【作者】 王明田；

【导师】 马均；

【作者基本信息】 四川农业大学 ， 作物栽培学与耕作学， 2012， 博士

【摘要】 1.四川省气候变化既与全球、全国总体一致,又由于特殊的地理位置和地形地貌等原因而具有其独特性。1961—2007年,四川省年平均气温、年平均最高气温、年平均最低气温、高温日数均呈上升趋势；四季中,冬、秋季增暖较为显著,春、夏季呈略微增温趋势；区域间比较,川西北高原增温幅度最大,四川盆地增温幅度相对较小。同时,四川省降水量持续减少,平均每10a约减少20mm；四季中,春季降水量变化不大,夏、秋季降水量减少,冬季降水量有所增加；区域间比较,盆地减少最为显著,川西北高原和川西南山地略有增加。2.降水总量的减少使四川省水资源呈下降趋势；大雨以下天气过程减少,连续无雨或少雨日数增多,暴雨、大暴雨呈上升趋势,导致降水有效性下降,水土流失加剧,土壤保水保肥能力下降,农业干旱的季节性和阶段性问题更加突出；气候变暖导致农田蒸散加剧,高原、高山积雪减少,河流水位下降,有效灌溉用水减少,水分亏缺量进一步上升,农业生产将面临更加严重的干旱威胁。3.收集四川省149个气象站50a(1959年—2008年)的逐日降水量、气温、日照时数、相对湿度、风速、水汽压等气象资料,选用国家标准中相对湿润度指数(M)作为干旱指标,以年、季为时间尺度,研究四川省干旱频率和强度的空间分布特征,并分析近50a干旱强度和发生范围的年际变化规律。结果表明：四川年尺度干旱频率和强度均呈西高东低的带状分布。高发区主要在川西高原、川西南山地、盆中及盆南局部,高发区的干旱强度以中旱以上为主；少发区主要在达州、泸州、宜宾等地和乐山—眉山—雅安一带,少发区的干旱强度以轻旱为主。年际变化趋势上,干旱强度有所减弱,但最近10a明显增强,且干旱范围扩大。从季尺度看：干旱频率和干旱强度都是冬季最大,春季次之,秋季较小,夏季最小；季尺度的年际变化趋势,春旱强度呈减小的趋势,但范围略扩大；夏旱强度和范围都略有增大；秋旱强度呈略减弱的趋势,但干旱范围有所增大,特别是近10a来,秋旱范围增大趋势明显；冬旱强度呈略减趋势但范围有所增大。2006年等典型年实况与分析结果十分吻合,说明本文采用的干旱分级方法在四川省具有较好的适用性。4.基于水分亏缺原理,建立玉米干旱监测模型,结果表明：四川盆地玉米生育期干旱频率较高的时段主要为拔节-乳熟阶段，且发生面积最广。按空间分布特征把盆地划分为3个干旱区,其中大巴山以南、涪江及沱江流域在玉米全生育阶段出现干旱的频率最高,普遍都在50%以上。5.依据气温、海拔、干燥度、地形地势、地理位置等特点,将四川农业生态区划分为8个不同类型区,比较分析各区典型站点及其主要种植模式的降水满足度、降水满足度保证指数、降水盈亏产量降低率、产量降低率风险指数、降水利用效率和降水经济效率等,在此基础上,提出各区防旱避灾种植制度优化模式。主要结论：1)四川省各种植模式多年平均降水满足度、降水保证指数地区之间差异较大,攀枝花最低,雅安最高。2)四川省不同区域、不同种植模式、不同作物及其不同生育阶段基于降水盈亏的产量降低率多年均值差异较大。区域分布上,雅安最低,仅23%,攀西最高,达50%以上,其余地区30%—-40%；种植制度上,麦—玉—苕等旱三熟低于麦—稻等水旱轮作两熟制；作物中,小麦、油菜、秋播马铃薯高于水稻、玉米、棉花、红薯和大豆；生育阶段上,冬小麦、冬油菜、秋播马铃薯作物开花前后普遍较高,各种作物生育末期较低。3)基于自然降水,攀枝花等川西南山地干热河谷区、西昌等川西高原安宁河平原半湿润区和平武等川北半湿润山地丘陵过渡区、遂宁等川中丘陵夏伏旱频发区、巴中等川东北盆周湿润山区遭遇旱灾的风险极大,麦—玉—苕等旱三熟的产量降低率风险指数相对较小；雅安等盆地内其余地区由于阶段性降水过多引起湿害偏重,导致麦—稻等水旱轮作两熟制略优于旱三熟。4)基于降水利用效率和降水经济效率,各地比较一致,较优的种植制度首先是麦(油、薯)—稻两熟制,其次才是麦(油)—玉—苕(豆)旱三熟。5)综合旱涝灾害风险、降水利用效率和降水经济效率,以及复杂地形等因素,有较好灌溉条件的农田应以麦(油、薯)—稻水旱轮作两熟制为主,而无水源保障的旱地则以麦(油)—玉—苕(豆)旱三熟为主。6.利用四川省盆盆地区玉米产量资料、生育期资料和相关气象资料,针对农业保险费率厘定等干旱灾害风险转移技术服务需求,建立四川省盆地区玉米干旱风险评估的气候干旱风险模型、作物干旱风险模型、产量灾损风险模型、抗灾性能模型、旱灾综合风险评估模型和相应的指标体系,并以此为依据,将四川省盆地区玉米划分为高、中、低3个风险区。风险高值区主要集中在盆西北大部、盆中及盆南部分地区,中值区主要在盆北及盆南部分地区,低值区主要在盆东北、盆西南及盆东南部分地区。更多还原

【Abstract】 1. The climate change in Sichuan showed its unique characteristics due to its special geographic position and topography, though the general change was consistent with the global and national changes. The annual mean temperature, annual mean maximum air temperature, annual mean minimum air temperature and high temperature days increased during1961-2007. There was a warming trend in all seasons, and the temperature in winter and autumn increased more significantly than spring and summer. The increase of temperature was the greatest in Northwest Sichuan Plateau and relatively smaller in Sichuan basin. The annual precipitation declined continuously at a rate of20mm every ten years averagely, caused by the decreasing rainfall in summer and autumn, though the precipitation in spring did not change much and there was more rainfall in winter. The comparison of the precipitation between regions showed a great decrease of precipitation in Sichuan basin, and an increase in Northwest Sichuan Plateau and the mountainous area of Southwest Sichuan.2. The water resources were decreased due to the declined total precipitation. The extreme events, like rainstorm and continuous rainless days, became more common, and the occurrence of moderate and heavy rain was less frequent in the past over forty years. These caused the low water use efficiency, aggravated water and soil loss, and the poor soil fertility. The seasonal agricultural drought was more serious than in the past. The warming trend led to higher field evapotranspiration, less snow cover at plateau and mountain tops, low water levels and the lack of irrigation water. Water deficit became more severe; therefore, drought will become a serious threat to agricultural production.3. In this study, daily precipitation, air temperature, sunshine hours, relative humidity, wind speed and water vapor pressure, from1959to2008were collected from149meteorological stations in Sichuan province and used to calculate the relative moisture index (M). The author analyzed the spatial distribution of drought frequency and intensity in Sichuan at annual and seasonal time scale, and addressed the annual variation of drought intensity and distribution in the recent50years. The results showed that, drought frequency at annual time scale was high in the west, and low in the east, exhibiting pronounced zonation patterns in Southwest China. The areas with high incidence of drought mainly located at the western Sichuan plateau, the mountainous area in Southwestern Sichuan, the middle basin, and parts of the southern basin. In these areas, drought intensity was mainly moderate or severe. The areas with low incidence of drought included Dazhou, Luzhou, Yibin, Leshan, Meishan and Yaan, and it was mainly mild drought in these areas. Over the past50years, drought was less severe, apart from the recent10years. The variation of drought frequency was significant between seasons. Drought happened most frequently in winter, followed by spring, autumn and summer. Winter drought was the most severe among the four seasons, followed by spring drought, autumn drought and summer drought. Spring and winter drought was less severe but the region was widened. Summer drought was more serious both in density and spatial distribution. Autumn drought showed similar trend to spring drought, and it was more severe in the recent10years. A few samples were taken to test the drought classification method used in this study, and the results showed that the method was suitable in Sichuan province.4. A drought monitoring model for corn was developed based on water budget. The results showed that the maize drought occurred in high frequency between jointing stage and milk ripe stage, and it happened most widely in this period. Sichuan basin was divided into three arid areas, and the south of Daba mountains, Fu river and Tuo river basin had the highest drought frequency, generally over50%, through the whole growth season of corn.5. The ago-ecological areas in Sichuan were divided into eight ago-ecological zones according to temperature, altitude, dryness, topography and geographic characteristics. For each agro-ecological zone, analysis were done to compare the precipitation satisfied degree, precipitation satisfied degree guarantee index, yield reduction rate related to precipitation requirements, risk index of yield reduction rate, rainfall use efficiency and economic efficiency of precipitation at the typical station for the common cropping patterns. The results showed that,(1) the precipitation satisfied degree and precipitation satisfied degree guarantee index varied greatly among regions, and they were lowest in Panzhihua, and highest in Yaan.(2) The averaged yield reduction rates related to precipitation requirements varied with regions, cropping patterns, crop species and crop growth stages, significantly. It was lowest in Yaan,23%, and highest in Panxi, over50%. And it was around30-40%in other regions. For different cropping patterns, the yield reduction rates of dry triple cropping pattern with wheat-maize-Chinese trumpet creeper were lower than that of the rotation pattern with wheat-rice. The reduction rates of winter wheat, winter rape and autumn sowing potato were generally higher than that of rice, maize, cotton, sweet potato and soybean. It was higher before and after flowering for winter wheat, winter rape and autumn sowing potato, but was lower at the late growth stage for each crop.(3) Based on the natural precipitation, Panzhihua, Xichang, Pingwu, Suining and Bazhong encountered the highest risk of drought, but the risk index of yield reduction rate for the dry triple cropping pattern with wheat-maize-Chinese trumpet creeper was relatively lower. Due to excessive precipitation in Yaan, the waterloddging was more severe; therefore, the rotation pattern with wheat-rice was slightly superior to the dry triple cropping pattern with wheat-maize-Chinese trumpet creeper.(4) It showed a consistent rule in the comparison of rainfall use efficiency and economic efficiency of precipitation at all stations. The double cropping pattern with wheat (rape or potato)-rice was the most suitable in these regions, followed by the dry triple cropping pattern with wheat (rape)-maize-Chinese trumpet creeper (soybean).(5) Considering the risk of drought and flood, rainfall use efficiency, economic efficiency of precipitation and topography factors, the double cropping rotation pattern with wheat (rape or potato)-rice was advised in well-irrigated croplands, while dry triple cropping pattern with wheat (rape)-maize-Chinese trumpet creeper (soybean) was recommended for the dry lands with poor irrigation.6. Based on the information of maize yield, phonological period, related weather data, and the requirements of drought risk transfer technical service, such as agricultural insurance premium rate, four models (those of climatic drought risk, crop drought risk, yield loss risk, and drought resistant capability) applicable for the assessment of maize drought risk in Sichuan Basin and the corresponding index systems were established. The Sichuan Basin was divided into three regions, with high, medium and low maize drought risk, respectively. The region with high risk was mainly in the most areas of northwest basin, the middle basin, and parts of the south basin of Sichuan, the region with medium risk was in the north basin and some parts of the south basin, and the region with low risk was in the northeast and southwest basin, and parts of the southeast basin.更多还原