g·kg-1,重组黑碳(HFBC)平均含量分别为2.69 g·kg-1、1.44 g·kg-1,HFBC/HFOC在A11层(3.36%~8.08%)和A12层(3.21%~7.58%)之间没有显著差异(p>0.05)。另外,土壤中LFBC/LFOC显著高于HFBC/HFOC(p﹤0.01),LFBC/BC显著高于HFBC/BC(p﹤0.01)。[结论]长白山典型森林土壤中黑碳的含量、比例均较高;土壤表层(A11)有机碳、黑碳含量及各组分有机碳、黑碳含量均高于亚表层(A12),均随着土层加深而显著降低;轻组、重组有机碳中均含有一定比例的黑碳,黑碳主要分布在轻组分中;轻组、重组有机碳与组分中黑碳均显著相关,轻组中相关系数大于重组。  相似文献   

16.
采用常规方法,测定、分析了川西亚高山5种不同土地利用类型的土壤活性有机碳含量,结果显示土壤有机碳含量均是上层大于下层。在0~10cm土层土壤总有机碳含量表现为灌木林地落叶松林地退耕还林地云杉林地农田;10~20cm土层土壤总有机碳含量表现为灌木林地落叶松林地云杉林地退耕还林地农田。上下层平均值来看灌木林地有机碳含量最高为79.86g.kg-1,是云杉林地的2.85倍,是落叶松林地的1.49倍,是退耕还林地的1.62倍,是农田的3.34倍,表现为灌木林地落叶松林地退耕还林地云杉林地农田。上下层土壤微生物生物量碳含量均表现为灌木林地落叶松林地退耕还林地云杉林地农田;上下层土壤水溶性有机碳含量均表现为落叶松林地灌木林地云杉林地退耕还林地农田。  相似文献   

17.
以我国北亚热带地区退化灌木林改造11 a后形成的木荷-青冈栎混交林和杜英纯林为研究对象,并以保留的退化灌木林为对照,分析了不同树种组成对林分土壤活性有机碳含量的影响。结果表明:木荷-青冈栎混交林和杜英纯林0 50 cm各土层土壤有机碳含量比退化灌木林分别增加了52.33% 96.13%和77.93% 119.85%,土壤易氧化碳增加了57.89% 100.90%和21.44% 46.85%,土壤轻组有机质增加了74.50% 93.75%和27.24% 96.09%,而土壤水溶性有机碳变化不明显。不同树种组成林分土壤活性有机碳占土壤总有机碳的比率大小顺序,土壤水溶性有机碳/土壤总有机碳为退化灌木林 >木荷-青冈栎混交林 >杜英纯林,土壤易氧化碳/土壤总有机碳为木荷-青冈栎混交林 >退化灌木林 >杜英纯林。3种林分土壤各活性有机碳与土壤总有机碳的相关性均达到极显著水平(p<0.01),其中,木荷-青冈栎混交林相关系数大于其它两种林分。3种林分中,土壤总有机碳、易氧化碳、轻组有机质与土壤养分的相关性均达到极显著水平,而退化灌木林土壤水溶性有机碳与水解氮、速效钾相关性不显著,杜英纯林土壤水溶性有机碳与速效钾也无显著相关性。  相似文献   

18.
不同土地利用方式对土壤有机碳、氮含量的影响   总被引:3,自引:0,他引:3  
土壤有机C、N的定量动态变化是评价不同土地利用方式对土壤质量影响的重要内容。本文比较了研究地区种植黑麦草(Lolium multiflorum Lam.)、百喜草(Paspalum notatum Flugge.)、桔树(Citrus reticulata Blanco.)和马尾松(Pinus Massoniana Lamb.)的四种土地利用方式对植物生物量和土壤有机C、N多年变化的影响。试验初期,四种土地利用方式的植物生物量几乎处于同一水平。经过10年长期试验后,黑麦草和百喜草的累计生物量分别是桔树的3.68和3.75倍,马尾松的2.06和2.14倍。地下部生物量的差异更为明显,黑麦草和百喜草两种草类地下部累计生物量都较桔树和马尾松高10倍之多。这表明草类较之乔木更有利于提高土壤有机C、N的含量。土壤有机C、N的含量变化主要发生在0.40cm土层。统计计算表明,10年期问,种植黑麦草和百喜草可使土壤有机C、N贮量每公顷分别约增加1.5吨和0.2吨,而种植桔树使土壤有机C、N贮量每公顷分别约减少1.2吨和0.02吨,种植马尾松使土壤有机C、N贮量每公顷分别约减少0.4吨和0.04吨。表4参10。  相似文献   

19.
喀斯特石漠化地区不同植被群落的土壤有机碳变化   总被引:8,自引:0,他引:8  
研究贵州中部喀斯特石漠化地区不同植被群落土壤和小生境土壤中有机碳的数量和质量变化.结果表明:喀斯特石漠化区阔叶林土壤有机总碳含量和腐殖酸碳含量明显高于灌木林、灌草丛和稀疏草丛,而土壤水溶性有机碳含量的变化则相反;喀斯特森林退化后,土壤有机碳的累积量减少、流失量增加;喀斯特小生境土壤有机总碳和腐殖酸碳含量存在明显的水平空间变异:石坑>石沟>石缝>石洞.主成分分析结果表明:喀斯特土壤有机碳变化的第1主要因子由植被类型决定,第2主要因子由小生境类型所决定.  相似文献   

20.
After five years of growth at high-elevations (∼3000 m) in Utah, container lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) seedlings survived well (80–95%) and grew to similar heights regardless of nursery storage method and site preparation technique. Seedlings received one of three storage treatments: (1) spring-sown in the nursery, overwintered in cooler storage and outplanted in July; (2) spring-sown, overwintered in freezer storage, and outplanted in July; or (3) winter-sown, no storage, and hot-planted in late August. We outplanted seedlings at two locations that were clearcut and had received two treatments of surface organic matter (coarse wood, logging slash, and forest floor) removal: surface organic matter (OM) piled with a bulldozer and burned or surface OM remaining in situ. Compared to adjacent uncut stands, both site preparation treatments increased total soil bulk density, but retaining surface OM in situ maintained soil OM, carbon, and nitrogen levels. After one growing season, seedlings planted where surface OM had been bulldozed were taller and had more biomass, although survival was similar (≥96%) across site preparation treatments. The height growth advantage disappeared after five growing seasons and although overall survival was good, survival was highest where site preparation involved removal of surface OM and freezer-stored seedlings were planted. Total non-structural carbohydrates tended to be higher in roots than in shoots and were also higher in hot-planted seedlings than in stored seedlings. Our results indicate that nursery and forest managers have several options for successful nursery production and outplanting of container lodgepole pine seedlings in the central Rocky Mountains. Using hot-planted seedlings allows for a faster turnaround time (from seed to plantable seedling) and maintaining surface OM may be a cost-effective alternative to dozer piling and burning.  相似文献   

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