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71.
Dynamics of forest biomass carbon stocks from 1949 to 2008 in Henan Province,east-central China 总被引:1,自引:0,他引:1
We estimated forest biomass carbon storage and carbon density from 1949 to 2008 based on nine consecutive forest inventories in Henan Province,China.According to the definitions of the forest inventory,Henan forests were categorized into five groups: forest stands,economic forests,bamboo forests,open forests,and shrub forests.We estimated biomass carbon in forest stands for each inventory period by using the continuous biomass expansion factor method.We used the mean biomass density method to estimate carbon stocks in economic,bamboo,open and shrub forests.Over the 60-year period,total forest vegetation carbon storage increased from34.6 Tg(1 Tg = 1×10~(12)g) in 1949 to 80.4 Tg in 2008,a net vegetation carbon increase of 45.8 Tg.By stand type,increases were 39.8 Tg in forest stands,5.5 Tg in economic forests,0.6 Tg in bamboo forests,and-0.1 Tg in open forests combine shrub forests.Carbon storageincreased at an average annual rate of 0.8 Tg carbon over the study period.Carbon was mainly stored in young and middle-aged forests,which together accounted for 70–88%of the total forest carbon storage in different inventory periods.Broad-leaved forest was the main contributor to forest carbon sequestration.From 1998 to 2008,during implementation of national afforestation and reforestation programs,the carbon storage of planted forest increased sharply from 3.9 to 37.9 Tg.Our results show that with the growth of young planted forest,Henan Province forests realized large gains in carbon sequestration over a 60-year period that was characterized in part by a nation-wide tree planting program. 相似文献
72.
73.
ABSTRACT: High- and multi-frequency acoustic measurement systems and the multi-frequency inversion (MFI) method have been used to measure spatial distributions and abundances of zooplankton by size. In this study, the calibration method for high- and multi-frequency systems was developed and the validation of MFI method was carried out by scatterer measurement. The standard sphere calibration method that has not been applied to such high- and multi-frequencies was applied to calibrate our high- and multi-frequency system, TAPS-6 (Tracor Acoustic Profiling System, BAE Systems). An optimum size of standard sphere of tungsten carbide of 1 mm radius was derived to have a small target strength variation for the six frequencies of TAPS-6, and the practicability and precision of the standard sphere calibration method was confirmed for those frequencies. A school or cluster of dummy scatterers of zooplankton with small tungsten carbide spheres were designed to validate the MFI method, and volume back-scattering strength values were measured by the multi-frequency system. By comparing the result of the inversion with their real composition, the features of the MFI method could be validated and examined. 相似文献
74.
Improving agricultural productivity to keep pace with the fast-growing food demand is a huge challenge for sub-Saharan Africa (SSA). Fertilizer is a powerful productivity-enhancing input; nevertheless, farmers of SSA use only 5–9 kg ha?1 of fertilizer, which is ten times lesser than Latin America and Asia (50 and 80 kg ha?1, respectively). Rice (Oryza sativa) is one of the most important food crops of SSA, and its consumption is growing faster than any other commodity in Africa. Rice-based systems have high potential for improving food production through an efficient management of fertilizers. The biophysical environment, cropping systems and socio-economic status of farmers including market opportunities are the main factors for developing appropriate fertilizer recommendations. Many research efforts have been invested in different countries to develop fertilizer recommendation for rice. However, the diversity of rice ecologies, the type and the cost of fertilizers available on local market are the main constraints for development of blanket recommendations of fertilizer usually applied in many countries. Here, we make a reviews of the progress made on the development of fertilizer recommendations for rice-based systems in SSA. The utilization of the new concepts and decisions support tools for development of fertilizer recommendation and the main achievements and weakness are discussed. The opportunities offered by the new concepts, modeling and decision support tools are discussed in a regional strategic approach for better management of fertilizers in the diversified ecologies of rice-based systems. 相似文献
75.
Nahla Bassil Kim E. Hummer Joseph D. Postman Gennaro Fazio Angela Baldo Isabel Armas Roger Williams 《Genetic Resources and Crop Evolution》2009,56(3):339-352
Heritage apple (Malus domestica Borkh. hybrids) and pear (Pyrus communis L. hybrid) trees grow in villages throughout Terceira Island, Azores, Portugal. Some of these pears have different names but similar morphology. The objective of this study was to determine synonymy, homology, and phylogeny of apples and pears from Terceira and to examine potential relationships of the island pears with standard apples and pears of Portuguese or American descent. Nine apple microsatellite markers were used to determine genetic relationships. Distance- and parsimony-based cluster analysis grouped these genotypes into separate apple and pear clades. The Terceira apples were divided into two clades: the maçā and the reineta-reinette. Among the 17 heritage apple genotypes, seven unique accessions were identified and four groups of synonyms, or possibly clones, were detected including: ‘Reineta Agosto’ and ‘Reineta Verde’ from Altares; ‘Reineta Castanha’ and ‘Reineta Verde Miuda’; ‘Maçā Pêra,’ ‘Maçā Calhau’, ‘Pêro Branco’ from Salga and from Terra-Chā and ‘Maçā Marmelo’; and the five genotypes ‘Maçā Sao Joao’, ‘Malápio Rosa’, ‘Maçā Gaspar’, ‘Maçā Branca’ and ‘Maçā Pato’. In addition, two homonyms were detected. ‘Pêro Vermelho’ from Terra Chā was a separate genotype from a tree from Doze Ribeiras of the same name, but Pêro Branco from Terra Chā appears to be a clone that can be distinguished by an additional allele at CH1F07a from a tree with that name from Salga. One pair of apple clones, ‘Reineta Agosto’ and ‘Reineta Verde’ from Altares appear to be derived from an unreduced gamete of ‘Golden Delicious.’ Another apple genotype ‘Maçā Acida’ could be a sibling of the ‘Maçā Pêra’ clonal group. Other tested standard apples from the US genebank were unrelated to Terceira genotypes. Of the seven heritage pears, five unique genotypes and one pair of synonyms were detected. ‘Pêra Papo Pintassilgo’ from Raminho and ‘Pêra Vermelha’ from the nursery of Serviço de Desenvolvimento Agario da Terceira (SDAT) were synonyms. ‘Passans du Portugal’ was related to ‘Pêra Cabaca’ but other standard pears from the US genebank were unrelated to Terceira genotypes. Future studies will include additional apple and pear cultivars from other Islands of the Azores and continental Portugal, and wild Asian species to further explore genetic relationships. 相似文献
76.
为了分析河南省土壤养分变化,为河南省土壤施肥提供参考,运用GIS与地统计学相结合的方法,通过对比分析1982、2009年2个不同时期河南省土壤有效锌的含量,探讨20多年以来河南省土壤有效锌时空变异的规律。结果表明:2009年河南省有效锌质量分数比1982年增加了41.67%,2个时期土壤有效锌变异系数分别为29.1%和37.3%,变异程度均为中等变异,最优拟合模型为球状模型,具有中等的空间相关性。20多年来,河南省土壤有效锌含量只有北部地区呈减少趋势,其余地区大体呈现出不同程度的增加趋势,其中漯河市、驻马店市、信阳市增幅较大,焦作市、开封市减少较多,在农作物施肥、土壤管理等过程中,应及时控制有效锌元素含量的合理范围。 相似文献
77.
针对数控机床误差溯因方法复杂且适应性差的问题,提出了基于数控系统圆检测图形的特征角点分布规律,并与神经网络相结合实现对机床运动误差的快速溯因方法。首先,提取所生成圆图形的特征角点,构造反向间隙、周期误差等特征矩阵;然后结合神经网络将低维特征矩阵映射至高维特征空间,实现对数控机床误差的快速溯因。实验表明,该方法简单有效,误差识别准确率较高,且具有较强的通用性。 相似文献
78.
农产品追溯标识双向转换设备研究 总被引:2,自引:0,他引:2
条码、RFID等已成为追溯系统中产品标识的重要手段,实现不同标识间的快速转换已成为追溯环节无缝衔接的基础。在分析现有追溯系统标识特点的基础上,设计了集成工业控制器、RFID读写模块、嵌入式打印模块、条码扫描模块的农产品追溯标识双向转换设备,突破了RFID-条码转换中的二维条码动态加密技术,构建了条码-RFID转换中的控制流程,实现了标识读取、双向转换、标识打印、状态监测等功能。利用设计的设备进行了不同转换内容和转换数量下的双向测试,结果表明在RFID-条码的转换中转换成功率均达到了100%;在条码-RFID的转换中随着转换数量的增加、转换内容的增多,转换成功率存在下降趋势。2种转换方式下,转换时间均随转换数量和转换内容增多存在增加趋势。设备可满足加工包装过程中不同包装载体标识跟踪与信息记录的需求。 相似文献
79.
The preparation of the antigen, details of the reagents, the titration of the antispecies conjugates and the execution of the indirect fluorescent antibody test are described. The sensitivity and specificity of the test and its applicability to the detection of antibodies to Cowdria ruminantium are recorded. The test is both highly specific and sensitive and can be applied to a wide range of studies on heartwater, including epidemiology, determination of the C. ruminantium infection rate of Amblyomma ticks and the evaluation of immunization against heartwater. The test can also be used to detect antibodies to the heartwater agent in the sera of game. 相似文献
80.
As the levels of radioactivity in seafood have fallen back into the safe range, Fukushima fisheries are considering reopening. However, even if seafood from the Fukushima area were sufficiently safe to distribute to seafood markets, its value may be undermined because of the damage done to its reputation by the Fukushima disaster. We quantified consumers’ preferences for seafood from Fukushima and adjacent prefectures to examine the extent of the reputational damage to Fukushima seafood. We conducted a choice experiment to measure consumers’ willingness to pay for seafood from the Fukushima area. We also measured the impact of displaying ecolabels [Marine Stewardship Council (MSC) and Marine Eco-label Japan (MEL)] on Fukushima products. The results indicated that Fukushima products are considerably discounted compared with products displayed as domestic; even products from adjacent prefectures are substantially discounted. By contrast, consumers positively evaluated locally labeled products. We also found that demersal fish are discounted more than pelagic fish that inhabit the ocean surface off the shore of Fukushima. 相似文献