Tillage and irrigation effects on carbon emissions and water use of summer maize in North China Plains

Abstract

No-tillage (NT) and appropriate irrigation before sowing can increase grain yield and water use efficiency (WUE) of summer maize. However, their combined effect on crop WUE and CO2 emissions is not clear. Here, our objective was to document the combined effects of NT and pre-summer maize sowing irrigation on utilization of water applied and carbon emission activity during crop production. Field experiments were carried out in the North China Plain (NCP) in 2016 and 2017 to test NT and conventional tillage (CT) (only performed during the winter wheat planting season), and three irrigation treatments (termed pre-summer maize sowing irrigation, 30, 70, and 110 mm) during the summer maize growing seasons. The results showed that, compared with CT, NT significantly reduced carbon cumulative emissions (CO2-C) and water consumption, and it increased grain yield by 11.3% and 7.4% in 2016 and 2017, respectively. No significant difference was found for WUE between the 70-mm and 110-mm pre-sowing irrigation treatments, but it was significantly higher in either case than WUE under the 30-mm pre-sowing irrigation treatment. Further, WUE and carbon emission efficiency (CEE) were highest under the 70- and the 110-mm irrigation treatment in both years, whereas carbon emissions per unit water consumption (WUECE) were the lowest under the 70-mm irrigation treatment. These results indicated that a combination of NT with 70-mm pre-sowing irrigation can improve the regulation of soil carbon emissions and water consumption by summer maize in the NCP.