中国西北地区近43年降水资源变化对农业的影响

Impact of precipitation vacillation on agriculture for the past 43 years in Northwest China

选取西北地区资料年代较长的171个地面测站1961～2003年历年降水量,深入研究了西北地区降水资源变化特征及其对农业生产的影响。结果表明:年降水量、越冬作物生育期降水量、春小麦生育期降水量和秋作物生育期降水量,1987～2003年与1961～1986年相比,西部增多,东部减少,分界线与黄河走向基本一致。西部呈增多变化趋势,洪水事件频数增多,可利用水资源略有增加,对农业的正面影响增大。东部呈减少变化趋势,干旱频繁发生,尤其是极端干旱事件频数增多,可利用降水资源更加紧缺,对农业的负面影响增大。西北地区冬季降水普遍增多,对土壤保墒、作物安全越冬和春播有利;但是,牧区雪灾增多,影响牲畜安全过冬。

Using the data of 171 observations from 1961 to 2003 in Northwest China, the paper analyzes the impact of precipitation resources vacillation on agriculture in Northwest China. The results show that the annual precipitation and the precipitation in the growing season of overwintering crops, spring wheat and autumn crops was increased in the west part but decreased in the east part during 1987~2003 compared to that during 1961~1986, with Yellow River as the rough line of demarcation. The precipitation, flood frequency and available water resources in the west part tended to be increased, causing a positive impact on agriculture; while the precipitation in the east part tended to be decreased, causing the increase of drought occurrence and a negative impact on agriculture. The precipitation in winter was generally increased in Northwest China, being beneficial to soil moisture conservation, safe overwintering of crops and spring sowing, but increasing the hazard of snow disaster in pastoral areas and affected the safe overwintering of animals.