M. Akbari; Z. Seif; H. Zare Abyane
Abstract
Abstract
Evapotranspiration (ET) is one of the most important components of the water balance, it is also one of the most difficult to measure. Despite the importance of ET, methods to obtain values of ET are still limited. Conventional methods are very local, ranging from point to field scale. Estimates ...
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Abstract
Evapotranspiration (ET) is one of the most important components of the water balance, it is also one of the most difficult to measure. Despite the importance of ET, methods to obtain values of ET are still limited. Conventional methods are very local, ranging from point to field scale. Estimates of the ET over the entire area, especially for irrigated areas, are essential, as these can differ substantially depending on the crop and the management applied. Today, actual and potential evapotranspiration under different conditions can be estimated by using satellites and remote sensing (RS) techniques. So that in this research, recent twenty years metrological data was assessed and based on precipitation, temperature and wind speed, three period include drought, normal and wet years (2000, 1995 and 2007 respectively) was chosen. The actual and potential evapotranspiration was estimated from a time series of NOAA-AVHRR satellite images using the SEBAL (Surface Energy Balance Algorithm for Land) algorithm in Abshar irrigation system in Esfahan during the three selected years. The results show that the maximum evapotranspiration (8.1 mm/day for ETa and 9.5mm/day for ETp) occurs in 2000 as a drought year. Comparing the potential evapotranspiration results of SEBAL method with Hargreaves and FAO-56 Penman-monteith methods show that, SEBAL method and conventional methods has the same results under current condition, so remote sensing techniques can estimated actual evapotranspiration and produce high spatial coverage of important terms in the water balance for large areas, but at the cost of a rather sparse temporal resolution. As water is highly manageable in irrigation systems, it is an application typically suitable to establish improvements in irrigation water management at large scale such as basin and irrigation systems.
Keywords: Evapotranspiration, Remote sensing, Water management, Abshar irrigation system
S.H. Sadrghaen; J. Baghani; S.A. Haghayeghi Moghaddam; M. Akbari
Abstract
Abstract
This study was conducted to determine the best drip irrigation method for pepper cultivation with the objective of water saving and obtaining maximum yield. The study was done during two years. Experimental design was randomized complete blocks design (RCBD) in split plot with four replications. ...
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Abstract
This study was conducted to determine the best drip irrigation method for pepper cultivation with the objective of water saving and obtaining maximum yield. The study was done during two years. Experimental design was randomized complete blocks design (RCBD) in split plot with four replications. Three different drip irrigation methods; drip irrigation with in-line emitter tubes, drip irrigation (tape), and drip irrigation with porous pipes as main plot and three different amount of water (50, 75 & 100% water requirement) were as sub-plot. The result in the first year showed that the effect of irrigation levels on the characteristics of plant except yield was no significant (α < 0.01), but the effect of irrigation methods on water use efficiency was significant (α < 0.05) .In the second year the effect of irrigation levels and irrigation methods on yield was significant (α < 0.05), but the effects of combination irrigation levels and methods on yield was not significant. The result in two years showed that the pepper is a sensitive plant to water deficit. The drip irrigation (tape) and 100% water requirement treatment had the highest yield and water use efficiency. The result also showed that the porous pipes had no good efficiency. According to the results, the best option for pepper is drip irrigation (tape) with using 100% water requirement.
Keywords: Drip irrigation, Pepper, Porous pipes, Tape irrigation, Water use efficiency
H. Sadrghaen; M. Akbari; H. Afshar; M.M. Nakhjavanimoghaddam
Abstract
Abstract
This study was conducted to determine the impacts of different drip irrigation method and amount of water on yield and water use efficiency of tomato in Varamin Agricultural Research Center, Iran. The study was done during two years. Experimental design was randomized complete blocks design ...
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Abstract
This study was conducted to determine the impacts of different drip irrigation method and amount of water on yield and water use efficiency of tomato in Varamin Agricultural Research Center, Iran. The study was done during two years. Experimental design was randomized complete blocks design (RCBD) in split plot with three replications. Three different drip irrigation method; surface drip irrigation with in-line emitter tubes, surface drip irrigation (tape), and subsurface drip irrigation (tape) as main plot and three different amount of water (50, 75 & 100% water requirement) were as sub-plot. The result showed that subsurface drip irrigation (tape) and 100% water requirement treatment has the highest yield, but there was no significant difference between it and surface drip irrigation with in-line emitter tubes and 75% water requirement treatment. Water use efficiency in surface drip irrigation with in-line emitter tubes with 75% water use and subsurface drip irrigation (tape) with 100% water use were greater than other treatments. According to the results, under no limitation on water resources, the best option is subsurface drip irrigation (tape) with using 100% water requirement and under water limitation the best option is surface drip irrigation with in-line emitter tubes using 75% water requirement.
Keywords: Micro Irrigation, Water Use Efficiency, Tomato, Varamin
M.M. Nakhjavanimoghaddam; H. Dehghanisanij; M. Akbari; H. Sadrghaen
Abstract
Abstract
In order to evaluate the effects of different depths of irrigation by sprinkler irrigation system on water use efficiency (WUE) of new early maize cultivar KSC302, an experiments was carried out in Karj during 2006 and 2007. Experimental design was split plot based on randomized complete blocks ...
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Abstract
In order to evaluate the effects of different depths of irrigation by sprinkler irrigation system on water use efficiency (WUE) of new early maize cultivar KSC302, an experiments was carried out in Karj during 2006 and 2007. Experimental design was split plot based on randomized complete blocks with three replications. Main plots were three irrigation levels: 75%, 100% and 125% ETc (estimating by Penman Monteith model) and sub plots were three plants densities: 80000, 90000 and 100000 plants per hectare. The results showed that increasing in the levels of irrigation from 75% ETc to 125% ETc, has a significant effect on yield. Yield increase in 125% ETc treatment indicated that water requirement has not fully supplied in 100% Etc treatment, and the effect of deficit irrigation was intensified in 75% ETc treatment. Maximum maize WUE was (1.159 and 1.044 kg m-3) for 100% ETc treatment in the first and second years, respectively. Maize WUE of 1.1 kg m-3 was recommended as optimum level to be considered in cropping system for Karaj. Applied irrigation depth for optimum level of maize WUE was 900 mm.
Keywords: Single cross 302 maize, Sprinkler irrigation, Yield , Water use efficiency
