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reza saeidi; AbdolMajid Liaghat
Abstract
This research aimed to simulate the yield of maize cv. S. C 704 under conditions of separate application of salinity stress at different growth stages in mini-lysimeter, in Qazvin area, Iran. The experiment was performed as factorial and in a completely randomized design. Soil salinity treatments, as ...
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This research aimed to simulate the yield of maize cv. S. C 704 under conditions of separate application of salinity stress at different growth stages in mini-lysimeter, in Qazvin area, Iran. The experiment was performed as factorial and in a completely randomized design. Soil salinity treatments, as the main factor, included four levels of 1.7(S1), 3(S2), 5(S3) and 7(S4) dS.m-1. The sub-factors included different growth stages as follows: one-stage at 6-leaves (C1), flowering (C2), and milk stage (C3); and two-stages of C1C2, C1C3 and C2C3. By combining saline water (from a salt marsh) with a well fresh water (0.5 dS.m-1), saline water was prepared according to the treatments. Irrigation was done in a way that the salinity of input and output water from the mini-lysimeters was equal. The control treatment was irrigated with fresh water. By combining the water uptake reduction functions, the derived models were presented and evaluated for simulating yield reduction coefficient (α). The stress application data in one and two-growth stages were used for models calibration and validation, respectively. Applying the highest salinity level led to decrease in dry matter yield from 157.2 g. plant-1 (in S1 treatment) to 115.9, 53.2, 77.7, 86.1, 97 and 46.5 g. plant-1 in the C1, C2, C3, C1C2, C1C3 and C2C3 treatments, respectively. The results showed that crop sensitivity was different in one-stage and two-stage stress application. Salinity stress at flowering (C2) and milk stage (C3) had a more negative effect relative to C1C2 and C1C3. In this research, Van Genuchten's additive model and Dirksen-Maas-Hoffman's multipliable model could be recommended as the optimal models for crop yield simulation. Also, application of two-stage salinity stress (up to level of 7 dS.m-1) in C1C2 and C1C3, had higher yield relative to application of one-stage stress in C2 and C3 growth stages.
mahdi mokari; hadi dehghan; Meysam Abedinpour
Abstract
The simultaneous effect of salinity and drought stress are among the major factors that limit agricultural production in many parts of the world, especially in arid and semi-arid regions. Accordingly, a greenhouse research was carried out to study the simultaneous effect of salinity and water stress ...
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The simultaneous effect of salinity and drought stress are among the major factors that limit agricultural production in many parts of the world, especially in arid and semi-arid regions. Accordingly, a greenhouse research was carried out to study the simultaneous effect of salinity and water stress on yield and yield components of turnip (Purple Top White Globe var.) in Kashmar region. The experiment was performed as factorial arrangement in completely randomized design with three replications including two factors; salinity and irrigation water volume. Treatments consisted of four levels of water salinity (S1=0.7, S2=4, S3=8 and S4=12 dS/m) and three levels of water (W1=100%, W2=75% and W3=50 percent of water requirement), which were applied in a sandy-loam soil texture. The results showed that effects of salinity and water stress and their interaction were significant on biomass, shoot wet biomass, tuber and leaf dry weight (P<0.01). W1S1 and W2S1 treatments had higher biomass than the others. In all of the salinity levels, there was no significant difference between biomass in W1 and W2 irrigation levels. Based on the results of this research it could be concluded that turnip is more sensitive to salinity stress than drought stress. In other words, the results showed that the best level of salinity to reach the maximum biomass was S1. Therefore, the best treatment recommended for turnip planting in Kashmar region is W2S1.