生物措施缓解酸性土壤铝毒害研究进展

酸性土壤在世界上广泛存在,Al毒是酸性土壤限制作物生长和产量的主要限制因子之一.本文概述了酸性土壤Al毒害问题以及作物的耐Al机制,总结了遗传改良植物的耐Al性、向土壤或植物根际接种外生菌根真菌和其他耐Al微生物以缓解酸性土壤Al毒害的研究进展.以上措施在酸性土壤中的生态系统恢复具有应用前景.     

南京市防灾减灾绿地类型与功能定位研究

论述了南京市防灾减灾绿地的类型主要为点状紧急避难绿地、带状防灾减灾绿地、块状应急避难绿地和片状临时生活绿地4种类型,并介绍了该4类防灾减灾绿地的特点及规划要求,确定了南京市各类防灾减灾绿地的功能定位及分布状况。     

Soil organic carbon accumulation and carbon costs related to tillage, cropping systems and nitrogen fertilization in a subtropical Acrisol

Conservation management systems can improve soil organic matter stocks and contribute to atmospheric C mitigation. This study was carried out in a 18-year long-term experiment conducted on a subtropical Acrisol in Southern Brazil to assess the potential of tillage systems [conventional tillage (CT) and no-till (NT)], cropping systems [oat/maize (O/M), vetch/maize (V/M) and oat + vetch/maize + cowpea (OV/MC)] and N fertilization [0 kg N ha⁻¹ year⁻¹ (0 N) and 180 kg N ha⁻¹ year⁻¹ (180 N)] for mitigating atmospheric C. For that, the soil organic carbon (SOC) accumulation and the C equivalent (CE) costs of the investigated management systems were taken into account in comparison to the CT O/M 0 N used as reference system. No-till is known to produce a less oxidative environment than CT and resulted in SOC accumulation, mainly in the 0–5 cm soil layer, at rates related to the addition of crop residues, which were increased by legume cover crops and N fertilization. Considering the reference treatment, the SOC accumulation rates in the 0–20 cm layer varied from 0.09 to 0.34 Mg ha⁻¹ year⁻¹ in CT and from 0.19 to 0.65 Mg ha⁻¹ year⁻¹ in NT. However, the SOC accumulation rates peaked during the first years (5th to 9th) after the adoption of the management practices and decreased exponentially over time, indicating that conservation soil management was a short-term strategy for atmospheric C mitigation. On the other hand, when the CE costs of tillage operations were taken into account, the benefits of NT to C mitigation compared to CT were enhanced. When CE costs related to N-based fertilizers were taken into account, the increases in SOC accumulation due to N did not necessarily improve atmospheric C mitigation, although this does not diminish the agricultural and economic importance of inorganic N fertilization.     

Successful eradication of the European rabbit (Oryctolagus cuniculus) and house mouse (Mus musculus) from the island of Selvagem Grande (Macaronesian archipelago), in the Eastern Atlantic

The Portuguese island of Selvagem Grande (Great Salvage) in Macaronesia is an important seabird breeding station in the eastern Atlantic. Significant populations of Cory's shearwater Calonectris diomedea (Scopoli, 1769), Bulwer's petrel Bulweria bulweria (Jardine & Selby, 1828) and little shearwater Puffinus assimilis baroli (Bonaparte, 1857) are present, and white-faced storm-petrel Pelagodroma marina (Latham, 1790) and Madeiran storm-petrel Oceanodroma castro (Harcourt, 1851) populations are of global significance. Selvagem Grande also provides diverse habitats for an extensive flora, including 11 endemic species. The 270-ha island was also inhabited by two alien invasive mammals: the European rabbit Oryctolagus cuniculus (Linnaeus, 1758) and the house mouse Mus musculus (Linnaeus, 1758). Both are known to have had adverse impacts on breeding seabirds and island vegetation. In 2002, the Natural Park of Madeira conducted a program using brodifacoum bait formulations aimed at rabbit and mouse eradication. Approximately 17 000 individual baiting points were established on a 12.5 × 12.5 m grid. Baits were also applied by hand “seeding” on steep slopes and cliffs where bait stations could not be placed. Rabbits were removed after a month. However, mice persisted for considerably longer and strategic bait applications against them continued for a further six months. Subsequent assessments by trapping, bait takes and systematic observation of signs over three years, has confirmed the removal of both alien invasive species. This paper presents information on these operations, on measures adopted to mitigate adverse impacts of the eradication program on important vertebrate non-target species, including Berthelot's pipit Anthus berthelotii Bolle, 1862 and a species of gecko Tarentola bischoffi Joger, 1984 and on the initial response of the island's ecosystem to the eradication of rabbits and mice.     

Climate Change Mitigation and Adaptation in Agriculture

Mitigation and adaptation are two principle strategies for managing human-induced climate change. Agriculture plays a duet role in climate change. It has been a major source of greenhouse gases to the atmosphere. It is also one of the sectors most vulnerable to the risks and impacts of global climate change. This paper first indentified the mitigative and adaptative options and potential in agriculture, then addressed the integrated analysis of mitigation and adaptation and its benefits for agriculture. Finally, it discussed the implications to Chinese agriculture in dealing with the global climate change.     

Fate and legacy of an invasion: extinct and extant populations of the soft‐shell clam (Mya arenaria) in Grays Harbor (Washington)

1. The soft‐shell clam, Mya arenaria, was intentionally introduced to Washington State during the mid‐1870s. Presently, extensive shell deposits cover parts of the intertidal flats of Grays Harbor, an estuarine ecosystem that has received much attention because of its role as nursery ground for Dungeness crab (Cancer magister), a commercially significant species. 2. Preliminary observations revealed that shells in the deposits belonged to clams that were much larger than extant conspecifics. Shell deposits and extant populations have spatially disjoint distributions; few individuals are found living within the deposits. The purpose of our study was to determine the cause of the different size characteristics between extinct and extant clams, when and how the deposits originated, and why the extant population does not prosper in what appears to be prime habitat. 3. We (i) surveyed extant populations and shell deposits, (ii) followed the extant population through periodic sampling over a 3‐year period, (iii) investigated growth and survival in extant and extinct populations, (iv) experimentally manipulated growth conditions, and (v) searched archival sources for information about the origin of the deposits. 4. We conclude that extinct clams grew faster and lived longer, apparently because they occupied the best habitats available. Archival records suggest that the population expanded rapidly during the period around 20 years after its introduction, but was decimated between 1895 and 1897 by a mass‐mortality episode that resulted in the formation of the deposits. The population since then has never rebounded in its prime habitat, in spite of potential settlers being regularly available. 5. Dungeness crab larvae settle preferentially in the shell deposits, where the abundance of 0+ age juveniles is orders of magnitude higher than in the adjacent flats. We hypothesize that predation by juvenile crabs limits clam recruitment. 6. The introduction of Mya to Grays Harbor during the 1870s has had long‐lasting effects, which persist a century after their once large populations were decimated by a mass‐mortality event. Copyright © 2000 John Wiley & Sons, Ltd.     

林业活动在吸收大气CO2与减缓全球变暖中的作用

森林生态系统是陆地生态系统的重要组分 ,对全球气候变化有重要的贡献。介绍了吸收大气CO2 和减缓全球变暖的林业活动的主要形式 ,即保存现有碳、固定大气碳和替代碳排放 ,论述了全球和我国森林碳保存及其固定潜力 ,同时为这些林业活动的有效实施提出了建议     

Evaluation of origanum oil,hydrolysable tannins and tea saponin in mitigating ruminant methane: In vitro and in vivo methods

The objective of this study was to investigate the effects of origanum oil (ORO), hydrolysable tannins (HYT) and tea saponin (TES) on methane (CH₄) emission, rumen fermentation, productive performance and gas exchange in sheep by using in vitro and in vivo methods. The ORO, HYT and TES additive levels were normalized per kg dry matter (DM) in both in vitro and in vivo experiments: ORO-0, 10, 20 and 40 ml/kg; HYT-0, 15, 30 and 60 g/kg; and TES-0, 15, 30 and 60 g/kg, respectively. During in vitro incubation, 40 ml/kg ORO linearly decreased CH₄ emission (p < 0.05); 20 and 40 ml/kg ORO cubically decreased carbon dioxide (CO₂) production (p < 0.05), and rumen pH was cubically raised with the increasing ORO additive level (p < 0.01). The 60 g/kg HYT cubically decreased CH₄ production (p < 0.05). The pH of 60 g/kg HYT was higher than that of 15 and 30 g/kg (p < 0.01); the pH of 20 g/kg TES was higher than that of 5 g/kg (p < 0.05). In the in vivo experiments, 40 ml/kg ORO inhibited dry matter intake (p < 0.01) cubically and reduced average daily gain (ADG) and feed conversion ratio (FCR) cubically (p < 0.05), and 20 or 40 ml/kg ORO linearly decreased CH₄ production based on per day or metabolic weight (W^0.75) (p < 0.05). Both 30 and 60 g/kg HYT linearly inhibited CH₄ emission on the bases of per day and W^0.75 (p < 0.05). The 20 g/kg TES improved the apparent digestibility of crude protein (p < 0.05), 10 and 20 g/kg of TES decreased CH₄ emission (p < 0.05), and 5 g/kg of TES reduced O₂ consumption and CO₂ production (p < 0.05). In conclusion, these three plant extracts all showed the abilities on mitigating CH₄ emission of sheep with appropriate additive ranges.