气候变更的敏感性对预测水土流失量的影响

研究气候变更的空间敏感性，将提高对大规模预测水土流失量的精度。2006年美国学者x．C．Zhang在3个温室、3种耕作措施下，模拟2070～2099年气候变化对水土流失的影响。研究结果表明：在种植季节，温度每增长1℃，导致小麦减产10％；CO2累积量每增长50％，产量增加26％；降雨量每减少1％，产量降低0．9％；传统耕作和保土耕作的土壤流失减少了3。8％。根据全部预测结果得知，径流介于-33％～3％，土壤流失介于-33％-0％。来自不同空间的气候预测的平均水土流失的多样性与气候模拟的多样性一致。由全球气候模型具有预测功能时，应在空间分布规律下评估气候的影响；当分布规律未知时，应在多个空间分布下评估气候的影响。由于空间分布的不确定性，预测的影响随之不确定。

A "Yellow Cap" on Quaternary Red Clay in Jiujiang,Jiangxi Province

A thin layer of yellow-brown-colored earth was generally found on Quaternary red clay in Jiujiang,Jiangxi Province. A typical profile was established. Both particle size distribution and REE (rare earthelements) characteristics of the yellow-brown-colored earth of the profile fully suggested its aeolian origin andclose similarity to Naming Xiashu loess. The study also implied aeolian origin of the underlying Quaternaryred clap Compared with the red clay, the yellow- brown- colored earth was less weathered because of its lowercontent of free iron and higher mole ratios of SiO2/A12O3 and SiO2/(Fe2O3+A12O3 ) as well as its lessdeveloped chemical microtextures of quartz grains.In order to study the aged of the two deposits comparatively, the thermoluminescent dating method wasused. As a result, the bottom of the yellow-brown-colored esrth was dated to 6015 ka B. P. and the upperpart of the red clay 38854 ka B. P. It was suggested that the yellow- browm- colored earth was formed inthe Late Pleistocene and was probably the aeolian deposit of the Last Glacial, which corresponded with theMalan loess in the Loess Plateau of the northwestern part of China; while the underlying red clay was formedin the Middle Pleistocene.A "yellow cap" on Quaternary red clay in Jiujiang implied a great climatic and environmental varistionin the beginning of the Late Pleistocene in the southern pot of China, especially in the middle and lowerreaches of the Yangtze River. The eveal not only halted the rubification, once dominating the region, butalso produced a widespread covering of aeolian deposit, as only occurred in the cold and dry environment.

The Development of a Seed Stock Industry Using Indigenous Livestock from Rural Keepers for Sustainable Production

The majority of livestock in the rural areas of Africa are indigenous types that are not well defined as breeds as perceived by the developed world. The animals in this important sector have remained largely uncharacterised and face the risk of genetic dilution due to indiscriminate crossbreeding, breed replacement and neglect. This article uses two examples to describe a system that has been implemented in South Africa that allows indigenous livestock from rural keepers to enter the seed stock industry as recognized breeds. The first example is the indigenous Nguni breed of cattle that has been successfully developed into a seed stock breed, with a society celebrating its 25th anniversary in November 2011. The second example involves the challenges of developing a seed stock industry for some of the unimproved indigenous goat breeds of South Africa. Climate change is expected to have a more extreme effect on southern hemisphere continents than on other continents. Such negative effects will include high ambient temperatures, nutritional stress and altered patterns of animal diseases. With the likelihood of global warming, these adapted genotypes can play a very important role in sustainable livestock production.

社会百科

社会百科人类未来食物丰富多采人类早期的食谱是很广的，只是后来才越来越窄了。实际上只要放开视野，未来的食物将极其丰富多采。生物学家们估计，地球上拥有５００万至１０００万种生物，仅植物就有３５万至４０万种。这些植物中可２供人们食用的至少有８万种之多。人类...

The climate change variations in the northern Greater Khingan Mountains during the past centuries

The Greater Khingan Mountains （Daxinganling） are China＇s important ecological protective screen and also the region most sensitive to climate changes. To gain an in-depth understanding and reveal the climate change characteristic in this high-latitude, cold and data-insufficient region is of great importance to maintaining ecological safety and corre- sponding to global climate changes. In this article, the annual average temperature, precipi- tation and sunshine duration series were firstly constructed using tree-ring data and the me- teorological observation data. Then, using the climate tendency rate method, moving-t-testing method, Yamamoto method and wavelet analysis method, we have investigated the climate changes in the region during the past 307 years. Results indicate that, since 1707, the annual average temperature increased significantly, the precipitation increased slightly and the sun- shine duration decreased, with the tendency rates of 0.06~C/10a, 0.79 mm/10a and -5.15 h/10a, respectively （P〈~0.01）. Since the 21 st century, the period with the greatest increase of the annual average temperature （also with the greatest increase of precipitation） corresponds to the period with greatest decrease of sunshine duration. Three sudden changes of the an- nual average temperature and sunshine duration occurred in this period while two sudden changes of precipitation occurred. The strong sudden-change years of precipitation and sunshine duration are basically consistent with the sudden-change years of annual average temperature, suggesting that in the mid-1860s, the climatic sudden change or transition really existed in this region. In the time domain, the climatic series of this region exhibit obvious local variation characteristics. The annual average temperature and sunshine duration exhibit the periodic variations of 25 years while the precipitation exhibits a periodic variation of 20 years. Based on these periodic characteristics, one can infer that in the period from 2013 to 2030, the temperature will be at a high-temperature stage, the precipitation will be at an abundant-precipitation stage and the sunshine duration will be at an less-sunshine stage. In terms of spatial distribution, the leading distribution type of the annual average temperature in this region shows integrity, i.e：, it is easily higher or lower in the whole region; and the second distribution type is more （or less） in the southwest parts and less （or more） in the northeast parts. Precipitation and sunshine duration exhibit complex spatial distribution and include four spatial distribution types. The present study can provide scientific basis for the security in- vestigation of homeland, ecological and water resources as well as economic development programming in China＇s northern borders.

Disaster Risk Reduction Efforts in the Greater Horn of Africa

This article assesses the current state of disaster risk reduction(DRR) in the Greater Horn of Africa(GHA),and focuses on interventions and policies to mitigate hydrometeorological risks. The research analyzes, as main case study, the program 'Regional Climate Prediction and Risk Reduction in the Greater Horn of Africa'funded by the Office of U.S. Foreign Disaster Assistance(USAID OFDA) in the early 2000 that targeted risk preparedness.The research method combines a desk review of relevant documents and research papers with surveys and interviews directed to key proponents of DRR across the GHA. Results highlight current strengths and weaknesses in the way DRR is implemented in the GHA. Significant improvements in the climate-forecasting capabilities in the GHA since the 2000 s are acknowledged, but the practice of DRR remains technology driven and impacts on the ground are limited. The key findings highlight the significant communication gaps that exist between the producers of climate information and their end users, the communities at risk. The article urges the establishment of bridges that connect climate experts, policymakers, and representatives of the local communities, and for the implementation of a feedback loop from forecast users to their producers, in order to strengthen risk resilience across the GHA.