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Saeid Habibi; Mojtaba Khoshravesh; Rassol Nouri Khajebelagh
Abstract
Water, food, and energy are three essential sources for maintaining life and fostering socio-economic development, and they are inseparably interconnected. The aim of the present study was to examine the indicators of water, energy efficiency, and global warming potential of major agricultural products, ...
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Water, food, and energy are three essential sources for maintaining life and fostering socio-economic development, and they are inseparably interconnected. The aim of the present study was to examine the indicators of water, energy efficiency, and global warming potential of major agricultural products, namely wheat and rapeseed, in two different climates in Sari and Sharifabad plains. To investigate these indicators in wheat and rapeseed crops, data from the agricultural year 1400-1401 were utilized. Initially, the sample size was determined based on the Cochran formula. Subsequently, sampling was done using a questionnaire designed by the researchers themselves. The questionnaires numbered 300, and the collected information included input consumption and production quantities. The results of water physical efficiency showed that the average water physical efficiency in Sari plain for wheat and rapeseed crops was 1.13 and 0.67 kilograms per cubic meter, respectively, while in Sharifabad plain, it was 0.83 and 0.35 kilograms per cubic meter, respectively. Furthermore, the results for energy indicators indicated that the highest level of input energy in Sari and Sharifabad plains for wheat was 80618 and 71072 megajoules per hectare, respectively. The results also showed that greenhouse gas emissions were higher in Sari than in Sharifabad, attributed to excessive fertilizer and pesticide use in Sari. The highest greenhouse gas emissions in Sari for wheat were 2495 kilograms of CO2 per hectare, and in Sharifabad, it was 2299 kilograms of CO2 per hectare. Overall, the results indicated that crop performance in humid regions is higher than in dry and semi-dry regions, and this indicator depends on various parameters, including water consumption and management discussions.
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Mostafa Yaghoobzadeh; Farhad Azarmi Atajan; Mehdi Arabi Ayask; Amir Hossein Ghadirian
Abstract
Optimal use and management of water resources is very important. Also, choosing the appropriate irrigation method plays a vital role in saving water consumption in the agricultural sector. Therefore, in the current research, the effect of the irrigation method on the simulation of sugar beet yield was ...
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Optimal use and management of water resources is very important. Also, choosing the appropriate irrigation method plays a vital role in saving water consumption in the agricultural sector. Therefore, in the current research, the effect of the irrigation method on the simulation of sugar beet yield was investigated using the AquaCrop model. In this study, the effect of two methods of drip irrigation (tape) and surface irrigation (furrow) and three levels of irrigation water (50%, 75%, and 100% of the plant's water requirement) on the yield of sugar beet plants was investigated in Sarayan-Ayask region, Iran. A factorial experiment was conducted based on a completely randomized design with 4 replications in 2021-22. The results showed that irrigation method had a significant effect on leaf diameter, leaf length, leaf weight, tuber diameter, and tuber length and weight of sugar beet tuber. Also, according to the results, drip irrigation had greater effect than furrow irrigation on the studied traits. Then, the grain and biomass yield was simulated using the AquaCrop model and the simulated values were calibrated and verified using observational data. Calibration was done using two replications of 100% and 50% stress levels, and validation was done using the replication of 75% stress level. The NRMSE, RMSE, RD and R2 coefficients of the model calibration values showed that the simulated and validated values were close to each other and these values were more precise in drip irrigation than in furrow irrigation. Validation values of two irrigation methods also showed the ability of model in simulating grain yield and biomass.
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Tahereh Gholami Estalkhi Kohi; Maryam Navabian; Mehdi Esmaeili Varaki
Abstract
Construction of drainage systems is inevitable in paddy fields to control the level of waterlogging during rice harvest and cultivation of the second crop. Finding the best design option of drainage is very important from the point of view of environmental and economic issues. This study was conducted ...
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Construction of drainage systems is inevitable in paddy fields to control the level of waterlogging during rice harvest and cultivation of the second crop. Finding the best design option of drainage is very important from the point of view of environmental and economic issues. This study was conducted with the aim of investigating the performance of open drains including pressure head and depletion flux in controlling the water level in the cultivation of rice plants and the second plant in paddy fields. In this regard, the performance of open drains during rice and the second crop growth period was simulated using HYDRUS-2D model. To calibrate and validate HYDRUS-2D model, the required information was collected from 130 hectares of paddy fields in Nodeh, Jirsar and Nupashan villages in Soumesara region, in 2019. Soil texture, bulk and specific density, porosity and infiltration rate were measured. Also, pressure head of water was measured monthly in the region by piezometers. After validation, different open drain design options (bottom width and depth of drain) were run in HYDRUS-2D and its results were compared. The simulation results showed that the HYDRUS-2D had a reasonable accuracy in simulating the changes in water pressure head. The statistical indexes including R2, RMSE, nRMSE and MAE in the calibration stage were 0.98, 4.39 cm, 1.6%, and 3.55 cm, respectively, and 0.98, 4.33 cm, 1.67%, and 3.37 cm in the validation stage, respectively. The results showed that the open drain with a depth and bottom width of, respectively, 200 and 170 cm had the best performance for controlling water table during rice and the second crop cultivation, with a discharge rate of 726440 and 169960 cm3 per unit of drain length, and the reaction coefficient of 0.293 and 0.583 per day, respectively.
2
parisa shahinrokhsar; Aslan Egdernezhad
Abstract
Despite Gilan Province being a rainy region in Iran, inappropriate distribution of rainfall during the growing season has a negative impact on the growth of crops, including borage. This study was conducted to determine the proper irrigation regime for borage at different stages of growth. For this purpose, ...
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Despite Gilan Province being a rainy region in Iran, inappropriate distribution of rainfall during the growing season has a negative impact on the growth of crops, including borage. This study was conducted to determine the proper irrigation regime for borage at different stages of growth. For this purpose, fifteen field experiments, based on 15 combinations obtained from the Central Composite Design, were conducted using high and low levels of treatments including water requirement (without irrigation (I1) and full water supply (I2)), two growth stages (stem elongation (D1), stem elongation and flowering (D2)), and two years with different rainfall (drought (Y1) and wet season (Y2)). The experiments were performed in Giulan Agricultural and Natural Resources Research and Education Center located in Rasht. Irrigation and stage of growth had the most and the least effects on borage yield and growth parameters, respectively. Dry season increased the grain yield, oil yield and oil percentage, while other parameters reached their maximum value in wet year. The value of 1000-seed weight for D2 was equal to 18.9 g, and the values of dried flower yield, fresh flower yield, seed yield, and economic yield are equal to 468, 858, 486 and 983 kg.ha-1, respectively. Oil yield and oil percentage for D2 were equal to 160 kg.ha-1 and 33.5%, respectively. Considering the optimal levels for all parameters based on the interpolation of factor values in the central composite design, if the percentage and yield of oil is less important than the other parameters, it is necessary to provide 88% of irrigation water for the stem and flowering stages in the wet season. In order to achieve maximum yield and oil content, full supply of irrigation needs in dry season and in the stem stage should be considered.
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Faranak Baradaran-Hazaveh; Hossein Babazadeh; Ebrahim Amiri; Hossain ebrahimi
Abstract
Pulses have a special position, after wheat and rice, in the Iranian people diet. The growth of these plants is very fast and water stress has an important effect on their yield. The objective of this study was to evaluate the DSSAT Model in simulating the growth and yield of cowpea under different levels ...
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Pulses have a special position, after wheat and rice, in the Iranian people diet. The growth of these plants is very fast and water stress has an important effect on their yield. The objective of this study was to evaluate the DSSAT Model in simulating the growth and yield of cowpea under different levels of irrigation water. An experiment was conducted as a randomized complete block design (RCBD) with three replications in Kiashahr City, Iran, in the crop seasons of 2017 and 2018. The main treatments included irrigation with management of 40%, 60%, 80%, 100%, and 120% of plant water requirement and the three sub-treatments included irrigation at vegetative or reproductive stages, and full irrigation. In this experiment, the DSSAT simulation model was used to evaluate water efficiency and water balance components. Evaluation of simulated and measured values of grain yield was performed using the parameters of coefficient of determination, t-test, root mean square error (RMSE) and root mean square normalized error (nRMSE). The results showed that the difference between the predicted grain yield and the observed values was acceptable (RMSE=92 and nRMSE = 12.62%). Total biomass was also well simulated (RMSE=130 and nRMSE = 5.91%). Using the measured grain yield and water balance components simulated from the DSSAT model, the water productivity based on evapotranspiration (WPET) was about 33% lower than that based on transpiration (WPT). According to the results, irrigation with 100% water requirement at both vegetative and reproductive stages resulted in the highest transpiration (383mm), and was selected as the optimum irrigation management during the growing season.
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Sara bulukazari; Hossein Babazadeh; Nyazali Ebrahimipak; Seyed Habib Mousavi-Jahromi; Hadi Ramezani_etedali
Abstract
In exploitation of low-quality water in arid and semi-arid regions, irrigation management is essential to increase water use efficiency. Determination of crop-water-salinity production function is an essential tool for proper irrigation management. In this study, the AquaCrop model was first evaluated ...
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In exploitation of low-quality water in arid and semi-arid regions, irrigation management is essential to increase water use efficiency. Determination of crop-water-salinity production function is an essential tool for proper irrigation management. In this study, the AquaCrop model was first evaluated by considering 4 soil and water salinity levels and 4 deficit irrigation levels for the major cereal crops including wheat, barley, and corn in Qazvin Plain. The results showed that the coefficients of determination for wheat, barley, and corn yield were 0.97, 0.86 and 0.91, respectively. Therefore, the model can evaluate the performance in salinity and deficit irrigation conditions with a good approximation. To determine the optimal production functions of each crop, the results of the plant model were compared with three models of linear and nonlinear regression, and artificial neural network. The neural network model was able to estimate the performance compared to the AquaCrop model with lower error and higher correlation (0.99). These values in the linear function for wheat, barley, and corn were 0.98, 0.95, and 0.78 and in the nonlinear function as 0.92, 0.86 and 0.81, respectively. Also, the error calculated in the neural network method for wheat, barley, and maize was 40.16, 62.09, and 57.08 kg, respectively, which were less than the linear model by 75 %, 70 %, and 95 %; and less than the exponential model by 90 %, 85 %, and 93%, respectively. The best trained network for determining the water-salt production function for barley and wheat 5 Nero and for corn 7 Nero was introduced in the single layer structure. Sensitivity analysis on wheat and barley showed that this model had low sensitivity to irrigation and salinity parameters and only corn plant showed a moderate range sensitivity to salinity parameter.
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Farzin Parchami-Araghi; Adnan Sadeghi-Lari
Abstract
It is important to assess the uncertainties involved in agro-hydrologic simulations because they are subject to varying degrees of uncertainty. Uncertainty analysis of the agro-hydrological models can provide useful insights into the degree of confidence in the model results. In this study, uncertainty ...
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It is important to assess the uncertainties involved in agro-hydrologic simulations because they are subject to varying degrees of uncertainty. Uncertainty analysis of the agro-hydrological models can provide useful insights into the degree of confidence in the model results. In this study, uncertainty analysis of a distributed application of the SWAP model to a sugarcane field with subsurface controlled drainage was conducted using a hybrid uncertainty analysis scheme, combining Generalized Likelihood Uncertainty Estimation (GLUE) and Unified Particle Swarm Optimization (UPSO). The results revealed a high variability of the calibrated parameters and the necessity of an uncertainty assessment for the SWAP simulations. Strong parameter correlations highlighted the need for calibration of the model parameters against diverse calibration data in a simultaneous manner. The 95% prediction uncertainty bands obtained for the hydrological (soil water content, water table level, sub-surface drainage outflow), solute transport (soil water solute concentration and sub-surface drainage outflow salinity), and biophysical (leaf area index, cane, and sucrose dry yield) simulations enveloped 73-80%, 45-58%, and 75-100% of the corresponding total observed data (including both calibration and validation datasets), respectively, with an r-factor (the ratio of the average thickness of the 95PPU band to the standard deviation of the corresponding measured variable) of 0.83-0.98, 1.43-1.96, and 0.75-1.11. The thickness of the derived 95PPU bands for the biophysical simulations showed an increasing trend over the simulation period.
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mohammad amin khandan barani; Peyman Afrasiab; mehdi akbari; Masoomeh Delbari
Abstract
In this research, the status of water productivity for wheat production and strategies to increase water productivity in different quantitative conditions of water was determined and analyzed in the irrigation district of Sistan Dam. In this regard, the SWAP simulation model was calibrated and validated ...
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In this research, the status of water productivity for wheat production and strategies to increase water productivity in different quantitative conditions of water was determined and analyzed in the irrigation district of Sistan Dam. In this regard, the SWAP simulation model was calibrated and validated by considering the current water resources operation, various quantities of irrigation water, and use of field information. Water production functions were used to determine the irrigation schedule (time and depth) for wheat crop. The results of field measurements in the crop year 2016-2017 in the irrigation district showed that farmers irrigate wheat on average four times in the current conditions. Farmers' average crop yield and water productivity were about 1450 kg/ha and 0.41 kg/m3, respectively. These results show that available water is not appropriately used and should be addressed with practical solutions to improve water productivity. The validation and calibration results of the SWAP model also showed the high accuracy of the model in the case study. The results of different management scenarios of eliminating some irrigation shifts compared to the existing conditions indicated that, although there was no significant difference in water productivity, crop yield decreases about 37%. The results of evaluating the scenarios of reducing the depth and frequency of irrigation (using 640 mm per season and applying 40 mm at each shift) showed that, with reliable and timely water supply and more frequent irrigation, water productivity could be increased by 30% compared to the baseline scenario; and crop yield can be doubled. In these scenarios, the presence of adequate moisture in the plant's root zone increases the yield, and the amount of deep percolation is greatly reduced. The amount of water used by farmers is excessive for various reasons. Therefore, it is recommended to train farmers on how to improve irrigation and crop management according to the water available in the irrigation district, so that they can distribute water according to the real needs of the plant and irrigate at the right time and sufficient quantity.