Contrasting impacts of the 2-year application of biofertilizers and organic manure on grain yield of winter wheat summer maize cropping system in North China Plain

Organic nitrogen and biofertilizers in a mixture with synthetic nitrogen could prove to reduce the cost of production without compromising crop yield with increasing soil organic carbon improvement. The study investigated 2-year incorporation of organic manure and biofertilizers on winter wheat and summer maize in the North China Plain (NCP). The two-year field experiment (2016–2018) has illustrated the responses of grain yield and yield components. Seven fertilization treatments included pig farm-yard-manure and biofertilizer amendments combined with five ratios of chemical fertilizer NPK plus organic fertilizer plus + biofertilizer and as control without fertilizer. Seven fertilization approaches include pig farm-yard-manure and biofertilizers amendments combined with four NPK% drop levels of chemical fertilizer ratio + organic fertilizer + biofertilizer (T2 = 100% (NPK), T3 = 100% (NPK) + (BF), T4 = 75% NPK + 25% OM + BF, T5 = 50% NPK + 50% OM + BF, T6 = 100% OM + BF, and T7 = 100% OM), without fertilizer as control (T1); T1 = non-treated control (no fertilizers applied), without chemical fertilizer (NPK), organic manure (OM) and biofertilizers (BF). Results showed that the grain yields for wheat for treatment T2 = 100% (NPK) to T5 = 50% NPK + 50% OM + BF varied from 38 to 73% in the 2017 growing season and from 39 to 98% higher in the 2018 growing season compared to the control T1. For maize, significantly increased grain yield by the combined application of chemical fertilizer enhanced with biofertilizers which were 17 to 50% higher in the 2017 growing season, while there was an increase from 15 to 50% higher in the 2018 growing season compared to control T1. The results revealed that the application of 50% NPK plus 50% organic manure plus biofertilizers could be an effective fertilizer dose, considering the importance of the cropping system in NCP. Key word: Biofertilizers, organic manuring, grain yield, winter wheat, summer maize, sustainable agriculture.