The Effect of Crop Rotation and Nitrogen on Weed Infestation in Potato Field

Weeds are important problem in all cropping systems including potato. In order to evaluate the effect of crop rotation and nitrogen on weed structure and potato yield an experiment was conducted from 2007 to 2010 at the agricultural research site، University of Mohaghegh Ardabili. The experiment was established as split plot with tow factors، potato in crop rotation (with wheat، canola، sugar seed beet and potato) and nitrogen rate (0، 80، 160 and 240 kg ha-1) using a randomized complete block design with three replication. Results showed that weed density in secondary period of crop rotation was 26% lower than first period. Weed density in canola- potato rotation was 58% greater than other rotations. Increasing nitrogen rate increased weed cover. In continues cropping of potato، without or with applied 240 kg N ha-1 potato cover was lower 35%. Also continues cropping decreased potato yield 3 to 6 t ha-1. This finding show that crop rotation and nitrogen management can help in non-chemical weed management programs in sustainable agriculture.