At present, Northeast spring corn is in the big bell stage, Northwest spring corn is in the heading stage, and Huanghuaihai summer corn is in the jointing stage,which is the window period for corn population construction and yield formation. Recently, there At present, Northeast spring corn is in the big bell stage, Northwest spring corn is in the heading stage, and Huanghuaihai summer corn is in the jointing stage,which is the window period for corn population construction and yield formation. Recently, there