Abstract: 【Objective】Continuous cropping is normally employed for maize cultivation with plastic film mulching in arid oasis irrigation regions. Lower resources use efficiency and residual film pollution usually result from unreasonable management of irrigation/N application and single planting pattern. The purpose of this study was to determine the enhanced effect of two years plastic film mulching with reduced tillage on grain formation of wheat with reduced amount of irrigation and N application, so as to provide the theoretical basis for exploiting of planting pattern with lower resources input and greater resources use efficiency.【Method】A field experiment was conducted at Zhuwangpu county, Hexi Corridor of Gansu province in 2016 and 2017. Two tillage patterns were designed as: wheat planted with two years used plastic film mulch and no-tillage in the preceding fall (RT), wheat strip planted with conventional tillage and without mulching (CT). Wheat growth under two irrigation levels (the reduced 20% amount of traditional irrigation (I₁), the amount of traditional irrigation (I₂)) and three nitrogen levels (the reduced 40% amount of traditional nitrogen application (N₁), the reduced 20% amount of traditional nitrogen application (N₂), and the amount of traditional nitrogen application (N₃)). 【Result】 The significant difference of growth and yield was not observed between 2016 and 2017. Growth rate of wheat was enhanced by RT as 8.5% at jointing, as 9.0% from booting to flowering compared with that of CT; The growth rate of wheat was not significant difference between different irrigation levels or nitrogen application levels, respectively, in each growth stage. Average leaf area index (LAI) of RT was greater as 13.9% than that of CT. However, the LAI was decreased under reduced irrigation, the average LAI of the I₁ was decreased by 12.2% than that of I₂. LAI of wheat was also affected by nitrogen application level, the LAI of N₁ was decreased by 13.3% than that of N₂, and LAI of N₂ was decreased by 13.3% than that of N₃. Under I₁ irrigation level, RT had the greater improving effect on grain yield than conventional tillage. RT enhanced grain yield of wheat by 9.1% in comparison to CT. Two years used plastic film mulch achieved the greatest grain yield in I₁ irrigation level and N₂ nitrogen application level, which was 7 168 kg·hm^-2 in 2016 and 7 537 kg·hm^-2 in 2017, and grain yield of RTI₁N₂ was equaled to that of traditional irrigation and nitrogen application levels. While biomass yield was decreased and harvest index was increased under reduced irrigation and nitrogen application. The harvest index of I₁ was increased by 10.7% than that of I₂. The N₁ and N₂ had higher the harvest index by 9.2% and 7.1% than that of N₃, respectively. Under I₁ irrigation level, the transfer amount from photosynthetic product for grain after flowering was increased by 26.2% under RT, compared with CT, meanwhile the contribution was increased as 4.9%. The significant difference on the transfer amount from photosynthetic product for grain between the reduced 20% and traditional nitrogen was not observed. Yield component factors and the path analysis indicated that, improving kernel weight via greater leaf area index support photosynthetic product and translation to grain was useful for achieving high yield. 【Conclusion】 RT had improved wheat grain yield with the I₁ irrigation level and N₂ nitrogen application. It was therefore suggested that, in arid oasis irrigation regions, the treatment of RTI₁N₂ was one of effective cultivation patterns for the integrated measures with the reduced amount of water, nitrogen and plastic film resources.

Key words: spring wheat, two years used plastic mulch, crop rotation, translation of photosynthetic product, yield component, reduced irrigation and nitrogen application