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Crop yield and water use efficiency (WUE) in a wheat‐maize double cropping system are influenced by short and uneven rainfalls in the North China Plain (NCP). A 2‐year experiment was conducted to investigate the effects of irrigation on soil water balance, crop yield and WUE to improve irrigation use efficiency in the cropping system. Soil water depletion (ΔSWS) by crop generally decreased with the increase of irrigation and rainfall, while ΔSWS for the whole rotation was relatively stable among these irrigation treatments. High irrigations in wheat season increased initial soil moisture and ΔSWS for subsequent maize especially in the drought season. Initial soil water influenced mainly by the irrigation and rainfall in the previous crop season, is essential to high yield in such cropping systems. Grain yield decreased prior to evapotranspiration (ET) when ET reached about 300 mm for wheat, while maize showed various WUEs with similar seasonal ET. For whole rotation, WUE declined when ET exceeded about 650 mm. These results indicate great potential for improving irrigation use efficiency in such wheat‐maize cropping system in the NCP. Based on the present results, reasonable irrigation schedules according to different annual rainfall conditions are presented for such a cropping system.

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. 2007. Row spacing and irrigation effects on water consumption of winter wheat in Taian, China. Can. J. Plant Sci. 87: 471-477. Management practices can have a major impact on the successful production of winter cereals. A field experiment was conducted with winter wheat (Triticum aestivum) to compare the effects of two row spacing planting patterns (row width set at 30 cm, 30; or row widths set at a narrow row of 20 cm and a wide row of 40 cm, 20 + 40) and four irrigation schedules (no irrigation, T0; irrigation given at stem elongation stage, T1; at stem elongation and heading stage, T2; at stem elongation, heading and milk stage, T3) on yield, water use efficiency (WUE), evapotranspiration (ET) and soil water content (SWC) for the 2003/2004 and 2004/2005 seasons at Taian, Shandong Province, China. Mean soil daily evaporation (Es) was greater in the wide row than the narrow row, and resulted in decreased SWC in the wide row. For the same irrigation treatment, no significant differences in changes of SWC and yield were found between the row-spacing planting patterns in either season. Differences in ET were found in 2005 with ET from the T0 treatment being much lower than the irrigated treatments for both planting patterns. During the cropping season in 2005, WUE of the T3 treatment was lower than from the T1 and T0 treatments at the same planting patterns. The WUE of the 20 + 40 planting pattern was lower than that of the 30 planting pattern with the same irrigation schedule, perhaps due to elevated levels of evaporation from the soil beneath the canopy and decreased yields for the 20 + 40 planting pattern. Therefore, based on WUE, the effect of the 30 planting pattern was better than that of the 20 + 40.