Soil acidification and factors controlling topsoil pH shift of cropland in central China from 2008 to 2018

•A large range in cropland soil acidification occurred in Henan from 2008 to 2018.•Topsoil pH decline was more widespread and serious in the south than in the north.•Nitrogen fertilization was the most important factor related to soil acidification.•Croplands in Henan face the risk of accelerating soil acidification.