effect of potassium on yield and yield components of two barley varieties irrigated with saline water

it is very important to find new and replaceable water resources for agricultural usage because of the increasing need of urban population and industries for high-quality water and decrease of drinking water supplies. to investigate the effect of different levels of irrigation water salinity, potassium sulfate, and their interactions with yield and yield components of two barley cultivar, an experiment was conducted using a factorial arrangement in a completely randomized block design with four replications in 2012 at the greenhouse of sari university of agricultural sciences and natural resources. the varieties of barley included productive and sahra, which were treated with different levels of water salinity (sea water) including well water (as control), mixture of 1/4, 2/4 , 3/4 sea water with well water, and sea water (pure). potassium treatments included 0, 0.5, 1, and 1.5 g potassium per kg soil. in this experiment, seed yield, 1000 grain weight, number of heads, plant height, number of grains, number of spikes, biological yield, stem and leaf dry weight, and harvest index were measured. the results showed thatirrigation water salinity had negatively affected all these plant traits, except for harvest index. the highest decrease of salinity with 51.8% was observed in the number of spikes. application of potassium also led to the improvement of yield and yield components and decreased harvest index, but was non-significant for all the traits except straw yield. the stem and leaf dry weight and biological yield showed the highest effect in response to addition of 1.5 g potassium per kg soil, with increases of 35.70% and 25.2%, respectively.