宁夏玉米和小麦干旱风险评价研究

DROUGHT RISK ASSESSMENT OF MAIZE AND WHEAT CROPPING IN NINGXIA

关键词:  宁夏农业干旱风险评价玉米小麦

Key words:  Ningxia  agricultural drought  risk assessment  maize  wheat

摘要:

［目的］分析宁夏23年(1993—2016年）玉米和小麦干旱时空分布格局及演变趋势，探讨各县玉米和小麦的干旱风险成因及关键作用因子，以期为宁夏县级作物防旱抗灾工作提供科学依据。［方法］本文基于成灾综合评价法，从干旱对玉米和小麦种植的危险性、玉米和小麦在干旱环境下的暴露性、玉米和小麦种植在干旱胁迫下的脆弱性和区域农业抗旱能力4个方面选取指标构建作物干旱风险模型，利用1981—2016年气象数据资料及玉米、小麦生育期资料、玉米小麦产量和面积等数据，分析计算宁夏各地区的玉米和小麦的干旱风险。［结果］23年间（1993—2016年）宁夏玉米和小麦干旱风险整体上呈逐步上升趋势，玉米干旱风险上升趋势明显，最高达到45%。而小麦干旱风险趋势较平缓，干旱风险水平在30%~40%之间。品种间的差异主要在于干旱危险性指数和暴露性指数间差异较大，玉米干旱暴露度高，生育期较长，潜在蒸散量大，降水无法供应生育期内的需水量，因而玉米干旱风险较大。从空间分布来看，小麦干旱风险高值区分布范围较广，由于小麦生育期在雨季初期，降水量较少，且种植面积大，因而受旱面积较大。各县（市）玉米和小麦危险性、暴露性指数权重均在03以上，是导致玉米和小麦干旱风险较高的主要原因。［结论］因此调整种植比例，减少小麦的种植面积，加强农村脱贫，增加农民收入，是减少干旱危害的有效措施。

Abstract:

The research is intended to analyze the spatial and temporal distribution patterns and evolution trends of maize and wheat drought in Ningxia from 1993 to 2016 and explore the causes and key factors of drought risk of maize and wheat in each county, so as to provide a scientific basis for the drought prevention and disaster relief work of county level crops in Ningxia. Based on the theory of disaster risk, this research established a crop drought risk model by selecting indexes from four aspects including the drought hazard of maize and wheat planting, the exposure of maize and wheat in drought environments, the vulnerability of maize and wheat planting under drought stress and the regional drought resistance of agriculture. Moreover, it calculated the drought risk of maize and wheat and discussed the causes and key factors of drought risk in different regions of Ningxia by adopting the data, such as the meteorological data in Ningxia from 1981 to 2016, the growth period data of maize and wheat, and the yield and area of maize and wheat. The results show that from the 1993 to 2016, the drought risk of maize and wheat in Ningxia increases gradually, and the trend of maize drought risk increases significantly, reaching a maximum of 45%.The trend of wheat drought risk is relatively gentle, and the drought risk level is between 30%~40%.The differences between the varieties are mainly due to the drought hazard index and the exposure index, the high drought exposure of maize, the long growth period, the large potential evapotranspiration, and the precipitation can′t supply the amount of water needed during the growth period, so the maize drought risk is larger. From the perspective of spatial distribution, the high value of wheat drought risk distribution area is relatively wide, because the wheat growth period is in the early rainy season, the precipitation is less, and the planting area is large, so the area affected by drought is larger. The weights of the hazard and exposure indexes of maize and wheat in all counties (cities) are all above 0.3, which is the main reason for the higher drought risk of maize and wheat. Therefore, we should adjust the proportion of planting, reduce the wheat planting area, strengthen poverty alleviation in rural areas, and increase farmers′ income, which is an effective measure to reduce the damage caused by drought.