The Effect of Conjunctive Irrigation with Seawater and Fresh Water on Yield and Yield Components of Dill (Anethum graveolens L.)

Due to the limited freshwater, farmers have to use exotic waters such as seawater. One of the management methods is the conjunction use of fresh and seawater. The goal of this study was to investigate the effect of conjunctive irrigation with seawater and fresh water on the yield and yield components of Dill (Anethum graveolens L.) in greenhouse conditions. The research was done based on a completely randomized design including 3 replications as pot planting in Gorgan University of Agricultural Sciences and Natural Resources during 2016. In this study, there were five irrigation regimes (Irrigation with one-third of the sea water with tsp water, Irrigation with half seawater and then one more half with fresh water, Alternate irrigation with seawater and tap water, and Conjunction irrigation). The results inducted that the effect of different irrigation regimes on Umbrellas per plant, umbels per umbrellas and thousand kernel weights was highly significant (P<0.01), but the number of leaves per plant, branches number, the number of seeds per plant, and the seed number in umbrellas were significant at 5 percent level (P<0.05). In this study, all parameters were decreased significantly with the increase at all levels of water salinity. The results showed that one-third seawater and tap water irrigation regime, as compared to other regimes after control regimes, had the highest Umbrellas per plant, umbels per umbrellas, the number of leaves per plant, branches number, the number of seeds per plant, and the seed number in umbrellas. One-third, half alternate, alternate and the mixture of sea water and tap water resulted in the decrease of thousand kernel weights, reaching ti 13.6, 19.0, 30.1 and 65.1 percent, respectively.