فهرست مطالب

  • Volume:3 Issue:3, 2016
  • تاریخ انتشار: 1395/04/06
  • تعداد عناوین: 3
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  • Meysam Abedinpour * Pages 50-57
    The global water crisis reminds the important of enhancing water productivity in agriculture to increase the crop production and food security. Declining availability of fresh water resources has become a worldwide problem which promotes the new alternative sources of water-supply to overcome to this issue. In this goal, the effects of different irrigation intervals and water quality on soybean growth and soil properties were investigated by a field split plot experiment in a randomized completely block design water in three replications. Different saline water levels (1, 4 and 7 dS m-1) and three irrigation intervals (7, 10 and 13 days) were arranged as studied factors in main and subplot, respectively. The maximum performance was obtained by the treatment of 7 days irrigation interval+non-saline water which produced 3760 and 8355 kg ha-1 grain yield and biomass, respectively. Also, maximum water use efficiency of 9.08 kg ha-1mm-1 was obtained by 13 days irrigation interval+7 dS m-1 salinity. Maximum soil salinity (ECe) in different soil layers was observed in the highest irrigation saline water treatment (7 dS m-1) in all irrigation intervals. Moreover, irrigation with highest salinity level (S3) resulted in the salt accumulation in the root zone from 1.4 dS m-1 (before sowing) up to 5.7 dS m-1 at the end of growing period. Therefore, based on soil salinity and crop yield, irrigation interval 7 days at lower levels of irrigation water salinities (up to 4 dS m-1) is suitable for soybean production in the semi-arid environment.
    Keywords: Interval irrigation, Salinity, Soybean, Sustainability, Water use efficiency
  • Farzin Salmasi*, Behnam Mansuri Pages 58-65
    Water penetration from beneath of built structures on permeable soils causes uplift force along the contact of structure with foundation. This uplift force reduces hydraulic structure stability. Typically, these instabilities occur due to under-pressure development (uplift force), gradual inner degradation of foundation material (piping) or sand boil phenomenon. Thus, it seems necessary to calculate the pressure applied to the contact surface of the dam. One method for preventing piping phenomenon, reduction in exit gradient as well as decrease of uplift force beneath diversion dams includes implementation of weep hole. This study aims to study the effect of radius, depth and location of pipe drains under stilling basin upon how much uplift force decreases. The benefit of this study in agricultural field for soil and water engineers is to have a safe design of lined canals, weirs or diversion dams. To do this, numerical simulation of Tabriz diversion dam with Geo-Studio software was carried out. Results showed that application of drain pipe under the structure reduced uplift force respect to without drain under the structure. Increasing of drain radius; caused reduction of uplift pressure more but increased of seepage flow slightly. Installation of drain in upper part of stilling basin had a tendency to decrease uplift pressure more. Existence of drain near the stilling basin bottom caused in more reducing of uplift pressure than of installation of it in deeper depth.
    Keywords: Drain, Geo-Studio, Seepage, Uplift pressure, Weep hole
  • Ali Mehrban Jafarlou, Mohsen Poursoltan, Bahareh Deltalab, Saleh Amiri* Pages 66-69
    In order to evaluate the effect of green pruning times on some physiologic and morphologic characteristics of peach Redtop cultivar in Moghan region, a factorial experiment was arranged based on randomized complete block design with three replications. First factor (the pruning severity) included 3 treatments (⅓ pruning, ½ pruning, complete pruning and non pruning as control) and second factor (pruning time) included 4 treatments (31 May, 15 June and 1 June). Morphologic characteristics such as length of seasonal branches, fruit size, physiologic characteristics; total soluble solids (TSS), acidity, rate of sugar and yield were measured, and evaluated. Results showed that effect of green pruning times had significant effect on length of seasonal branches, yield, fruit size, total soluble solids, acidity and rate of sugar. The superior treatment was (½ pruning at 15 June) that had the highest rate of sugar, biggest fruit, highest yield, high total soluble solids and lower amount of total acidity. Finally, it was concluded that among the seven studied characteristics, the treatment (June 25, ½ pruning severity) had the most significant effects in comparison with other treatments.
    Keywords: Green pruning, Morphologic, physiologic characteristics, Peach