共查询到20条相似文献,搜索用时 78 毫秒
1.
河西走廓草地退化现状及其可控因素和分类综合治理 总被引:3,自引:0,他引:3
河西走廓草地正处于面积缩减,草地组成劣化,生产力下降,草地生境日趋恶化的困境,在造成草地退化的众多因素中,可控因素主要有过度放牧,垦殖,樵采以及政策的导向,针对可控因素,提出了河西走廓退化草地分类综合治理的策略。即在山区,采取封育和保护性利用相结合的策略;在绿洲区,分核心区,缓冲区和保护区分别采取不同的治理措施;在荒漠区,采取封育措施,严禁肆意垦殖。 相似文献
2.
三峡库区草地正处于面积缩小、草地组成劣化、生产力下降、草地生境日趋恶化的困境.针对造成草地退化的众多因素,如过度放牧、管理水平差、人为干扰等,提出了三峡库区退化草地分类综合治理的策略,即在高山区采取封育和保护性利用相结合的策略;在中低山区,采取封育、禁牧+补播和加强日常管理等不同治理措施. 相似文献
3.
三峡库区草地正处于面积缩小、草地组成劣化、生产力下降、草地生境日趋恶化的困境。针对造成草地退化的众多因素,如过度放牧、管理水平差、人为干扰等,提出了三峡库区退化草地分类综合治理的策略,即在高山区采取封育和保护性利用相结合的策略;在中低山区,采取封育、禁牧+补播和加强日常管理等不同治理措施。 相似文献
4.
两种不同封育方式对小嵩草草地地上生物量的影响 总被引:3,自引:0,他引:3
对高寒草甸类小嵩草-杂类草草地采用全封育(Ⅰ)和半封育(Ⅱ)两种封育措施.封育时间为2003~2006年.对封育草地内的地上生物量测定结果表明:全封育草地第一年优良牧草鲜草产量明显增加,由原来的271.3g/m2增加到345.3g/m2(P<0.01),封育的第二、三年优良牧草呈下降趋势,毒杂草成分呈上升趋势;半封育草地第一年优良牧草鲜草增加明显,由原来的271.3g/m2增加到328.3 g/m2(P<0.01),封育的第二、三年优良牧草有逐年上升的趋势.测定结果表明,半封育方式优于全封育.建议积极采取半封育措施,同时采取灭鼠、施肥、灌溉、除莠等综合技术措施改良退化草地. 相似文献
5.
不同植被重建管理方式对沙质草地土壤及植被性质的影响 总被引:2,自引:0,他引:2
以陕北横山县雷龙湾乡恢复15年的退化沙质草地为研究对象,对未封育自然恢复、封育自然恢复、未封育人工恢复和封育人工恢复4种管理方式对植被和土壤性质的影响及二者的相关性进行了研究,以期为退化沙质草地筛选科学的植被恢复模式选择提供科学依据.结果表明:与流动沙地对照组相比较,经过15年的植被恢复4种管理方式均可不同程度的改善退化草地土壤及植被性质,地表植被高度、盖度和生物量分别提高0.12~1.03 m,12.70%~53.18%和7.27~29.08 g·m-2,土壤容重降低0.12~0.27 g·cm-3,土壤总孔隙度提高6.80%~17.01%,有机质、阳离子交换量、全氮及速效养分含量也显著提高.封育管理方式下植被与土壤的恢复效果优于未封育方式,人工植被恢复优于自然植被恢复,采取封育与人工植被恢复相结合的管理方式,严重退化沙质草地在植被恢复过程中植被与土壤特征形成了相互作用、相互影响的协调关系.为了促进农牧交错带退化沙质草地生态恢复,研究区应该采取封育与人工恢复相结合的植被恢复管理方式. 相似文献
6.
7.
006-2007年,在泽库县 “黑土滩”大面积发生的典型地段,选择退化严重并在环境条件上具有代表性的2块“黑土滩”退化草地作为试验区,在进行灭鼠和围栏保护的基础上,采取耕翻单播多年生牧草、耕翻混播多年生牧草、重耙补播(混播)多年生牧草和围栏封育天然草地4种试验处理措施,对“黑土滩”退化草地进行了综合治理研究,提出治理“黑土滩”的综合措施是:灭鼠、施有机肥、耕翻、施无机肥、重耙,播种牧草,复磨,封育。 相似文献
8.
不同利用程度高寒干旱草地碳储量的变化特征分析 总被引:6,自引:2,他引:4
本研究对处于青海湖北部不同退化梯度草地的土壤碳储量以及植被的根系生物碳储量变化进行了研究。调查草地样本包括7个样地和4个土层,样地依次分别为严重退化草场、重度退化草场、中度退化草场、轻度退化草场、正常草场、封育3年草场和人工草场,土层分别为0~10,10~20,20~30与30~40 cm 4个土层。结果表明,在不同退化梯度上,土壤碳储量随着退化程度的减轻依次增大,总体上各样地之间的变化趋势为,在5-7月为轻度退化草地>无退化草地>中度退化草地>重度退化草地>人工草地草地>封育草地>严重退化草地;在8-10月为无退化草地>轻度退化草地>中度退化草地>重度退化草地>封育草地>人工草地>严重退化草地,严重退化草地土壤碳储量最低,其次为封育草地;封育草地和人工草地的碳储量显著的低于轻度退化和无退化草地(P<0.05),但在封育草地和人工草地之间无显著差异(P>0.05)。在不同的土层,土壤碳储量从上至下依次降低,且各层之间表现出显著差异(P<0.05)。在不同的月份,各土层深度的土壤碳储量,总体上均表现为5-6月份降低,6-10月份呈递增的变化趋势,而且不同退化草地都表现出了较为一致的变化趋势。 相似文献
9.
10.
为探索围栏封育对河西走廊北部温性荒漠草原植被动态变化的影响,对甘肃省民勤县2007年封育的温性荒漠草原植被特征及产草量进行了调查分析.结果表明:封育7年后,持续封育对河西走廊北部温性荒漠草原的产草量、植被盖度、植被高度和植物种数无显著影响(P>0.05),并未呈现持续增加效果.鉴于民勤县生态条件较为严酷的自然现状,建议... 相似文献
11.
Beran GW 《Preventive veterinary medicine》2008,86(3-4):198-207
When early people made their appearance, zoonotic infectious diseases were already waiting, but epidemic diseases did not appear in human history until people began to live in large numbers under conditions of close contact, mainly during the last 10,000 years. Disease has decimated urban populations, conquered armies, and disrupted society. The focus here is on (1) the plague of Athens and the Black Death; (2) smallpox, influenza, and rabies; (3) avian influenza prion diseases, and foot & mouth disease; and (4) emerging and re-emerging diseases. All have veterinary public health associations. In Athens, Greece, in 430 BC, when the Spartans ravaged the countryside, hordes crowded into Athens so that orderly movements, space in which to live, and adequate supplies of food became impossible. Crowding of any population fosters disease transmission; chaos and disorder enhance it all the more. Out of northern Egypt came a terrible plague from across the Mediterranean Sea. The identity of the plague of Athens remains unsure, but the well-considered conclusion is Rift Valley Fever, a mosquito borne, viral zoonosis. The Black Death, also called the Plague, raged in Asia for centuries. In 1347, the Black Death was brought by a ship out of Asia to Sicily. The scenes of devastation were repeated throughout Europe, with 90% or more of the people dying in city after city. Influenza, too, has been a cause of periodic human epidemics, but the great pandemic of influenza occurred in the last months of World War I. In the years of highest occurrence, more than half the world's population became clinically infected. If veterinary public health had been born earlier, it could have led to elucidating the epidemiology of influenza and the plagues of Athens, Europe, and Asia. In turn, smallpox had also caused continual tragedy. In 1796, Edward Jenner began to harvest pustules of cowpox from children or infected cows and inject them into susceptible children. In 1980, the World Health Organization declared that smallpox had been eliminated from the world. Rabies, though, still strikes terror. A number of animal diseases, broadly termed emerging and re-emerging diseases, need surveillance because they have the potential to impact human health. From late in 2003 to 2007, the highly pathogenic H5N1 influenza virus in poultry infected at least 121 people and caused 62 deaths in four countries. The prion diseases, too, all have very high numbers in concentrated contacts. To control these diseases, veterinary public health is essential, with diagnosis, epidemiological surveillance, clinical manifestations, and prevention as primary measures. 相似文献
12.
Dekker A Dercksen D Snoep J van Wuyjckhuise L 《Tijdschrift voor diergeneeskunde》2007,132(18):695-701
On 26th of july 2007 a new case of bluetongue was notified in the Netherlands and on 2nd of august 2007 foot-and-mouth disease was diagnosed in Surrey, England, which raised the threat of having both infections simultaniously in one area. Bluetongue and foot-and-mouth disease have a different pathogenesis, but symptoms may resemble each other at a later stage of infection. The pathogenesis and possible clinical symptoms of both infections are discussed and illustrated with pictures. 相似文献
13.
14.
15.
16.
在动物的异常行为中以刻板行为最为常见,而咽气癖又是马最常见的口部刻板行为之一。作者就咽气癖在生理方面和心智方面对马体产生的影响、行为基础、诱因的研究进展及常见的防治措施进行综述。 相似文献
17.
近几年,世界饲用添加剂市场增长较快,预计今后将进一步增长,据世界粮农组织(FAO)首领会议的倡议,到2015年,将使世界营养不良的人口削减一半,其间,肉制品将会以每年2%的速度增长,特别是加快猪肉和禽肉增长。这将促进世界添加剂,尤其是蛋氨酸和赖氨酸需求量的增加。 相似文献
18.
19.