期刊文献+
共找到832篇文章
< 1 2 42 >
每页显示 20 50 100
National Soil Organic Carbon Stocks Inventories under Different Mangrove Forest Types in Gabon
1
作者 Rolf Gaël Mabicka Obame Neil-Yohan Musadji +5 位作者 Jean Hervé Mve Beh Lydie-Stella Koutika Jean Aubin Ondo Farrel Nzigou Boucka Michel Mbina Mounguengui Claude Geffroy 《Open Journal of Forestry》 2024年第2期127-140,共14页
Gabonese’s estuary is an important coastal mangrove setting and soil plays a key role in mangrove carbon storage in mangrove forests. However, the spatial variation in soil organic carbon (SOC) storage remain unclear... Gabonese’s estuary is an important coastal mangrove setting and soil plays a key role in mangrove carbon storage in mangrove forests. However, the spatial variation in soil organic carbon (SOC) storage remain unclear. To address this gap, determining the SOC spatial variation in Gabonese’s estuarine is essential for better understanding the global carbon cycle. The present study compared soil organic carbon between northern and southern sites in different mangrove forest, Rhizophora racemosa and Avicennia germinans. The results showed that the mean SOC stocks at 1 m depth were 256.28 ± 127.29 MgC ha<sup>−</sup><sup>1</sup>. Among the different regions, SOC in northern zone was significantly (p p < 0.001). The deeper layers contained higher SOC stocks (254.62 ± 128.09 MgC ha<sup>−</sup><sup>1</sup>) than upper layers (55.42 ± 25.37 MgC ha<sup>−</sup><sup>1</sup>). The study highlights that low deforestation rate have led to less CO<sub>2</sub> (705.3 Mg CO<sub>2</sub>e ha<sup>−</sup><sup>1</sup> - 922.62 Mg CO<sub>2</sub>e ha<sup>−</sup><sup>1</sup>) emissions than most sediment carbon-rich mangroves in the world. These results highlight the influence of soil texture and mangrove forest types on the mangrove SOC stocks. The first national comparison of soil organic carbon stocks between mangroves and upland tropical forests indicated SOC stocks were two times more in mangroves soils (51.21 ± 45.00 MgC ha<sup>−</sup><sup>1</sup>) than primary (20.33 ± 12.7 MgC ha<sup>−</sup><sup>1</sup>), savanna and cropland (21.71 ± 15.10 MgC ha<sup>−</sup><sup>1</sup>). We find that mangroves in this study emit lower dioxide-carbon equivalent emissions. This study highlights the importance of national inventories of soil organic carbon and can be used as a baseline on the role of mangroves in carbon sequestration and climate change mitigation but the variation in SOC stocks indicates the need for further national data. 展开更多
关键词 Mangroves Forest Soil Organic Carbon stocks Rizophora Racemose Avicenia germinans GABON
下载PDF
Exploiting Data Science for Measuring the Performance of Technology Stocks
2
作者 Tahir Sher Abdul Rehman +1 位作者 Dongsun Kim Imran Ihsan 《Computers, Materials & Continua》 SCIE EI 2023年第9期2979-2995,共17页
The rise or fall of the stock markets directly affects investors’interest and loyalty.Therefore,it is necessary to measure the performance of stocks in the market in advance to prevent our assets from suffering signi... The rise or fall of the stock markets directly affects investors’interest and loyalty.Therefore,it is necessary to measure the performance of stocks in the market in advance to prevent our assets from suffering significant losses.In our proposed study,six supervised machine learning(ML)strategies and deep learning(DL)models with long short-term memory(LSTM)of data science was deployed for thorough analysis and measurement of the performance of the technology stocks.Under discussion are Apple Inc.(AAPL),Microsoft Corporation(MSFT),Broadcom Inc.,Taiwan Semiconductor Manufacturing Company Limited(TSM),NVIDIA Corporation(NVDA),and Avigilon Corporation(AVGO).The datasets were taken from the Yahoo Finance API from 06-05-2005 to 06-05-2022(seventeen years)with 4280 samples.As already noted,multiple studies have been performed to resolve this problem using linear regression,support vectormachines,deep long short-termmemory(LSTM),and many other models.In this research,the Hidden Markov Model(HMM)outperformed other employed machine learning ensembles,tree-based models,the ARIMA(Auto Regressive IntegratedMoving Average)model,and long short-term memory with a robust mean accuracy score of 99.98.Other statistical analyses and measurements for machine learning ensemble algorithms,the Long Short-TermModel,and ARIMA were also carried out for further investigation of the performance of advanced models for forecasting time series data.Thus,the proposed research found the best model to be HMM,and LSTM was the second-best model that performed well in all aspects.A developedmodel will be highly recommended and helpful for early measurement of technology stock performance for investment or withdrawal based on the future stock rise or fall for creating smart environments. 展开更多
关键词 Machine learning data science smart environments stocks movement deep learning stock marketing
下载PDF
室温下Yb^(3+)和Er^(3+)掺杂的NaYS_2粉末材料的Stocks和Anti-Stocks发光 被引量:1
3
作者 张继森 张立国 +3 位作者 任建岳 段配华 骆永石 吕少哲 《发光学报》 EI CAS CSCD 北大核心 2013年第7期824-828,共5页
合成了NaYS2:0.20Yb3+,0.03Er3+和NaYS2:0.03Er3+粉末材料,通过材料的Stocks和Anti-Stocks光谱,研究了Er3+和Yb3+跃迁几率对激发方式的依赖特征,以及局域环境对S2-Re3+(Re3+=Yb3+或Er3+)电荷迁移态的影响,探讨了在共掺杂和单掺杂状态下Y... 合成了NaYS2:0.20Yb3+,0.03Er3+和NaYS2:0.03Er3+粉末材料,通过材料的Stocks和Anti-Stocks光谱,研究了Er3+和Yb3+跃迁几率对激发方式的依赖特征,以及局域环境对S2-Re3+(Re3+=Yb3+或Er3+)电荷迁移态的影响,探讨了在共掺杂和单掺杂状态下Yb3+和Er3+间的能量传递和Er3+的Stocks和Anti-Stocks辐射跃迁机制。 展开更多
关键词 稀土 stocks和Anti-stocks发光 CTS
下载PDF
Dynamics of ecosystem carbon stocks during vegetation restoration on the Loess Plateau of China 被引量:7
4
作者 WANG Kaibo DENG Lei +3 位作者 REN Zongping SHI Weiyu CHEN Yiping SHANG-GUAN Zhouping 《Journal of Arid Land》 SCIE CSCD 2016年第2期207-220,共14页
In the last few decades, the Loess Plateau had experienced an extensive vegetation restoration to reduce soil erosion and to improve the degraded ecosystems. However, the dynamics of ecosystem carbon stocks with veget... In the last few decades, the Loess Plateau had experienced an extensive vegetation restoration to reduce soil erosion and to improve the degraded ecosystems. However, the dynamics of ecosystem carbon stocks with vegetation restoration in this region are poorly understood. This study examined the changes of carbon stocks in mineral soil (0-100 cm), plant biomass and the ecosystem (plant and soil) following vegetation restoration with different models and ages. Our results indicated that cultivated land returned to native vegetation (natural restoration) or artificial forest increased ecosystem carbon sequestration. Tree plantation sequestered more carbon than natural vegetation succession over decades scale due to the rapid increase in biomass carbon pool. Restoration ages had different effects on the dynamics of biomass and soil carbon stocks. Biomass carbon stocks increased with vegetation restoration age, while the dynamics of soil carbon stocks were affected by sampling depth. Ecosystem carbon stocks consistently increased after tree plantation regardless of the soil depth; but an initial decrease and then increase trend was observed in natural restoration chronosequences with the soil sampling depth of 0-100 cm. Moreover, there was a time lag of about 15-30 years between biomass production and soil carbon sequestration in 0-100 cm, which indicated a long-term effect of vegetation restoration on deeper soil carbon sequestration. 展开更多
关键词 AGES carbon stocks natural vegetation restoration tree plantation Loess Plateau
下载PDF
Does tree species composition control the soil carbon stocks of the Hyrcanian forest in the Northern Iran?(A case study in Guilan province,Iran) 被引量:3
5
作者 Vilma Bayramzadeh 《Journal of Forestry Research》 SCIE CAS CSCD 2014年第1期143-146,共4页
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, Fuma... 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. 展开更多
关键词 beech forest canopy coverage soil carbon stocks tree composition
下载PDF
Impact of nutrient losses from agricultural lands on nutrient stocks in Dianshan Lake in Shanghai, China 被引量:2
6
作者 Shou-bing WANG Xiao-xue MA +2 位作者 Zheng-qiu FAN Wei-qian ZHANG Xiao-yong QIAN 《Water Science and Engineering》 EI CAS CSCD 2014年第4期373-383,共11页
Abstract: The water quality of Dianshan Lake in Shanghai Municipality, China, is impacted by nutrient losses from agricultural lands around the lake. In this study, nine types of agricultural land use were monitored ... Abstract: The water quality of Dianshan Lake in Shanghai Municipality, China, is impacted by nutrient losses from agricultural lands around the lake. In this study, nine types of agricultural land use were monitored in 2010 and 2011, and a correlation analysis between nutrient losses from agricultural non-point sources (NPS) and nutrient stocks in the lake was conducted over monthly and seasonal time periods. The results indicate that the monthly average concentration of total nitrogen (TN) ranged from 1.41 to 7.34 mg/L in 2010 and from 1.52 to 5.90 mg/L in 2011, while the monthly average concentration of total phosphorous (TP) ranged from 0.11 to 0.26 mg/L in 2010 and from 0.13 to 0.30 mg/L in 2011. The annual loss of TN from agricultural NPS was 195.55 tons in 2010 and 208.40 tons in 2011. The cultivation of water oat made the largest contribution to the loss of TN. The annual loss of TP was 44.58 tons in 2010 and 48.12 tons in 2011, and multi-vegetable cultivation made the largest contribution to the loss of TP. The results of correlation analysis show that the monthly stocks of TN and TP in the lake have a positive correlation with the monthly losses of TN and TP from agricultural NPS. According to the seasonal data, the stocks of TN and TP in the lake both have a much stronger correlation with the losses of TN and TP from agricultural NPS in summer than in other seasons. Agricultural NPS pollution control should be the main focus for the water resource conservation in this area. 展开更多
关键词 agricultural non-point source pollution nutrient losses nutrient stocks totalnitrogen (TN) total phosphorus (TP) Dianshan Lake
下载PDF
Carbon stocks of different land uses in the Kumrat valley, Hindu Kush Region of Pakistan 被引量:8
7
作者 Adnan Ahmad Syed Moazzam Nizami 《Journal of Forestry Research》 SCIE CAS CSCD 2015年第1期57-64,共8页
Changes in land use cover, particularly from forest to agriculture, is a major contributing factor in increasing carbon dioxide(CO2) level in the atmosphere.Using satellite images of 1999 and 2011, land use and land... Changes in land use cover, particularly from forest to agriculture, is a major contributing factor in increasing carbon dioxide(CO2) level in the atmosphere.Using satellite images of 1999 and 2011, land use and land use changes in the Kumrat valley KPK, Pakistan, were determined: a net decrease of 11.56 and 7.46 % occurred in forest and rangeland, while 100 % increase occurred in agriculture land(AL). Biomass in different land uses,forest land(FL), AL, and range land(RL) was determined by field inventory. From the biomass data, the amount of carbon was calculated, considering 50 % of the biomass as carbon. Soil carbon was also determined to a depth of 0–15and 16–30 cm. The average carbon stocks(C stocks) in all land uses ranged from 28.62 ± 13.8 t ha-1in AL to486.6 ± 32.4 t ha-1in pure Cedrus deodara forest. The results of the study confirmed that forest soil and vegetation stored the maximum amount of carbon followed by RL. Conversion of FL and RL to AL not only leads to total loss of about 56 %(from FL conversion) and 37 %(RL conversion) of soil carbon in the last decades but also the loss of a valuable carbon sink. In order to meet the emissions reduction obligations of the Kyoto Protocol, Conservation of forest and RL in the mountainous regions of the Hindu Kush will help Pakistan to meet its emissions reduction goals under the Kyoto Protocol. 展开更多
关键词 Hindu Kush Kumrat valley Land uses Biomass Carbon stocks
下载PDF
Using Data Mining with Time Series Data in Short-Term Stocks Prediction: A Literature Review 被引量:2
8
作者 José Manuel Azevedo Rui Almeida Pedro Almeida 《International Journal of Intelligence Science》 2012年第4期176-180,共5页
Data Mining (DM) methods are being increasingly used in prediction with time series data, in addition to traditional statistical approaches. This paper presents a literature review of the use of DM with time series da... Data Mining (DM) methods are being increasingly used in prediction with time series data, in addition to traditional statistical approaches. This paper presents a literature review of the use of DM with time series data, focusing on shorttime stocks prediction. This is an area that has been attracting a great deal of attention from researchers in the field. The main contribution of this paper is to provide an outline of the use of DM with time series data, using mainly examples related with short-term stocks prediction. This is important to a better understanding of the field. Some of the main trends and open issues will also be introduced. 展开更多
关键词 DATA Mining Time Series FUNDAMENTAL DATA DATA Frequency Application DOMAIN SHORT-TERM stocks PREDICTION
下载PDF
Assessing current stocks and future sequestration potential of forest biomass carbon in Daqing Mountain Nature Reserve of Inner Mongolia, China 被引量:3
9
作者 Yahui Sun Li Meng +2 位作者 Lü Tian Guoliang Li Osbert Jianxin Sun 《Journal of Forestry Research》 SCIE CAS CSCD 2016年第4期931-938,共8页
Assessment of regional forest carbon stocks and underlying controls is critical for guiding forest management in the context of carbon sequestration. We investigated the variations in tree biomass carbon stocks relati... Assessment of regional forest carbon stocks and underlying controls is critical for guiding forest management in the context of carbon sequestration. We investigated the variations in tree biomass carbon stocks relating to forest types, and estimated the total tree biomass carbon stocks and projected gains through natural stand development by 2020 and 2050 in the Daqing Mountain Nature Reserve based on Category II data of the Forest Inventory of Inner Mongolia for the period ending 2008. Over a total area of 388,577 ha,this nature reserve currently stores an estimated 2221 Gg C in tree aboveground biomass alone, with potential to grow by more than 30 % to reach 2938 Gg C by 2020 and nearly double to 4092 Gg C by 2050 through natural development of the existing forest stands. The tree biomass carbon density and potential gain in tree biomass carbon stocks vary markedly among forest types and with stand development.The variations in the potential change of tree biomass carbon density for the periods 2008–2020 and 2008–2050 among forest types partly reflect the varying relationships of tree biomass carbon density with stand age for different tree species, and partly are attributable to variations in the stand age structure among different forest types. Of the major forest types, the ranking of projected changes in tree biomass carbon density are not consistent with variations in the relationship between tree biomass carbon density and stand age, neither are they explainable by variations in stand age structures, implying the interactive effect between forest type and stand dynamics on temporal changes in tree biomass carbon density. Birch rank highest for future biomass carbon sequestration because of its dominance in cover area and better age structure for potential gain in tree biomass carbon stocks. Poplar and larch were out-performers compared to other forest types given their greater contribution to total tree biomass carbon stocks relative to their distributional areas. Findings in this study illustrate that protection and proper management of under-aged forests can deliver marked gains in biomass carbon sequestration. This is of great importance to policy-makers as well as to scientific communities in seeking effective solutions for adaptive forest management and mitigation of anthropogenic greenhouse gases emissions using forest ecosystems. 展开更多
关键词 sequestration biomass stocks stand forests Reserve Birch projected gains anthropogenic
下载PDF
Comparative study of haematological,serum electrolyte and nonelectrolyte parameters of male and female Persian sturgeon(Acipenser persicus)brood stocks 被引量:1
10
作者 ADEL Milad PALANISAMY Satheesh Kumar +2 位作者 SHAFIEI Shafigh FAZLI Hasan ZORRIEHZAHRA Mohammad Jalil 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第8期39-43,共5页
Sturgeons are the most important principal market species in the Caspian Sea. In the present study, measurement of blood parameters was carried out with the aim of evaluating the normal value of hematological and seru... Sturgeons are the most important principal market species in the Caspian Sea. In the present study, measurement of blood parameters was carried out with the aim of evaluating the normal value of hematological and serum biochemical parameters of brood stocks Acipenser persicus during spawning season. Blood samples were collected from 36 brood stocks of A. persicus(18 males and 18 females) during the spawning season. Higher value of red blood cells, white blood cells, haemoglobin, haematocrit was observed in male breeders with significant differences between female breeders(p〉0.05). Haemoglobin and haematocrit value in this study was within the range of 8.70 to 9.2 g/d L and 29.73% to 30.26%, respectively. The statistically significant differences between mean corpuscular volumes, mean corpuscular haemoglobin, lymphocyte and neutrophil percentages, aspartate aminotransferase, alkaline phosphatase and creatine kinase were observed in the male and female brood stocks.It is concluded from this study, some of the hematological and serum biochemical parameters of male and female A. persicus breeders were significantly varied from each other. In comparative investigation with earlier reports,the values of red blood cells, haemoglobin and haematocrit are highly varied due to age variations of fish.However, further studies are necessary to understand the impact of sexual, age, size, length, and season and habitat variation. Serum biochemical parameters can be used for confirming the maturity of A. persicus and monitoring any changes in the water quality parameters and soil. 展开更多
关键词 aquaculture brood stocks biochemistry haematology spawning
下载PDF
Floristic diversity and carbon stocks in the periphery of Deng–Deng National Park,Eastern Cameroon
11
作者 Louis Paul Roger Kabelong Banoho Louis Zapfack +16 位作者 Robert Bertrand Weladji Cedric Chimi Djomo Melanie Chichi Nyako Yannick Enock Bocko Damien Marie Essono Julliete Mancho Nasang Nade`ge Madountsap Tagnang Charles Innocent Memvi Abessolo Kenneth Roger Mvondo Sakouma Farikou Mamadou Souahibou Florence Jeanne Sarah Palla Tonga Ketchatang Peguy Remi Jiagho Thierry Loic Kenmou Ulrich Arnaud Choumele Kana Jumo Boris Armel Anyam Yi Andjik Roger Bruno Tabue Mbobda 《Journal of Forestry Research》 SCIE CAS CSCD 2020年第3期989-1003,共15页
Carbon is continuously being removed from the atmosphere by photosynthesis and stored in carbon pools(live,dead,and soil carbon)of forest ecosystems.However,carbon stock in dead wood and of trees with diameters at bre... Carbon is continuously being removed from the atmosphere by photosynthesis and stored in carbon pools(live,dead,and soil carbon)of forest ecosystems.However,carbon stock in dead wood and of trees with diameters at breast height(dbh)between 5 and 10 cm is often not considered in many studies carried out in the Congo Basin Forest.The relationship between tree diversity,life-forms and carbon stocks has received little attention.This study was carried out on the outskirts of Deng Deng National Park(DDNP)to determine tree diversity(dominant families,species richness and Shannon index),assess carbon stocks in the five carbon compartments(living tree,understory,fine roots,dead wood and litter)as well as to analyze the relationship between(1)carbon stocks and tree diversity;and,(2)between carbon stock and life-forms.The Shannon index of trees≥10 cm dbh ranged from 2.6 in riparian forest to 4.3 in secondary forest;and for the tree between 5 and 10 cm,it ranged to 1.56 in riparian forest to 3.68 in the secondary forest.The study site housed 16 species,7 genera and 3 families which are only found in trees of dbh between 5 and 10 cm.The average total carbon stock of the five compartments varied from 200.1 t ha-1 in forest residues to 439.1 t ha-1 in secondary forest.Dead wood carbon stock varied from 1.2 t ha-1 in riparian forests to 12.51t ha-1 in agroforests.The above ground carbon stocks for trees with diameter between 5 and 10 cm varied from 0.7 t ha-1 in young fallow fields to 5.02 t ha-1 in old secondary forests.This study reveals a low but positive correlation between species richness and total carbon stocks,as well as a significant positive relationship between life-forms and total carbon stocks.The findings highlight the need for more data concerning carbon content of dead wood,carbon of trees≥5 cm<10 cm dbh and the relationship between carbon stocks and tree diversity from other areas of the Congo Basin for a good understanding of the contribution of tropical forests to climate change mitigation. 展开更多
关键词 DENG DENG national PARK Carbon stocks Land COVER types Species diversity DEAD wood
下载PDF
Effects of forest management on biomass stocks in Romanian beech forests
12
作者 O.Bouriaud A.Don +2 位作者 I.A.Janssens G.Marin E.-D.Schulze 《Forest Ecosystems》 SCIE CSCD 2019年第3期179-193,共15页
Background: Forest management aims at obtaining a sustainable production of wood to be harvested to generate products or energy. However, the quantitative influence of forest management and of removals by harvest on b... Background: Forest management aims at obtaining a sustainable production of wood to be harvested to generate products or energy. However, the quantitative influence of forest management and of removals by harvest on biomass stocks has rarely been analysed on a large scale based on measurements. Two hypotheses prevail: management induces a reduction of wood stocks due to cuttings, versus no impact because of increased growth of the remaining trees. Using data collected for 2840 permanent plots across Romania from the National Forest Inventory representing^2.5 Mha, we have tested to what extent different management types and treatments can influence the biomass stock and productivity of beech forests, and attempt to quantify these effects both on the short and long terms. Three main types of beech forest management are implemented in Romania with specific objectives: intensive wood production in production forests, protection of ecosystem services (e.g. watersheds, avalanche protection) in protection forests, and protection of the forest and its biodiversity in protected forests. Production forests encompass two treatments differing according to the stand regeneration method: the age class rotation management and the group shelterwood management. Results: We show that forest management had little influence on the biomass stocks at a given stand age. The highest stocks at stand age 100 were observed in production forests (the most intensively managed forests). Consequences of early cuttings were very short-termed because the increase in tree growth rapidly compensated for tree cuttings. The cumulated biomass of production forests exceeded that of protected and protection forests. Regarding the treatment, the group shelterwood forests had a markedly higher production over a full rotation period. The total amount of deadwood was primarily driven by the amount of standing deadwood, and no management effect was detected. Conclusions: Given the relatively low-intensity management in Romania, forest management had no negative impact on wood stocks in beech forests biomass stocks at large scale. Stand productivity was very similar among management types or treatments. However cumulated biomass in production forests was higher than in protection or protected forests, and differed markedly according to treatments with a higher cumulated biomass in shelterwood forests. 展开更多
关键词 FOREST MANAGEMENT FOREST PRODUCTIVITY BIOMASS stocks NATIONAL FOREST INVENTORY
下载PDF
Study on the Carbon Stocks of Soils under Five Kinds of Plantations
13
作者 Tao ZHANG Fuxu WAN Zhengxin TAN 《Asian Agricultural Research》 2015年第4期58-60,共3页
Based on the field data and laboratory analysis,we studied the soil organic carbon storage and vertical distribution features about five kinds of plantations in Xuyi,and the results showed that soil carbon density in ... Based on the field data and laboratory analysis,we studied the soil organic carbon storage and vertical distribution features about five kinds of plantations in Xuyi,and the results showed that soil carbon density in the five forest types changed greatly,with a range of 0. 8-3. 04 kg / m2 for five soil layers. Furthermore,soil carbon density decreased generally with the depth,as well as carbon content. In the whole soil profile,the range of carbon density in these five forests was from 4. 79 kg / m2 to 5. 62 kg / m2. However,60% carbon was concentrated in40 cm depth of soil. The calculated result of soil organic carbon reserve was as follows: Cupressus lusitanica( 50. 264 t / hm2),hackberry( 47. 859 t/hm2),Populus L.( 53. 216 t/hm2),Red bayberry( 49. 581 t/hm2),Amygdalus persica L.( 58. 202 t/hm2),with the average storage of 51. 824 t / hm2,lower than the national average level,so,people should pay attention to the artificial forest tending and management.According to the above analysis,this paper concluded that the afforestation was the effective measure for increasing the soil organic carbon accumulation,and the effects of planting the indigenous tree species Cupressus lusitanica and Amygdalus persica L. were best. 展开更多
关键词 ORGANIC CARBON DENSITY of SOILS CARBON stocks PLAN
下载PDF
Morphological characteristics and identification of new monosomic stocks for cotton (Gossypium hirsutum L.)
14
作者 Marina F. Sanamyan Julia E. Petlyakova +1 位作者 Elnora A. Sharipova Ibrokhim Y. Abdurakhmonov 《Advances in Bioscience and Biotechnology》 2010年第5期372-383,共12页
The presence of distinct morphological markers in monosomics is important for selection and maintenance of the monosomic plants in subsequent generations and for a well-targeted chromosome substitutions. Here we prese... The presence of distinct morphological markers in monosomics is important for selection and maintenance of the monosomic plants in subsequent generations and for a well-targeted chromosome substitutions. Here we present cytological and morphological features of the cotton (Gossypium hirsutum L.) monosomic lines developed in Uzbekistan, and their identification by means of translocation tests. We report “reduced” stigma as a new phenotypic marker for cotton monosomics, which makes it possible to distinguish cytotypes without cytological analyses. We identified eleven cotton monosomes by translocation tests using our 28 translocation cotton lines. We determined such features of the cotton monosomic lines as significant lowering of the pollen fertility, genetic determination of variation in pollen fertility in different flowers of the same monosomic plants and variation of both meiotic index and tetrads with micronuclei in different buds. New features of cotton monosomic lines, described herein, should be useful for future cotton genome investigation and development of new chromosome substitution lines. 展开更多
关键词 COTTON Monosomic stocks MORPHOLOGICAL MARKERS TRANSLOCATION Test IDENTIFICATION of Monosome Reduced STIGMA
下载PDF
The Assessment of Carbon Stocks in the Oak Scrub Forest of Sheringal Valley Dir Kohistan
15
作者 Alamgir Khan Adnan Ahmad +3 位作者 Ziaur Rahman Siraj-ud-Din   Rahmatullah Qureshi Juma Muhammad 《Open Journal of Forestry》 2015年第5期510-517,共8页
The present study estimates carbon stocks (C-stocks) of the Oak scrub forest of Sheringal valley through field inventory. Stem density (ha&#451), tree height (m), basal area (m2&#183ha&#451), stem volume (... The present study estimates carbon stocks (C-stocks) of the Oak scrub forest of Sheringal valley through field inventory. Stem density (ha&#451), tree height (m), basal area (m2&#183ha&#451), stem volume (m2&#183ha&#451), stem biomass (t&#183ha&#451), total biomass (t&#183ha&#451), and total C-stock (t&#183ha&#451), were calculated. Stem density varied between 80±8.16 to 510 ± 42 trees ha&#451, with a mean value of 226 ± 7 tress ha&#451. The average tree height, basal area and stem volume were 5.47 ± 0.76 m, 12.82 ± 0.25 m2&#183ha&#451 and 46.37 ± 0.85 m3&#183ha&#451 respectively. The total calculated stem biomass was 32.46 ± 0.60 t&#183ha&#451 and total tree biomass was 51.61 ± 0.60 t&#183ha&#451. The calculated C-stocks in the Oak scrub forest ranged from 2.005 ± 1.32 t&#183ha&#451 to 63.1 ± 3.34 t&#183ha&#451 and the mean C stocks was 25.80 ± 0.47 t&#183ha&#451. The results of the study confirmed that the Oak scrub forest acts as a valuable sink of carbon, but this valuable storage factory of carbon faced the problems of excess uses for fuel wood, forage, domestic uses (mostly for construction) and unscientific management. Proper scientific management and proper utilization of the forest can be significant measures to enhance the potential of the forest to stored and sink more carbon and can be included for CDM and REED++ under Keyto protocol. 展开更多
关键词 Sheringal OAK SCRUB FOREST Biomass and Carbon stocks
下载PDF
Soil Carbon Stocks Evolution in Organic Cotton-Based Cropping Systems in Southern and Northern Sudanese Agro-Ecological Zones of Burkina Faso
16
作者 Mamadou Traoré Bazoumana Koulibaly +4 位作者 Kalifa Coulibaly Issouf Traoré Moussa Gnissien Tahibou Paré Hassan Bismarck Nacro 《Journal of Agricultural Science and Technology(B)》 2019年第6期392-402,共11页
Variation of soil carbon stock in the cropping systems is an important indicator of their sustainability.The present study was conducted in 2015 and 2018 in seven organic cotton production areas distributed over the S... Variation of soil carbon stock in the cropping systems is an important indicator of their sustainability.The present study was conducted in 2015 and 2018 in seven organic cotton production areas distributed over the Southern and Northern Sudan agro-ecological zones in Burkina Faso.Soil samples were collected in 2015 as baseline and in 2018,after three years of cropping seasons,to determine the variations in carbon stocks in plots under organic farming systems.Surveys were also conducted to understand the fertilization practices implemented by producers during the same period.The results revealed that the recommended fertilization packages were not respected due to low production capacity and under using of organic manure.After three years of cropping in 2018,the deficit of organic restitution has led to a high decline of the soil carbon stocks.This decline was more severe in the 0-10 cm depth in some soils where the decrease in carbon stocks ranged from-4.6 t/ha to-5.5 t/ha.The correlation between soil types and their carbon stocks in the 0-10 cm soil layer was found to be significant(p<0.05)in the Northern Sudan agro-ecological zone with adjusted R2=74%and 54%in 2015 and 2018,respectively,and adjusted R2=56%(2015)and 44%(2018)in the Southern Sudan agro-ecological zone.After three years of organic cotton-based farming,a decrease in the correlation between soil types and their carbon content was observed in the majority of cases.These results show that the process of carbon storage in soil is more influenced by agricultural practices and agro-ecological conditions than by the soil type. 展开更多
关键词 Organic cotton soil carbon stocks cropping system Burkina Faso
下载PDF
Floral diversity and carbon stocks and of protected forest ecosystem: A case of UENR’s Bat Sanctuary, Sunyani, Ghana
17
作者 Nat Owusu-Prempeh Osei Owusu Antobre Thomas Agyei 《Open Journal of Forestry》 2018年第1期29-41,共13页
The study assesses the functional status of the University of Energy and Natural Resources’ (UENR) bat sanctuary by examining its floral diversity and carbon stocks. Twenty-nine sampling points (plots) were randomly ... The study assesses the functional status of the University of Energy and Natural Resources’ (UENR) bat sanctuary by examining its floral diversity and carbon stocks. Twenty-nine sampling points (plots) were randomly generated by using the ArcGIS random sampling algorithm. Using a three-nest sampling plot of 100m2, 25m2, and 1m2 quadrat, the enumeration of trees (DBH>10cm), saplings (>2cm DBH 0.05) between the 10m buffer created and the core area with respect to species diversity and carbon stocks. The study has provided valuable information on the functional status of the bat sanctuary which will help promote its conservation for sustained provision of ecosystem services. 展开更多
关键词 Carbon stocks FLORAL Species DIVERSITY Protected Area (PA) Edge Effects GEOSTATISTICS Ghana
下载PDF
Soil Properties, and Soil Organic Carbon Stocks of Tropical Andosol under Different Land Uses
18
作者 Girma Abera Endalkachew Wolde-Meskel 《Open Journal of Soil Science》 2013年第3期153-162,共10页
Land use effect of tropical Andosol, with two from crop lands (Site 1 and Site 2) and one from Agroforestry coffee plantation (Site 3) was explored under laboratory conditions to understand their physical, chemical an... Land use effect of tropical Andosol, with two from crop lands (Site 1 and Site 2) and one from Agroforestry coffee plantation (Site 3) was explored under laboratory conditions to understand their physical, chemical and biological properties and soil organic carbon (SOC) stocks from the rift valley of Ethiopia. Site 3 that acquired less cultivation than others exhibited better aggregate size fraction (AF, 55%), higher aggregate stability (AS, 91%), and greater active microbial biomass (AMB), reflecting better soil structure development. Comparatively, higher total carbon (TC), organic carbon (OC) and total nitrogen (TN) concentrations were recorded in bulk soils and microaggregate fractions of Site 2 and Site 3 than in intensively cultivated Site 1. As expected, microaggregate fractions displayed greater OC and TN than bulk soils across all land uses. Site 1 revealed higher metabolic quotient (qCO2) and lower SOC stock (2.1 Mg·ha-1), suggesting microbial stress, while micro nutrients deficiencies were observed with the alkaline soil (Site 2). Conversely, the highest SOC stock was exhibited with Site 3 (4.2 Mg·ha-1), indicating the importance of coffee land use in C sequestration. Crop lands, depleted much of their native carbon stocks had significant CO2 sink capacity. Hence, management practices that increase the input of organic resources should be adopted to build SOM and enhance soil fertility. 展开更多
关键词 AGGREGATE Fraction AGGREGATE Stability Crop LAND USE Coffee LAND USE SOC and SON stocks
下载PDF
Development of New Interspecific Monosomic F_1 Substitution Stocks for Investigations in Cotton Genome
19
作者 SANAMYAN M F PETLYAKOVA J E SHARIPOVA E A RAKHMATULLINA E M 《棉花学报》 CSCD 北大核心 2008年第S1期98-,共1页
As it is known a complete coverage of cotton(Gossypium hirsutum L.) genome with hypoaneuploids is not still realized.Therefore the detection of new types of aneuploids especially in different cytogenetic collections i... As it is known a complete coverage of cotton(Gossypium hirsutum L.) genome with hypoaneuploids is not still realized.Therefore the detection of new types of aneuploids especially in different cytogenetic collections is very useful.In Uzbekistan,long-term investigations towards development 展开更多
关键词 In Development of New Interspecific Monosomic F1 Substitution stocks for Investigations in Cotton Genome
下载PDF
Land-Use Change on Soil C and N Stocks in the Humid Savannah Agro-Ecological Zone of Ghana
20
作者 Johnny Kofi Awoonor Fowzia Adiyah Bright Fafali Dogbey 《Journal of Environmental Protection》 2022年第1期32-68,共37页
Land-use conversion and unsustainable farming practices are degrading native forest ecosystems of Ghana’s humid savannah agro-ecological zone. This study assessed the impact of land-use change on soil C and N stocks ... Land-use conversion and unsustainable farming practices are degrading native forest ecosystems of Ghana’s humid savannah agro-ecological zone. This study assessed the impact of land-use change on soil C and N stocks in different land-use systems and soil types. A total of eighty (80) composite soil samples at two depths (0 - 20 cm and 20 - 50 cm) were sampled from five land use types (Forest, Woodland savannah, Grassland, Fallow and Cropland) for laboratory analyses. Particle size distribution, bulk density, pH, SOC and TN were determined using standard procedures. Results of the study indicated that C and N stocks were significantly lower in croplands (p < 0.05) compared to other land-use systems. There were significant interactions (p < 0.05) within land-use systems, soil types, and soil depth for soil C and N stocks. Acrisol and associated soils had the highest C and N stocks. A strong positive significant correlation (p < 0.05) was observed between C and N stocks with an R<sup>2</sup> value of 0.85 and 0.93 for the 0 - 20 and 20 - 50 cm depth, respectively. Soil C and N stocks in the study area were estimated to be 34.56 kg/m<sup>2</sup> and 4.63 kg/m<sup>2</sup> for soil types and 26.89 kg/m<sup>2</sup> and 3.39 kg/m2 for land use types, respectively for the 0 to 50 cm soil depth. Our findings indicated that the conversion of native forest to arable land has significantly reduced soil C and N stocks in the top 50 cm (0.50 m) soil layer by 50.77% and 47.77%, respectively. Therefore, we conclude that land-use change, soil type, and soil depth influenced soil C and N stocks of land-use systems in the humid savannah agro-ecological zone of Ghana. 展开更多
关键词 Land Conversion Nutrient Dynamics Soil C and N stocks Soil Type Land-Use
下载PDF
上一页 1 2 42 下一页 到第
使用帮助 返回顶部