Irrigation
Seyed Abolghasem Haghayeghi Moghaddam; Fariborz Abbasi; Abolfazl Nasseri; Peyman Varjavand; Sayed Ebrahim Dehghanian; Mohammad Mehdi Ghasemi; Saloome Sepehri; Hassan Khosravi; Mohammad Karimi; Farzin Parchami-Araghi; Mustafa Goodarzi; Mokhtar Miranzadeh; Masoud Farzamnia; Afshin Uossef Gomrokchi; Moinedin Rezvani; Ramin Nikanfar; Seyed Hassan Mousavi fazl; Ali Ghadami Firouzabadi
Abstract
Introduction
The basic strategy to mitigate water crisis is to save agricultural water consumption by increasing productivity, which will result in more income for farmers and sustainable production. Due to the economic importance of barley production in the country, it is necessary to study the volume ...
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Introduction
The basic strategy to mitigate water crisis is to save agricultural water consumption by increasing productivity, which will result in more income for farmers and sustainable production. Due to the economic importance of barley production in the country, it is necessary to study the volume of irrigation water and water productivity to produce this strategic product. Based on extensive field research on irrigation water management and application of different irrigation methods in barley farms, the innovations of this research were: a) measuring water consumed and determining water use efficiency in barley production, b) the up-to-date of the measurements and research findings, c) findings applicability for application in agricultural planning at the national and regional levels, d) the ability to development the findings in barley farms at the national level to improve water use efficiency. The hypotheses of this research are: a) barley irrigation water is various in different regions, b) water applied in barley farms is more than the required one, c) the water use efficiency of barley is different in the main production areas, and d) The applied water of barley is not the same in different irrigation methods. Therefore, the main objective of this study is to determine the water consumed and water use efficiency in barley production; to measure the water applied to barley farms in the main production areas; to compare the water measured in the production areas with the net irrigation requirement; and finally to determine water use efficiency of the barley in the main production areas in the Iran.
Materials and Methods
For this purpose, the volume of irrigation water and barley yield in 296 selected farms in 12 provinces (about 75% of the area under cultivation and production of barley in Iran) including Khuzestan, East Azerbaijan, Ardabil, North Khorasan, Fars, Khorasan Razavi, Tehran, Semnan, Markazi, Isfahan, Hamedan and Qazvin were measured directly. Farms in the mentioned provinces were selected to cover various factors such as irrigation method, level of ownership, proper distribution and quality of irrigation water. By carefully monitoring the irrigation program of selected farms during the growing season, the amount of irrigation water for barley during one year was measured. At the end of the season and after determining the average yield of barley during the 2020-2021 year, the values of irrigation water productivity and total water productivity (irrigation+effective rainfall) were determined in selected barley farms in each region. The volume of water supplied was compared with the gross irrigation requirements estimated by the Penman-Monteith method using meteorological data from the last ten years, and compared with the values of the National Water Document. Analysis of variance was used to investigate the possible differences in yield, irrigation water and water productivity in barley production.
Results and Discussion
To assess the reliability of statistical analysis, we evaluated the sufficiency of the number of measurements needed for both the quantity of irrigation water and the ley yield on the farms. Subsequently, we computed statistical indices, such as the mean and standard deviation. The results showed that the number of measurements of irrigation water and barley yield was to be 296 and 283, respectively, which was more than the number of measurements required for irrigation water (41 dataset) and yield (50 dataset). Therefore, the sufficiency of the data for the statistical analysis was reliable. The results showed that the difference in yield, volume of irrigation water and water productivity indices were significant in the mentioned provinces. The volume of barley irrigation water in the studied areas varied from 1900 to 9300 cubic meters per hectare and its average weight was 4875 cubic meters per hectare. The average barley yield in selected farms varied from 1630 to 7050 kg ha-1 and the average was 3985 kg ha-1. Irrigation water productivity in selected provinces ranged from 0.22 to 1.53 and its weight average was 0.90 kg m-3. Average gross irrigation water requirement in the study areas by the Penman-Monteith method using meteorological data of the last ten years and the national water document were 4710 and 4950 cubic meters per hectare, respectively. Irrigation efficiency of barley fields in the country is estimated at 62-65% without deficit irrigation.
Conclusion
In order to reduce water consumption and improve water productivity, it is suggested to manage water delivery to farms during the season and deliver water rights to them according to crops water requirements. To reduce water losses and enhance productivity in the barley farms, it is suggested the application of modern irrigation systems according to the farms conditions with the suitable operation; and modification and improvement of surface and traditional irrigation methods. Note that, water is only one of several necessary and effective inputs in the optimal and economic production of barley. On the other hand, attention should be paid to the optimal application of other inputs including: seeds, fertilizers, equipment and tools etc.
Irrigation
M. Goodarzi; F. Abbasi; A. Hedayatipour
Abstract
IntroductionThe lack of water resources and increase in water demand are among the effective factors in the imbalance of the water resources in each region, and it is necessary to manage the proper use of available water resources in all activities. Water in the agricultural sector is one of the main ...
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IntroductionThe lack of water resources and increase in water demand are among the effective factors in the imbalance of the water resources in each region, and it is necessary to manage the proper use of available water resources in all activities. Water in the agricultural sector is one of the main factors of production, which should be conveyed by irrigation systems to the field level and made available for the plant roots. The necessity of macro-planning in water management and consumption imposes a comprehensive study of the amount of water consumed in the agricultural sector. Hence, this study was conducted with the objective of directly measuring and field-assessing the applied water, water productivity, and water footprint associated with the primary crops cultivated in Markazi Province, all managed by local farmers.MethodologyFor this purpose, 141 farms were selected in the major production areas of the main agricultural and horticultural crops of Markazi province with the coordination of the Agricultural Jihad centers. Then, the volume of water applied was measured without interfering in the irrigation scheduling of the users. To do so, first, the flow rate of the water source (canal, well, aqueduct or spring) was measured with a suitable device (flume and meter) in each of the selected farms. Then, by carefully monitoring the irrigation schedule of the farm, including the time of each irrigation, the number of irrigation throughout the year, as well as measuring the area under crop cultivation, the amount of water used by the crop was measured for each of the selected farms during the season. Also, based on the measured data, the amounts of blue, green and gray water footprints were determined for each of the examined crops. For this purpose, the blue, green and gray water footprints of different crops were calculated using the framework provided by Hoekstra and Chapagain (2008), and Hoekstra et al., (2011).Results and DiscussionThe irrigation intervals in the studied fields varied between 3 and 15 days with an average of 8 days and the average irrigation depth varied between 26.2 and 99 mm with an average of 67.8 mm in different crops. The results showed that the average volume of applied water for the studied crops in Markazi province was 10782 cubic meters per hectare. Also, the minimum and maximum amount of applied water for the evaluated crops was as follows: barley 3783 and 7232, alfalfa 10382 and 19797, beans 8280 and 17840, watermelon 5333 and 7174, walnuts 4420 and 29600, almonds 3850 and 13932, peaches 6872 and 17727, cherries 7050 and 14645, pomegranates 7156 and 20790, and grapes 5937 and 18168 cubic meters per hectare. Furthermore, the average value of irrigation water efficiency index and water footprint was as follows: barley 0.46 and 1642, alfalfa 0.92 and 700, bean 2924 and 0.24, watermelon 9.37 and 117, walnut 0.1 and 6706, almonds 0.16 and 6857, peach 2.48 and 242, cherries 0.73 and 875, pomegranates 1.33 and 636, and grapes 11.2 and 322. Based on the obtained results, the average total water footprint index was equal to 2102 cubic meters per ton. On average, the almond with a water footprint of 6857 cubic meters per ton had the highest share in allocating the water footprint in the crop production of the province. Whereas, the lowest water footprint related to the watermelon with a water footprint of 117 cubic meters per ton. he average values of the irrigation application efficiency index, irrigation water productivity, and water footprint for the examined farms were 72.5%, 1.79 kg/m3, and 2,102 m3/ton, respectively. In summary, the results indicate that the combined volume of irrigation water and beneficial rainfall in the irrigated fields within Markazi Province surpasses the actual water demand of the crops. This underscores the substantial impact of irrigation management on water utilization in the region.ConclusionOn average, the total volume of irrigation water and effective rainfall in irrigated fields and gardens in Markazi Province is more than the actual water requirement of the plant. In general, the results showed that irrigation management has a great impact on the amount of water use in the region. Based on the obtained results, considering that most of the farms and gardens receive water in an intermittent manner, in principle, no special attention is paid to the need for water and even effective rainfall, and the amount of water availability has the greatest impact on water consumption. Therefore, in order to reduce water consumption and improve water efficiency, it is suggested to manage the delivery of water to farmers during the season and according to their crop water needs. Also, the results of the water footprint can be used to improve water resource policies at the province level, land use studies, cropping pattern modification, and environmental sector policies.
Irrigation
A,. Uossef gomrokchi; J. Baghani; F. Abbasi
Abstract
Introduction: One of the modeling methods researchers have considered in various sciences in recent years is artificial neural network modeling. In addition to the artificial neural network and regression models, today, the capabilities of data mining methods have been used to improve the output results ...
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Introduction: One of the modeling methods researchers have considered in various sciences in recent years is artificial neural network modeling. In addition to the artificial neural network and regression models, today, the capabilities of data mining methods have been used to improve the output results of prediction models and field information analysis. Tree models (decision trees) along with decision rules are one of the data mining methods. Tree models are a way of representing a set of rules that lead to a category or value. These models are made by sequentially separating data into separate groups, and the goal in this process is to increase the distance between groups in each separation. Research shows that plant yield is a function of various plant, climatic, and water, and soil management conditions. Therefore, calculating the amount of plant yield and related indices follows complex nonlinear relationships that also have special difficulty in modeling. Considering that the response of irrigated wheat to different inputs in different climates by field method is time-consuming, costly, and in some cases impossible, so the introduction of an efficient model that can predict yield and analyze yield sensitivity to various parameters is a great help. It will be to solve this problem. This study aimed to develop and evaluate the capability of three models of the neural network, tree, and multivariate linear regression in predicting wheat yield based on parameters affecting its yield in major wheat production hubs in the country. Materials and Methods: The information used in this study includes the volume of water consumption and yield of irrigated wheat and the committees related to these two indicators in irrigated wheat fields under the management of farmers (241 farms) in the provinces of Khuzestan, Fars, Golestan, Hamadan, Kermanshah, Khorasan Razavi, Ardabil, East Azerbaijan, West Azerbaijan, Semnan, south of Kerman and Qazvin, which were harvested in a field study in the 2016-17 growing season. According to the Ministry of Jihad for Agriculture statistics, these provinces have the highest area under irrigated wheat cultivation in the country and cover about 70% of the area under cultivation and production of this crop in the country. One of the most widely used monitored neural networks is the Perceptron multilayer network with error replication algorithm, which is suitable for a wide range of applications such as pattern recognition, interpolation, prediction, and process modeling. In the present study, in order to develop the neural network, the capabilities of R software with Neuralnet package have been used. After the normalization step, the data were randomized. This step aims to have a set of inputs and outputs in which the input-output categories do not have a special system. After the randomization of the data, the amount of information that should be used in the network training process is determined. This part of the data was considered for training (70%) and another part for network test (30%). Perceptron neural network activator functions in the implementation of network training and testing. The hyperbolic tangent activity function has been used to limit the range of output data from each neuron and the pattern-to-pattern training process. In the present study and the neural network modeling capability, the tree model method has been used to predict wheat yield. Tree modeling is one of the most powerful and common tools for classification and forecasting. The tree model, unlike the neural network model, produces the law. One of the advantages of the decision tree over the neural network is that it is resistant to input data noise. The tree model divides the data into different sections based on binary divisions. Each data partition can be re-subdivided into another binary, and a model fitted to each subdivision. In this research, the capabilities of WEKA software have been used to run a tree model. It is worth noting that after grouping, the prediction model is applied to the grouped data. Results and Discussion: In this study, the efficiency of three models of the artificial neural network, multivariate linear regression, and tree model to predict the performance of irrigated wheat in major production areas in the country was evaluated based on field information recorded in 241 farms. The results showed that the coefficient of explanation of the model in predicting the yield of wheat production in the model of artificial neural network and a multivariate linear regression model was 0.672 and 0.577, respectively, which was applied by grouping the data by tree method. The coefficient of explanation has been increased to 0.762. The output results of the tree model showed that the major wheat production areas in Iran in terms of water consumption could be divided into four independent groups. Finally, it can be concluded that the tree model, considering the purposeful grouping in the input data, can be used as a powerful tool in estimating irrigated wheat yield in major wheat production areas in Iran. Conclusion: In this study, the need to use data mining methods in analyzing field information and organizing large databases and the usefulness of data mining methods, especially the decision tree in estimating wheat crop yield, were investigated and compared with other forecasting methods. The general results of the research show that purposeful separation of input data into forecasting models can increase the output accuracy of forecasting models. However, it is not possible to provide a general approach to selecting or not selecting a forecasting model in different regions. In some studies, neural networks have shown a high ability to predict the performance of different products, but it is important to note that if there is sufficient data and correct understanding of the factors affecting the dependent variable, the accuracy of the models can be applied by data mining methods. It also improved the neural network. In a general approach, considering the accuracy of estimating the predicted models under study, these techniques can be used to estimate other late-finding characteristics of plants and soil.
sonia zebardast; Seyed Hassan Tabatabaei; Fariborz Abbasi; Manouchehr Heidarpour; Carlo Gualtieri
Abstract
Introduction: It is important to understand the processes of diffusion and transporting solute in the furrow irrigation system, because of their role in diffusion of pollutants in the environment. Movement pattern of fertilizer from the source ofplants is usually under the effect of advection and turbulent ...
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Introduction: It is important to understand the processes of diffusion and transporting solute in the furrow irrigation system, because of their role in diffusion of pollutants in the environment. Movement pattern of fertilizer from the source ofplants is usually under the effect of advection and turbulent diffusion processes. Maximum solute diffusion length (SDL) is the minimum distance which materials such as a fertilizer, could uniformly spread in the whole flow cross section. The SDL depends on hydraulic properties, condition of vegetation and channel specifications. Velocity profile of furrows as a result of parabolic shape of the cross-section is different thanthe rivers and rectangular channels. The main objectives of this study were to investigate SDL in a permeable parabolic channel and evaluate the effect of different discharges and bed roughness on diffusion length in a parabolic cross-section of a furrow.
Materials and Methods: In this research, the effect of different levels of discharge and the bed roughness coefficient was studied on transverse diffusion coefficient (TDC) and the maximum solute diffusion length (SDL) in a parabolic channel with permeable and impermeable beds. The channel had a 10 m length, 0.5 m width and 0.3 m depth with a parabolic shape (similar tothefurrow irrigation system). Before entering the channel, the water flow passed the lattice filters to slow the flow. To increase the rate of flow development, the first half meter of the channel’s bed covered with gravels (maximum 5 cm thickness) and non-submerged woods. Three levels of discharge about were conducted including 5, 10 and 15 L/s as well as three levels of bed roughness coefficient including 0.2, 0.04 and 0.06. Different rates of roughness were created using various thickness of net and vegetation cover on the furrow’s bed and wall. This research was conducted in channels with beds of permeable and impermeable. In bed of with permeability, 15 holes with a diameter of 1.5 mm construct along the bed of channel. In this experiment, Sodium chloride as a tracer was injected to the water at the upstream cross section. The place of injection was 2.5 meters far from the channel inlet where flow was completely developed and water surface swings were constant. The tracer concentration in the water and the velocity profile were measured at eight cross sections along the channel including 3, 4, 5, 6, 7, 8, 9 and 9.5 m from upstream. The velocity profile was measured using Pitot tube. No specific equation is introduced to calculate the SDL. For this reason, dimensional analysis was used in this study.
Results and Discussion: The results show that, the values of TDC for different treatments ranged between 0.23 to 0.56 cm2/s in impermeable channel where it is 0.30 to 0.58 cm2/s in the permeable channel. Also the values of SDL ranged 108-170 m in impermeable channel and 91 -129 m in the permeable channel for different treatments. TDC has direct relation todischarge and bed roughness. In stationary bed roughness with increased discharge, and in stationary discharge with increasing bed roughness, TDC increased. Also In stationary bed roughness, discharge has positive and direct relation with SDL. However, in stationary discharge, roughness value has the negative relation with SDL. A statistical analysis of T-test indicated that the difference between the values of TDC and SDL in permeable and impermeable beds in the 1% level is significant. The Darcy Weisbach coefficient is the most important parameter in justifyingchanges SDL that this parameter depends on the velocity of flow, and the velocity of flow depends on discharge and shape of channel too. According to the results of the experiments and the regular values of discharge, infiltration and roughness coefficient in furrows, it was shown that the maximum solute diffusion length of furrows would be less than 70 meters.
Conclusions: The objective of this research was to develop an approach for the determination of solute diffusion in afurrow irrigation system where the cross section is parabolic. For this reason, solute diffusion length, in different bed roughness and inflow rate was studied. Eventually, an equation was developed to explain SDL in a permeable parabolic channel andthese experimental results could prove useful to predict the fertilizer transport in furrow irrigation method as well as other areas where mixing and contaminant decay is of interest.
farid feizolahpour; mehdi kouchakzadeh; fariborz abbasi; Mohammad nabi Gheibi; Rajab Choukan
Abstract
Introduction: Broadcast fertilization method increases fertilizer losses while results in lower nutrient absorption by plant roots. Fertigation is an effective method to increase water and fertilizer efficiency and to reduce the losses of nitrogen. Moreover, it allows farmers to apply the nutrients in ...
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Introduction: Broadcast fertilization method increases fertilizer losses while results in lower nutrient absorption by plant roots. Fertigation is an effective method to increase water and fertilizer efficiency and to reduce the losses of nitrogen. Moreover, it allows farmers to apply the nutrients in splits and few amounts in response to crop needs. In the present study, a field experiment was conducted to investigate the effects of split application of fertilizer in furrow fertigation on nitrogen losses and corn yield.
Materials and Methods: Field experiments were carried out factorially in a randomized complete block design with four replicates. Experimental treatments were consisted of three fertilizer splits (two, three, and four splits) and three levels of urea fertilizer (60, 80 and 100% of required urea fertilizer), which compared with the common method (broadcasting fertilizer) as used by farmers in the fields. Experiments were conducted on a one hectare field in 120 meter long and open end furrows. During the crop season, Irrigation water was applied in the same way for all fertigation treatments and the third type of the WSC flumes was used to measure the amount of input and output water in irrigation events. Moreover, for determining the indexes of uniformity of water distribution in carrying out fertigation experiments, the amount of infiltration into the soil was calculated using the Kostiakov-Louis equation. The parameters of this equation were determined using the water volume balance method. Injection of Urea fertilizer was done by using 40-liter barrels were placed at the beginning of Furrows. In this study, the injection of fertilizers was applied in the last 10 to 20 minutes of irrigation time.
Results and Discussions: Results showed that water distribution uniformities of low quarter and low half in all tests were very high. Such that the water low quarter distribution uniformities for all treatments were between 90.5 to 98.3 percent and the low half distribution uniformities of water for different treatments were between 94.4 to 99.0 percent. So, according to the high water distribution uniformity and injecting fertilizer in 20-10 minutes at the end of irrigation, it should be stated that the distribution uniformities of fertilizer, used in the experiments, were high too. Statistical analysis showed that nitrogen usage amount and interaction of splits-usage rates of fertilizer had a significant influence on run-off nitrogen losses. The most nitrogen losses were achieved in treatment using 100 percent of fertilization recommendation and there were not significant differences between 60 and 80 percent of fertilization recommendation. It is nothworthy that, in addition to the nitrogen loss by surface runoff, nitrogen deep percolation losses always are also considered. In fertigation treatments, because of high rate of nitrogen injection in short intervals at the end of irrigations, the amount of nitrogen in the surface layer (20-0 cm) was significantly higher than the lower depths and this could led to low percolation losses of nitrogen, but the broadcast fertilization method provided the highest percent of remaining nitrogen in the soil after fertilization, which almost is unusable for plant and in the case of over irrigation or rainfall, the risk of groundwater pollution could be raised. Besides, the results showed that application of nitrogen in 4 splits provided more grain yield compared to the 3 splits level. Also, grain yield of corn increased significantly with increasing nitrogen rate application. The fertigation treatments had better performance of water and fertilizer application efficiencies compared to broadcast fertilization method. The most grain yield was achieved in the fifth treatment by application of 100 percent of fertilization usage recommendation in three splits.
Conclusion: In this study, the effect of furrow fertigation on nitrogen losses and corn yield was studied under different splits and amounts of fertilizer consumption. Eventually, fertigation treatments were compared with traditional treatments (fertilizer broadcasting method). According to the obtained results, evaluate the interactions of the effect of split × N usage showed that, the fourth treatment (60% of fertilizer application in 4 splits) can be suggested, owing to its lower N losses by runoff. In addition there were no statistical significant differences of grain yield between the fourth and fifth treatments (100% of fertilizer application in 3 splits). Consequently, it can be concluded that by the usage of 60 percent of the recommended fertilizer application in four equal splits during the growing season, the potential of environmental pollution will be reduced while achieving optimal performance.
foroogh abbasi teshnizi; M. Kouchakzadeh; F. Abbasi
Abstract
Water for agriculture is one of the most important factors in arid and semi-arid areas and municipal wastewater treatment is an important resource for this purpose. Therefore, potential of transfer contaminations is a serious problem regarding use of treated wastewater for agriculture. Due to the risk ...
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Water for agriculture is one of the most important factors in arid and semi-arid areas and municipal wastewater treatment is an important resource for this purpose. Therefore, potential of transfer contaminations is a serious problem regarding use of treated wastewater for agriculture. Due to the risk of transfer contaminations through the use of wastewater, the study of transfer microbes in soil in recent decades has been of interest to researchers. In the present study, the transfer of bacteria fecal coliform was investigated in a lysimeter and the HYDRUS-1D model was used to simulate water flow and the fecal coliform in the soil. For calibration of the model and estimating the model input parameters, soil hydraulic and transport parameters, were inversely estimated. Results represented that the HYDRUS-1D with reasonably accurately simulated the outlet flow. To simulate the transfer of the bacteria in the soil, one site sorption model, two kinetic sites model (particle transport using attachment/detachment) and one kinetic site model were used. In the simulation of bacterial transfer, one site sorption model was selected as the proper model for this study. One site sorption model estimated solid-phase growth coefficient ( ) about sextuple more than liquid-phase. It showed that deposited cells had a higher division rate compared with the cell in liquid-phase. The calibrated model was used for surveying the effect various irrigation intervals and irrigation times on bacterial transfer. The results showed that by increasing irrigation times, more bacteria leached out from the soil. Also by increasing irrigation intervals, more bacteria observed in the soil profile, due to favorable environmental conditions and food for the bacteria growth. According to the results, the best interval and irrigation times were one day and four hours, respectively.
F. Abbasi; A.; N. Salamati
Abstract
Introduction: Application of simultaneous nitrogen fertilizer and water as fertigation in surface irrigation systems is developing. In fertigation is possible to increase water and fertilizer use efficiency and it allows growers to apply nutrients in split and small amounts throughout the season in response ...
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Introduction: Application of simultaneous nitrogen fertilizer and water as fertigation in surface irrigation systems is developing. In fertigation is possible to increase water and fertilizer use efficiency and it allows growers to apply nutrients in split and small amounts throughout the season in response to crop needs. In this study, sugarcane furrow fertigation experiments is carried out in Dehkhoda agro-industry company to improve fertilizer management, water and nitrogen use efficiency, and reduce urea fertilizer consumption.
Materials and Methods: Large scale furrow experiments were conducted on a plant field. Field experiments were carried out as split plot with a complete randomized block design. Experimental treatments consisted of three fertilizer splits (2, 3, and 4 splits) in main plots and three levels of urea fertilizer (60, 80 and 100% of required urea fertilizer) in subplots and compared with the common method (control) used in the agro-industry fields. Experiments were conducted on a 25 hectare field in 250 meter long and blocked end furrows. Irrigation water during the crop season was applied the same for different fertigation treatments and measured using the WSC flumes in each irrigation events. Irrigation interval varied from 8 to 15 days during the crop season. Qualitative and quantitative traits (e.i., stalk height, cane yield, purity, brix, white sugar yield, and water, fertilizer, and sugar use efficiency) at harvest were measured and analyzed using the MSTATC software.
Results and Discussions: A total of 21 irrigation events during the growing season were measured. Average water consumption in each irrigation event was 865 cubic meters per hectare. Total applied irrigation water during the growing season was 18,155 cubic meters per hectare. Results showed that fertilizer split factor significantly affected the qualitative and quantitative traits at a 5% level of significance. So that, all qualitative and quantitative traits in four split treatments were significantly (P
F. Abbasi
Abstract
Water movement in unsaturated soils is commonly affected by hysteresis which is often ignored in the mathematical description of water flow and solute transport. In this study, hysteresis in soil water retention curve was quantified at lysimeter scale in sandy loam and silty loam soils and results of ...
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Water movement in unsaturated soils is commonly affected by hysteresis which is often ignored in the mathematical description of water flow and solute transport. In this study, hysteresis in soil water retention curve was quantified at lysimeter scale in sandy loam and silty loam soils and results of the Scott’s and Mualem’s models were compared. Three undisturbed soil monoliths (80 cm diameter by 105 cm height) were collected for each soil and water movement was studied for various boundary conditions. Monoliths were equipped with different measuring devices to monitor soil water contents, pressure heads, and outlet water fluxes. Four unsaturated steady state water flow experiments were conducted on each monolith. Hydraulic properties were determined by inverse method using the WAVE model and a global multilevel coordinate search inversion algorithm. First soil hydraulic parameters in the soil water retention and hydraulic conductivity functions were estimated neglecting hysteresis and compared with the functions obtained using approaches considering hysteresis. Hysteresis was simulated using the simple empirical model proposed by Scott and using the universal conceptual model of Mualem. Results of measured and modeling data indicated that hysteresis was observed in both soils. The effect of hysteresis was different on various components of water flow (i.e., pressure head, water content, and water flux) in two studied soils. Water retention curves, pressure head, and water content were significantly influenced by hysteresis in both soils. The Scott's model considerably improved pressure head estimates in the silty loam soil and Mualem's model somewhat improved the soil water content estimates in the sandy loam soil. Outlet water fluxes in both soils were less sensitive to hysteresis. In general, the simple hysteretic model of Scott was more successful in studying hysteresis in both studied soils.
M. Moayeri; E. Pazira; H. Siadat; F. Abbasi; hossein dehghani
Abstract
This study was conducted to assess yield, water consumption, and water productivity of maize and the factors affecting it under farmers’ management conditions at the Karkheh River Basin, Iran, during 2006 and 2007 growing seasons. The studied farms were in Evan Plain that is located in the northern ...
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This study was conducted to assess yield, water consumption, and water productivity of maize and the factors affecting it under farmers’ management conditions at the Karkheh River Basin, Iran, during 2006 and 2007 growing seasons. The studied farms were in Evan Plain that is located in the northern part of the lands downstream of the Karkheh River Dam, where summer maize is planted in 75 cm spaced rows and irrigated by furrows. During the two years of the research and considering the prevailing diversity of the sources of irrigation water (Based on the ratio), seven irrigated field units were selected as follows: two units using groundwater (wells), three units receiving surface water from irrigation network, one unit taking water directly from the river, and one unit using network and well water. In each irrigation unit, three farms were chosen with regard to irrigation and farming management. In the field trials, some physical and chemical properties of the soil, soil test for nutrition (NPK) availability, the volume of inflow applied to the field by the farmer and runoff water in each irrigation, and total crop yield was measured and maize evapotranspiration was calculated. Then, the irrigation and rain water productivity (WPI+R), water application efficiency (WAE), and maize crop water productivity (CWP) was determined for each field. Based on the two years results, the average yield of maize kernel, WPI+R , WAE, and CWP values were, 4844 kg/ha, 0.38 kg/m3, 38.6,%, and 1.01 kg/m3, respectively. The results and observations made during this study indicated that the most important reasons for low water productivity were inadequate knowledge of farmers in irrigation, plant nutrient deficiencies, and improper crop management practices.
A. Mohseni; H. Mirseyed Hosseini; F. Abbasi
Abstract
Fertilizing method plays an important role in fertilizer and water use efficiency and plant yield and losses fertilizer. A field experiment was carried out at 16 treatments with factorial a complete randomized block design during 2010 for free drainage furrows. First factor was four levels of water (60, ...
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Fertilizing method plays an important role in fertilizer and water use efficiency and plant yield and losses fertilizer. A field experiment was carried out at 16 treatments with factorial a complete randomized block design during 2010 for free drainage furrows. First factor was four levels of water (60, 80, 100 and 120% of full irrigation) and second factor was four levels of fertilizer (0, 60, 80 and 100% of required fertilizer) for fertigation method. The 16 treatments mentioned above, were compared with common fertilizing method. Nitrogen requirement was applied in four stages of the growth: before cultivation, in seven leaves, shooting and earring stages, the first portion (before cultivation) was applied by manual distribution and others by fertigation. In conventional treatment, the whole of required fertilizer was used in two split applications (before planting and in seven leaves). Results showed, the highest yield, yield component and use efficiency of corn was obtained on 100% irrigation and 100% fertilizer treatments. While the highest amount percolation of nitrate into soil was related to conventional treatment.
Y. Abbasi; A. Liaghat; F. Abbasi
Abstract
Suitable management of water and fertilizer is one of the important factors, affecting water and fertilizer efficiency and environmental pollution. In this study, nitrate deep leaching was evaluated in a furrow irrigated experimental field in Karaj. Experiments were conducted in randomized complete blocks ...
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Suitable management of water and fertilizer is one of the important factors, affecting water and fertilizer efficiency and environmental pollution. In this study, nitrate deep leaching was evaluated in a furrow irrigated experimental field in Karaj. Experiments were conducted in randomized complete blocks in free-drainage furrows having 162 m length in 12 experimental blocks. The first factor consisted of 60%, 80% 100% and 120% of required irrigation water and the second factor 60%, 80% and 100% of nitrate fertilizer requirement applied by fertigation method. Nitrogen requirement was determined based on soil analysis and applied in four stages of the crop growth: before cultivation, in seven leaves, shooting and earring stages in which the first part (before cultivation) was applied by manual distribution and other three parts by fertigation. To determine soil nitrate concentrations, soil samples were taken from depths 20, 40, 60, and 80 cm in all of treatments. After air-drying, soil samples were passed through 2 mm sieve. Then, nitrate concentration of samples were analyzed by spectra photometer. Nitrate losses through runoff were measured by sampling of outlet water. Accumulated nitrate in maize was determined by randomized sampling of plants in all treatments. Finally, to determine nitrate leaching, nitrate mass balance was made. Results showed that 120% water level treatment provided 12% water deep percolation from root zone, while 60% water level treatment resulted in 4.5% water deep percolation. Both water and fertilizer levels had pronounced effect on nitrate leaching. The highest nitrate leaching occurred in 100% fertilizer level treatment decreasing by water reduction level. In some cases such as 80% fertilizer level, water level of 60% and 80% didn’t have any effect on nitrate deep percolation. Therefore, water level selection in this situation depends on other factors such as yield. Considering maize as a plant with root depth to be about 80 cm, water and nitrate deep percolation was evaluated up to 80 cm soil depth for all treatments. 60% and 80% water levels did not provide nitrate leaching below the mentioned root zone depth.
M. Panahi; S.M. Mirlatifi; F. Abbasi
Abstract
Abstract
This study addresses two dimensional infiltration from irrigated furrows. The basic approach is to develop a two-dimensional infiltration as a combination of the corresponding one-dimensional vertical and an edge effect. The edge effect is the difference between the cumulative infiltration ...
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Abstract
This study addresses two dimensional infiltration from irrigated furrows. The basic approach is to develop a two-dimensional infiltration as a combination of the corresponding one-dimensional vertical and an edge effect. The edge effect is the difference between the cumulative infiltration per unit of adjusted wetting perimeter and the corresponding one-dimensional infiltration. This approach was evaluated using field measured furrow experiments and double ring infiltration tests. In this study, two series of experiments was conducted in 2010 on a clay loam soil. The first series of the tests included five experiments with inflow rate (0.3-0.8 ls-1) on free draining furrows having 110 meters in length, 75 cm wide and general slope of 0.008 m m-1. The second series of the experiments were carried out using double ring. A general conclusion was that the edge effect was linearly related to time. Using minimizing root mean square error (RMSE) the two empirical coefficients of the model including γ and W*/W were determined. The values of 0.62 and 1.15 were determined for the two empirical parameters in the clay loam soil studied. The results showed that the RMSE and the absolute error (AE) were 0.0031 and5.9 %, respectively. Model sensitivity analysis showed that the lowest sensitivity was to initial water content and the highest sensitivity was to saturation water content. The approach leads to an infiltration function for irrigation furrows without the need to perform a fully two-dimensional simulation.
Keywords: Furrow irrigation, Two-dimensional infiltration models, Warrick model, Edge effect
M. Navabian; A. M. Liaghat; R. Kerachian; F. Abbasi
Abstract
Abstract
Optimal management of water and nutrient could consider as effective on farm method to reduce pollution because agriculture is none point pollution. In this research, an optimal model was presented to reduce nitrate loss in furrow fertigation. The optimal model contains four simulation models ...
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Abstract
Optimal management of water and nutrient could consider as effective on farm method to reduce pollution because agriculture is none point pollution. In this research, an optimal model was presented to reduce nitrate loss in furrow fertigation. The optimal model contains four simulation models for predicting runoff, deep percolation, nitrate concentration in runoff and nitrate concentration in deep percolation. Genetic algorithm was used for model solution. Decided values were inlet discharge, cutoff time of irrigation, starting time and duration of fertigation. Simulation model’s ability to simulate fertigation event cause a comprehensive optimal model of fertigation in different climate, plant, irrigation and fertigation situations. Field experiment of furrow irrigation under continues regime was used to evaluate optimal model. Optimal decided values for inlet discharge, cutoff time of irrigation, starting time and duration of fertigation was determined 0.184 L/s, 595.2 min, 7.5 min and 162.9 min in plant conditions. These values were 0.21 L/s, 537.1 min, 6.5 min and 143 min in none plant condition. Optimal decided values cause 113.86 and 118.3 mg/L mean nitrate loss from farm as runoff and deep percolation under plant and none plant conditions, respectively. Optimal model was increased nitrate concentration in deep percolation or decreased nitrate concentration in runoff by increasing inlet discharge because plant increase nitrate concentration in deep percolation. Results show plant has effect on optimization then it is appropriate to determine optimal decided values under plant and none plant conditions.
Keywords: Furrow irrigation, Optimization, Fertigation, Water and nutrient management, Nitrate
H. Ebrahimian; B. Ghanbarian-Alavijeh; F. Abbasi; A. Hourfar
Abstract
چکیده
نفوذ، مهمترینترین و مشکلترین پارامتر ارزیابی سامانههای آبیاری سطحی است. اهمیت دانستن معادله نفوذ جهت تشریح هیدرولیک آبیاری سطحی، همراه با مشکلات تخمین قابل ...
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چکیده
نفوذ، مهمترینترین و مشکلترین پارامتر ارزیابی سامانههای آبیاری سطحی است. اهمیت دانستن معادله نفوذ جهت تشریح هیدرولیک آبیاری سطحی، همراه با مشکلات تخمین قابل اطمینان پارامترهای آن، موجب صرف وقت و هزینه زیادی برای طراحی یک سامانه آبیاری میشود. هدف از این مطالعه، ارزیابی روشهای مختلف تخمین پارامترهای نفوذپذیری و ارائه روش دو نقطهای جدیدی براساس معادله نفوذ فیلیپ است. در این راستا از هفت سری داده صحرایی با شرایط مختلف مزرعهای از جمله طول، شیب و دبی ورودی استفاده گردید. همچنین با استفاده از مدل هیدرودینامیک نرم افزار SIRMOD و با تخمین پارامترهای معادله نفوذ به روش پیشنهادی و روشهای دو نقطهای الیوت و واکر، پیشروی بِنامی و اُفِن، یک نقطهای شپارد و همکاران و یک نقطهای والیانتزاس و همکاران، مراحل پیشروی و پسروی آبیاری شبیهسازی شدند تا دقت روشهای مختلف تخمین پارامترهای معادله نفوذ مورد بررسی قرار گیرد. نتایج نشان داد که در برآورد میزان آب نفوذیافته به خاک در آبیاری نواری روش پیشنهادی (8/4درصد) و در آبیاری جویچهای روش شپارد و همکاران (9/13درصد) و روش پیشنهادی (2/14درصد) دارای کمترین خطای نسبی میباشند. در پیشبینی مرحله پیشروی در آبیاری جویچهای و نواری به ترتیب روش پیشروی بنامی و افن (5/19درصد) و روش پیشنهادی (6/6درصد) و در پیشبینی مرحله پسروی در آبیاری جویچهای و نواری به ترتیب روش شپارد و همکاران (3/1درصد) و روش پیشنهادی (2/2درصد) دارای کمترین خطای استاندارد بودند.
واژههای کلیدی: روش دو نقطهای، تخمین پارامترهای نفوذ، آبیاری جویچهای، آبیاری نواری
F. Abbasi; A. Liaghat; H. A. Alizadeh; Y. Abbasi; A. Mohseni
Abstract
چکیده
در این تحقیق، به منظور مطالعه و بررسی اثرات کودآبیاری بر تلفات نیترات از طریق رواناب سطحی در آبیاری جویچه ای و همچنین ارزیابی یک مدل ریاضی کودآبیاری، 12 آزمایش ...
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چکیده
در این تحقیق، به منظور مطالعه و بررسی اثرات کودآبیاری بر تلفات نیترات از طریق رواناب سطحی در آبیاری جویچه ای و همچنین ارزیابی یک مدل ریاضی کودآبیاری، 12 آزمایش در دو سال زراعی 1387 و 1388در مقیاس بزرگ و در حضور گیاه ذرت روی جویچه های انتها باز در یک خاک لومی انجام شد. تعداد جویچه های هر آزمایش 5 عدد، طول جویچه ها 165 متر، فاصله بین جویچه ها 75 سانتی متر و شیب عمومی مزرعه 006/0 متر بر متر بود. کود مصرفی مورد نیاز مطابق توصیه کودی از منبع کود اوره و طی چهار تقسیم مساوی (قبل از کاشت، مرحله هفت برگی، مرحله ساقه رفتن و مرحله سنبله زدن) اضافه گردید. دبی جویچه ها با استفاده از فلوم WSC و غلظت نیترات خروجی از روش طیف سنجی اندازه گیری شد. از داده های سال اول برای تعیین بهترین زمان تزریق کود با هدف دستیابی به کمترین درصد تلفات نیترات استفاده شد. در سال دوم، تزریق کود فقط در زمان بهینه شده بر اساس نتایج سال اول انجام گرفت. نتایج نشان داد که بهترین زمان تزریق کود به سیستم آبیاری جویچه ای 20 دقیقه انتهایی آبیاری می باشد. تلفات نیترات از طریق رواناب سطحی در سال اول بسته به زمان تزریق کود بین 7/5 تا 0/42 و در سال دوم با اعمال مدت زمان تزریق بهینه بین 4/1 تا 3/12درصد متغیر بود. همچنین، نتایج نشان داد که مدل کودآبیاری مورد استفاده در این تحقیق قابلیت برآورد تلفات نیترات از طریق رواناب سطحی را دارد. ضریب تبیین (R2) بین مقادیر اندازه گیری و شبیه سازی شده تلفات آب در دو سال زراعی به طور متوسط 85/0 و برای تلفات کود به طور متوسط 80/0 بود.
واژه های کلیدی: کودآبیاری، تلفات نیترات، مدل ریاضی کودآبیاری، آبیاری جویچه ای
H.A. Alizadeh; A. Liaghat; F. Abbasi
Abstract
Abstract
Water and nitrogen are the main limiting factors affecting agricultural production in arid and semiarid regions. Therefore, improving the efficiency of these factors is very important. The method of fertilizer application is affecting water and fertilizer use efficiency. The objective of this ...
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Abstract
Water and nitrogen are the main limiting factors affecting agricultural production in arid and semiarid regions. Therefore, improving the efficiency of these factors is very important. The method of fertilizer application is affecting water and fertilizer use efficiency. The objective of this study was to investigate the effect of furrow fertigation on fertilizer use efficiency (FUE), water use efficiency (WUE), and corn yield. A field experiment was carried out in furrows which have 165m length and 0.006 (m/m) slope in Karaj. The corn Hybrid 370 double-cross was planted on June 2008. A factorial design based on randomized complete block design with 4 replicates. Four levels (0, 60, 80 and 100%) of the recommended fertilizer value and four levels (60, 80, 100, and 120%) of the irrigation water requirement were applied. These 16 treatments were compared with traditional fertilizer application method. Fertilizer treatments were accomplished in four critical stages of the growth (before cultivation, in seven leaves stage, shooting stage and Flowering stage) for fertigation treatments and two stages (before cultivation and seven leaves stage) for the traditional method. Results showed that effects of levels of different water and fertilizer on yield component were significant. Water use efficiency (WUE) was significantly affected by nitrogen rate. On the other hand, water treatments significantly affected fertilizer use efficiency. Increasing fertilizer increased water use efficiency. Increasing water levels to 100% of ETC resulted in increasing fertilizer use efficiency. Highest yield was obtained from the full irrigation treatments (W100%). Albeit the difference among W120%, W100% and W80% was not significant (P=0.05), because W100% was always higher than W120%, treatment of W80% recommends as optimum water level for arid and semi arid region. The maximum and minimum WUE was 2.24 and 0.66 (kg/m3) in W80%N100% and W100%N60%, and The maximum and minimum FUE was 29.85 and 8.52 (kg/kg) in W100%N100% and traditional method, respectively.
Key words: Fertigation, Fertilizer use efficiency, Productivity, Corn
A. Liaghat; F. Abbasi
Abstract
Abstract
In this study, distribution uniformity of fertigation in different furrow irrigation regimes was evaluated. The experiments included injection of fertilizer during only the first half of the irrigation event (FH), injection in the second half (SH) and injection during the entire irrigation ...
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Abstract
In this study, distribution uniformity of fertigation in different furrow irrigation regimes was evaluated. The experiments included injection of fertilizer during only the first half of the irrigation event (FH), injection in the second half (SH) and injection during the entire irrigation (T) event. These options were conducted under free draining and blocked-end conditions with cutback method. The experiments were carried out in Golmakan Agricultural Research Station in 2006. Potassium nitrate was used in the experiments. Distribution uniformity of low half (DULH) and low quarter (DULQ) of water and fertilizer was calculated to evaluate different fertigation scenarios. The results showed that there is no significant difference among the distribution uniformities in the three application times (FH, SH, T). No significant difference was observed between distribution uniformity of free-draining and blocked-end experiments. The best case in blocked-end conditions was injection during the entire irrigation event preferably starting before completing advance phase. Because in this case, solute losses due to runoff from the outlet is zero and also distribution uniformity is somewhat higher whereas in free-draining conditions, fertilizer application during the first half of irrigation provides acceptable fertilizer uniformity and least losses due to runoff. The results also showed that fertilizer losses due to deep percolation in this method of fertilizer application (fertigation) would not be a threat in case of selecting proper irrigation parameters.
Key words: Furrow irrigation, Fertigation, Distribution uniformity, Mathematical model
