effect of silicon, potassium and zinc foliar application on some agronomic characteristics, blast and stem borer (chilo suppressalis walker) control in rice (cv. tarom hashemi)

in order to study the effects of foliar application of si (5/1000 ratio), k (2/1000 ratio) and zn (2/1000 ratio) on rice (cv. tarom hashem), an on-farm experiment carried out based on randomized complete block design with three replications in 2012. some traits such as paddy yield and yield components, neck blast disease and stem borer damage were evaluated. results showed that the effect of foliar application in terms of all traits except panicle length, 1000 grain weight and tiller number were significantly different than control. mean comparison showed that the highest paddy yield (4518 kg ha-1), grain number per panicle (185.2), filled grains (174.6), panicle fertility percentage (94.3%) and the lowest sterile grain number per panicle (10.6), blast disease (3%) and stem borer (0.3% death heart and 1.2 % white head) were obtained in si application. a negative and significant correlation was observed between filled grain number and blast damage percentage (r=-0.71**), percentage of stem borer infection (r=-0.72**) and percentage of white head (r=-0.89). according to results it seems that foliar spraying of zn, si and k had a positive effect on grain yield (closely increase 2-14%) and also suppress stem borer (closely 9-87%) and neck panicle blast (closely 27-87%) as compared to control. in conclusion, si foliar application had the most positive effect rather than zn and k.