Variation characteristics of climatic potential yield and resources utilization efficiency of maize under the background of climate change in agro-pastoral transitional zone of Gansu, China.

To evaluate the effects of changes in radiation, accumulative temperature, precipitation and climate resources on climate resource utilization efficiency in the agro-pastoral transitional zone of Gansu Province, we analyzed the variations of climate potential yield loss rate, light, heat, precipitation and comprehensive utilization efficiency of climate resources in the agro-pastoral transitional zone of Gansu Province by the step-by-step correction and indexation method, with the 1971-2020 weather data from 45 meteorological sites and the maize phenology data. The results showed that solar radiation showed fluctuating downward trend at a rate of -22.03 MJ·m·(10 a), the accumulative ≥11 ℃ temperature showed significant upward trend at a rate of 60.89 ℃·(10 a), the precipitation showed slow upward trend at a rate of 2.05 mm·(10 a) during the study period. The climate potential yield loss rate due to temperature and precipitation limitations was relatively high in Gannan and the northern part of Longzhong, while it was relatively low in the most areas of Longdong. Except for the central part of the study area and part of Longdong, the climate potential yield loss rate due to temperature and precipitation limitations in other regions of the study area showed decreased trend at the rate of -2.0%·(10 a) and -0.6%·(10 a). The low-value areas of light and heat utilization efficiency distributed in the northern and southern parts of Longzhong and part of Gannan, the low-value area of precipitation utilization efficiency distributed in Gannan, and the low value of comprehensive utilization efficiency distributed in Lanzhou and Baiyin which were 0.41 and 0.47, respectively. Longdong was the most suitable for maize planting, where the climate resources utilization efficiency of maize was highest, followed by Gannan and Longzhong. The average tendency rate of light, heat, precipitation and climate resources comprehensive utilization efficiency in the study area showed increased trend, which were 0.1%·(10 a), 0.07 kg·hm·℃·d·(10 a), 1.17 kg·hm·mm·(10 a) and 0.05 ·(10 a), respectively, showing a good potential to increase maize yield.