n s; h p; r a; y m
Abstract
In order to evaluate the possibility and compare different irrigation methods in ricecultivation, an experiment was conducted in factorial based randomized complete blockdesign at Rice Research Institute of Iran, Mazandaran (Amol), during 2011. Treatments weredifferent irrigation regimes including alternate ...
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In order to evaluate the possibility and compare different irrigation methods in ricecultivation, an experiment was conducted in factorial based randomized complete blockdesign at Rice Research Institute of Iran, Mazandaran (Amol), during 2011. Treatments weredifferent irrigation regimes including alternate wet and drying (AWD), semi-dry cultivation(SDC), combining shallow water depth with wetting and drying (SWD) and traditionalirrigation (TI); and two different cultivars, namely, Tarom and Fajr, as local and improvedcultivars, respectively. Results of ANOVA indicated that different cultivars and irrigationmethods were significantly different in terms of irrigation and total water productivity. SDCwith 4042.5 m3ha-1 (nearly 54 percent water saving), irrigation water productivity of WPI=1.68 kg m-3, and total water productivity of WPI+R=1.38 kg m-3 showed better performance ascompared to the other irrigation regimes, especially compared to the traditional management(TI). In conclusion, regarding the better performance in water productivity, advancedirrigation methods (SDC, AWD and SWD, respectively) could be recommended for furtherinvestigations.
N V; E GH
Abstract
In order to evaluate drought tolerance of some genotypes of indeterminite soybean in Uromia, a field experiment using randomized complete block design with split plots was conducted in three replications at Research Farm of Uromia Agricultural High School during 2012. The main plots were allocated ...
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In order to evaluate drought tolerance of some genotypes of indeterminite soybean in Uromia, a field experiment using randomized complete block design with split plots was conducted in three replications at Research Farm of Uromia Agricultural High School during 2012. The main plots were allocated to three levels of drought stress including: no tension i.e. irigation after every 60 mm evaporation from Class A pan; moderate drought stress with irrigation after 110 mm evaporation and severe drought stress, irrigation after 160 mm evapration). Also, three soybean genotypes (Clark, Wiliyams, and Anion) were planted in the sub-plots. Five drought tolerance indices including stress susceptibility index (SSI), stress tolerance index (STI), tolerance index (TOL), Mean Productivity (MP) and geometric mean productivity index (GMP) were calculated based on grain yield in normal and stress conditions. Stress intensity (SI) for mild and severe stress was, respectively, 0.44 and 0.62. The lowest indexes of SSI and TOL in both stress conditions was related to the genotype Williams. Under irrigation after 160 mm evaporation and based on MP, GMP, and STI indices, genotype Williams had the lowest rank and was sensitive to drought stress. In this experiment, under mild and severe drought stress conditions, genotype Anion had the highest MP, GMP, and STI indices, therefore, it was recognized as drought tolerant compared with the other genotypes.
M Dastoorani; S. Poormohammadi; Mohammad Hassan Rahimian
Abstract
Reliable estimation of actual evapotranspiration of the plants plays an important role on planning and optimization of water use especially in dry land environments, where water scarcity is an important problem. In this study, Surface Energy Balance Algorithm for Land (SEBAL) was used for estimation ...
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Reliable estimation of actual evapotranspiration of the plants plays an important role on planning and optimization of water use especially in dry land environments, where water scarcity is an important problem. In this study, Surface Energy Balance Algorithm for Land (SEBAL) was used for estimation of actual evapotranspiration (ETa) in Ardakan pistachio orchards, Yazd province, Iran. For this purpose, a time series of satellite images including 13 cloud free MODIS data were employed to generate actual ET map of pistachio orchards. Results of this study indicated that seasonal ETa for pistachio trees was about 1150 mm, which was significantly less than the applied irrigation depth, Results of this study emphasize the necessity of a proper irrigation scheduling, irrigation interval, and depth in Ardakan pistachio orchards. Consequently, water productivity will improve and considerable amounts of water will be saved as the result of these improvements.
H B; A A; A KH
Abstract
In order to investigate the effect of irrigation and straw mulch on yield andyield components of bean, a split-plots experiment with randomizedcomplete block design in three replications was conducted in AstanehAshrafiyeh city during 2012. In this study, irrigation managementtreatments including ...
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In order to investigate the effect of irrigation and straw mulch on yield andyield components of bean, a split-plots experiment with randomizedcomplete block design in three replications was conducted in AstanehAshrafiyeh city during 2012. In this study, irrigation managementtreatments including no irrigation, irrigation frequencies of 6, 12, and18days, and different amounts of straw mulch as 0, 1, 2, and 3 cm thicknesswere examined. The results of the analysis of variance revealed thatirrigation management and different levels of mulch had significant effectson seed yield. But, their interaction was not significant on seed yield. Thetrend of variations indicated that the highest seed yield with 2431.3 kg ha-1was associated with irrigation frequency of 6 days. [n response to the maineffects of mulch levels, the highest average seed yield (1585.6 and 1518.4kg ha-1) was obtained in the 2 and 1 cm treatments, respectively. Also,using straw mulch in irrigation conditions prevented severe seed loss incomparison with no mulch condition. The highest water use efficiencywas in irrigation frequency of 18 days with an average of 0.58 kg m-3.Water use efficiency at straw mulch levels of 1 and 2 cm was observed as0.63 and 0.6 kg m-3, respectively.
A haghayeghi moghadam; m farzamniya
Abstract
Access to fresh groundwater plays an important role in stable crop production and secure livelihood of people living in the Neyshabour plain. Decline in groundwater table and annual aquifer abstraction of more than 200 million cubic meters are the most important challenges in this plain, where about ...
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Access to fresh groundwater plays an important role in stable crop production and secure livelihood of people living in the Neyshabour plain. Decline in groundwater table and annual aquifer abstraction of more than 200 million cubic meters are the most important challenges in this plain, where about 110,000 ha of agricultural land are cultivated annually and 96% of groundwater resources are used in the agricultural sector. In this study, Soil-Water-Atmosphere-Plant (SWAP) model was calibrated and validated using measured data from six different fields located in the Neyshabour plain. For this purpose, field information and other SWAP required data were collected in the six farm conditions. Calibrated and validated SWAP model was then used to quantify the effects of existing irrigation practices on water balance components and different water productivity indicators and to determine improved irrigation schedules for wheat, barley, sugar beet, cotton, silage corn, and tomato. Estimation of the net water saving as a result of improved irrigation schedules is also discussed. The results showed that under the current irrigation practices, soil evaporation reduced WPET (Yact/ETact) over WPT (Yact/Tact) by 24%, 26%, 27%, 21%, 8% and 16% for wheat, barley, sugar beet, cotton, silage corn and tomato, respectively. The reduction in WPETQ (Yact/ETact+qbot) over WPET because of deep percolation was even higher: 50%, 44%, 33%, 37%, 14% and 56% for wheat, barley, sugar beet, cotton, silage corn and tomato, respectively. The substantial differences in WP values emphasized the need to control non-beneficial soil evaporation and deep percolation losses, and change traditional irrigation system by a more efficient one. Model simulations by improved irrigation schedule revealed that a seasonal irrigation amount of 520 mm for wheat, 440 mm for barley, 1010 mm for sugar beet, 930 mm for cotton, 870 mm for silage corn and 1050 mm for tomato would be enough to get the maximum yields. The optimized irrigation schedule uses 26% less irrigation water as compared to current irrigation practices and increases WPI (Yact/Irrig) by a factor of 1.2 for wheat, 0.7 for barley, 1.6 for sugar beet, 6.7 for silage corn and 8.3 for tomato because of reduced soil evaporation and moisture storage in the root zone. Considering the total area of cultivation of the six studied crops in the Neyshabour plain (80000 ha), it is estimated that adoption of optimal irrigation schedules can save up to 165 million m3 of water.
6
ali mokhtaran; Peyman Varjavand; Hossein Dehghanisanij; Shokrola Absalan; Azarakhsh Azizi; Alireza Jafarnejadi
Abstract
This study was conducted to compare and monitor drip and surface irrigation systems for corn and wheat crops in three planting seasons from summer 2016 to spring 2018 in one of the agricultural research stations in Khuzestan, located in Ahvaz. The source of irrigation water was Karun River with salinity ...
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This study was conducted to compare and monitor drip and surface irrigation systems for corn and wheat crops in three planting seasons from summer 2016 to spring 2018 in one of the agricultural research stations in Khuzestan, located in Ahvaz. The source of irrigation water was Karun River with salinity of 3 dS/m in Ahvaz section. This study was performed using randomized complete blocks design with three replications. The basis of blocking in corn cultivation was 2 and 4 days irrigation intervals, and in wheat cultivation, the distances between drip lines were 40, 60, and 75 cm. The results showed that the volume of water used in the drip system for corn and wheat was 24% and 32% lower than the surface irrigation system, respectively. Also, water productivity in the drip system was higher than surface irrigation system by 16% and 21%, for corn forage and grain, respectively, and by 35% for wheat. Wheat water productivity for different distances of drip lines was not significantly different. Therefore, in heavy-textured soils, drip irrigation lines at 75 cm spacing can be used for wheat cultivation. In soil monitoring analysis, the drip system reduced soil quality such that, after three planting seasons, the initial non-saline-sodic soil (ECe = 3.09dS / m, ESP = 6.18%) became saline (ECe = 7.63dS / m, ESP = 12.63%). Despite accumulation of salts at the periphery of the wetted soil under the drippers, the plants had a better growth and yield in the drip system than the surface irrigation, because of the high soil water potential around the roots and under the drippers, which reduced salt effects. The results of this study showed that if a drip system is used for the climate similar to the central and southern regions of Khuzestan, land drainage and leaching operations at the end of the growing season are necessary to protect the soil.
A KHARAZMI; M MASHAL; GH ZAREI; M VARAVIPOUR
Abstract
The Guelph Permeameter technique (GP) is one of the proper methods for measuring the saturated hydraulic conductivity (Kfs) above the water table. This study was done by Guelph Permeameter model 2800k1 in 20 auger holes at Research Farm of Abourayhan Campus. Soil texture was determined for the Research ...
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The Guelph Permeameter technique (GP) is one of the proper methods for measuring the saturated hydraulic conductivity (Kfs) above the water table. This study was done by Guelph Permeameter model 2800k1 in 20 auger holes at Research Farm of Abourayhan Campus. Soil texture was determined for the Research Farm, using the hydrometer method. Water outlet flow of the permeameter was measured in four phases under constant ponding heads (H) of 5, 10, 15 and 20 cm, respectively. The field saturated hydraulic conductivity (Kfs) and matric flux potential (Øm), based on successful testing and Guelph analysis, were evaluated by different methods. The results indicated that, in heavy soils, increasing submergence depth of H2 relative to H1, is an appropriate solution for reducing the Guelph's two-head analysis failure in soil hydraulic conductivity estimation. In this study, well shape factor (C) was also calculated by five different methods. Later, the effect of the calculated C factor by various methods was studied in Guelph's two-head analysis. The results showed that using unsaturated effect in the calculations lowers the possibility of obtaining negative values of Kfs and Øm in Xiang Solution. Also, there was a very high correlation between Guelph successful two-head analysis when Xiang and Numeral Solutions were used for calculating C factor (r=0.98).
8
Hossein Jafari; ali morshedi
Abstract
Estimation of crop water requirement and evapotranspiration by lysimeter is costly and time-consuming and could not be applied to larger field scale. Remote sensing technology can overcome this limitation. The goal of this research was to estimate alfalfa actual evapotranspiration using satellite imagery ...
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Estimation of crop water requirement and evapotranspiration by lysimeter is costly and time-consuming and could not be applied to larger field scale. Remote sensing technology can overcome this limitation. The goal of this research was to estimate alfalfa actual evapotranspiration using satellite imagery and compare it with the in-situ measurement by lysimeter. The study was carried out from 2017 to 2020 in the agricultural lands of Alborz and Charmahal and Bakhtiari provinces employing Surface Energy Balance Algorithm for Land (SEBAL) method. Lysimeter has been implemented under standard conditions. The cold pixels of each satellite image were extracted to estimate net alfalfa crop water requirement. In-situ net crop water requirement for Alborz and Charmahal and Bakhtiari provinces were obtained as 1383 and 1087 mm, respectively. The coefficients of determination (R2) were 73% and 76%, respectively, for the two studied provinces. The statistical analysis showed that there were small deviations from the mean values. The standard evapotranspiration measurements using lysimeter were higher than the satellite estimations. This technique can be useful for the estimation of crop water consumption since it is simple, cheap, fast, and can be used for large areas.
Abstract
Nitrogen is the primary nutrient that shows deficiency in saline areas, therefore, proper nitrogen fertilizer management is one of the strategies to achieve higher wheat grain yield. A field experiments in a saline soil was performed on wheat with a factorial arrangement in randomized complete ...
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Nitrogen is the primary nutrient that shows deficiency in saline areas, therefore, proper nitrogen fertilizer management is one of the strategies to achieve higher wheat grain yield. A field experiments in a saline soil was performed on wheat with a factorial arrangement in randomized complete block design with four replications, in Rostagh area, 25 km from Yazd. The first factor was nitrogen sources including urea, ammonium nitrate, and ammonium sulfate fertilizer, and the second factor was fertilizer use management consisting of four levels: 1- control (no nitrogen application), 2- recommended amount of fertilizer in three equal installments at the time of sowing, tillering, and heading stage, 3- recommended amount of fertilizer in three installments and 30% nitrogen in addition to the recommended rate in the tillering stage, and 4- recommended amount of fertilizer in three installments and 30% nitrogen in addition to the recommended rate at the heading stage. The results showed that the additional use of fertilizer at various growth stages had no significant effect on yield and its components. In comparison of urea to the other two fertilizers, ammonium nitrate had no significant effect in total yield of wheat in different fertilizer treatments, but using 30% nitrogen in addition to the recommended rate at tillering stage could cause significant differences in total yield when ammonium sulfate was used. Based on the results of this experiment, using nitrogen in peak times of consumption i.e. at tillering and heading, can reduce the loss of nitrogen from the soil, in addition to increasing grain and straw yield under saline conditions.
m m; k d; b gh; h a; a h
Abstract
Crop growth simulation models have been developed for predicting the effects of water and salinity on grain and biomass yields and water productivity of different crops. These models are calibrated and validated for different regions using the data generated from field. This study was carried in Mashhad ...
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Crop growth simulation models have been developed for predicting the effects of water and salinity on grain and biomass yields and water productivity of different crops. These models are calibrated and validated for different regions using the data generated from field. This study was carried in Mashhad for two years (2010 and 2011) in order to evaluate the AquaCrop model under simultaneous salinity and water stress. Calibration was done using the data of 2009-2010 and validation with the data of 2010-2011.Results indicated that AquaCrop successfully simulated yield, biomass, water productivity, harvest index, soil moisture and salinity profiles for spring wheat under salinity and water-limiting treatments with high accuracy, although simulation of harvest index and soil salinity profiles were less accurate. Average value of normalized root mean square error (NRMSE), maximum error (ME), index of agreement (d), coefficient of the residual mass (CRM) and coefficient of determination (R2) in both the calibration and verification were 13.3 %, 36.1 %, 0.95, -0.072, and 0.87, respectively, for grain yield, while these measures were 12.59%, 34.46%, 0.92, 0.057, and 0.77, respectively, for biomass. Also, value of NRMSE, ME, d and CRM were 11.84 %, 25.72 %, 0.93, and 0.032, respectively, for soil moisture, while these measures were 26.25%, 58.5%, 0.91 and -0.12, respectively, for soil salinity. Sensitivity analysis revealed that crop transpiration coefficient (KC-Tr), normalized crop water productivity (WP*), reference harvest index (HIO), volumetric water content at field capacity, soil water content at saturation[S1] , and air temperature were the most sensitive parameters. Although the accuracy of the model simulation decreased with increasing salinity and water stress, AquaCrop can be a valuable model for simulating spring wheat yield and soil water content and salinity in Mashhad region, because the model requires few input data which can be readily available or easily collected. [S1]This is probably”initial conditions” and not saturation.
M GH; A D; A M
Abstract
Intermittent irrigation is a method to increase water productivity of rice (Oryza sativa L.). In this study, the effects of this type of irrigation combined with two periods of midseason drainage on growth parameters of two rice cultivars were investigated in subsurface drained paddy fields. The experiment ...
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Intermittent irrigation is a method to increase water productivity of rice (Oryza sativa L.). In this study, the effects of this type of irrigation combined with two periods of midseason drainage on growth parameters of two rice cultivars were investigated in subsurface drained paddy fields. The experiment was laid out as split plot in a randomized complete block design with three replications during 2014 growing season. The main factor consisted of drainage systems in the study field including three conventional subsurface drainage systems with drain depths and spacing of, respectively, 0.9 m and 30 m (D0.9L30), 0.65 m and 30 m (D0.65L30), and 0.65 m and 15 m (D0.65L15). In addition, a bi-level subsurface drainage system with drain spacing of 15 m and drain depths of 0.65 and 0.9 m as alternate depths (bilevel), and a treatment without subsurface drainage (control) were included in the study. Sub-factors including rice cultivars Hashemi and Daylamani Tarom were planted in the study area. Midseason drainage was conducted in two periods of 10- day (25 to 34 days after transplanting) and 5-day (43 to 47 days after transplanting). During the growing season, sampling was done to determine leaf area index (LAI), total shoot dry weight (TDW), crop growth rate (CGR), relative growth rate (RGR), leaf area ratio (LAR) and net assimilation rate (NAR). Conducting such water management through subsurface drainage systems increased most of the studied parameters of Hashemi cultivar so that significant differences were found between CGR, NAR, and RGR of D0.9L30 and the control treatment. Maximum dry weights of Hashemei and Daylamani cultivars were 858.8 and 1006.6 g m-2 related to D0.65L15 treatment and maximum leaf area indexes of these cultivars were 4.87 and 5.43 related to bilevel and control treatments, respectively. However, there were not significant differences among different treatments for each cultivar. Based on the results, two periods of midseason drainage through subsurface drainage would improve rice growth characteristics if proper drainage time is selected.
azhdar onnabi milani; sedghali zamani
Abstract
Proper use of water resources in arid and semi-arid regions is important and vital. This study was conducted to evaluate the effect of irrigation scheduling by various methods on crop yield and water use efficiency (WUE) by wheat, and determining suitable irrigation-scheduling method for irrigation of ...
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Proper use of water resources in arid and semi-arid regions is important and vital. This study was conducted to evaluate the effect of irrigation scheduling by various methods on crop yield and water use efficiency (WUE) by wheat, and determining suitable irrigation-scheduling method for irrigation of wheat in Saeedabad, Tabriz. A field experiment was conducted with 10 irrigation treatments (I1 to I10) in randomized complete block design with 4 replications. The irrigation timing treatments comprised of two ratios of irrigation depth to evaporation from class A pan i.e. 0.8 (I1) and 1.0 (I2), two soil water potentials -40 (I3) and -60 (I4) kPa, two soil water contents i.e. 40% (I5) and 60% (I6) soil available water in root zone, two canopy temperatures i.e. stress degree days equal to 10 (I7) and 12 (I8), and irrigations at different physiological growth stages i.e. crown root initiation (CRI) + flowering (I9) and CRI + late tillering + boot + milk stages (I10). Results indicated that there was significant difference between treatments in biomass, grain yield, WUE, kernel weight, protein content and harvest index (HI). Among the treatments, I2 had the maximum biomass, grain yield and kernel weight. I9, I10 and I3 were the best treatments in WUE, seed protein content, and HI, respectively. Although the selection of the best irrigation scheduling method depends on water resources availability and existing facilities, in general, with due attention to irrigation frequencies and other consideration such as volume of applied water, grain yield, WUE, and simplicity of the method, we can recommend irrigation at –40 kPa soil water potential as a suitable method for timing of irrigation under this experimental condition.
d gh; f r; a e
Abstract
Nowadays, mycorrhizal fungi are widely used due to their symbiosis relation with roots of so many plants. By facilitating absorption of some plant minerals and water, these fungi have a key role in all ecosystems. In this research, the effects of mycorrhizal fungi and different levels of phosphorous ...
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Nowadays, mycorrhizal fungi are widely used due to their symbiosis relation with roots of so many plants. By facilitating absorption of some plant minerals and water, these fungi have a key role in all ecosystems. In this research, the effects of mycorrhizal fungi and different levels of phosphorous chemical fertilizers on some yield components and macro elements uptake of Zea mays L. under different levels of irrigation water were studied. The experiment was performed in completely randomized block as a split factorial design with four replications using different irrigation levels (A1=60, A2=120, A3=180 mm of evaporation from class A pan) as the main plots and different P levels (P1=0, P2=60 and P3=120 kg P/ha on the basis of P2O5) and mycorrhizal fungi (at two levels: un-inoculated and inoculated with 6 g of mycorrhizal inoculant placed 3 cm under each seed) in the subplots. The results indicated that the effects of Mycorrhizal inoculation were significant and positive on measured indices. Among triple interactions i.e. irrigation/ chemical phosphorus/ mycorrhizal inoculation, significant effects (p<0.05) on grain yield (maximum 5045 kg/ha) and 1000 seed weight (157.75 g) and also on P concentration (p<0.01) were observed in treatments with proper amount of water and fertilizer P and mycorrhizal inoculation (A1P2G2). Under water stress, the highest grain yield, 1000 seed weight, fresh forage, and P concentration were obtained in treatment with moderate water stress and proper amount of chemical P (60g/kg) and mycorrhizal inoculation (A2P2G2). Also, the highest plant height (242.87 cm) was obtained in the same treatment. Results showed that in moderate water stress, using proper amount of chemical P and mycorrhizal inoculation can compensate decrease in grain yield, while under high level of drought stress, grain yield decreased.