Yield Response of Winter Wheat to Row Spacing under Irrigated and Rainfed Conditions

Zhou, X. B. and Y. h. Chen, 2011. Yield response of winter wheat to row spacing under irrigated and rainfed conditions. Bulg. J. Agric. Sci., 17: 158-166 In China, wheat (Triticum aestivum L.) is cultivated across a wide range of climatic conditions. The average rainfall was recorded at 696.6 mm per year from 1971 to 2008 at Taian in northern China. Considerable variability in the row spacing (RS) per unit area, usually referred to in agricultural practice, is expected as variation in factors affects the agronomic characters of winter wheat in different ways. Furthermore, previous studies have reported that RS limitations may affect yield in wheat. The objective of this study was to quantify the effects of RS and water availability on yield in wheat crops. The experiment reported in this article was conducted during the crop seasons of 2006/2007 and 2007/2008. Four types of RS were calculated under two different water conditions (rainfed and irrigated) and were set up as a randomized plot design. The results showed that irrigation and uniformity of monthly rainfall could increase crop yield. The population number of RS49 was the lowest in all treatments, and that of RS7 was significantly higher than all other treatments after irrigation. The LAI average of RS14 was highest under different RS treatments at 44.4% (the rainfed) and 42.1% (the irrigated) and higher than that of RS49. The order of the grain yield can be presented as RS7≈RS14>RS24.5>RS49, and grain yields for RS7 and RS14 were significantly higher than those for RS24.5 and RS49 in both years (P < 0.05). Consequently, we conclude that high yields of wheat can be achieved in northern China by reducing RS under uniform plantingdensity conditions. Winter wheat production in the northern China area can thus be cultivated with an acceptable optimum RS wherein yields increase.