Abstract: 【Objective】 This study exploited the potential of intercropping and conservation tillage on optimizing carbon emission and water utilization, and integrated them into one cropping system to promote their respective and coordination effect. Thereby, to establish an effective intercropping system with double-wins on carbon emission reduction and water conservation. 【Method】 The study employed wheat (Triticum aestivum)/maize (Zea mayz) intercropping, which was cultivated as a long-term and large-scale cropping mode in Hexi irrigation areas, as the research object. The field experiment was conducted by integrating minimal/zero tillage into wheat/maize intercropping and established four tillage and straw retention patterns, which were: (a) no-till with 25 cm wheat stubble standing in the field (NTSSI, stubble standing), (b) no-till with 25 cm height of wheat straw chopped and spread evenly on the soil surface (NTSI, straw mulching), (c) tillage with 25 cm height of straw was incorporated in the soil (TISI, straw incorporated), and conventional tillage (CTI, tillage without straw retention). Meanwhile, the study also applied conventional-tilled sole wheat (SW) and sole maize (SM) as the controls, and investigated the conditions of soil respiration and crop water consumption in various treatments. An EGM-4 system (Environmental gas monitor-4, UK, PP system) was used to measure soil respiration and there from calculating the carbon emission during the growing season. Two methods of water use efficiency were determined, i.e., based on grain yield (WUE_GY) and carbon emission (WUE_CE, that is carbon emission per unit of water) in order to make a proper assessment of water use condition in the intercropping system. 【Result】 Among the three cropping systems, the sole maize had the highest soil respiration rate (1.57 μmol CO₂·m^-2·s^-1), which was almost twice as higher as the intercropping (0.83 μmol CO₂·m^-2·s^-1), while among four straw retention patterns, NTSI had the lowest soil respiration, which was decreased by 20.4% in 2011 and 11.9% in 2012 as compared to CTI. Accordingly, carbon emission of NTSI was reduced by 12.4% compared to CTI. Integration of no-till and straw mulching into wheat/maize intercropping effectively lowered the crop water consumption while improving grain yield and WUE_GY. Compared to CTI, the water consumption of NTSI was reduced by 4.1%, while grain yield and WUE_GY was respectively increased by 29.7% and 15.6%. Furthermore, the carbon emission per unit of water was decreased by 5.9%, although carbon emission efficiency was promoted by 28.2%. 【Conclusion】 The results suggested that the integration of no-till and straw mulching into wheat/maize intercropping optimized the relationship between grain yield, carbon emission, and crop water consumption in this cropping system. The cropping mode could promote more water to produce more grain yield, meanwhile reducing the carbon emission during the crop production process. Consequently, it achieved a win-win effect on coordinating carbon emission reduction and efficient use of soil water in a wheat/maize intercropping system.

Key words: oasis irrigation area, strip tillage, wheat/maize intercropping, carbon emission, water use efficiency