evaluation of nitrogen and phosphorous levels on forage yield and characteristics of kochia scoparia in irrigating with two saline waters

kochia scoparia is a salt resistant plant that can be used in producing forage in the areas with salt water and soil resources. one of the problems which produce the forage plants in these areas decreases the function and quality of the forage in irrigation condition with salt water. therefore, using the chemical fertilizers can be considered as a useful solution. this study was conducted to evaluate the effects of various levels of phosphorus and nitrogen fertilizer in irrigating condition with saline water on forage yield and characteristics of kochia by applying split plot experiments based on randomized complete block design with three replications. the main plots consisted two levels of salinity of irrigating water, 5.2 and 16.5 ds/m, and the subplot consisted of factorial of three nitrogen levels in the form of urea (0, 100, 200 kg/h) and three phosphorus levels in the form of triple super phosphate (0, 75, 150 kg/h). results showed that salinity had no significant effect on height, stem diameter and dry matter percentage. but, nitrogen application leads to increase in height, lateral shoots and forage yield compared with control. phosphorous had significant effect of dry forage yield. the interactions of salt with nitrogen and phosphorus showed that the fertilizers can partially reduce the negative effects of salt stress on kochia and improve the forage characteristics and biomass production.