Effects of preceding crops and nitrogen rates on grain yield and yield components of wheat (triticum aestivum l.)
The aim of this study was to evaluate the effects of preceding crops and nitrogen rates on yield and yield components of wheat. The experiment was conducted at the Experimental Farm of Rarmin Agricultural and Natural Resources University, Ahwaz, Iran during 2008-2010 growing seasons. The experimental design was split plot arrangement (RCBD) with three replications. Main plots were different preceding crops wheat, canola, maize, mungbean, rice and berseem clover-barley mixture with control (fallow). Sub plots were nitrogen fertilizer rates (0, 45, 90 and 135 kg N ha• 1). Results showed that effects of preceding crops and nitrogen fertilizer rates for grain yield, total dry matter, spike m• 1, grains spike• 1 and 1000 grain weight were significant during both years, while harvest index was significantly different during 2010. There were preceding crop × nitrogen rate interaction for grain spike• 1 and 1000 grain weight during both years while significant preceding crop × nitrogen rate interaction were determined for grain yield, total dry matter, harvest index and spike mG1 in 2010. Results indicated that species of preceding crops significantly affect wheat yield and grain legumes such as mungbean might help to maximize wheat yield in a crop rotation system. © IDOSI Publications, 2012.