西部干旱地区农户旱地种植行为实证研究

作者： 叶晶晶   来源： 南京农业大学 年份： 2010 文献类型 ： 学位论文 关键词： 农户   旱地   水资源   决策   干旱风险  

描述： ncentrated v}}ith 85% of the total dry lands. and it is important for the national economy and the countr<0's strategic agricultural growth. Northwest arid areas basically depend on natural precipitation. water shortage has seriously affected the farmers practices. The decision of farmers to plant dry land is a two-stage decision-making behavior: They first have to decide whether to plant dry land, and then decide what kind of crops planted in the dry lands. It is essential to find effective ways to raise the enthusiasm of farmers planting and reasonable arrangements for dry land crop structure. However. ver}} few people study dry land farming practice from the perspective of water shortages.

全文：、农民风险偏好的相关研究、农户投资决策行为和影响农户决策的相关因素等内容；第三章首先回顾了甘肃省农业生产自然条件,然后分析了研究区域张掖市民乐县的水资源利用情况,最后对该区域的调查资料做了一个简单的描述

西北旱作农区农作制优先序研究

作者： 成敏   来源： 西北农林科技大学 年份： 2010 文献类型 ： 学位论文 关键词： 西北旱作农区   BP神经网络   农作制优先序   抗旱减灾对策?  

描述： est region, which c ombined with the water-saving, agricultural soil and water conservation techniques, and then taken " drought resistance, reduce erosion, increase efficiency" as a principle.

全文：了以资源节约高效利用、抗旱减灾为主的农作制以及合理有效的抗旱减灾对策。主要得出以下结论: (1)通过在甘肃天水、定西、平凉、庆阳地区,宁夏银南地区、固原地区,陕西宝鸡、咸阳、渭南、铜川、延安、榆林

民国时期青海自然灾害与社会应对

作者： 袁瑞   来源： 青海师范大学 年份： 2014 文献类型 ： 学位论文 关键词： 社会应对   自然灾害   民国时期   青海  

描述： 由于所处地理位置的特殊性，自古以来青海就是一个自然灾害不断的地区。民国时期干旱、洪涝、雹灾、雪灾、地震等自然灾害更是频繁发生。这些灾害给民众带来了沉重的灾难，并给这一时期青海社会经济的发展带来了极大的影响。本文以民国时期青海自然灾害与社会应对为研究对象，结合史料，对这一时期自然灾害的类型及其特点、灾

全文：成因进行深入地分析。这一时期青海自然灾害主要分为气象灾害、地质灾害和其它生物灾害三个方面。笔者以史料为依据，重点反映干旱、洪涝、雹灾、地震等灾害的基本情况，并总结得出自然灾害呈现多样性和频发性、群发

黄土高原北部农牧交错带庭院集雨提高水分转化效率技术途径的研究

作者： 马治国   来源： 中国农业大学 年份： 2005 文献类型 ： 学位论文 关键词： 提高水分转化效率   黄土高原农牧交错带   集雨补灌   庭院经济  

描述： 本研究以内蒙古准格尔旗为例,研究了在半干旱气候条件下,建设集雨补灌农业.发展高效节水庭院经济的途径和对策。本区位于黄土高原北部农牧交错带,自然环境恶劣,水土流失严重,土壤生产力低下,由于过度开垦和放牧,植被破坏严重,生态恶化,急需治理。在此条件下,发展生态节水型庭院经济,可缓解生态压力,对于促进区域

全文：B=R×C_1×C_2×C_3为线索,具体分析了C_1、C_2和C_3这3个参数。当庭院面积和路面的面积比例为1:2、1:1和2:1三种情况下,C_1分别为48%、52.6%和57.0%。对于不同

中国北方地区节水农作制度研究

作者： 王婧   来源： 沈阳农业大学 年份： 2009 文献类型 ： 学位论文 关键词： 北方地区   节水   节水技术   节水农作制度   种植模式  

描述： ium between the grain production and water resource: the drought and the irrigation area in northeast china, the drought and the irrigation region in Huanghuaihai area, the drought and the irrigation area in northwest china.The article analized the characteristic of water using of the main crops and the main cropping systems, compared the economic benefit of the water-saving planting patterns, studied the economic benefit, the water-saving benefit and participatory farmers survey results etc. of the water-saving technologies.

全文：节水种植模式的产量与节水效益,分析各区主要节水技术的节水效果、经济效益与参与式农民调查结果,主要结论如下: (1)东北灌区面临的主要问题是如何提高农业水资源的利用率,主要通过节水技术的应用与推广来实现

黄土沟壑区不同下垫面条件对农田降雨入渗及产流关系影响的研究

作者： 宋孝玉   来源： 西北农林科技大学 年份： 2001 文献类型 ： 学位论文 关键词： 降雨入渗产流   黄土沟壑区   不同下垫面   数值模拟   农田  

描述： 水土资源短缺和生态环境恶化已成为全世界普遍关注的严重问题，这使人们认识到节约用水和保护环境的重要性。为确保粮食安全和生态环境良性发展，必须加强农田水土资源的管理和生态系统重建的研究，处理好水资源利用和生态重建之间的关系，大力推广节水灌溉技术和雨水资源利用技术，以水资源作为主要约束条件，调整农业产业结

全文：—入渗—产流关系的数学模型，得到以下主要结论： 1．本论文野外试验是在中国科学院长武农业生态试验站进行，室内实验是在西北农林科技大学干旱半干旱研究中心进行。在对试验区的土壤机械组成，土壤水分常数

曹魏两大政治集团论析

作者： 王建明   来源： 山东大学 年份： 2009 文献类型 ： 学位论文 关键词： 曹魏政治集团   汝颍   谯沛  

描述： Group headed by Cao Cao, Shuzhong Group led by Liu Bei, Jiangdong Group led by Sun Quan. The political bloc led by Cao Cao had the most abundant strength and talents came forth in large numbers. During the long-term expedition two major factions within formed: Ru一Ying Group and Qiao Pei Group. Ru-Ying Group charged civil service mainly and Qiao Pei Group was mainly made up of generals. These two groups had a long-term punitive expedition since Cao Cao fought against Dong Zhuo. Finally they unified vast areas of Northern China and carried out fruitful management, which avoided serious damage in the region by a long war and laid a good economic, political and military foundation for the unification of China in the future. Cao Cao fought against Dong Zhuo at the beginning, seizing Yanzhou, Zhangxiu, Xuhuai, Guandu, the four states, Wuhuan and Jingzhou, beat the seemingly invincible powerful opponents one after another. His forces got stronger and stronger. The two major political groups of Cao Wei supported Caocao on political and military aspects. Because these two groups represented the interests of their own, inevitably buried hidden dangers of can get on well with in adversity but can not share wealth. Ru-Ying Group is represented by the family of Han who was in the name of safeguarding the rule of the Eastern Han dynasty but to protect their interests. They can support Cao Cao's domination, but resolutely oppose his taking over Han dynasty. Qiao Pei Group on behalf of Cao Cao's family numbers who wished to gain greater benefits through Cao Cao's taking over Han dynasty. AD 209 years, The Battle of Red Cliff, which was Cao Cao's great cause of reunification of the most important ended in failure. As the highest strategic staff groups, Ru Ying Group throughout the campaign process simultaneously inconceivable aphasia, and the army of Cao Cao was defeated. Cao Cao became unable to dominate the country again in the rest of his life. This result was what Sun Quan, Liu Bei would like to see, Ru Ying Group was also willing to see it. From the historical records there was no record of staff at the Advanced Medium's death to give people the impression that Ru-Ying Group seemed to have known the defeat in advance. When Cao Cao was still alive, Qiao Pei Group holded the upper hand. But after the death of Cao Cao, Ru-Ying Group strongly supported Cao Pi to be the king. Finally Chen Qun put forward "Jiupinzhongzheng system", which established the family of Han's political monopoly. The two major political groups gradually moved towards a balance. After the death of Wei Ming King, the two major political groups split from co-operation, eventually formed a situation of endless immortality. Cao Shuang and He Yan of Qiao Pei Group were launched by Sima Yi through Gaopingling case when the situation was good. Sima Yi killed Cao Shuang and holded military and political power in the country. He cruelly blowed members of the Group Qiao Pei through a series of charges against them. Then, Jin Dynasty took place Wei. Ru-Ying Group obtained a comprehensive win. While Qiao Pei Group after its three generations with a heavy heart exit stage of history.

全文：政治集团从合作最终走向分裂,最终形成了不死不休的局面。谯沛集团的曹爽、何晏在形势一片大好的情况下,被司马懿发动高平陵事件,罢废曹爽(之后灭三族),独掌军国大权,并通过一系列的罪名对谯沛集团的成员进行残酷打击

唐代西北地区政治地理格局变动研究

作者： 魏昀   来源： 陕西师范大学 年份： 2009 文献类型 ： 学位论文 关键词： 唐朝   疆域   羁縻府州   屯田   交通  

描述： th about three of culture and materials the country's territory changed a lot. The country's territory was in an extending period before and the An-Shi Armed Rebellion, and once extended to the Central Asia area.At the same time, the Tang government founded the Ji-Mi-Fu-Zhou system in the Western Regions. The situation changed rapidly when the An-Shi Armed Rebellion broke out. Then the central government mobilized the troops in the Western Regions to participating in putting down the Rebellion, so the border defence was weakened. Tu-bo took the chance to occupy a large amount of territory. Almost Long You Area was oppupied by Tu-bo later in Tang Dynasty. The thesis is divided into five chapters: political geography circumstance in northwest area in early Tang Dynasty，including the situation of physical geography and the nation regime; the political geography situation in the extending period of territory from Tai Zong to Gao Zong;the political geography situation in the stable period of territory from Wu-zhou era to An-Shi Armed Rebellion;the political geography situation in the shrinking period of territory after An-Shi Armed Rebellion;relationship between the change of political geography situation and economy and traffic. Conclusion: From A.D. 7th to 9th century，Asia-Erope Continent was a place where Tang, Da-shi and Tu-bo contended for political space. The country's power of politics, economy and military strengthened before An-Shi Armed Rebellion, and part of the Central Asia area belonged to Tang government. The territory reached to an unparalleled scale at that time, which can be divided into three parts: the capital area where Chang-an and Luoyang were located in was the empire's center of politics, culture and military; the Zheng-zhou that around the captals was where the finance of central government stemmed from; the Ji-mi-fu-zhou system Tang government founded in the frontier area was the military buffer zone with nation regimes in vicnity. At the same time, Tu-bo appeared in the stage of history in A.D 7th century. After the King Song-zan-gan-bu unified the Tibet plateau, Tu-bo's power strengthed rapidly and harassed Tang's frontiers inceasingly. The Tang government put the defense police actively into effect so as to resist Tu-bo's aggression and defend country's benefit in Long-you area. When An-Shi Armed Rebellion broke out, Tu-bo took the chance to occupy vast territory of Tang Dynasty, like Minzhou, Lanzhou, Kuozhou, Guazhou, and so on. Eventually, almost all Long-you areas belonging to Tang Dynasty was occupid by Tu-bo. In the field of geopolitics, the national power strengthened in the earlier stage of Tang Dynasty and stronger than Tu-bo. Tu-bo didn't have the strength contending with Tang Dynasty, even harassed the frontier once a while. Until the An-Shi Armed Rebellion, the Tang government had no more advantage and the national power was weakened.

全文：情况:第二部分论述太宗至高宗朝疆域扩展时期的政治地理格局,包括唐初进军西域之初、西突厥旧地的羁縻府州化和葱岭以西地区的羁縻府州化三节;第三部分论述武周至安史之乱前疆域稳定时期的政治地理格局,包括驻防

农杆菌介导的抗寒基因转化羽衣甘蓝的初步研究

作者： 张文玲   来源： 西南大学 年份： 2010 文献类型 ： 学位论文 关键词： 抗寒转录调控基因TCF   羽衣甘蓝   甜菜碱合成基因BADH   转基因植株  

描述： siea. Low temperature is the key factor that limits the growth, colour and appreciatability in winter in the northern of China. Introducing foreign gene into kale through genetic engineering may create novel variety with cold tolerance. In this study, BADH(encoding betaine aldehyde dehydrogenase) and TCH(encoding transcription regulation factors) were used to be transformed into kale with Agrobacterium-mediated transformation.

全文：个羽衣甘蓝品种 通过对不同激素配比的培养基上,9种基因型羽衣甘蓝的带柄子叶、下胚轴、真叶的再生情况进行比较分析,从中筛选出皱白1,06-56和05-25这3种高效再生基因型,其最适培养基分别为

甘肃省黄河沿岸地区水资源承载能力分析

作者： 刘建兰   来源： 兰州大学 年份： 2010 文献类型 ： 学位论文 关键词： 甘肃省   沿黄地区   水资源   承载能力   系统动力学  

描述： th, the demand of water resource is continuously increasing. That is to say water shortage has become a global problem. Water resources carrying capacity is the basis and prerequisite of regional socio-economic development, which is significant to realize the coordinated development of regional "water resources- ecological environment-socio-economy" composite system. So it has become the focus and hot topic in water science field nowdays.

全文：可流转和不可流转的两种假设前提下,对比分析了甘肃省沿黄地区水资源承载能力的变化趋势以及承载状况。结果表明：在水资源的配置不受空间约束的情况下,区域2020年虽可实现全面小康的目标,但内部的差异巨大