Production of nutrients in dual-purpose wheat pastures managed with different doses of nitrogen as topdressing – exponential model oleh LUIZ CARLOS TIMM, IONE MARIA P. HAYGERT-VELHO, DELVACIR R. BOLKE, DILETA REGINA M. ALESSIO, MARCOS BUSANELLO, SIRINEU JOSÉ SICHESKI, CÁSSIO RODRIGO GEHRKE, JOÃO PEDRO VELHO