JWSS - Journal of Water and Soil Science

In order to study the effects of different irrigation regimes and different levels of salinity on the growth parameters of Quinoa (Chenopodium quinoa Willd.), this experiment was performed in the research green house of Water Engineering Department, at f Gorgan University of Agricultural Sciences and Natural Resources, during 2016. The experimental design was a factorial with n a randomized complete design in three replications. Treatments included three irrigation levels (100, 75 and 50 percent of water requirements calculated by the evaporation pan class A) and five salinity levels (0.5, 4.3, 8, 11.8, 16 dSm^-1). The results showed that the effect of irrigation on the Leaf area index, chlorophylls and RWC (P<0.01) and Leaf length, and width (P<0.05) was significant. The effect of salinity levels on the Leaf area index, chlorophylls, Leaf length and width, RWC, Specific leaf weight (P<0.01) and Leaf petiole length (P<0.05) was significant too. The interaction between irrigation and salinity levels on chlorophylls and RWC (P<0.01) and Leaf width (P<0.05) was significant as well. According to the results, Quinoa had a good tolerance to the elevated levels of deficit irrigation. Decreasing the irrigation levels from 100 to 50 percent of pan evaporation resulted in the reduction of the Leaf area index and RWC to 24.6 and 7.3 percent, respectively. The result also showed that Quinoa had a good tolerance to the elevated levels of salinity, the mixing sea water, and tap water at rate of 30 percent, with control treatment having no significance for all of the parameters. It seems that good stand establishment in the saline soils and water conditions could be insured if proper management is applied in the farms.

Yield is a function of root distribution and activity. In flood conditions, root growth and efficiency are essential for crop productivity. The goal of this study was to investigate the effect of different irrigation regimes on the root development, yield and yield components of green pepper (green Hashemi cultivars). This study, which was based on a completely randomized design with three replications under greenhouse conditions, was done at Gorgan University of Agricultural Sciences and Natural Resources in 2016. Different irrigation regimes consisted of 3 levels (100, 125 and 150 percent of water requirement). The results showed that the effect of different irrigation regimes on root volume, root length, root area and number of fruit was significant at 1 percent level (P<0.01), but water use efficiency, and fresh and dry weight of fruit were significant at 5 percent level (P<0.05). The results also revealed that green pepper plants were sensitive to over irrigation. Increasing irrigation levels from 100 to 125 percent of pan evaporation resulted in the reduction of root volume, root length, water use efficiency, number of fruits, and pepper fresh weight to 20, 13.8, 26, 29and 6.4 percent, respectively. As the conclusion, with the increase in water irrigation level, the fresh weight of the fruit was significantly decreased.

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.