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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.
fatemaeh hajiabadi; Farzad Hassan Pour; Mostafa Yaghoubzadeh; Hossin Homami; Seyed Mohsen seyedi
Abstract
Salinity and drought stress are the most important factors that limit plant growth, especially in dry and semi-arid regions. To investigate the effects of irrigation water levels and salinity on yield and yield components of wheat cultivar Sirvan, a factorial experiment was conducted in a complete randomized ...
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Salinity and drought stress are the most important factors that limit plant growth, especially in dry and semi-arid regions. To investigate the effects of irrigation water levels and salinity on yield and yield components of wheat cultivar Sirvan, a factorial experiment was conducted in a complete randomized block design with three replications in the research field of agricultural faculty of the University of Birjand during the growing season of 2017-18. The treatments included irrigation at four levels (125%, 100%, 75%, and 50% water requirement) and water salinity in three levels (1.6 dS.m-1, 6 dS.m-1, and 7.8 dS.m-1). The results showed that yield components, biological yield, and grain yield of wheat were affected by water irrigation levels and water salinity. Moreover, these treatment significantly reduced the yield components, harvest index, and water use efficiency (WUE). In biological and grain yield of wheat, the highest and the lowest amounts belonged to 125% water requirement × salinity of 1.6 dS m-1 by 1535and 588.76 g m-2, respectively. In biological yield and grain yield, there was no significant difference observed between 125% wheat water requirement × salinity’s of 1.6% dS.m-1 and 100% water requirement × salinity of 1.6% dS.m-1 treatments. Biological and grain yield of wheat decreased to 65% in 50% water requirement × salinity of 7.8 dS m-1 compared with 125% water requirement × salinity of 1.6% dS.m-1. According to results of this experiment, 125% and 100% water requirement treatments had the highest biological and grain yield. Although 125% wheat water requirement had the highest value in all traits but they were not significant compared to 100% water requirement treatment. In water salinity treatments, non-stress levels had the best performance. According to the results of this study, to avoid salt accumulation in the root zone under saline water irrigation and to decrease negative salinity effects, irrigation must be applied based on wheat water requirement.
mokhtar Salehi Tabas; Mostafa Yaghoubzadeh; Reza Hashemi; Hamed Mansori; Saeed ghavamsaeedi
Abstract
Moisture content of surface soil is an important variable in nature's water cycle, which plays an important role in the global equilibrium of water and energy due to its impact on hydrological, ecological, and meteorological processes. Soil moisture is a determining factor in many complex environmental ...
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Moisture content of surface soil is an important variable in nature's water cycle, which plays an important role in the global equilibrium of water and energy due to its impact on hydrological, ecological, and meteorological processes. Soil moisture is a determining factor in many complex environmental processes and plays a determinative role in the occurrence of agricultural drought. In this study, based on estimated soil moisture data by SWAP model and data of the IPCC Fifth Assessment Report, agricultural drought was determined by the use of soil moisture deficit index for the future period. The climatic data was estimated using six GCM models and two RCP4.5 and RCP8.5 emissions scenarios, and downscaled by LARS-WG model, and was entered into the SWAP model. Finally, by using soil moisture data of 30 cm depth, agricultural drought was evaluated using SMDI index. The results of climate parameter changes showed that the minimum and maximum temperatures and rainfall in the future period would increase compared to the base period and RCP8.5 scenario estimated higher temperatures and less rainfall than RCP4.5 scenario. Results of estimated SMDI values for the future period showed that RCP4.5 scenario has a higher average of SMDI amount than RCP8.5 scenario. Also, both scenarios show the normal moisture amount for future period and the predicted SMDI amount for the future period is higher than the base period.
m y; Mohsen Ahmadee; s b; a h
Abstract
Climate change has important impacts on most of the natural processes, including hydrological cycle. Evapotranspiration, as a part of hydrological cycle, will also undergo these changes. Due to the importance of evapotranspiration in water resources and agricultural management, this research was ...
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Climate change has important impacts on most of the natural processes, including hydrological cycle. Evapotranspiration, as a part of hydrological cycle, will also undergo these changes. Due to the importance of evapotranspiration in water resources and agricultural management, this research was conducted to study climate change effect on evapotranspiration in Neyshabour plain. Evapotranspiration was calculated for five farms in Neyshabour plain using SWAP software and meteorological and agronomic data. In irrigated farms, the HADCM3, ECHAM5OM and CGCM3T47models were used to calculate crop actual evapotranspiration for 2020-2039 and 2080-2099 periods based on A2, B1 and A1B scenarios and the climate model used in rainfed farms was the HADCM3 based on A2 and B1 scenarios. The greatest calculated difference in evapotranspiration was found between the period 2080-2099 and base period (1992-2011) in the A2 scenario. Also, evapotranspiration values for the period 2080-2099 will increase compared to the period 2020-2039 in all three scenarios. Among the crops of investigate, wheat will have the greatest changes (12%) in evapotranspiration in the future periods compared to the base period, while changes of maize will be only 3%. However, the average daily evapotranspiration of maize during the growing season (about 12 mm/day) will be more than the other crops.
M Y; S B; Z I; H S
Abstract
Accurate estimation of evapotranspiration plays an important role inquantification of the water balance at regional scale for better planningand managing water resources. Evapotranspiration can be obtained fromeither estimation of potential ET using data of meteorological stations or,directly, from field ...
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Accurate estimation of evapotranspiration plays an important role inquantification of the water balance at regional scale for better planningand managing water resources. Evapotranspiration can be obtained fromeither estimation of potential ET using data of meteorological stations or,directly, from field measurements. ET is subject to rapid changes in timeand space, attributable to the wide spatial variability of precipitation,hydraulic characteristics of soils, and vegetation types and densities.Therefore, it is nearly impossible to determine its spatial and temporaldistributions over large areas only from lysimeter and precise measuringinstruments. Thus, researchers have used remote sensing data to estimateareal actual ET. In this study, actual evapotranspiration variations ofNeyshabour plain was investigated by algorithm of energy balance of theearth since 2000 to 2013 by using MODIS images and meteorologicaldata. Also, the determined evapotranspiration was compared and evaluatedwith Penman-Monteith and Hargreaves-Samani models. Low amount ofcoefficients of the error between Penman-Monteith model and SEBALalgorithm showed the accuracy of SEBAL model in the estimation ofevapotranspiration and its parameters. The results derived fromcomparison of evapotranspiration and NDVI vegetation index indicated agood correlation between vegetation and evapotranspiration (R2=0.908).Also, the variations of NDVI index, land surface temperature, andevapotranspiration in the studied fields showed that evapotranspirationincreased by lower land surface temperature and higher densities ofvegetation.