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Using non-chemical weed control methods play an important role in the reduction of herbicide use as well as environmental protection. Appropriate land prepration, specially puddling has been known as one of the best factors for weed control in rice fields. Once plowing in late winter and second plowing at one or two weeks before trans planting in spring, is the current method in Guilan province. Number of puddlings
and type of equipment used, depends on conditions and farming system in different sites in Guilan province. Kind of equipment and number of secondary tillages affect weed density. An expriment was conducted in 1999 with 6 treatments in RCBD. The treatments included : Conventional method with once and twice puddling the second
puddling after a 10 day interval, puddling once or twice with a rotivator as well as puddling once or twice with cone- puddler. These trials were conducted in rice fields of Rice Research Institute of Iran (RRII) with 3 replications. Main noxious weeds were: Echinochlea crus-galli(water grass),Cyperus difformis (smallflower)and Alisma plantago-aquatica (water plantain). The results indicated that, number of tillage and
kind of equipment affected weed population and density. The best treatment was conventional method with two puddlings which reduced weed density 2.3 times in comparison with the worst treatment that is, cone puddler with once puddling.