Abstract: Six types of treatment with different contents of (NH₂)₂CO, KH₂PO₄ and broad-leaved herbicide 75% tribenuron dry suspension concentrate (SC) and 28% wettable powder sulphinpyrazone (WP T-Y) were applied to Elymus sibiricus cv. chuancao NO.2 grassland at the jointing stage. The mixed treatment affected weed species, weed biomass per unit area, and weed rate to total biomass. Three treatments, 7 500 g/ha (NH₂)₂CO+300 g/ha KH₂PO₄+27 g/ha 75% tribenuron dry SC, 7 500 g/ha (NH₂)₂CO+27 g/ha 75% tribenuron dry SC, and 15 000 g/ha (NH₂)₂CO+300 g/ha KH₂PO₄+75 g/ha 28% WP T-Y significantly improved the vegetative growth, and resulted in coefficients of variation of 12.42% (P=0.000 6), 29.98% (P<0.000 1), 25.93% (P<0.000 1) for height, fresh forage yield and hay yield, respectively. The other three treatments, 7 500 g/ha (NH₂)₂CO+300 g/ha KH₂PO₄+27 g/ha 75% tribenuron dry SC, 7 500 g/ha (NH₂)₂CO+75 g/ha 28% WP T-Y, and 15 000 g/ha (NH₂)₂CO+300 g/ha KH₂PO₄+75 g/ha 28% WP T-Y, significantly (P=0.000 9) increased seed yield of E. sibiricus. However, the correlation coefficients of these mixed treatments with production performance were low, which may be due to the interaction of fertilizer and herbicides. Overall, the mixed application of fertilizer and herbicides is worth applying widely, because of the reduced number of field operations and management costs, and the dual effect of fertilization and weed control achieved.