Density and fertilization mode are the key factors regulating crude protein synthesis in forage maize; however, there is a lack of systematic understanding regulation mechanism. Here, nitrogen/potassium ratio (N/K), free amino acid (AA) content, enzyme activities (nitrate reductase (NR), glutamine synthetase (GS) glutamic pyruvic transaminase (GPT)) content yield leaves, stems, grain maize, as ...
