In the past two decades, regional inequality in China's educational development, especially between urban and rural areas, has continued to narrow. An in-depth discussion of this phenomenon and the mechanisms behind it will not only help China build a high-quality educational system, but also draw lessons from Chinese practices to guide the reduction of global educational inequality. The comprehensive evaluation results show that China's rural EDL surpassed urban EDL in 2013; in 2003–2019, the urban/rural EDL increased from 0.29 to 0.22 to 0.50 and 0.54, respectively, and the urban-rural EII decreased from 1.31 to 0.92. Spatially, urban/rural EDL in the eastern and northeastern regions is higher than that in the central and western regions, the urban-rural EII in the eastern and northeastern regions is lower than that in the central and western regions. The CV and Theil index show that regional disparity in national urban/rural EDL has been narrowing, and regional inequality in urban-rural EII has also been declining; the decomposition of the Theil index indicates that these decreases in inequality are mainly from the reduction of the urban/rural educational development gap within the regions. The large-scale population migration driven by rapid industrialization and urbanization, and the adjustment of urban-rural and regional relationship promoted by the transformation of national policies such as regional coordinated development strategy and hukou system reform, are the main reasons for the evolution of regional inequality in China's urban and rural educational development.

Chemical fertilizers are important inputs in agricultural production. They not only increase crop yield but also bring many negative effects, such as agricultural non-point source pollution. Therefore, a scientific understanding of the regional differences in chemical fertilizer application and its environmental risks is of significance to promote China’s agricultural development. In this study, we analyzed the spatiotemporal pattern of chemical fertilizer application intensity (CFAI) in China since 2000, evaluated the environmental risks of provincial CFAI, and investigated the internal mechanism behind them. The results showed that the total amount and intensity of chemical fertilizer application in China from 2000 to 2019 presented a trend of increasing first and then decreasing. In 2000 and 2019, provincial CFAI in eastern China was generally higher than that in central and western China, and the environmental risks of provincial CFAI were spatially characterized by “high in the north and low in the south”. Factors such as poor soil conditions, unreasonable farming structure and backward fertilization methods are the main reasons for the continuous increase in the total amount and intensity of chemical fertilizer application, while the construction of ecological civilization and the transformation of society and economy are the main reasons for their decline. Finally, measures such as targeted fertilization, adjusting the use structure of chemical fertilizers, improving fertilization methods and replacing chemical fertilizers with organic fertilizers are proposed to promote the quantity reduction and efficiency increase of chemical fertilizer application in China.