【作者】 于玲玲；

【导师】 廖允成；

【作者基本信息】 西北农林科技大学 ， 作物栽培学与耕作学， 2010， 硕士

【摘要】 陕西处于我国生态环境脆弱带上,深居内陆,远离海洋,加之地形地貌复杂,气候悬殊,大部地处干旱、半干旱区,雨量稀少,旱灾成为最主要的气象灾害。随着经济的发展,用水量不断增加,造成可用水量不断减少,水环境持续恶化,陕西农业干旱呈加重趋势;而且伴随经济的快速发展和人口的持续增长,由干旱所致的损失继续呈增大的趋势,干旱灾害直接危及区域农业可持续发展。对此,开展干旱的研究及评估工作意义重大。本研究将陕西旱作农区划分为陕北北、陕北南、渭北、关中西和关中东五个研究区域(简称亚区),分析了陕西旱作农区旱灾发生的时空规律。依据历史资料,分析了陕西旱作农区1470～1949年的干旱灾害,从全区看,480年内大范围的旱灾共有247次,占总年数的51.5%,陕北北296次,陕北南260次,渭北246次,关中东234次,关中西227次。利用1950～2008年近59a的旱灾统计资料,分析得出:59a间,五亚区共发生旱灾594次,旱灾发生次数呈上升趋势;20世纪90年代,陕西旱作农区旱灾最为严重;本区以春旱和夏旱为主;陕北北部旱灾发生次数最多,关中西最少; 59a中,全区性重旱年共12次。基于马尔科夫理论的原理,将各种致灾因素变化过程视作马尔科夫过程,分析了1990～2008年陕西旱作农区的旱灾结构变化。通过转移矩阵和趋势因子的计算,得出1994、1995、1999和2000年旱灾结构变化明显,并以2008年陕西旱作农区的旱灾负荷系数作为初始向量,预测了今后10年的旱灾变化情况,预测2011～2014年前后极有可能出现严重旱情。分析了陕西旱作农区干旱发生的原因,结果表明,大陆性季风气候,降水不均且降水变幅大是本区干旱发生的根本原因,同时,干旱灾害与人类活动有很大的关系,人类活动在很大程度上破坏了生态平衡,加大了旱灾发生的频度,水利设施落后也使干旱进一步加剧。针对陕西旱作农区的实际情况,提出了以下抗旱减灾对策:(一)从宏观战略层次出发,确立与降水资源相适应的有助于提高水分利用效率的作物种群。(二)大力推广配方施肥、土壤耕作等技术措施。(三)研发与陕西旱作农区资源状况相适应的适于不同降水年型的稳产性能高的新型农作制度及其技术体系。更多还原

【Abstract】 Shaanxi located in the fragile ecological environment belt in china. It was secluded inland, faraway form the sea and low air fall. Drought is the most important meteorological disasters in Shaanxi province. The most part of Shaanxi was located in the arid and semi arid areas. With the economic development, the water consume increased dramatically and the water availability was reduce. The environment of water was deterioration. So Shaanxi agricultural drought was exacerbated. With the economic’s development and population’s growth, the losses, caused by drought, was also in increasing trend. Drought disaster council was directly related to region or even the national sustainable development. So,it was extremely important to research and assessment of drought.The dry-land farming area in Shaanxi were divided into five survey region(following shortened for subdistricts ) ,they were North Shanbei,South Shanbei,North Wei,West Guanzhong and East Guanzhong. According to the historical drought materials of dry-land farming area in Shaanxi province during A.D1950-2008, this paper analysis the regular pattern of the drought. The results showed that: in the 59 years, the total times of the drought in the five subdistricts were 594; The drought frequency was in a rising trend. The most serious drought was 20th century 90’s; In this region,the mainly drought were in spring and summer ;The most highly frequency of drought was North Shanbei and the least was West Guanzhong; In the 59 years, the whole region’s serious drought was 12 times; This paper pointed out the causes of drought.Based on the principle of Markov theory, considering the change of all kinds of disaster-causing factors as a Markov process to analyze the structural change of dry-land farming area in Shaanxi from 1990 to 2008. Counting of transfer matrix and trend factor came to the results that: the structural of drought changes significant in 1994,1995,1999 and 2000.Using the load coefficient of 2008 as the initial vector to predicte the change of drought about the next 10 years. Forecasting arrive at a conclusion that there will be to occur a serious drought around 2011～2014 and put forward several suggestions of how to defense the drought disaster.This article analysis the cause of drought in dryland farming in Shaanxi. The results show that: The underlying causes of droughts were uneven rainfall and the large precipitation. Drought has a great relationship with human activities. The ecological balance was destroyed by human activities and the frequency of drought was increased. Water facilities’behind also have aggravated the drought. For the actual situation of Shaanxi dryland agricultural areas proposed following measures to mitigation drought.(1) Starting from the macro-strategic level, to establish the crop species that can compatible with precipitation and improve the use efficiency of water.(2) Promote fertilization, soil tillage and other technical measures.(3) Research and development new agricultural technology system and technical system which can suitable for different precipitation years and the dependable crop was high stable.更多还原