[1]Agronomy College Shenyang Agricultural University Shenyang 110866 P.R.China;
[2]Dandong Academy of Agricultural Sciences Fengcheng 118109 P.R.China;
[3]College of Life Sciences Northwest A&F University Yangling 712100 P.R.China;
[4]Institute of Crop Sciences Chinese Academy of Agricultural Sciences Beijing 100081 P.R.China;
maize; N remobilization; post-silking N uptake; stay green; plant density;