Irrigation
O. Raja; M. Parsinejad; M. Tajrishi
Abstract
Introduction Surface and groundwater conjunctively interact at different spatial or temporal scales within a plain. In many plain, surface and groundwater resources are used in combination in agriculture. Therefore, it is important to accurately predict the components of groundwater and surface ...
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Introduction Surface and groundwater conjunctively interact at different spatial or temporal scales within a plain. In many plain, surface and groundwater resources are used in combination in agriculture. Therefore, it is important to accurately predict the components of groundwater and surface water balance. Despite the rapid expansion of numerical models over the past two decades, there is still a need for comprehensive and integrated assessment of surface and groundwater components. In particular, the interconnection of both surface and groundwater models is important to connect both surface and groundwater, especially the water balance in the unsaturated root zone. In this study the effect of water recharge due to deep percolation from simultaneous supply of irrigation water from surface and groundwater sources, and rainfall from the SWAT model were used to simulate groundwater balance using the combined MDOFLOW-NWT model.Materials and Methods In this study, the effect of recharge values obtained from the SWAT model was analyzed to simulate the fluctuation of water table, and groundwater balance components using the integrated model of MODFLOW-NWT model in the Mahabad plain. One of the important steps in quantifying the impact of irrigation management, and the change in land-use on the surface and groundwater balance was the simulated recharge due to the deep percolation of rainfall and irrigation water. This was done by the SWAT model, and was used as the boundary condition to the MODFLOW-NWT model. Calibration and validation of groundwater model were also done by trial-and-error and automatic PEST methods. The simulation period was performed for 10 years from the hydrological year of 2009-2010 to 2018-2019, from which 6 and 4 years were used as the period for calibration and validation were from 2009-2010 to 2014-2015 and 2015-2016 to 2018-2019, respectively. Groundwater balance components are naturally different for different years. Therefore, the study was conducted for dry, wet, and normal years. Hydraulic conductivity and specific yield were the used as initial calibration parameters in the MODFLOW-NWT model.Results and Discussion The results showed a higher hydraulic conductivity and specific yield values for the aquifer was in the southern, central, and northeastern areas of the plain, and the lowest values were in the northern and near the outlet of the plain. After the calibration process, the results showed that an average, 9% of rainfall, and 36% of irrigated water percolate to the aquifer. These observations were confirmed based on a satisfactory and acceptable estimate of the water table level of the model for both calibration and validation periods. The statistical RMSE criteria for calibration and validation periods were 0.35 and 0.34 m, respectively. Also, the results of R2 and NSE criteria were estimated as 0.94 and 0.91 for the calibration period, and 0.93 and 0.89 for the validation period, which indicates that the model was properly calibrated and was well able to simulate groundwater level. The groundwater hydrographs developed from piezometers’ readings, show that the recharge values estimated by the SWAT model, considering the change in land use and irrigation management across the plain, were able to properly simulate groundwater level across the aquifer. Specifically, the studies showed a continuous drop in groundwater level created in the southern and southwestern regions of the aquifer (piezometers of Fakhrighah, Gorg tapeh, and Serah Haji Khosh) due to the presence of high-consumption crops such as apple and alfalfa, and the higher number of operation wells.ConclusionThe results of this study showed that the recharge values obtained from the calibrated SWAT model was crucial parameters for proper simulation of groundwater, and can significantly improve the model results. The results of the main components of the groundwater balance for different years showed that the amount of recharge due to the infiltration of rainfall, and irrigation were different for each year. Also, interactions between surface and groundwater resources vary from about 30 to 50 million cubic meters between years, indicating a significant interaction between the water resources. In general, the SWAT-MODFLOW-NWT model can be used as a practical tool for proper management of surface and groundwater resources under different management scenarios.
M. Sarai Tabrizi; H. Babazadeh; mahdi homaee; F. Kaveh Kaveh; M. Parsinejad
Abstract
Introduction: Several mathematical models are being used for assessing the plant response to the salinity of the root zone. The salinity of the soil and water resources is a major challenge for agricultural sector in Iran. Several mathematical models have been developed for plant responses to the salinity ...
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Introduction: Several mathematical models are being used for assessing the plant response to the salinity of the root zone. The salinity of the soil and water resources is a major challenge for agricultural sector in Iran. Several mathematical models have been developed for plant responses to the salinity stress. However, these models are often applicable in particular conditions. The objectives of this study were to evaluate the threshold value of Basil yield reduction, modeling Basil response to salinity and to evaluate the effectiveness of available mathematical models for the yield estimation of the Basil .
Materials and Methods: The extensive experiments were conducted with 13 natural saline water treatments including 1.2, 1.8, 2, 2.2, 2.5, 2.8, 3, 3.5, 4, 5, 6, 8, and 10 dSm-1. Water salinity treatments were prepared by mixing Shoor River water with fresh water. In order to quantify the salinity effect on Basil yield, seven mathematical models including Maas and Hoffman (1977), van Genuchten and Hoffman (1984), Dirksen and Augustijn (1988), and Homaee et al., (2002) were used. One of the relatively recent methods for soil water content measurements is theta probes instrument. Theta probes instrument consists of four probes with 60 mm long and 3 mm diameter, a water proof container (probe structure), and a cable that links input and output signals to the data logger display. The advantages that have been attributed to this method are high precision and direct and rapid measurements in the field and greenhouse. The range of measurements is not limited like tensiometer and is from saturation to wilting point. In this study, Theta probes instrument was calibrated by weighing method for exact irrigation scheduling. Relative transpiration was calculated using daily soil water content changes. A coarse sand layer with 2 centimeters thick was used to decrease evaporation from the surface soil of the pots. Quantity comparison of the used models was done by calculating statistical indices such as maximum error (ME), normalized root mean square error (nRMSE), modeling efficiency (EF), and coefficient of residual mass (CRM). At the end of the experiment, dry matter yield at the different treatments was measured and relative yield was calculated by dividing dry matter yield of treatments on dry matter yield at no stress treatment (control treatment). Leaching requirement in experimental treatments was calculated by Ayarset al., (2012) equation.
Results and Discussion: The results indicated that Basil threshold value based on soil salinity was 2.25
dSm-1 with the yield reduction of 7.2% per dSm-1. The mathematical model of van Genuchten and Hoffman (1984) had a higher precision than other models in simulating Basil yield reduction function based on saturated soil extract salinity. The overall observations revealed that van Genuchten and Hoffman (1984), Steppuhnet al., (2005) and Homaeeet al., (2002) models were accurate for simulating Basil root water uptake and yield response to saturated soil extract salinity. Considering the presented results, it seems that among math-empirical models for salinity stress conditions, model of van Genuchten and Hoffman (1984) is more accurate than Maas and Hoffman (1977), Dirksen and Augustijn (1988) and Homaeeet al., (2002a) models. The works of Green et al., (2006) and Skaggs et al., (2006) came to the same conclusion. Our work indicated that mostly statistical models have lower precision than math-empirical models. Steppuhn et al., (2005a) reported that statistical models had the higher accuracy than math-empirical model of Maas and Hoffman (1977) and among statistical models, the modified Weibull model had the best fit on measured data which is in good agreement with the results of this study.
Conclusion: The goals of this research were to evaluate Basil response to saturated soil extract salinity, to estimate threshold value of Basil crop coefficients, to obtain yield reduction gradient, and also to investigate efficiency of available math-empirical models in estimating reduction functions. The results of this study indicated that the Basil threshold value obtained based on saturated soil extract salinity was 2.25 dSm-1 and the gradient of yield reduction was 7.2% per dSm-1 according to Maas and Hoffman (1977) linear fitting. The reached general conclusion was that among the math-empirical reduction functions, the model of van Genuchten and Hoffman (1984) had the highest accuracy when compared to the models of Maas and Hoffman (1977), Dirksen and Augustijn (1988) and Homaee et al., (2002a). Therefore, it is recommended to use the van Genuchten and Hoffman (1984), Steppuhn et al., (2005), and Homaee et al., (2002) models respectively, instead of the other models in this research.
M. Hassanli; H. Ebrahimian; M. Parsinejad
Abstract
Using of saline water for irrigation of crops is known as a strategy of on-farm irrigation water management. In this study, the cyclic using of saline and fresh water and its effect on soil salinity were investigated. Field experiments were carried out in randomized complete block design under drip irrigation ...
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Using of saline water for irrigation of crops is known as a strategy of on-farm irrigation water management. In this study, the cyclic using of saline and fresh water and its effect on soil salinity were investigated. Field experiments were carried out in randomized complete block design under drip irrigation for maize crop with 9 treatments. The treatments were based on alternative irrigation management of saline and fresh water use on three salinity levels 0.4, 3.5 and 5.7 dS/m and freshwater application in every one, three and five saline water application (1:1, 3:1 and 5:1, respectively). The results showed that in 1:1 management, soil salinity at the end of growing season compared with the beginning of growing season did not change considerably (reducing of 1.0% and 17.9% for 1S1:1F and 1S2:1F). In 3S2:1F and 5S2:1F treatments, the amount and frequency of fresh water was not enough to remove salts from the soil and at the end of growing season, salt accumulation was seen in soil profile (increasing of 39.0% and 46.2% in soil salinity). In 3S1:1F and 5S1:1F treatments, soil salinity increased 17.9% and 31.6%, respectively, while increasing of soil salinity in S1 treatment was 40.7%. Thus, by 4 irrigations with fresh water in 3S1:1F treatment and 2 irrigations with fresh water in 5S1:1F treatment, reducing of 22.8% and 9.1% in soil salinity was seen in compared with S1 treatment.
H. Molavi; M. Parsinejad; A.M. Liaghat
Abstract
Abstract
One of the ways to increase economic and environmental efficiency of drainage systems is water table management. Water table management consists of, controlled drainage and subirrigation. This study examines the effect of controlled drainage on yield, root distribution pattern and water use ...
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Abstract
One of the ways to increase economic and environmental efficiency of drainage systems is water table management. Water table management consists of, controlled drainage and subirrigation. This study examines the effect of controlled drainage on yield, root distribution pattern and water use efficiency of maize (SC 704) in Karaj. The experiment was performed as a randomized complete design with three replicates including three treatments: free drainage (FD) and controlled drainage with 40 cm (CD40) and 60 cm (CD60) controlled water tables. Lysimetric station is equipped with drainage system and water table control system. Irrigation intervals in all of the lysimeters were based on MAD = 0.65 in FD treatment. For all treatments, irrigation depths were determined based on deficiency of soil moisture from field capacity with 70 percent application efficiency. The results showed that 30 percent irrigation losses during implementation of treatments in CD treatments did not cause rise of the water table to the desired control levels, due to extra consumption of plant. So between two water table control treatments there was no significant difference. In free drainage treatment which drainage water discharge was facilitated lower plant consumption were noted. Effect of water table management on yield, irrigation amount, root dry weight and water use efficiency was significant (p
M.R. Asgari; A.M. Liaghat; M. Parsinezhad
Abstract
Abstract
Although lateral drains play the main role in removal of excess water from soil profile in subsurface drainage systems, but it is assumed that perforated collectors can directly remove a part of drainwater from soils. This part of discharge in subsurface drains is not usually taken into consideration ...
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Abstract
Although lateral drains play the main role in removal of excess water from soil profile in subsurface drainage systems, but it is assumed that perforated collectors can directly remove a part of drainwater from soils. This part of discharge in subsurface drains is not usually taken into consideration in drainage design criteria, due to lack required information and its difficult estimation. If the level of collectors’ drain discharge is determined, drainage coefficient for laterals can be adjusted depending. Consequently the distance between laterals is increased and economic value of drainage system design is more justified. This research was conducted in drainage network of Amirkabir Agro-Industrial Unit with the purpose of determining collectors’ discharge level and lateral’s drainage coefficient adjustment. Therefore, measurement of water table, discharge of laterals and collectors in ARC2-14 farm having 25 hectare size was measured. Results obtained from field measurements indicate collectors directly discharge approximately 2.8 litter water per second or 2 mm per day or about 24% of total drainage discharge within the system. The actual drainage coefficient will then be reduced from 8.24 to 6.24 mm/day. This change will result an increase in lateral distance from 40 to 44 m.
Keywords: Drainage coefficient modification, Collector or collecting drainage, Constant flow
M. Soleymani Nanadegan; M. Parsinejad; Sh. Araghinejad; A. Massah Bavani
Abstract
Abstract
In this study, impact of climate change on net irrigation requirement (In) and yield of wheat using CGCM3 climate projection model, one of the AOGCM models, in Behshahr area is evaluated. changes in temperature and precipitation were simulated run under the IPCC scenario A2 for 2011-2040, 2041-2070 ...
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Abstract
In this study, impact of climate change on net irrigation requirement (In) and yield of wheat using CGCM3 climate projection model, one of the AOGCM models, in Behshahr area is evaluated. changes in temperature and precipitation were simulated run under the IPCC scenario A2 for 2011-2040, 2041-2070 and 2071-2100 periods. This work was done by using statistical and proportional downscaling techniques. For In estimating, Potential evapotranspiration (ETo) and effective rainfall (Pe) were calculated using Hargreaves – Samani equation and USDA method, respectively. Impact of water deficit on crop yield was estimated using the linear crop-water production function developed by FAO. Results showed that Net irrigation requirement (In) will increase when sowing date is moved toward winter season which would be of further limitations under climate change conditions. For the specific proposed sowing dates, the relative crop yield reduction (YD) was not significantly changed in the future compared to base period. If the sowing date is moved forward to winter season, YD will increase due to a higher evapotraspiration and lower available effective rainfall.
Keywords: Climate change, Net irrigation requirement, Wheat yield, General Circulation Model, CGCM3
M.J. Nahvinia; A. Liaghat; M. Parsinejad
Abstract
چکیده
در مدیریت آبیاری سطحی، تابع نفوذ از اهمیت زیادی برخوردار است. معادلات ریاضی که تاکنون برای نفوذ توسعه یافته اند، توابع تک متغیره ای از زمان فرصت نفوذ می باشند. در ...
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چکیده
در مدیریت آبیاری سطحی، تابع نفوذ از اهمیت زیادی برخوردار است. معادلات ریاضی که تاکنون برای نفوذ توسعه یافته اند، توابع تک متغیره ای از زمان فرصت نفوذ می باشند. در این تحقیق پیش بینی متوسط میزان نفوذ در آبیاری جویچه ای توسط مدل های شبکه عصبی و عصبی- فازی به عنوان مدل های تجربی و مدل رگرسیونی به عنوان مدل آماری با استفاده از رطوبت اولیه ی خاک و دبی ورودی به جویچه مورد بررسی قرار گرفت. به همین منظور از یک سری آزمایش های صحرایی که به روش آبیاری جویچه ای در پنج مزرعه آزمایشی گلمکان مشهد، توتون ارومیه ، صفی آباد دزفول ، دانشگاه بیرجند و موسسه اصلاح بذر کرج در طی دوره ی زمانی تابستان 1376 تا تابستان 1385 انجام شده بود و دارای طیف گسترده ای از نظر بافت خاک (سبک، متوسط و سنگین) بودند، استفاده شد. برای تعیین عوامل معادله ی نفوذ کوستیاکوف لوییس از روش بیلان حجم در آبیاری جویچه ای استفاده گردید. نتایج نشان داد که دقت مدل رگرسیونی در خاک های سنگین در مقایسه با خاک های متوسط و سبک بیشتر است. مدل شبکه های عصبی در خاک های متوسط (Silty Clay Loam) دقت مناسبی دارند و در خاک های سنگین (Clay Loam) تمایل به بیش برآورد و در خاک های نسبتا سبک (Silty Loam) تمایل به کم برآورد دارند. اما سیستم استنتاج فازی عصبی قادر است قابلیت تخمین را در تمام شرایط حفظ کند که این امر نشان از دقت بیشتر و قابلت تخمین زیاد سیستم استنتاج فازی عصبی دارد.
واژه های کلیدی: نفوذ، آبیاری جویچه ای، مدل رگرسیونی، شبکه ی عصبی ، شبکه ی فازی عصبی
A. Shahidi; M.J. Nahvinia; M. Parsinejad; A. Liaghat
Abstract
Abstract
Various mathematical water uptake models have been introduced for plants response to combined drought and salinity stress. The reduction functions are classified as additive, multiplicative and conceptual models. In this study six different macroscopic reduction functions, namely; Van Genuchten ...
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Abstract
Various mathematical water uptake models have been introduced for plants response to combined drought and salinity stress. The reduction functions are classified as additive, multiplicative and conceptual models. In this study six different macroscopic reduction functions, namely; Van Genuchten (additive and multiplicative), Dirksen et al., Van Dam et al, Skaggs et al and Homaee were evaluated. The experiment was carried out at Research farm of Birjand University in a factorial split plot design with 3 replicates. The treatments consisted of four levels of irrigation (50, 75, 100 and 120%of crop water requirement), and three water qualities (1.4, 4.5, 9.6 dS/m) and two wheat cultivars. The results indicated that the additive model estimates relative yield less than the actual amount. In other word, the effect of combined stresses on wheat yield was less than the summation of separate effects due to salinity and water stress. The effect of drought stress on yield reduction was more than salinity stress. The results also revealed that reduction function of Skaggs et al and Homaee's models agreed well with the measured data when compared with other functions.
Keywords: Salinity stress, Drought stress, Reduction function, Wheat, Birjand
H. Noory; A.M. Liaghat; M. Parsinejad; M. Vazifedoust
Abstract
Abstract
In this study, evaluation of SWAP model in simulating crop yield, water and salt movement in soil were investigated in the wheat- fodder maize cultivated units. The research was conducted in the Voshmgir network, Golestan province. The crop yield, soil humidity and moisture data in different ...
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Abstract
In this study, evaluation of SWAP model in simulating crop yield, water and salt movement in soil were investigated in the wheat- fodder maize cultivated units. The research was conducted in the Voshmgir network, Golestan province. The crop yield, soil humidity and moisture data in different times of agriculture year of 2007-2008 were measured. The measured and simulated data were analyzed. The statistical comparison which was done base on the root mean square error (0.49 ton/ha), correlation coefficient (0.85) and modeling efficiency (0.84), for estimating the total crop dry matter of wheat and fodder maize showed that the estimated crop yield by SWAP agree well with observed values. Suitable values of statistical indexes obtained for estimating soil moisture and soil salinity by SWAP, indicated that considering suitable bottom boundary condition in SWAP which has important role on water and solute balance in soil, has affected on estimation of soil moisture and salinity considerably.
Keywords: Crop yield, Soil salinity, SWAP model, Water and salinity limitations
H. Ramezani; B. Nazari; A.R. Tavakoli; M. Parsinejad
Abstract
Abstract:
Deficit irrigation technique can be used for produce more yield for every unit of irrigation water, and cause to increase crop economical benefit. Main purpose of deficit irrigation is high water use efficiency with decreasing in irrigation sufficiency. In this research potential of CROPWAT ...
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Abstract:
Deficit irrigation technique can be used for produce more yield for every unit of irrigation water, and cause to increase crop economical benefit. Main purpose of deficit irrigation is high water use efficiency with decreasing in irrigation sufficiency. In this research potential of CROPWAT model in deficit irrigation management for two crops, wheat and barley in Karaj climate was studied. The results of reliability index such as RMSE and CRM with about are 9.8-17.2 percent and 0.32-0.51 value respectively, showed that the model in both crops underestimated the yield reduction compared with actual data. Negative values of EF index achieved for both crops with 14 days irrigation interval show inefficiency of model in yield reduction predicting in this irrigation interval. This difference was more obvious in deficit irrigation treatments. Considering only drought stress and neglecting other stresses -such as salinity- is the most important limitation of CROPWAT model. Model crop coefficients could also caused differences between actual data and model results. This study shows that application of CROPWAT model without calibration of crop coefficients and soil characteristics would be result in significant errors and this is should be considered. In this study water use efficiency for studied crops were achieved in the range of 1.3-2.3 Kg/m3 and maximum values of that was in 20% deficit irrigation. Applying optimum deficit irrigation management could have considerable role in increasing water use efficiency.
Keywords: Water use efficiency, Yield reduction, Production function, CROPWAT
H. Ebrahimian; A. Liaghat; M. Parsinejad; M. Akram
Abstract
Abstract
By evaluating the performance of the current drainage systems and exploration of their strengths and weaknesses a comprehensive perspective can be given to designers and organizers for optimum design and implementation of drainage systems for future plans. This study was conducted to evaluate ...
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Abstract
By evaluating the performance of the current drainage systems and exploration of their strengths and weaknesses a comprehensive perspective can be given to designers and organizers for optimum design and implementation of drainage systems for future plans. This study was conducted to evaluate the performance of subsurface drainage systems using rice husk as envelope in Behshahr, a coastal region in the northern part of Iran. For this purpose, eleven piezometers were installed between two subsurface drains designated as S3PD14 and S3PD15. Subsurface drainage system was monitored during rainfall seasons in 1383 and 1385. Parameters such as daily water table fluctuations and drain discharge rate were recorded. The overall conclusion was that subsurface drainage system performance was not satisfactory due to poor control of water table depth and low water discharge, which was mainly because of the drain envelope clogging. Therefore, the Hooghoudt’s equation should not be used for evaluation of design parameters, due to the fact that this equation is only valid for normal conditions (envelope without clogging).
Key words: Subsurface drainage, Rice husk envelope, Water table, Discharge rate, Behshahr, Iran
