Abstract: In order to explore the characteristics of spring wheat grain filling and dry matter translocation under the condition of limited irrigation and the factors limiting the grain filling of spring wheat, and thus to increase the water productivity of intercropped spring wheat, the influences of limited irrigation (four levels: 298, 328, 358, 388 mm) of two intercropping modes (spring wheat intercropped with maize or sunflower) on the characteristics of spring wheat grain filling were studied based on the present situation of water shortage in Hetao irrigated region, Inner Mongolia. The results showed that under same irrigation conditions, the dry matter translocation yield of wheat stem and leaf intercropped with sunflower were 1.08-1.86 times and 1.12-2.17 times as high as that intercropped with maize, respectively, while the dry matter translocation yield of wheat glume and cob under the maizeintercropped model was 1.00-1.19 times as high as that under the sunflowerintercropped model. The process of wheat grain filling was consistent with the “S” growth curve that could be simulated by a Logistic equation under different water treatments and planting modes. The wheat intercropped with maize reached a peak grain filling rate after 25-30 d of flowering, with 1.26-2.85 d in advance compared to the control treatment (wheat monoculture with 388mm irrigation). The wheat intercropped with sunflower reached a peak grain filling rate after 25-30 d of flowering, with 1.80-2.44 d in advance compared to the control treatment. The maximum grain filling rate and average grain filling rate of wheat under the two intercropping modes with various water treatments were all higher than those under the control treatment, and the time needed for maximum grain filling rate decreased. The lower rates of irrigation (298-328 mm) were found to be conducive to extension of the active filling stage of wheat intercropped with maize, while the higher rates of irrigation (358-388 mm) were conducive to extension of the active filling stage of wheat intercropped with sunflower.

Key words: carbon emission, carbon footprint, food security, global warming