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Mehdi Akbari; Fariborz Abbasi; Abolazal Nasseri; Mohammad Ali Shahrokhnia; Mohammad Khorramian; Masoud Farzamnia; majid keramati targhi; Azarakhs Azizi; Mohamad Abasi; Eshag Zare; Hasan Khosravi; Esmaeil Moghbeli; Mohammad Mehdi Nakhjavanimoghaddam; Nader Abbasi; Javad Baghani
Abstract
This project was implemented with the aim of measuring water applied to onion under farmers’ management in 190 selected sites at the production hubs of onion in Iran including Azarbaijan Sharghi, Isfahan, Khusestan, Zanjan, Kerman, Fars, Khorasan Razavi, Khorasan Shomali, and Hormozgan provinces. ...
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This project was implemented with the aim of measuring water applied to onion under farmers’ management in 190 selected sites at the production hubs of onion in Iran including Azarbaijan Sharghi, Isfahan, Khusestan, Zanjan, Kerman, Fars, Khorasan Razavi, Khorasan Shomali, and Hormozgan provinces. According to the results, differences between the average volumes of irrigation water in those provinces, different irrigation methods, various sources and salinities of irrigation water and soil, and different onion varieties were significant (p<1%), during the growing season of 2020-2021. The average amount of applied water by farmers in those provinces was 9502, 13273, 9740, 16588, 9618, 13880, 11998, 8438 and 7057 m3/ha, respectively, with the weighted average of 10823 m3/ha. The onion yield in selected sites, varied from 20000 to 90000 kg/ha, with an average of 49980 kg/ha. The measured values were compared with the net irrigation water requirement estimated by the FAO Penman-Monteith method and with the National Water Document values. The results showed that the differences between average volumes of applied water by farmers, yield and irrigation water productivity, and irrigation water plus effective rainfall productivity in the selected sites were significant at 5% probability level. Irrigation water productivity varied from 3.13 to 6.30 kg/m3 and its average was 4.93 kg/m3. The average irrigation water plus effective rainfall productivity for onion in Iran was 4.50 kg/m3. The average net irrigation water requirement in the study areas by the Penman-Monteith method and the National Water Document were 8834 and 6972 m3/ha, respectively. These results showed that the average applied water in surface, sprinkler, and drip irrigation methods were 11453, 12740 and 10317 m3/ha, respectively, with significant (p<5%) difference. These results showed that in drip irrigation method, applied water was 10% lesser while irrigation water plus effective rainfall productivity was 35% higher. Transplanting seedling compared to direct seeding caused 14.7% reduction in applied water and 16.7% increase in water productivity. According to the results of this study, drip irrigation and transplanting method for onion fields is recommended.
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.