Effects of row spacing on soil water and water consumption of winter wheat under irrigated and rainfed conditions

Field experiments were carried out in China in 2006-2007 and 2007-2008 in order to investigate the effect of four types of row spacing (RS, 7 x 7 cm, 14 x 3.5 cm, 24.5 x 2 cm, 49 x 1 cm) and two water conditions (rainfed and irrigated) on soil water content (SWC), evapotranspiration (ET), total dry matter (TDM), and harvest index (HI) of wheat. A randomized plot design was used. RS did not exhibit any obvious effects on SWC during the study period. SWC was enhanced by irrigation, especially in the 10-60 cm soil layer. Irrigation increased the ET. When using RS 14 x 3.5 cm, the ET at the seeding-jointing stage was significantly higher than when using the other three RS. Irrigation increased yields, ET, and TDM, while it decreased water use efficiency and HI. There were significantly negative correlations between TDM and RS. The HI of the rainfed crop was higher than that of the irrigated crop. Our results showed that high yields of wheat could be achieved in northern China by reducing RS under uniform planting density conditions.