Inluence o dierent crop rotations on yield , yield components, and stability o irrigated wheat in Golestan Province

In order to investigate the inluence o cropping systems and crop rotation characteristics, yield, yield stability in wheat production in Golestan province. This project was conducted during two periods or six years (2003-2011) in agricultural research station o Gorgan. During the irst period (2003-2006) experiment were done with a split-plot design based on a randomized complete blocks design (RCBD), with three replications. Main plots consisted o ive crop rotations:1-wheat\\allow\\canola\\soybean,2-wheat\\soybean,3-heat\\allow\\canola\\corn, 4-wheat\\corn and ,5- wheat\\corn\\allow\\cotton , subplots included our wheat varieties; 1-Tajan, 2-Shiroodi, 3-Morvarid and 4-N-80-19. The disease and soil microbial population was determind. Results showed, the highest grain yield was achieved in Rot. 1. The line o N-80-19 had the highest and Tajan had the lowest grain yield. During the second period (2006-2011) experiment was conducted with a strip–plot based on randomized complete blocks design (RCBD) with three replications. Horizontal actor included six crop rotations ;1-wheat\\soybean,2-wheat\\corn,3-wheat\\canola\\wheat,4-wheat\\cotton\\wheat, 5-wheat\\canola\\barley\\wheat and 6- wheat \\canola \\soybean \\cotton \\wheat. Vertical actor included six cultivars;1- Tajan, 2-N-80-19, 3-Morvarid, 4-Moghan, 5-Arta and 6-Darya. Results showed, the rotations in the irst and second years were not signiicantly dierent, but in crop year (2010-2011) the highest grain yield was achieved in Rot. 6. Continiuous cultivation o wheat \\ corn decreased wheat grain yield sharply.Overall, Increased crop diversity in cultivars o abaceae amily caused yield increase , higest and lowest perormance obtained rom rot.6 and rot.1 ,respectively. Morvarid cultivar improved has prodused the highest yield