第二节自然灾害对粮食安全的影响粮食产量不仅与一国的耕地面积、农业劳动人口、农业机械化水平和农业科技水平等因素相关，还与一国的自然灾害有着密切的关系。
中国自古以来自然灾害种类多，发生频率高，分布范围广，极易受灾害袭击且受灾严重。
因此，要制定恰当的粮食安全政策必须研究自然灾害对粮食产量的影响。
本节分析所用数据分为两类：一类是我们所调查的2004～2008年农民种粮行为的微观数据；另一类是基于年鉴数据，涉及国家自然灾害及粮食产量的宏观数据。
Chapter twoThe influence of the natural calamities on food security Grain production is not only related to these factors, such as the arable land area of a nation, the population of farming, the level of agricultural mechanization and technology, but also have a close relationship with natural calamities. Since ancient times, the natural calamities in China are varied with high frequency, covering large areas, and easy to be seriously affected by them. Therefore, we need to make appropriate grain security policies by investigating the effects to the grain production caused by natural disasters. In this chapter, the data we will utilize fall into two categories: one is the micro data concerning the grain production behaviors of farmers based on our survey between 2004 and 2008, and the other grounds on the data of yearbook related to the natural calamities and the grain output in China.1．农户受灾情况分析我们在对农户种粮行为进行问卷调查时，询问了2004～2008年经历灾情的农户受灾及减产情况，收到有效问卷1619份。
表13-1显示，2004～2008年受灾农户占调查农户的百分比相当稳定，除一年为20.07%外，其余均为22%稍高。
受灾农户平均减产15%～21%，平均为17.27%，且有相当的稳定性，没有趋势性变化。
1．An analysis on farmers’ disaster situationDuring the questionnaire survey concerning the production behaviors of farmers’, we enquired those suffered the disasters between 2004 and 2008 about their production situation, and got 1619 valid questionnaires. Table 13-1 shows that the farmers affected had a quite stable proportion in the survey during that period, except one year 20.07%, the others being 22% or more. The affected farmers’ crops got a production by 15%~21%, and 17.2 7% on average, and this situation was stable, having no changes in tendency.Table 13-1: The Affected Farmers’ SituationYearAffected farmersPercentage they occupied in our surveyTheir average reduction percentage表13-1 受灾农户情况2．全国受灾情况分析《中国统计年鉴2009》报告了历年农业受灾面积、成灾面积。
受灾面积是指如冰雹、大风暴、洪涝灾害、持续干旱、台风、暴雪等自然灾害造成农业损失所覆盖的面积。
成灾面积是指在遭受上述自然灾害的受灾面积中，农作物实际收获量较常年产量减少3成以上的播种面积。
据此计算受灾面积、成灾面积占播种面积的比例以及成灾面积占受灾面积的比例。
图13-1报告了受灾比例、成灾比例，图13-2报告了成灾面积与受灾面积之比。
2. An analysis on the disaster situation in our nationChina Statistical Yearbook 2009 gives us a clear description about the affected area and disastrous area of agriculture in the past years. The affected area refers to the area where natural disasters, such as hails,storms, floods, sustaining droughts, typhoons or blizzards, hit and caused certain damage. The disastrous area refers to the place where any of the natural disasters given above attack and crops have a production by 30% in contrast with the ordinary years. Based on these, we can calculate the proportion of the affected area and the disastrous area in the sown area. Table 13-1 shows us the affected area and the disastrous area, and table 13-2 represents the proportion of them accordingly.The affected percentageThe disastrous percentageThe percentage they occupy in the sown areaYearTable 13-1: the ratio between the affected area and the disastrous area Source from China Statistical Yearbook 2009The ratio of the disastrous area occupied in the affected area图13-1 受灾比例、成灾比例资料来源：《中国统计年鉴2009》图13-2 成灾面积与受灾面积之比资料来源：《中国统计年鉴2009》根据以上分析我们得出如下基本判断：第一，中国农业仍然受自然灾害影响较重，1978～2008年平均受灾比例达31.60%，成灾比例达16.84%。
就我们所调查的河南地区来说，受灾农户占调查农户的百分比仅为22%左右，受灾农户平均减产为15%～21%，可能与全国相比，河南受自然灾害影响较小。
第二，从全国范围来说，自然灾害发生的波动性相对较小。
从1978到2008年，受灾比例和成灾比例波动的幅度较小；自然灾害所造成的影响也相对稳定，表现为成灾与受灾面积比相对稳定。
第三，以上两点意味着，自然灾害可以对局部地区造成重大影响，甚至颗粒无收，但不会对全国的粮食生产及安全带来重大影响。
中国是一个幅员辽阔的国家，这一特征决定了中国每年都会面临自然灾害，但很难形成全国性的自然灾害，这与幅员狭小的国家有着明显的差别。
这使得中国的粮食产量表现出相当大的稳定性，中国粮食总产量的大波动往往是政策的产物，而不是自然灾害的产物。
因此，我们不应该过分夸大自然灾害对全国粮食产量的影响。
将来中国应重视农业基础设施的建设从而增强抵御自然灾害的能力，不断改善中国交通运输的基础建设从而提高中国粮食在空间上的调拨能力，如此，自然灾害对中国粮食产量的影响将会进一步缩小。
Based on the analyses we’ve made above, we can make some fundamental judges as follows:Firstly, the agriculture in China is still influenced badly by natural disasters. The average affected proportion was 31.60% between 1978 and 2008, the disastrous proportion amounted to 16.48%. In terms of the area of Henan province we surveyed, the farmers of affected accounted for only about 22%, and the average reduction of their farming production ranges from 15% to 21%. Possibly, compared with other areas in China, Henan province is less affected by natural disasters.Secondly, in terms of the whole nation, the occurrence of natural disasters fluctuate relatively less. From 1978 to 2008, the proportion of amplitude fluctuations in both affected and disastrous is less as well. The effects caused by natural disasters are relatively stable, featured by the stable percentage of the affected area and the disastrous area.Thirdly, the two points we’ve mentioned above mean that natural calamities may cause significant loss to some certain areas, even to the degree that not a single grain is reaped, whereas they can not bring abouta fatal influence on our national grain production and security. As we all know, China is a vast country, and this trait determines that our country is likely to be confronted with natural calamities annually. However, it is quite difficult to form a national one, which is clearly different from those small countries. This character makes China’s grain production quite stable, and those major fluctuations are mainly the outcome of policy, not because of natural calamities. So, we should not exaggerate the effects to the grain production caused by the natural disasters. In the future, China needs to attach more importance to the establishment of agricultural infrastructure, thereby enhancing the ability to withstand natural disasters. By means of improving transportation infrastructure gradually in China, we can promote the ability to allocate in space. Only by doing so can we make the bad influence on grain production caused by natural disasters reduce to a small and limited degree.此外，中国从北方到南方一年可耕种的作物从一熟到三熟，这意味着，如果粮食一旦短缺，提高复种指数也可在短时间内（不超过半年）有效增加粮食产量，从而缓解粮食短缺。