effects of calcium, potassium and method of application on sorghum (sorghum bicolor l (. morphological and physiological traits in the presence of salinity

abstract in order to study salt stress, calcium and potassium effects and type of application on sorghum plant, a field experiment was arranged in randomized complete block in split plot design at the research field of center of excellence for special crops, ferdowsi university of mashhad at 2008. experimental treatments were included two levels of salinity (5 and 10 ds.m-1) as main plots and factorial of 2 types of application and four levels of ca2+ and k+ as main plots in 3 replication. growth parameters such as plant hight, leaf, stem and plant dry weight, stem diameter measured at 4 growth stages. chlorophyll index, rwc and lai measured in 3 stages of growth. result of statistical analysis showed that salt stress leads to decrease the plant height, chlorophyll index and rwc, but did not affect biomass and lai. application of ca and k only affected rwc, height and stem dry matter. result showed that use of ca and k lead to improved growth parameters of sorghum at salt stress conditions but no significant differences between application of sole k and k+ca treatments were obsered. so, to reduce production expenses, application of only k fertilizer is proposed for soghum production under salt stress conditions.