Effects of different planting methods on decline of herbicides consumption and weeds population in corn

To evaluate the efficiency of different methods of corn planting, for reducing the use of herbicides and weed populations in corn, carried out an experiment with 10 treatments and 4 replications in a randomized complete block design in 2011 at Karaj. Treatments were: corn on ridge + strip spraying (Nicosulfuron 2 lit/ha), corn on ridge + once cultivator, corn on ridge + twice cultivator, corn on ridge with hand weeding, corn on ridge without hand weeding, corn in furrow and overall spraying (Nicosulfuron 2 lit/ha), corn in furrow and strip spraying (Nicosulfuron 2 lit/ha), corn in furrow and replacement furrow with ridge, corn in furrow with hand weeding and corn in furrow without hand weeding. The results at four weeks after replacement ridge with furrow, showed that difference of treatments were intensity significant in population and dry weight of major weeds(pr 0.01). Weed population and total dry weight of weed in treatments of" corn in furrow and overall spraying", corn in furrow and strip spraying","corn on ridge + overall spraying" were more decrease compared with other treatments. Also weed population decreased in"corn on ridge + twice cultivator" and" corn in furrow and replacement furrow with ridge" considerably. ANOVA based on corn yield showed that the effect of treatments was highly significant on biological yield and corn grain yield(pr 0.01). Maximum of biological yield obtained after hand weeding from the treatments, (corn in furrow and replacement furrow with ridge), (corn on ridge + strip spraying), (corn on ridge + twice cultivators) and (corn in furrow + overall spraying). Also, after hand weeding treatments, (corn in furrow and overall spraying), (corn on ridge + strip spraying) and (corn in bed of the furrow and replacement furrow with ridge), produced 6/43 , 5/98, 5/55 t/ha grain respectively.