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运用1971-2010年甘肃旱作玉米主产区降水资料及产量资料,分析了40年干旱时空变化特征,建立了干旱影响玉米产量的风险评估指数,对玉米不同时期不同等级干旱风险进行了分析评估。结果表明:春旱以陇东黄土高原及陇西黄土高原的定西出现频率最高,均在0.35次/年以上;徽成盆地及两江流域出现频率最少,为0.18次/年;初夏旱出现频次最高的地区为环县,为0.35次/年,最少为西峰、成县及秦安;伏旱出现频率最高地区为环县及麦积,最低为定西一带;秋旱出现频率最高为陇东黄土高原平凉一带,最低为陇南地区。各地干旱均以轻旱为主,其次为中旱。40年中,上世纪90年代干旱出现频次最多,80年代最少。进入21世纪,秋旱发生频次明显减少,春旱则有相对增多的趋势。玉米全生育期陇南地区受旱灾影响风险最小,种植保险率最高;其次为陇西黄土高原;陇东黄土高原种植保险程度最低,干旱影响最大。
Based on the precipitation data and yield data of the main maize producing areas in Gansu from 1971 to 2010, the spatial and temporal variations of drought in 40 years were analyzed, and the risk assessment index of drought-affected maize yield was established. The risk of drought at different grades of maize was analyzed and evaluated . The results showed that the spring droughts had the highest frequency of Dingxi in Longdong Loess Plateau and Longxi Loess Plateau, all of which were above 0.35 times per year; the lowest occurred in Huicheng Basin and the two rivers, 0.18 times per year; the highest frequency appeared in early summer drought The area is ring county with 0.35 times per year, with the least being Xifeng, Chengxian and Qin’an. The highest frequency of drought is ring counties and Maiji, and the lowest is Dingxi. The highest frequency of autumn drought is the Pingliang area of Longdong Loess Plateau, The lowest for the Longnan area. Droughts dominated by drought all over the country, followed by drought. In the 40 years, the drought occurred most frequently in the 1990s and the least in the 1980s. In the 21st century, the frequency of autumn droughts has obviously decreased, while that of spring droughts has been relatively increased. In the whole growth period of corn, the risk of drought was the least in Longnan, with the highest planting insurance rate, followed by Longxi Loess Plateau, the lowest in Longdong Loess Plateau, and the most affected by drought.