Nader Naderi; Ali Ghadami Firouzabadi; Mahmud Froumadi
Abstract
Semnan province faces water and soil limitations due to its geographical location, desert and semi-desert climate. Pressurized irrigation methods are used as one of the options for improving water use efficiency in this province. In this study, sprinkler irrigation systems were evaluated in Semnan province. ...
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Semnan province faces water and soil limitations due to its geographical location, desert and semi-desert climate. Pressurized irrigation methods are used as one of the options for improving water use efficiency in this province. In this study, sprinkler irrigation systems were evaluated in Semnan province. For this purpose, 6 sprinkler irrigation systems including wheel move, classic with portable sprinkler, and center pivot systems were evaluated in different farms. Potential and actual application efficiency (PELQ and AELQ), uniformity, and distribution coefficients (CU and DU) for wheel move systems were 40.7%, 29.6%, 57.2% and 52.7%, respectively, and for classic systems with portable sprinkler they were 54.8%, 54.8%, 75% and 65%. For center pivot system, these parameters were 83%, 79.6%, 5/94%, and 91%, respectively. In center pivot system, these parameters were the best. Good designing, new and appropriate sprinklers, and low height of sprinklers were the factors causing better operation of this system. Next to center pivot, the classic system with portable sprinkler had better performance. New and appropriate sprinklers, low height of sprinklers, and appropriate pressure in this system increased the efficiency in farm No.4, while in farm No. 5, inappropriate sprinklers distance decreased efficiency of the classic system with portable sprinkler. In other farms, low pressure of sprinklers, decreasing the discharge and spray radius of sprinklers relative to nominal values and high pressure difference in the system caused low efficiency of wheel move system.
Nader Naderi; f a
Abstract
Qanat is one of the most surprising structures that is used for extraction of underground water in arid and semi-arid regions. There are 607 qanats in Semnan province, providing a total discharge of 93.5 million m3 of water per year. In this research, existing conditions and irrigation in agricultural ...
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Qanat is one of the most surprising structures that is used for extraction of underground water in arid and semi-arid regions. There are 607 qanats in Semnan province, providing a total discharge of 93.5 million m3 of water per year. In this research, existing conditions and irrigation in agricultural fields of 15 qanats of Semnan province were studied and some executive strategies were recommended to improve qanats’ performance. , quantity and quality changes of qanat water, application efficiency and water productivity downstream the studied qanats were evaluated. Results showed that insufficient credit, tunnel and wells collapsing due to lack of necessary construction and resistant covering, entrance of flood into qanats, numerous owners and rural migration were the most important reasons of discharge reduction and qanats destruction. Variations of EC and pH in qanats water were relatively low for a long period of time. Average of application efficiency in cultivated lands downstream the studied qanats was about 51.6%. Whereas it was 45.5% downstream the studied wells in the same regions. Average water productivity for various crops was 0.63 kg/m3. Establishment of strong groups to better partnership of owners in operation and maintenance of qanats, regular dredging, tunnel staining, well covering, tunnel tubing and fixing valve in qanat outlet, construction of qanat water reservoir and establishment of proportion between crops water requirement and amount of irrigation water in downstream lands of qanats are the most important practical strategies for improving qanats conditions.
Parisa Shahinrokhsar; Mohammadsmaeil Asadi
Abstract
Among the main causes of low water use efficiency are use of an improper irrigation method and applying excessive irrigation. To evaluate tape and furrow irrigation methods for soybean cultivation under different irrigation regimes, a field experiment was conducted in two years (2006-2007) at Gorgan ...
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Among the main causes of low water use efficiency are use of an improper irrigation method and applying excessive irrigation. To evaluate tape and furrow irrigation methods for soybean cultivation under different irrigation regimes, a field experiment was conducted in two years (2006-2007) at Gorgan Agricultural Research Station located in Golestan province in north of Iran. The experiment was laid out in a split plot design in the form of completely randomized blocks where each treatment was replicated three times. Irrigation systems of tape and furrow were set up as the main plots, and three irrigation regimes of 100%, 75% and 50% of total crop water requirement were allocated to the subplots. Comparison of water consumption (m3/ha) between the two systems showed that tape irrigation had 33 percent less water use than furrow irrigation. Results indicated that the soybean yield was not affected by irrigation systems. But, the different irrigation regimens had some impact on crop yield. Water use efficiency in the full irrigation (100 %) regime under drip tape irrigation was 1.6 times that of furrow irrigation system. In tape irrigation, mean water distribution uniformity (Ed) in full irrigation was 96% and in furrow irrigation it was 95%. Application efficiency (Ea) under tape irrigation was 84%, which was much higher than furrow irrigation. Also, based on the results, most of water losses in furrow irrigation systems were due to surface run off, while these losses were not observed in the tape irrigation. Overall, in drip tape irrigation, less water was consumed and water use efficiency increased compared to furrow irrigation