s h; m kh; m m
Abstract
Considering water resources deficiency, optimum use of water is very important and has led to recognition of the significance of water productivity. This study was carried out for evaluation of three irrigation systems including surface, subsurface tape drip irrigation and sprinkler irrigation for ...
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Considering water resources deficiency, optimum use of water is very important and has led to recognition of the significance of water productivity. This study was carried out for evaluation of three irrigation systems including surface, subsurface tape drip irrigation and sprinkler irrigation for corn. The experiment was conducted in 2007, 2008, and 2009 at Irstea Research Institute located in Montpellier (southeastern France). Five experimental treatments included surface drip irrigation (full irrigation (FI) and deficit irrigation (DI)), subsurface drip irrigation with lateral spacing of 120 and 160 cm, and sprinkler irrigation. For treatments evaluation, different productivity indices i.e. WP, BPD, NBPD, and B/C were used. Results showed that in 2007 FI was more economical than DI and sprinkler irrigation, and had more net benefit. Grain yield from 13800 kg/ha in sprinkler irrigation increased to 16400 and 17400 kg/ha in DI and FI, respectively. In 2008, subsurface irrigation treatment was better than sprinkler irrigation according to above indices. In 2009, water productivity of subsurface drip irrigation was more than sprinkler irrigation, but none of treatments had net benefit. In 2008 and 2009, water used in subsurface drip irrigation decreased at least 16% and grain yield increased at least 18% as compared with sprinkler irrigation. Considering different conditions, such as water resources of Iran, use of subsurface drip irrigation system for row crops such as corn is recommended.
h p; m kh; m.h b; p sh
Abstract
As irrigation system installation is expensive and time consuming, it would be better to have an estimate of the water content provided by the system in the active root zone before designing an irrigation system. In this study, HYDRUS-2D performance was assessed under a tape irrigating in-situ with a ...
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As irrigation system installation is expensive and time consuming, it would be better to have an estimate of the water content provided by the system in the active root zone before designing an irrigation system. In this study, HYDRUS-2D performance was assessed under a tape irrigating in-situ with a heavy textured and relatively heterogeneous soil in Rasht region. Three different flows i.e. 2.5, 5, and 6 L/h/m and four irrigation times i.e. 1, 2, 3, and 4 hours were considered as the main treatments with three replications. Measured data were compared with the simulated results for both the whole soil profile and the part under the tape using two statistical indices, i.e. RMSE and efficiency factor (EF). The model performance was evaluated as good, with a low average RMSE of 0.0123 and 0.0236 cm3/cm3 for the whole soil profile and under the tape, respectively, with the corresponding average EF values of 77% and 76%, for this soil texture. Overall, the model could satisfactorily simulate soil moisture in a heavy textured and heterogeneous soil.
h a; m kh; a a; m r
Abstract
In recent years, the groundwater resources in Guilan province have played an important role in irrigating paddy fields. The goal of this study was to evaluate temporal and spatial variations of groundwater quality in a 4-year period using ordinal kriging. Water samples for this study ...
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In recent years, the groundwater resources in Guilan province have played an important role in irrigating paddy fields. The goal of this study was to evaluate temporal and spatial variations of groundwater quality in a 4-year period using ordinal kriging. Water samples for this study were collected from 130 wells across Guilan province, in September and March from 2003 to 2006. Maps of EC and TDS in the region were prepared using ArcGIS software. The maps showed that regarding TDS, western parts of Guilan province had no problem of groundwater TDS (less than 500 mg/L), whereas central and eastern parts had a moderate TDS (500-1000 mg/L). Results showed that salinity increased with time (except in 2005, due to more rainfall in 2004) and the highest EC was recorded in the central zone, particularly areas neighboring eastern parts of Guilan province. Delineated areas of EC and TDS classes were determined in each year. EC in the east and some other parts of Guilan province covering 23 to 34% of the studied area was between one to 1.5 dS/m which have a negative impact on the yield of sensitive plants such as rice. Uncontrolled digging of deep wells and over exploitation of groundwater can be regarded as the main cause of increasing salinity in paddy areas of Guilan province.