Effect of silicon application and nitrogen rates in two irrigation systems on yield and yield components of rice (Oryza sativa L.)

This research was conducted to evaluate the effects of silicon of application and nitrogen rates on yield and yield components of rice in two irrigation systems. Field experiment was conducted as split-split plot laid out in a randomized complete block design with four replications in Sari, in 2007. Three factors: irrigation system at two levels (continuous flooding and alternative irrigation system) as main plots and nitrogen rates in four levels (N0, N46, N92, and N138 kg ha-1) as sub plots and silicon application in two levels (Si0 and Si500 Kg ha-1) as sub-sub plots. Results showed that there were significant differences on biological yield, tiller number and fertile tiller number among irrigation systems at 1% probability level but, was not significant difference between grain yield. Biological yield in flooding was higher than deficit irrigation. Grain and straw yield significantly differed between nitrogen rates. N0 and N138 had minimum and maximum grain yield with 4306 and 6128 Kg ha-1. There were significant difference on grain yield, straw yield and HI at 1% probability level and filled and blank spikelet number per hill at 5% probability level. N138 and N0 had maximum and minimum tiller number with 15 and 9.63, respectively. Si500 and Si0 had maximum and minimum grain yield with 5090 and 5355 Kg ha-1, respectively. Spike number per m2, tiller number and fertile tiller number, spikelet number per hill and filled and unfilled spikelet number were affected by nitrogen rates. Fertile tiller percentage in N0 and N138 were maximum and minimum, respectively. Fertile tiller percentage obtained from Si0 and Si500 were 93.2% and 91.5%, respectively. Si0 and Si500 had the maximum and minimum spikelet number, respectively. Increase of nitrogen rates reduced 1000-grain weight.