Research Paper
Abdolhamid Mohebi; Majid Alihouri
Abstract
In recent years, larg parts of agricultural lands in the country have been at the risk of degradation because of quantative and qualitative limitations of water resources and soil salinization. Therefore, to increase plant yield per unit of consumed water, proper planning and selection of adaptable irrigation ...
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In recent years, larg parts of agricultural lands in the country have been at the risk of degradation because of quantative and qualitative limitations of water resources and soil salinization. Therefore, to increase plant yield per unit of consumed water, proper planning and selection of adaptable irrigation method for optimum use of the limited water resources is necessary. This study was carried out in randomized complete blocks design with four treatments and three replications at Haji Abad Agricultural Research Station during four years. The treatments of irrigation included surface (basin) and drip irrigation with irrigation depth equal to 75% and 100% net irrigation requirement based on cumulative evaporation from class A pan. The results showed that effects of irrigation treatments on fruit yield, leaf number, leaflet number, trunk perimeter, and plant canopy area were not significant, probably because the applied water based on pan evaporation was more than the actual plant water requirement. But, there was significant difference between water productivity, at 1% probability level. The maximum and minimum water productivity values were obtained in drip irrigation with irrigation depth equal to 75% and in the basin irrigation with a depth equal to 100% of the cumulative evaporation from the class A pan, respectively. The drip irrigation treatment with irrigation depth of 75% of cumulative evaporation from the class A pan is recommendable for date palm plantations.
Research Paper
Simindokht Ghasaemian; Ali Darijani; حسینی Hossini
Abstract
The high consumption of gas oil and electricity in utilization of water resources and the high share of agricultural water in the total water consumption of the county is one of the most important economic problems in agricultural sector. The aim of this study was to determine the effect of price changes ...
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The high consumption of gas oil and electricity in utilization of water resources and the high share of agricultural water in the total water consumption of the county is one of the most important economic problems in agricultural sector. The aim of this study was to determine the effect of price changes of energy carriers (electricity and gas oil) on each cubic meter of water used in agriculture, the cost share of energy carriers (gas oil and electricity), water share, and cost of wheat production in Golestan province. To this end, using techniques of adjusted industrial cost accounting and Delphi approach, in three scenarios of "before the plan" (165 Rial/liter for gas oil and 20 Rial/unit for electric power), "during the plan" (1500 and 3500 Rial/liter gas oil and 140 Rial for unit of electrical power), and " complete elimination" (7900 Rial/liter for gas oil and 550 Rial/unit electrical power). The results showed that share of water cost would change from 4 and 12 percent "before the plan" to 42 percent (complete elimination of gas oil subsidy) and 84 percent (complete elimination of electric power subsidy). Implementation of the plan would increase the unit cost of wheat from 2120 Rial to 4420 Rial (complete elimination of gas oil subsidy) and 16890 Rial (complete elimination of electric power subsidy), respectively.
Research Paper
Mostafa Ghasemi; Kazem Arzani; Abbas Yadolahi; Hossin Hokmabadi
Abstract
Chlorophyll fluorescence is a non-destructive tool for estimation of the efficiency of photochemistry and photosynthesis status in plants and has extensively been used in assessing plants response to environmental stresses. The aim of this study was to evaluate the effect of drought stress on chlorophyll ...
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Chlorophyll fluorescence is a non-destructive tool for estimation of the efficiency of photochemistry and photosynthesis status in plants and has extensively been used in assessing plants response to environmental stresses. The aim of this study was to evaluate the effect of drought stress on chlorophyll fluorescence, chlorophyll content, chlorophyll index, and biomass in four pistachio seedling rootstocks grown under greenhouse conditions. The rootstocks were Pistacia vera cv. Badami-e-Zarand, P. vera cv Ghazvini, P. vera cv. Sarakhs, and P. mutica. The results showed that water stress reduced FV/Fm ratio (which is an indicator for the maximum efficiency of photosystem II), chlorophyll contents, and biomass in plants. Highest amount of FV/Fm ratio was observed in the control treatment (full irrigation) and had significant difference with the severe stress treatment. In most cases, there was no significant difference among studied rootstocks, except P. mutica that showed the highest quantum yield of PSII. The maximum and minimum chlorophyll concentrations in irrigation treatments were also obtained in the control and severe stress treatments, respectively. The effects of genotypes on the chlorophyll contents (a, b, total and CCI) were significant and the highest and the lowest of these parameters belonged to P. mutica and P. vera cv. Sarakhs, respectively. In the case of shoot, root, and leaf dry weight, the rootstocks P. mutica and P. vera cv. Badami showed lower reduction under water stress. Based on the results, water stress had negative effects on pistachio seedling rootstocks and P. mutica showed more resistance than the other genotypes.
Research Paper
Mohammadjavad Fereydooni; Hooshang Farajee; Hamidreza Oliaee
Abstract
This study was carried out in Yasouj research station to examine the effects of urban sewage and nitrogen on absorption of mineral nutrients in sweet corn, in 2009. Experimental factors consisted of five irrigation treatments including: (I1)common irrigation water from emergence (SG=10) to milk stage ...
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This study was carried out in Yasouj research station to examine the effects of urban sewage and nitrogen on absorption of mineral nutrients in sweet corn, in 2009. Experimental factors consisted of five irrigation treatments including: (I1)common irrigation water from emergence (SG=10) to milk stage (SG=82), (I2)from SG=10 to tasseling (SG=50) with sewage effluent and from SG=50 to SG=82 with common irrigation water, (I3)from SG=10 to SG=50 with common irrigation water and from SG=50 to SG=82 with sewage effluent, (I4) alternate irrigation with common irrigation water and sewage effluent till stage (SG=82), and (I5)sewage effluent till stage (SG=82); and 3 nitrogen rates (N0=0, N80= 80 and N160=160 kg N ha-1). The treatments were laid in a split plot in a completely randomized block design with three replications. Results indicated that the effect of irrigation on macro and microelements concentrations was significant in forage and seed sweet corn. Maximum mineral nutrient absorption was in I5 and I4 while the minimum mineral nutrient absorption was in treatment I1.The effect of nitrogen fertilizer was significant on absorption of N, P, Fe, and Mn elements in forage and N in the seed. Maximum concentrations of those elements were in N80 and the minimum concentration was in N0. Interaction of irrigation and nitrogen fertilizer on N absorption of seed was significant. Maximum amount of N absorption of seed was in treatment I5N160 and amounted to 2.17 percent, while the was in treatment I1N0 and equaled 1.2 percent. The results indicated that application of sewage effluent reduced nitrogen fertilizer application rate in forage of sweet corn. Generally, applying urban sewage for food crops is not recommendable and has been warned in this field.
Research Paper
davod Akbari Nodehi; Aliakbar Azizizohan; Reza Rezaee
Abstract
In order to study the effects of deficit irrigation on tomato yield and to determine the production function and water use efficiency, an experiment was conducted based on randomized complete block design in three replications for two years, in Mazandaran province. Irrigation treatments were based on ...
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In order to study the effects of deficit irrigation on tomato yield and to determine the production function and water use efficiency, an experiment was conducted based on randomized complete block design in three replications for two years, in Mazandaran province. Irrigation treatments were based on 0, 20, 40, 60, 80 and 100% of water requirements. The minimum and maximum yield belonged to I0 and I100 treatments. Water use efficiency and irrigation water use efficiency in I100 treatment was significantly higher than the other treatments. The results showed that the maximum yield of tomato occurred when full water requirement was provided. Therefore, I100 treatment with 5635 m3.ha-1 of water consumption and tomato yield of 45,020 kg.ha-1 was the best treatment and can be recommended to farmers where water resources are not limited. Water use efficiency (WUE) and irrigation water use efficiency (IWUE) were in the range of 5-9.25 and 9.2-14.6 kg m-3, respectively. The two-year average of yield response factor (Ky) for tomato was 1.18.
Research Paper
Maryam Mazidi; Isa Maroofpour
Abstract
There are different methods for measuring soil moisture. The TDR method (Time Domain Reflectometry) is a relatively modern method in which soil water content is estimated based on the velocity of electromagnetic waves. The effect of soil compositions on calibration curve necessitates further calibration ...
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There are different methods for measuring soil moisture. The TDR method (Time Domain Reflectometry) is a relatively modern method in which soil water content is estimated based on the velocity of electromagnetic waves. The effect of soil compositions on calibration curve necessitates further calibration of the instrument. The aim of the current study was to present a calibration equation for soils with five different amounts of organic matter. This study was carried out in laboratory on three soil textures i.e. light, medium, and heavy. The results showed that the moisture measured in windows of 10 NS was more accurate than that of other windows. Also, in low moisture contents, the amount of moisture measured by TDR was higher than the gravity method and the difference between the two methods increased with increase in the clay and organic matter content. With higher organic matter in soil, RMSE increased. It was shown that soil organic matter content influenced the accuracy of TDR. Analyses of variance showed significant difference between TDR and gravity method for moisture content of soils with different amounts of organic matter (P<0.05). Finally, calibration curves with high coefficients of regression were obtained for the studied soil textures.
Research Paper
hadi varvani; Mohammadamin Moradi; Javad Varvani
Abstract
Evapotranspiration is one of the main components of hydrologic cycle and its data is needed to determine the irrigation demand. Artificial intelligence system has been widely used to estimate the hydrological events during the recent decades. The aim of this research was to use the regression tree method ...
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Evapotranspiration is one of the main components of hydrologic cycle and its data is needed to determine the irrigation demand. Artificial intelligence system has been widely used to estimate the hydrological events during the recent decades. The aim of this research was to use the regression tree method to estimate the reference evapotranspiration (ETo) and to compare with FAO-Penman-Monteith method in different climatic condition across Iran. One of advantages of the Regression Tree model compared to other intelligent models like Neural Networks is that it lacks the time-consuming process of trial-and-error; and representing the results mathematically. Different data such as monthly minimum, average and maximum temperature, relative humidity, wind speed, and solar radiation were used as input to the model. Finally, the results showed that regression tree model can estimate the reference evapotranspiration for different climatic conditions including arid to semi-arid, temperate, and cold climate conditions with 0.78, 0.8, and 0.89 correlation coefficients, respectively.
Research Paper
Razieh Sarabadabani; Mohammadreza Bihamta; Zahra Shobar; Maryam Shahbazi; Amin Karami; Mohammadreza Naghavi; Hamidreza Nikkhah; Hossein Dehghanisanij
Abstract
To study the effects of terminal drought stress on yield and some physiological traits of barley (Hordeum vulgare L.), four cultivars, namely, Nosrat, Fajr 30, Yousef, and Moroco, and 2 advanced lines i.e. 17 and 67 were evaluated under terminal drought stress condition in Agriculture Biotechnology Research ...
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To study the effects of terminal drought stress on yield and some physiological traits of barley (Hordeum vulgare L.), four cultivars, namely, Nosrat, Fajr 30, Yousef, and Moroco, and 2 advanced lines i.e. 17 and 67 were evaluated under terminal drought stress condition in Agriculture Biotechnology Research Institute of Iran, in 2011. The glasshouse experiment was arranged as a split-plot in a randomized complete block design with three replications. The results of the experiment revealed that total biomass, grain yield, yield components, harvest index (HI), relative water content (RWC), leaf water potential (WP), stomatal conductance, and chlorophyll content significantly decreased while relative water loss (RWL), unfilled grains per spike, canopy temperature and electrolyte leakage significantly increased in drought condition. Yousef and Moroco could be considered as, respectively, drought-tolerant and drought-sensitive genotypes, with grain yield (575 and 142 g.m-2), relative water content (78.2% and 69 %) and decrease in rate of stomatal conductance (63% and 93 %) in drought stress, respectively. The results of principal component analysis suggested that some of the physiological traits such as RWC, stomatal conductance, and canopy temperature, as the first important component, could be used for genotype screening under terminal drought stress.
Research Paper
Jaefar Nikbakht; Marzieh Khadehrouyan; Afshin Tavakoli; Mehdi Taheri
Abstract
The purpose of this study was to evaluate the effect of deficit irrigation with magnetized water on yield and water productivity of maize. The research was carried out as factorial with 2 factors arranged in complete randomized blocks design with 4 replications in the greenhouse of Zanjan Agricultural ...
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The purpose of this study was to evaluate the effect of deficit irrigation with magnetized water on yield and water productivity of maize. The research was carried out as factorial with 2 factors arranged in complete randomized blocks design with 4 replications in the greenhouse of Zanjan Agricultural and Natural Resources Research Center from July to September 2011. The factors were the amount of irrigation water consisting of 100%, 80%, 60% and 40% of crop water requirement (T1 (control treatment), T2, T3, T4) and water type consisting of magnetized and tap water. Based on the results, passing the tap water through a magnetic field reduced the amount of calcium and chlorine ions by 41.11 and 35.5 mg/lit, respectively. Leaf area, leaf chlorophyll content, total wet and dry mass, and water productivity of plants irrigated with magnetized water increased by 9.5%, 10.68%, 8.31%, 17.41%, and 9% compared to plants irrigated with tap water. These differences were statistically significant. The results showed that deficit irrigation caused significant difference at 4 levels in leaf area, leaf chlorophyll content and total wet and dry mass. Total wet weight and water productivity (based on total wet weight) in the magnetized and tap water treatments were 31.56 ton/ha and 14.22 kg/m3, and 28.94 ton/ha and 12.94 kg/m3, respectively.
Research Paper
Hamed Nozari; Majid Heydari; Saeed Azadi
Abstract
One of the agricultural development strategies is to establish irrigation and drainage networks that will lead to higher productivity and greater economic benefits. In the present study, by using system dynamics approach, a computer model was developed that can estimate the crop yield of an irrigation ...
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One of the agricultural development strategies is to establish irrigation and drainage networks that will lead to higher productivity and greater economic benefits. In the present study, by using system dynamics approach, a computer model was developed that can estimate the crop yield of an irrigation network according to the quantity and quality of simulated irrigation water and to estimate the net profit of the products. In order to calibrate and validate the model results, the data collected from the research lands of the right side of Abshar Irrigation Network were used. After statistical analysis and calculation of RMSE, relative error, the standard error, and correlation coefficient, adjustment between the measured and simulated network products performance was calculated. The value of these product indexes according to the conditions of the network was estimated as 209.98 kg/ha, 1.36 percent, 0.007, and 0.99, respectively. The results showed that the model had reasonable accuracy in simulation of the irrigation network, its cropping pattern, and definition of other scenarios. Also, an initial check showed that groundwater exploitation in the mentioned area was more than the permitted limit. Considering the importance of water resources, two scenarios were defined i.e. irrigation according to water requirement of crops and irrigation based on limitation of exploiting groundwater resources. Analysis of the results showed that the average of the products income to cost ratio for irrigation of the network in 2006-2007, the first scenario, and the second scenario was, respectively, 2.58, 2.88, and 2.75.
Research Paper
Mohammad Kafi; Farzad Hoseinpanahi
Abstract
A field experiment was conducted to evaluate wheat response to low irrigation at the Ferdowsi University of Mashhad, in 2011. Experimental design was split plot with 7 irrigation treatments (main plot), 2 cultivars (sub plot), and 3 replications. Irrigation treatments included full irrigation (FI), without ...
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A field experiment was conducted to evaluate wheat response to low irrigation at the Ferdowsi University of Mashhad, in 2011. Experimental design was split plot with 7 irrigation treatments (main plot), 2 cultivars (sub plot), and 3 replications. Irrigation treatments included full irrigation (FI), without irrigation during spring (NI), irrigation at stem elongation and pollination stages (SP), irrigation at stem elongation and beginning of grain filling stages (SG), irrigation at pollination and beginning of grain filling stages (PG), irrigation at stem elongation, pollination and beginning of grain filling stages (SPG), irrigation at stem elongation, pollination and beginning and middle part of grain filling stages (SPGG). The varieties included Pishgam (drought-resistant) and Gascogne (drought-susceptible). The Results showed that the grain yield of SP، SG، PG، SPG و SPGG treatments decreased by 36%, 40%, 47%, 31%, and 17% compared with the control (FI), whereas their water use decrement were 59%, 58%, 57%, 49%, and 38%, respectively. The drought-resistant cultivar had higher biological and economic yield than the drought-susceptible one, but the biological yield difference between them was more than their economic yield (14% vs. 5%). The highest and the lowest rates of WUE were related to SPGG (1.71) and NI (0.69) treatments. In overall, stem elongation and pollination were the most drought sensitive stages based on this experiment results, therefore, in order to reach high yield under water shortage, irrigation at both of these stages are essential.
Research Paper
Ali Reza Tavakoli
Abstract
In order to improve irrigation water productivity and to allocate the saved water to limited irrigation of the adjacent areas, different deficit irrigation methods were studied under surface and sprinkler irrigation systems for two wheat cultivars (Pishtaz and Shiraz), during 2006-07, in Selseleh region ...
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In order to improve irrigation water productivity and to allocate the saved water to limited irrigation of the adjacent areas, different deficit irrigation methods were studied under surface and sprinkler irrigation systems for two wheat cultivars (Pishtaz and Shiraz), during 2006-07, in Selseleh region located in Lorestan province, Iran. The objectives of this study were to find the optimum water depth in sprinkler irrigation and non-effective irrigation in surface irrigation. Different levels of irrigation water were studied under sprinkler irrigation by using a single source. The treatments of surface irrigation included full irrigation, withholding the first irrigation in spring, withholding the first and third irrigation in spring time. The grain yield, irrigation water use, and water productivity were measured in different treatments. Under sprinkler irrigation, optimum level of deficit irrigation was realized with 29.4% of full irrigation treatment (220.5 mm). Under surface irrigation, withholding of the first spring irrigation (78 percent of full irrigation) was the optimum treatment. Under surface irrigation, deficit irrigation led to 22% irrigation water saving and 3.3% increase in grain yield. Root expansion in the deficit irrigation treatments and, consequently, increase in effective soil moisture availability limited grain yield reduction. Under deficit irrigation, deep root expansion was 10.5 percent more than full irrigation condition. Increasing the effective soil depth prevented yield decline. Water saving by deficit irrigation can be used for single irrigation of adjacent rainfed areas (at planting time or critical stages of spring time), which increases total water productivity by 9.3%.
Research Paper
Mohsen Dehghani; Majid Jafaraghaee; Reza Mohammadikia
Abstract
Due to the deficiency of available water resources in our country, use of unconventional water seems to be necessary. In this regard, in order to study the effect of irrigation water salinity on yield and yield components of three varieties of cotton, this experiment was carried out in a randomized complete ...
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Due to the deficiency of available water resources in our country, use of unconventional water seems to be necessary. In this regard, in order to study the effect of irrigation water salinity on yield and yield components of three varieties of cotton, this experiment was carried out in a randomized complete blocks design and three replications in Rodasht Agricultural Research Station during 2 years. The main variable studied was Electrical Conductivity of irrigation water at four levels i.e. 4, 7, 10, and 13 dSm-1, and the sub-main factor was cotton varieties that included B557, Tabladila, and Deltapain 16. Statistical analysis of the results showed that the effects of salinity (EC) as well as some minerals, especially sodium ions, in irrigation water were significant (at the 1% level) on the boll yield, water consumption, water use efficiency, weight of 10 bolls, the number of bolls in each plant, and the number of green plants. Also, yield, irrigation water use efficiency, boll weight, number of bolls per plant, and the number of germinated plants of the studied varieties differed significantly.
Research Paper
Ebrahim Babaean; Mehdi Homaee; Aliakbar Norouzi
Abstract
Monitoring soil water content as one of the important components of drought monitoring, especially in agriculture, is highly important to study the climate changes in Iran. In this study, we proposed a method to retrieve and monitor soil surface water content using microwave remote sensing data. The ...
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Monitoring soil water content as one of the important components of drought monitoring, especially in agriculture, is highly important to study the climate changes in Iran. In this study, we proposed a method to retrieve and monitor soil surface water content using microwave remote sensing data. The study was based on 8 images of ASAR C-band in global monitoring (GM) mode and horizontal-horizontal (HH) polarization, acquired January 2012 to March 2012, as part of Zanjanrood watershed located in Zanjan province. Total backscattering coefficient () contributed by soil was calculated. The relationship between processed RADAR signals and TDR based soil surface water content measurements was investigated using spatial autocorrelation (Morans Index) and modeling spatial relationships (ordinary least square, OLS). A significant coefficient of determination (R2=0.68**) was observed between both volumetric water content and total backscattering. Cross validation of the results indicated that the model had an acceptable performance with the RMSE and relative error of 0.032 cm3 cm-3and 11%, respectively. However, the proposed model had a tendency to slightly underestimate (MBE=0.011 cm3cm-3) the estimations. In all, ASAR GM data GM has the potential of being used to retrieve soil water content under no vegetation cover condition.
Research Paper
Mahboubeh Aghajani; Maryam Navabian; Majid Vazifehdost; Mojtaba Rezaee
Abstract
In recent years, discharge of Sefidroud River, which is the main source of agricultural water in Guilan province, has been decreasing because of construction of several dams in the upstream of Sefidroud basin. The future of rice production will depend on appropriate management strategy for optimization ...
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In recent years, discharge of Sefidroud River, which is the main source of agricultural water in Guilan province, has been decreasing because of construction of several dams in the upstream of Sefidroud basin. The future of rice production will depend on appropriate management strategy for optimization of water consumption in the paddy fields. In this research, to maximize water productivity in paddy fields, two optimal models were selected for irrigation management as fixed interval irrigation in the entire growing season and variable interval irrigation in different physiological growth stages of Hashemi variety, using SWAP model and Genetic Algorithm (GA). After validation of SWAP model, the chosen values were optimized by GA. In the optimal models, irrigation water depths and rice irrigation intervals were selected as the decision variables in different crop growth stages. Periodic irrigation management with fixed interval i.e. 7.33 days during the growing season, showed the maximum efficiency of irrigation water. However, the optimal variable intervals were 6.53, 4.60, 4.31 and 7.74 days during establishment, tillering stage, maturity, and harvest respectively. Finally, for saving of water, improvement of irrigation water productivity, reduction of evapotranspiration, proper irrigation interval in Sefidroud irrigation network, and ease of measurement of inflow water volume, a fixed irrigation interval of 8 days and irrigation depth of 52, 30, 40 and 12 mm in, respectively, establishment stage, tillering, maturity, and harvest stages was recommended. The highest water productivity obtained was 1.59 kg/ m3.