Rasoul asadi; Frzad hasanpour; Mitra Mehrbani; amin baghizadeh; Fatemeh Karandish
Abstract
Using proper irrigation management leads to optimum utilization of water, soil, and fertilizer and production of high yield and quality products. In order to investigate the effect of irrigation intervals and surface and subsurface drip irrigation systems on growth indicators of Rosmarinus officinalis ...
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Using proper irrigation management leads to optimum utilization of water, soil, and fertilizer and production of high yield and quality products. In order to investigate the effect of irrigation intervals and surface and subsurface drip irrigation systems on growth indicators of Rosmarinus officinalis L., a field experiment was carried out during 2015 growing seasons at an experimental farm in Kerman city. The treatments were laid out in split plot using a Randomized Complete Block Design with three replications. The treatments comprised three irrigation levels (I 1 =25, I 2 =40 and I 3 =55 mm evaporation from class A pan) in the main plots, and two drip irrigation systems (surface and subsurface) in the sub plots. The results showed that I 2 in comparison with I 1 treatment led to 44 mm water saving. However, dry weight, height of plants, number of shoots per plant and leaf area index decreased by 12.9%, 12.6%, 13.6% and 5.3 percent, respectively, while water use efficiency increased 3.6 percent. Also, results showed that water use efficiency, dry weight, height of plants, number of shoots per plant, and leaf area index increased by, respectively, 15.1%, 18.3%, 9.7%, 12.5% and 15 percent in subsurface drip irrigation compared to surface method. Therefore, for Rosmarinus officinalis L. cultivation in Kerman area, application of I 2 in subsurface drip irrigation system is the best way to increase the water use efficiency for the drought years.
halime piri
Abstract
In order to study the effects of different levels of irrigation, nitrogen fertilizer, and irrigation methods on yield and yield components of onions, a factorial split plot experiment was conducted in a randomized complete block design with three replications for two years at a research farm in ...
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In order to study the effects of different levels of irrigation, nitrogen fertilizer, and irrigation methods on yield and yield components of onions, a factorial split plot experiment was conducted in a randomized complete block design with three replications for two years at a research farm in Zahak, Iran. Fertilizer treatments were included four levels of nitrogen fertilizer of from urea fertilizer (130, 97.5, 65 and 32.5 kg/ha). Onion seedlings were planted in 2014 and 2015 and irrigation was carried out in the form of surface gravity irrigation, surface drip irrigation and subsurface drip irrigation. The highest yield and water productivity were obtained in the subsurface drip irrigation system (28.42 ton/ha and 5.9 kg/m3/ha) and the least in surface irrigation (19 ton/ha and 33.3 kg/m3/ha). Reducing the amount of nitrogen fertilizer to less than plant requirement reduced the yield of bulbs and the efficiency of onions. The highest yield and water productivity were observed in 100% nitrogen application (31.59 ton/ha and 4.75 kg/m3/ha) and the lowest was in 25% nitrogen fertilizer treatment (16.12 ton/ha and 2.67 kg/m3/ha).The effect of irrigation water on the yield of onion tubers and its efficiency showed that decreasing the depth of irrigation water to values lower than the water requirement of the plant decreases yield and efficiency, but, no significant effect was observed between treatments 100% and 75% of the plant water requirement. Therefore, according to the results, due to the lack of water in the region, irrigation of this plant can be done with 75% of the plant water requirement, without a significant effect on the yield. Also, due to the high production potential in subsurface drip irrigation and reduction of evapotranspiration, this irrigation method could be used for onions in the region. The best treatment for nitrogen fertilizer use is the 100% nitrogen fertilizer requirement, especially in water tension. Considering the contamination of subsurface waters due to the excessive use of nitrogen fertilizers and the prevention of nitrate accumulation in the bulbs, it seems that using drip irrigation improves nitrogen fertilizer management.
bakhtiar karimi; parva mohammadi
Abstract
One of the most important parameters in designing, managing, and operating surface and subsurface drip irrigation systems is the advance velocity of the wetting (moisture) front in soil, which enormously affects the performance of these systems. Emitter discharge, soil type (soil texture and structure) ...
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One of the most important parameters in designing, managing, and operating surface and subsurface drip irrigation systems is the advance velocity of the wetting (moisture) front in soil, which enormously affects the performance of these systems. Emitter discharge, soil type (soil texture and structure) and initial moisture content are the main factors affecting advance velocity under drip irrigation. Experiments were carried out in a transparent plexiglass tank (0.5 m*1.22 m*3 m) using three different soil textures (light, heavy, and medium). The drippers were installed at 4 different soil depths (surface, 15 cm, 30 cm, and 45 cm). The emitter outflows were considered 2.4, 4, and 6 L/hr. A simulation model was developed using artificial neural network (ANN) for predicting advance velocity of the wetting front (horizontal, downward, and upward direction) under point sources in surface and subsurface drip irrigation. The variables affecting wetting pattern included emitter discharge, emitter installation depth, application time, saturated hydraulic conductivity, soil bulk density, initial soil moisture content, and the proportions of sand, silt and clay in the soil. The results of the comparisons between the simulated and measured values showed that the ANN model was capable of predicting the advance velocity of the wetting front in different directions with high accuracy. The values of Root Mean Square Error (RMSE) varied from 0.09 to 0.35, from 0.02 to 0.17, and from 0.08 to 0.25 cm/min for horizontal, downward and upward velocity, respectively. Also, the values of Mean Absolute Error (MAE) varied from 0.06 to 0.27, from 0.02 to 0.07, and from 0.05 to 0.12 cm/min for horizontal, downward, and upward velocity, respectively. Using these models in designing and operating surface and subsurface drip irrigation systems could improve system performance.
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.