Characteristics of drought vulnerability for maize in the eastern part of Northwest China

Based on disaster theory, combined with the standardized precipitation index (SPI) and relative meteorological yield data, meteorological factors and social factors were comprehensively considered to assess the vulnerability of maize (Zea mays) to drought. The probability distribution curve for of the degree of meteorological drought and relative meteorological yield was obtained by using information distribution technology, using a two-dimensional normal information diffusion method to construct the vulnerability relationship between degree of meteorological drought and relative meteorological yield. This resulted in drought vulnerability curves for maize in the eastern part of Northwest China (Gansu, Ningxia, and Shaanxi), and calculations of drought risk for maize in each province. The probability of moderate drought in Shaanxi was relatively high, followed by Gansu and Ningxia. The probability distribution of Gansu was more discrete. The probability of strong meteorological drought in Ningxia was high, followed by Shaanxi and Gansu. Probability distribution of relative meteorological yield for maize in Gansu Province was highly discrete, with thick tailings, large uncertainties, and more extreme values, which were strongly affected by meteorological conditions, followed by Shaanxi and Ningxia. When the degree of meteorological drought was low, the relative meteorological yield of maize increased within 10%. This is because mild drought stress can promote the adaptability of maize to drought and stimulate maize’s overcompensatory effect. With an increased degree of meteorological drought, the relative meteorological yield of maize gradually declined. When the degree of meteorological drought exceeded –2.2, maize was most vulnerable to drought in Shaanxi followed by Ningxia and Gansu. When meteorological drought was < –2.2, maize was most vulnerable to drought in Shaanxi followed by Gansu and Ningxia. Shaanxi had the highest maize drought risk, followed by Gansu and Ningxia. This research had a clear physical background and clear risk connotations. The results provide a data foundation and a theoretical basis for drought prevention and disaster reduction for maize in the study area.