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ali mokhtaran; Peyman Varjavand; Hossein Dehghanisanij; Shokrola Absalan; Azarakhsh Azizi; Alireza Jafarnejadi
Abstract
This study was conducted to compare and monitor drip and surface irrigation systems for corn and wheat crops in three planting seasons from summer 2016 to spring 2018 in one of the agricultural research stations in Khuzestan, located in Ahvaz. The source of irrigation water was Karun River with salinity ...
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This study was conducted to compare and monitor drip and surface irrigation systems for corn and wheat crops in three planting seasons from summer 2016 to spring 2018 in one of the agricultural research stations in Khuzestan, located in Ahvaz. The source of irrigation water was Karun River with salinity of 3 dS/m in Ahvaz section. This study was performed using randomized complete blocks design with three replications. The basis of blocking in corn cultivation was 2 and 4 days irrigation intervals, and in wheat cultivation, the distances between drip lines were 40, 60, and 75 cm. The results showed that the volume of water used in the drip system for corn and wheat was 24% and 32% lower than the surface irrigation system, respectively. Also, water productivity in the drip system was higher than surface irrigation system by 16% and 21%, for corn forage and grain, respectively, and by 35% for wheat. Wheat water productivity for different distances of drip lines was not significantly different. Therefore, in heavy-textured soils, drip irrigation lines at 75 cm spacing can be used for wheat cultivation. In soil monitoring analysis, the drip system reduced soil quality such that, after three planting seasons, the initial non-saline-sodic soil (ECe = 3.09dS / m, ESP = 6.18%) became saline (ECe = 7.63dS / m, ESP = 12.63%). Despite accumulation of salts at the periphery of the wetted soil under the drippers, the plants had a better growth and yield in the drip system than the surface irrigation, because of the high soil water potential around the roots and under the drippers, which reduced salt effects. The results of this study showed that if a drip system is used for the climate similar to the central and southern regions of Khuzestan, land drainage and leaching operations at the end of the growing season are necessary to protect the soil.
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ali mokhtaran; mehrzad tavoosi; Peyman Varjavand; Saloome Sepehri Sadeghian
Volume 34, Issue 3 , September 2020, , Pages 337-354
Abstract
< p > < p >In Khuzestan Province, drainage water production from various activities, especially agriculture, is a serious problem. In order to optimize the use of drainage water, cultivation of salinity resistant crops can be considered as a suitable practice. Therefore, in 2019, a ...
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< p > < p >In Khuzestan Province, drainage water production from various activities, especially agriculture, is a serious problem. In order to optimize the use of drainage water, cultivation of salinity resistant crops can be considered as a suitable practice. Therefore, in 2019, a study was conducted to investigate the possibility of recycling drainage water of sugarcane fields for winter cultivation of quinoa in the Research Farm of Mirza Kuchak Khan Sugarcane Agro-Industry Company in southern Khuzestan. This study was performed as split plots with a complete randomized block design with two factors and three replications. The main factor was the management of irrigation water including the use of Karun river water, drainage water of sugarcane fields, and intermittent-periodic irrigation (alternating application of Karun water and drainage water). The sub-plots were allocated to four genotypes of quinoa including "Giza1, Titicaca, Rosada, and Q26". Interaction of irrigation water type with genotype showed that the highest biomass in terms of dry forage (3645.6 kg/ha) belonged to Giza1 genotype using irrigation with Karun water, which statistically had no difference with the Rozada biomass (2620 kg /ha) using irrigation with drainage water. Monitoring of soil "ECe" and "ESP" during the growing season showed that for the two treatments of irrigation with the water of the Karun River and intermittent-periodic irrigation, the farm soil up to 1 meter depth was non saline and non-sodic. This is while before cultivation of quinova, the soil layer of 0- 25 cm was saline (5.54 dS/m) and the deeper parts were non-saline. In irrigation with drainage water, the 0-25 cm layer soil remained saline due to the effect of evaporation. However, in layers deeper than75 cm, due to the accumulation of salts compared to pre-planting (ECe=2 dS/m), salinity reached ECe=4dS/m and ESP=7%. These results indicate the need for leaching at the end of the growing season and the importance of drainage for salt outflow from agricultural lands to maintain soil salt balance in areas where drainage water recycling is practiced.
Nader Salamati; Peyman Varjavand; Shokrola Absalan; Azarakhs Azizi; Moheydin Goosheh
Abstract
In order to optimize the efficiency of water in agriculture, it is necessary to know the extent of water leakage in the lined canals. In this study, water conveyance efficiency and seepage/leakage losses were determined to evaluate earth and concrete lined channels in Khuzestan irrigation networks. The ...
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In order to optimize the efficiency of water in agriculture, it is necessary to know the extent of water leakage in the lined canals. In this study, water conveyance efficiency and seepage/leakage losses were determined to evaluate earth and concrete lined channels in Khuzestan irrigation networks. The result of this assessment was to identify the problems of management and damages in these channels. Thirty channels were studied and evaluated in the main irrigation and drainage networks of Khuzestan province, including Karun, North Khuzestan, Karkheh, Shavour and, Zohreh and Jarrahi, and channels managed by the farmers. There were 17 tertiary and quaternary canals and 6 earth channels in irrigation networks, as well as 1 canal and 6 earth channels under farmers’ management. The water conveyance efficiency in canals ranged from 38.9% in Ramshir to 99.7% in Shushtar; and in the earth channels, from 46.9% in Baghmalek to 89.3% in Shush. The comparison of means of the measured and calculated indices was performed by t-test and showed that seepage per km length of the unlined earth canals was 3017.7 m3/day, which had no statistically significant difference with lined canals with a leakage of 2166.2 m3/day/km. The results of Pearson correlation coefficients showed that there was a negative and significant (at p<1%) correlation between distribution efficiency with the amount of seepage per kilometer channel length, and between losses and the input flow rate per km of channel length. Also, 16.7% of the total canals had a water distribution efficiency of less than 67.8% (between 38.9% and 67.8%), while 50% of the canals had a conveyance efficiency of less than 68.6%. The low water losses in half of the concrete lined canals and the excessive water loss in 11% of such canals, which even increased water losses in the earth's channels, reveals the necessity of paying attention to the optimal management of these canals. This optimal management should be considered at the design and construction stages of the structure as well as during the installation in agricultural lands. Attention should also be paid to use of proper seals and other suitable equipment to prevent water leakage.