宁夏中部生态移民区土地利用时空变化分析

通过解译宁夏中部红寺堡区1989年、1999年、2006年、2012年TM遥感影像,获取该区域生态移民前后4期土地利用数据,对1989~2012年以来土地利用变化情况进行了分析。结果表明,各个时间段的土地利用变化差异性显著。1989~1999年,由于大规模的土地开荒和红寺堡灌区的建设,耕地面积持续增加,同时该区域开始有了水浇地,而林草面积相应减少;1999~2006年,由于退耕还林还草政策的实施,耕地中的旱地被逐渐退耕为草地或发展为水浇地,林草面积开始由减少转为增加,区域土地利用开始合理化;2006~2012年,随着生态移民工程和生态建设工程的成熟发展,林草覆盖面积进一步增加,水浇地面积继续稳步增加,而未利用地和旱地面积持续下降。研究结果为区域土地资源的合理利用及生态移民工程的进一步顺利开展提供可靠依据。     

Cause and Consequence in Maize Planting Dates in Germany

An important part of agricultural adaptation is the timing of crop sowing dates, affecting yields and the level of risk incurred during a particular season. Cold stress is especially relevant in maize, Zea mays L., so that the timing of planting in the spring is a tactical response to short‐term weather, but is also subject to strategic planning with regard to longer‐term climate. Both factors compare the potential implications of cold stress to the additional yield obtainable through earlier planting. New cultivars suited to growing conditions in Europe and generally increasing spring temperatures have enabled earlier planting, but it is still dependent on short‐term weather during the planting period. In the context of field‐level decision‐making, a panel regression is used to estimate the relationship between weekly local temperature and precipitation and planting dates at specific sites throughout Germany. Next, localised weather data and planting behaviour are linked to yields at the district (Landkreis) level to show the effects of planting date on yield. Based on these relationships optimal planting dates are explored with some associated costs and benefits. Results show a trend towards earlier planting that follows observed increasing spring temperatures and the availability of more cold‐tolerant cultivars but this advance is buffered by the increasing severity of minimum temperatures during a critical period. Earlier planting potentially increases yield but this is offset by additional management costs and risk. A robust and simple depiction of farmer behaviour in climatic, technological and economic context can help to understand trends in crop management and productivity that effect agricultural landscapes.     

Managing soil quality for humanity and the planet

Rather than a human-centric, the basic strategy of achieving Sustainable Development Goals must be focused on restoring and sustaining planetary processes. The urgency of meeting the demands of the humanity must be reconciled with the necessity of enhancing the environment. Increasing and restoring soil organic matter content of the degraded and depleted soils is critical to strengthening planetary processes.     

酵母浸膏对北柴胡种子萌发的影响及评价

以北柴胡种子为试验材料,分别以0.5％、1.0％、1.5％和2.0％的酵母浸膏液对北柴胡种子进行浸种,在种子萌发过程中测定相关的生理生化指标,探讨酵母浸膏液对北柴胡种子萌发的影响.含水量的测定采用烘干减重法,体积的测定采用排水法,可溶性糖含量的测定采用蒽酮比色法,蛋白质含量的测定采用考马斯亮蓝-G 250染色法,氨基酸含量的测定采用茚三酮显色法;利用隶属函数法对各项指标进行综合评价.结果表明:北柴胡种子在萌发过程中,种子内含水量的变化和其体积的变化呈一定的相关性,都是呈先下降后上升再缓慢增加的趋势;可溶性糖含量的变化呈先下降后上升再下降的趋势;蛋白质含量整体呈先急剧下降后上升再缓慢下降的趋势;氨基酸含量整体呈先上升后下降的趋势.综合各项指标进行综合评价,酵母浸膏液浸种对北柴胡种子的萌发具有明显的促进作用,其中以1.0％酵母浸膏液浸种效果最佳.     

Foliage‐applied sodium nitroprusside and hydrogen peroxide improves resistance against terminal drought in bread wheat

Terminal drought is threatening the wheat productivity worldwide, which is consumed as a staple food by millions across the globe. This study was conducted to examine the influence of foliage‐applied stress signalling molecules hydrogen peroxide (H₂O₂; 50, 100, 150 μm ) and nitric oxide donor sodium nitroprusside (SNP; 50, 100, 150 μm ) on resistance against terminal drought in two bread wheat cultivars Mairaj‐2008 and BARS‐2009. These stress signalling molecules were applied at anthesis stage (BBCH 61); drought was then imposed by maintaining pots at 35% water holding capacity. Terminal drought caused significant reduction in grain yield of both tested bread wheat cultivars; however, foliage application of both stress signalling molecules at either concentration improved the performance of both bread wheat cultivars. Maximum improvement in 100‐grain weight (12.2%), grains per spike (19.7%), water‐use efficiency (WUE; 19.8%), chlorophyll content index (10.7%), total soluble phenolics (21.6%) and free leaf proline (34.3%), and highest reduction in leaf malondialdehyde contents (20.4%) was recorded when H₂O₂ was foliage‐applied at 100 μm . Foliage application of SNP enhanced the grains per spike, 100‐grain weight and grain yield by 14.9%, 11.3% and 20.1%, respectively, than control. The foliage‐applied stress signalling molecules improved the accumulation of soluble phenolics, proline and glycine betaine with simultaneous reduction in malondialdehyde contents, which enabled wheat plants to sustain the biological membranes under stress resulting in better stay green (high chlorophyll contents) under drought. This helped improving the grain number, grain weight, grain yield, WUE and transpiration efficiency. In crux, foliage‐applied H₂O₂ and SNP, at pre‐optimized rate, may be opted to lessen the drought‐induced yield losses in bread wheat in climate change conditions.     

半地下带保温夹套发酵罐的应用

通过对半地下带保温夹套的发酵罐与普通发酵罐24 h的温度变化和6 d的产气量的对比试验分析,结果表明:采用半地下带保温夹套发酵罐发酵,24 h的温度变化缓慢,受外界温度变化影响小,高温持续的时间较长,利于微生物发酵;产气总量多,持续时间长。     

Dietary plasticity in Arctic charr (Salvelinus alpinus) in response to long‐term environmental change

Corrigan LJ, Winfield IJ, Hoelzel AR, Lucas MC. Dietary plasticity in Arctic charr (Salvelinus alpinus) in response to long‐term environmental change.
Ecology of Freshwater Fish 2011: 20: 5–13. © 2010 John Wiley & Sons A/S Abstract –  In the face of widespread environmental change impacts, there is a need to better understand mechanisms promoting flexibility and resilience of ecosystem components to such change to inform strategies for conservation. Glacial relict species are especially vulnerable to such changes. We investigated the behavioural responses of a native, glacial relict species, Arctic charr (Salvelinus alpinus) to long‐term environmental changes. It was hypothesised that changes in feeding behaviour would occur as a key intermediary to reduction in habitat availability (through climate change and eutrophication) or competitive interactions [with introduced roach (Rutilus rutilus)]. Stomach content analysis was used to assess the diet of 199 charr caught from Windermere, United Kingdom, in the months of March, June, September and November 2003–2007. The results were compared to data from 1940 to 1951 prior to the environmental changes and revealed a marked increase in the contribution of benthic invertebrates in the present diet. Stable isotope analysis confirms the results of the stomach analysis, suggesting that the charr have switched their diet from zooplanktivory towards benthivory. We discuss the possibility that habitat modification and roach population expansion in Windermere have contributed to changes in charr diet. Complementary studies suggest that this diet shift is more likely to be a response to the increasing roach population than to habitat modification; however, further study in Windermere would be required to elucidate the exact mechanism. Long‐term data sets such as these provide information that is useful for determining the directivity of ecological change and the capability of species to respond to change.     

Projecting future habitat quality of three midwestern reservoir fishes under warming conditions

Rising temperatures caused by climate change are likely to affect cool‐water and warm‐water fishes differently. Yet, forecasts of anticipated temperature effects on fishes of different thermal guilds are lacking, especially in freshwater ecosystems. Towards this end, we used spatially explicit, growth rate potential (GRP) models to project changes in seasonal habitat quality for a warm‐water piscivore (largemouth bass Micropterus salmoides), a cool‐water piscivore (walleye Sander vitreus) and a hybrid piscivore (saugeye S. vitreus × S. canadensis) in two Midwestern reservoirs. We assessed habitat quality for two periods (early and middle 21st century) under two realistic greenhouse gas emission scenarios (a mid‐century emissions peak and a rapid continuous increase in emissions). Largemouth bass were projected to experience enhanced or slightly reduced habitat during all seasons, and throughout the mid‐21st century. By contrast, walleye habitat was projected to decline with anticipated warming, except during the spring in the smaller of our two study reservoirs and during the fall in the larger of our two study reservoirs. Saugeye habitat was projected to either increase modestly or decline slightly during the spring and fall and declines in habitat quality and quantity that were smaller than those for walleye were identified during summer. Collectively, our findings indicate that climate warming will differentially alter habitat suitability for reservoir piscivores, favouring warm‐water species over cool‐water species. We expect these changes in habitat quality to impact the dynamics of reservoir fish populations to varying degrees necessitating the consideration of climate when making future management decisions.     

泵闸建设对白莲泾河段水质的影响

2007年4月-2009年4月对上海白莲泾河段水体环境质量进行了调查,取黄浦江南码头上1个断面和白莲泾上的3个断面,于每月大、小潮当日采集各断面水样,获得了该河段的各项水质指标。2007年10月,白莲泾河道断流,泵闸工程实施。根据监测结果,以DO、BOD₅、COD_Mn、TN和TP为指标参数,利用标准类别指数评价法对建闸工程施工活动的环境影响进行评价,结果发现:TN、TP是白莲泾河段的最主要污染指标,TN的权重系数均超过40%,甚至50%,均为劣Ⅴ类;TP的权重系数均超过10%,甚至30%,其含量是地表水Ⅳ类标准的0.8~5.6倍。总体上,白莲泾河段3个站点的水质劣于黄浦江站点,而施工前水质优于施工后。施工前,大潮期白莲泾河道IV类水比例为29%,较小潮期(8%)高出21%。建闸施工后,大小潮期间出现劣V类水的比例分别为87%和88%,潮汐对白莲泾河段并无显著影响。