Effects of irrigation and compound fertilizer on yield of winter wheat and net ecosystem productivity of farmland

A 2-year experiment was conducted to study the effects of irrigation andsoil amendment fertilizer on yields of winter wheat and net ecosystem productivity (NEP) of farmland in 2009, 2010. Results showed that the maximum yield was 8 894.11 kg/hm2 with irrigation water of 60 mm in jointing stage and fertilized soil amendment fertilizer of 1350?kg/hm2. The optimum amount of SAF fertilization under no irrigation, irrigation once, irrigation twice was 656、920.13 and 872.38 kg/hm2 respectively. Plot CO2 emission under normal fertilizer treatment was lower than that of soil amendment fertilizer treatments. In jointing stage and seed filling stage which soil respiration of winter wheat were intensively, irrigation at jointing stage could significantly improve soil CO2 emission flux. SAF1800 treatment was recommend as the strategy for improving farmland carbon sequestration.