Abstract

Using non-chemical weed control methods can play an important role in reducing herbicide use as well as protecting the environment. Appropriate land preparation especially puddling has been known as one of the best factors for weed control in rice fields. Plowing once in late winter and tilling again at one or two weeks before transplanting in spring is the current method in Iran. Number of tillages and type of equipment used depends on conditions and farming system in different sites in Iran. Kind of equipment and number of tillage operations may affect weed density. An experiment was conducted in 2011 with 6 treatments in RCBD. The treatments included: conventional method with one or two tillage operation (tillages separated by a 10-day interval), tilling once or twice with a rotivator, or tilling once or twice with a cone-puddler. These trials were conducted in rice fields of Jhad Research Institute of Iran (JRII) with 3 replications. Main weeds were: Echinochlea crus-galli (water grass), Cyperus difformis (small flower) and Alisma plantago-aquatica (water plantain). The results indicated that number of tillages and kind of equipment affected weed population and density. The best treatment was conventional method of plowing followed by two tillage operations which reduced weed density 2/3 times in comparison with the worst treatment (cone puddler with one tillage operation).

Key words: Rice, weed density, plant population, tillage.