高寒围栏草地短期放牧育肥牦牛增重试验

选择 40头成年阉牦牛 ,( 2 0头为试验组、2 0头为对照组 ) ,进行围栏草地上短期放牧育肥试验。结果 ,在围栏草地上放牧育肥的试验组阉牦牛 ,试验组每头牦牛的总增重比对照组提高 3 .3 1kg ,平均日增重 83g ,提高 44 % ,(P <0 .0 1)。试验组比对照组牦牛每头分别增收 2 6.48元     

西藏沙化动态及其原区

西藏自治区是我国沙化最严重的地区之一。2004年调查结果表明，西藏沙化面积为216842．7km^2其中重度以上的沙化面积占总沙化面积的91．53％；沙化类型以戈壁占绝对优势：草地、未利用地是主要的沙化土地利用类型。全区沙化总体上呈恶化趋势，沙化土地面积增加，沙化程度加剧，但拉萨、山南等地沙化土地有所减少。西藏土地沙化变化是受自然因素与人为因素共同作用的结果。     

Rural depopulation and recent landscape changes in a Mediterranean region: Consequences to the breeding avifauna

We studied the vegetational and avifaunistic changes following rural depopulation in an area covering 2,600 ha north of Montpellier (Southern France). The study area is covered by a mosaic of Mediterranean habitats that includes cultivation, grasslands, shrublands, and woodlands and is representative of the natural features present and of the human usage practiced so far in this part of the Mediterranean. We sampled the vegetation and the bird fauna in the same 193 census plots in 1978 and in 1992. At both the habitat and landscape scales the cover of woody plants increased significantly. Open habitats tend to disappear. As a consequence the abundance of open-habitat bird species decreased significantly whereas the abundance of forest birds increased significantly. These changes favor a pool of forest species widespread in western Europe and reduce habitat availability for open habitat and shrubland species. Many of the latter are Mediterranean species whose distribution in Western Europe could become reduced under current landscape dynamics. Our observation of more woodlands and their typical birds and of less open habitats and their associated avifauna is not consistent with the traditional worry shown by the public and the managers about the regression of forests and woodlands in the Northern Mediterranean as a consequence of fire.     

西杂牛连续埋植“畜大壮”效果观察

本试验对甘肃河西地区西杂１－２岁和周岁以下的犊牛连续用促生长剂“畜大壮”分阶段进行耳根埋植,试验结果表明,４－６月龄犊牛全期１８０天,试验组增重和平均日增重分别为５．５ｋｇ和３０８．３３ｇ,试验组比对照组提高３７．２５ｋｇ和２０６．９４ｇ（Ｐ〈０．０１）,１－２岁牛全期１８０天,试验组平均增重和日增重分别为５６．４３ｋｇ和３１４．４９ｇ,试验缄比对照组分别提高３０．０３ｋｇ和１６６．８２ｇ差异显著     

Estimation of daily and total lactation milk yield of Chios ewes from single morning or evening records

Linear models were developed and evaluated for the estimation of daily (24 h) and total lactation milk yield of dairy sheep from single morning (am) or evening (pm) milking records. A total of 22,908 individual test-day milk records of 5110 ewes of the Chios breed, raised in 46 flocks, were used. Depending on the model, different daily milk yield estimates were derived for each ewe, accounting for lactation number, stage of lactation, season of previous lambing and interval between successive milkings. Daily milk yield was also estimated from doubling the single am or pm record. Actual and estimated yields were compared using root mean square errors (RMSEs), mean absolute differences, an accuracy parameter defined as the ratio of the actual yield variance over the sum of the variances of actual yield and absolute difference, and the product moment correlation between estimated and actual yield. Results were validated on independent datasets. Linear models resulted in less biased and more accurate estimates of the daily milk yield than simply doubling the am or pm record. Root mean square errors decreased by 7-37% and the mean absolute difference was reduced by 1-4% of the average daily yield. Higher accuracy and correlation were obtained from linear model application than doubling. Total lactation milk yield was predicted based on actual daily yield and compared to predictions based on estimated daily yield from am or pm records, as well as directly on single milking records. Root mean square errors obtained when daily yield had been estimated with linear models were 26-35% lower compared to doubling the am or pm yield and 0-13% lower compared to estimating the total lactation yield directly from single milking records. Linear model application also resulted in lower mean absolute difference and higher accuracy and correlation than doubling the am or pm record. Recording the yield of a single milking (am or pm) instead of both can benefit milk recording by reducing its cost and increasing farmer participation. In this context, linear models developed in the present study can be used for the accurate estimation of daily (24 h) and total lactation milk yield from single milking records.     

离体条件下水稻种衣剂对串珠镰刀菌生长及形态毒理影响

 检测了黑龙江水稻主产区4个当地主栽品种的种子内部镰刀菌寄藏情况,测定了20%克福甲和20%克多甲种衣剂对种子带菌消毒处理效果及对水稻串珠镰刀菌(Fusarium moniliforme)的抑菌作用和联合毒力,并借助扫描电镜观察了上述2种混配种衣剂对串珠镰刀菌的形态毒理影响。结果表明,种子内部镰刀菌的分离频率高达56.7%~96.0%,其中串珠镰刀菌的分离频率为32.6%~48.2%,2种种衣剂对带菌种子具有显著的消毒处理效果。20%克福甲和20%克多甲种衣剂对镰刀菌F.moniliforme的毒力指数分别为457.11和802.04,增效倍数分别为6.53和0.13。20%克多甲种衣剂(多菌灵:甲基立枯磷为5:5,W/W)对串珠镰刀菌的抑菌作用优于20%克福甲种衣剂(福美双:甲基立枯磷为8:6,W/W),增效作用低于20%克福甲种衣剂。电镜观察表明,种衣剂低浓度至高浓度处理下均可引起串珠镰刀菌菌丝不同程度的异常生长,表现为主菌丝局部膨大或形成菌丝束,菌丝顶端异常膨大、缢缩或形成穗状和花絮状分枝。     

内毒素介导动物急性肾功能衰竭机理的试验研究

为了阐明内毒素介导急性肾功能衰竭的机理,观察了内毒素性肾功能衰竭家兔血液凝固性变化和肾脏的病理形态学变化。与对照组家兔比较,模型组家兔血小板计数和血浆纤维蛋白原含量极显著降低(P<0 01),出血时间、凝血时间、凝血酶原时间和白陶土部分凝血活酶生成时间显著或极显著延长(P<0 05,P<0 01)。另一方面,内毒素注射在全部模型组家兔导致了弥漫性血管内凝血,71.4%的肾小球中发现了微血栓,肾小球纤维素密度指数达60 6%。此外,96.2%的肾小管上皮细胞变性坏死,84.1%的肾小管中有管型形成。对照组家兔均未发现这些病理变化。上述试验结果揭示,内毒素引发了弥漫性血管内凝血,而肾小球毛细血管内广泛形成的微血栓阻断了肾小球毛细血管血流,从而导致肾小球滤过率降低,这是内毒素介导急性肾功能衰竭的首要机理。此外,肾小管上皮细胞的变性、坏死可损害其重吸收和分泌功能,管型形成可阻塞肾小管管腔并增大肾球囊内的压力,这些也都是在内毒素介导急性肾功能衰竭发生发展过程中起重要作用的因素。     

芦苇和白刺空间格局对青土湖生态输水的响应

石羊河尾闾湖——青土湖位于腾格里沙漠和巴丹吉林沙漠边缘,是阻隔两大沙漠合围的生态屏障。自2010年开始连续5年向青土湖进行生态输水并形成一定规模的水面,对促进区域植被恢复和保护民勤湖区绿洲具有重要的生态意义。本研究选用2008年、2010年、2011年、2012年、2013年、2014年的高分辨率遥感影像资料同时结合研究区的实地调查资料,对形成人工水面的面积和输水前后的芦苇(Phragmites australis)、白刺(Nitraria tangutorum)群落面积进行了统计分析和对比。结果表明,5年连续输水形成叠加效应,水面面积成倍增加,芦苇相对频度逐年增加和白刺相对频度逐年减少,芦苇群落(Form.P.australis)面积增加了8.43倍,临接水域和水域中的白刺群落(Form.N.tangutorum)消失,白刺面积减少了68.00%。人工输水促进了芦苇群落依水蔓延,镶嵌于水域成片分布;距水面50 m范围的白刺群落由连续成片成点状。输水促进了湿生植物生长,导致荒漠植物种退化。     

王家沟小流域50a土地利用动态变化分析

以经过50多a水土保持综合治理的王家沟小流域为研究对象,利用其1959—2008年土地利用数据,对该流域土地利用动态变化进行分析。结果表明,调整土地利用结构是王家沟小流域水土保持综合治理的一项关键性措施。     

Effects of burning on soil macrofauna in a savanna-woodland under different experimental fuel load treatments

In West African savanna-woodland, the use of prescribed burning as a management tool has ecological implications for the soil biota. Yet, the effects of fire on soil inhabiting organisms are poorly understood. The aim of this study was to examine the responses of soil macro-invertebrates to early fires in a Sudanian savanna-woodland on a set of experimental plots subject to different fuel load treatments. The abundance of major macro-invertebrate taxa and functional groups, and taxon richness were quantified in soil cores collected from three different soil layers before and immediately after burning. The results indicated that, overall, there was substantial spatial and temporal variation in the composition of macro-invertebrate assemblages. The immediate effects of fire were to reduce total invertebrate numbers and numbers of many invertebrate groups dramatically. This is probably due to the fact that many of the surface-dwelling macrofauna perished as a result of less favorable microclimate due to fire, diminished resources, or migrate to safer environments. Fuel load treatment did not affect the community taxonomic richness or abundance of the soil-dwelling fauna. Furthermore, annual changes in community composition were more pronounced at the burnt site than in the control. This could be related to the inter-annual difference in precipitation pattern recorded during the two-year study period at our site. Since soil macrofauna population declines in fire-disturbed areas, increasing fire prevalence may jeopardize the long-term conservation of fire sensitive macrofauna groups. Special fire management attention is therefore recommended with due consideration to the type of burning and fuel properties to avoid the detrimental effects of intense fire affecting the resilience of savanna soil macrofauna species.