Research Paper
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 ...
Read More
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.
Research Paper
saeed saadat; mehdi homaee
Abstract
Plant response to salinity varies at different growth stages. Information on plant response to salinity at various growth stages can be used in managing saline waters for irrigation. In order to measure the quantitative response of salinity on germination of Sorghum (Sorghum bicolor L. Moench), a greenhouse ...
Read More
Plant response to salinity varies at different growth stages. Information on plant response to salinity at various growth stages can be used in managing saline waters for irrigation. In order to measure the quantitative response of salinity on germination of Sorghum (Sorghum bicolor L. Moench), a greenhouse experiment was conducted in a natural saline sandy loam soil, using plastic pots with 15 cm height and 8 cm diameter. Salinity treatments included a non-saline water (EC = 0.3 dS/m) and 12 saline waters with electrical conductivities of 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24 dS/m. The Maas and Hoffman, Van Genuchten and Hoffman, Dirksen et al., and Homaee et al. models were used to predict Relative Germinated Seeds (RGS) in different soil salinity treatments and to measure quantitative effect of salinity on seed germination. The results indicated that salinity threshold value (EC*) for sorghum was 5.5 dS/m at germination, and the germination rate was reduced to 50 percent at 9 dS/m soil salinity. The predicted EC* by the models were less than the actual values measured in the experiment and also by those reported by Maas and Hoffman (6.8 dS/m). The R2 values for predicting RGS by non-linear models of Van- Genuchten and Hoffman, Dirksen et al., and Homaee et al. were 0.98, 0.99, and 0.98, respectively.
Research Paper
alireza jafarnazhadi; seyyed mohammad hadi mousavi fazl
Abstract
Nowadays, application of unconventional water such as wastewater is one of the strategies for preventing water deficit. This study was conducted to evaluate effect(s) of treated wastewater application on microbial and chemical contamination of soil and wheat (Chamran V.). Five treatments included T1 ...
Read More
Nowadays, application of unconventional water such as wastewater is one of the strategies for preventing water deficit. This study was conducted to evaluate effect(s) of treated wastewater application on microbial and chemical contamination of soil and wheat (Chamran V.). Five treatments included T1 (irrigation with 100% fresh water), T2 (75% fresh water + 25% wastewater), T3 (50% fresh water + 50% wastewater), T4 (25% fresh water + 75% wastewater), and T5 (100% wastewater) that were conducted with three replications, in a randomized complete blocks design in the research station of Ahvaz Agricultural Research Center. The irrigations were done based on soil moisture monitoring. The volumes and the time of irrigation were determined based on the 70% soil Field Capacity. The soil (0-30 cm) and plant (seed) samples were taken during wheat growth periods and were analyzed for some parameters such as soil microbial population as well as cadmium (Cd) concentration and micronutrients in soil and plant. The results showed that the total soil Cd concentration in 95% of the samples was less than 1.6 mg.kg-1. However, soil DTPA-Cd concentrations in all the treatments decreased compared to initial Cd soil content. The results revealed that wastewater treatments had no significant (p<0.05) effect on seed microelements, except Fe. The average soil DTPA-Cd in each wheat growth stage did not increase compared to its initial concentration. The soil microbial population at different growth stages was not significantly different (p<0.05) in T3 and T5 treatments, possibly due to growth limitations as a result of nutrient accessibility limitation. It may be concluded that the application of wastewater (along with fresh water) had no adverse effect on soil and wheat quality in short term. However, long term application of unconventional waters may cause contamination in soil and agricultural products.
Research Paper
hamidreza salemi; ghasem zarei; davoud afiyuni; hamidreza sharifi
Abstract
Up to now, interactions between method and amount of nitrogen fertilizers application on plant density and variety of wheat under sprinkler irrigation systems have not been studied. Thus, this research was conducted during two years in Esfehan region with split factorial design. The treatments ...
Read More
Up to now, interactions between method and amount of nitrogen fertilizers application on plant density and variety of wheat under sprinkler irrigation systems have not been studied. Thus, this research was conducted during two years in Esfehan region with split factorial design. The treatments of this experiment were: Three fertilizers application methods (conventional manual application at the recommended rate, fertigation method with sprinkler irrigation system at the recommended rate, and fertigation with sprinkler irrigation method at 70 % of the recommended rate), three wheat varieties (Pishtaz, Shiraz, and Bahar), and three plant densities (300, 400, and 500 seed per square meter). In this study, the amount of water use, fertilizer requirement in case of fertigation, suitable density and variety of wheat under these conditions were determined and recommended for the region. Results showed that there were no significant differences in quantity of yield among the three fertilizer application methods. Mean grain yield in F1, F2,and F3 were 6914 and 7720 kg/ha for the first and second years, respectively. The amounts of grain produced per one kg applied urea were 17.51, 17.92, and 23.44 kg for the first year and 15.39, 15.54 and 22.78 kg for the second year in the three fertilizer treatments, respectively. Therefore, the nitrogen use efficiency in fertigation with 70% of the recommended rate (F3) was high. Mean grain yield for the inestigated varieties indicated that, in sprinkler irrigation, the most suitable variety were Bahar and Pishtaz, respectively.
Research Paper
mehdi babai; mostafa mardani; mashallah salarpour
Abstract
Water is one of the most important and limited inputs in agricultural productions. The aim of water resources management in agriculture is increasing production performance and raising water use efficiency. To achieve this, in the present research, the water use efficiency of the main agricultural products ...
Read More
Water is one of the most important and limited inputs in agricultural productions. The aim of water resources management in agriculture is increasing production performance and raising water use efficiency. To achieve this, in the present research, the water use efficiency of the main agricultural products and farmers of Zabol District was studied using data envelopment analysis (DEA) in 2011. The results showed that the average of farms efficiency in the constant and variable return to scale was 0.77 and 0.98, respectively. The average of efficiency of scale was 0.78, which shows inefficiency of scale. The average efficiency of irrigation water in the constant return to scale was 0.52 and 0.86, respectively. Also, , under the constant return to scale, to achieve perfect efficiency in wheat, barley, and corn silage, reduction of water use levels to 3269, 2377, and 7539 m3/ha, respectively, is recommended. According to the results, it seems that with the implementation of modern irrigation systems the amount of water use can be reduced.
Research Paper
hossein norouzi; habib roshanfekr; peyman hasibi; mousa mesgarbashi
Abstract
The effect of different salinity levels (1.7, 5, 10, 15 and 20 dS.m-1) on yield and forage quality of two millet cultivars (Nutrifeed and Bastan) was investigated in this experiment. A factorial test based on randomized complete block design with three replications was conducted during 2010-11 growing ...
Read More
The effect of different salinity levels (1.7, 5, 10, 15 and 20 dS.m-1) on yield and forage quality of two millet cultivars (Nutrifeed and Bastan) was investigated in this experiment. A factorial test based on randomized complete block design with three replications was conducted during 2010-11 growing season. The results showed that with increase in salinity, dry matter yield decreased. The highest total dry matter was observed in the control treatment of Nutrifeed millet (83.2 g. plant-1) and the lowest was measured in 20 dS.m-1 treatment of Bastan millet (23.5 g. plant-1). The results indicated that the forage quality and the mineral material in the aerial organs of the two studied cultivars were under the effects of the salinity stress. By increasing the salinity stress, the protein percentage, potassium content, and the shoot calcium and magnesium content decreased, but pure fiber percentage and the sodium content increased. The results of correlation of traits in salt stress conditions showed that there was a significant negative correlation between protein percentage and pure fiber percentage (r=-0.6*). Increase in pure fiber percentage decreased protein percentage. Treatment 20 dS.m-1 sodium chloride decreased dry weight of Nutrifeed and Bastan varieties (44% and 57%, respectively) compared to the control conditions. Treatment of 10 dS.m-1 sodium chloride decreased dry matter yield of Nutrifeed and Bastan varieties (24% and 34%, respectively) compared to the control. Therefore, the results of this experiment indicated that salinity tolerance threshold of Nutrifeed and Bastan varieties were 5 dS.m-1and 1.7 dS.m-1 (control treatment), respectively.
Research Paper
m d; m j; h t
Abstract
Due to limited water resources, applying efficient water use in agriculture is very important. This experiment was carried out in Kabootarabad agricultural research station for two years using split plots in a randomized complete block design with four replications. Six irrigation treatments based on ...
Read More
Due to limited water resources, applying efficient water use in agriculture is very important. This experiment was carried out in Kabootarabad agricultural research station for two years using split plots in a randomized complete block design with four replications. Six irrigation treatments based on evaporation from class A pan were applied as the main factor at three cotton growing stages, namely, four-leaf stage to early flowering, early flowering to early boll opening, early boll opening to the end of growing season. Besides, two cotton cultivars, namely, B557 and Tabladyla, were studied as the secondary factor. Results showed that irrigation regimes had a significant impact on the performance in the first harvest, total yield, and ten-boll weights, but no effect was observed on the boll number per plant and the number of green plants. Irrigation based on cumulative pan evaporation of 150 mm at the four-leaf stage to early flowering, irrigation after 70 mm cumulative evaporation during early flowering and early boll opening, and irrigation after 110 mm cumulative evaporation in early boll opening to the end of the growing season produced the highest cotton yield with 5113.3 kg/ha. Results showed that the effects of cultivar on yield and its components were not significantly different and B557 and Tabladyla both can be recommended.
Research Paper
k m; e a; b s
Abstract
Sustainable economical production of tea depends on the proper use of water and fertilizer. For this purpose, the role of supplemental irrigation and nitrogen fertilizer on economical production of tea plantations was studied by assessment of yield, production function, water use efficiency, and benefit/cost ...
Read More
Sustainable economical production of tea depends on the proper use of water and fertilizer. For this purpose, the role of supplemental irrigation and nitrogen fertilizer on economical production of tea plantations was studied by assessment of yield, production function, water use efficiency, and benefit/cost ratio, and final return in a field experiment at Feshalam Tea Research Station in Fouman, Guilan, during 2008-10. The experiment was conducted by line-source technique of irrigation and the strip plot experiment with randomized complete block design with four replications. Six levels of zero, 100, 200, 300, 400, and 500 kg N ha-1 were mixed with the soil (source urea) in the main plots and five irrigation levels consisting of full irrigation (I4), deficit irrigation (I1, I2, I3) and no-irrigation (I0), were applied as sub-plots. The full irrigation (342 mm) by sprinkler method and application of 320 kg N ha-1 in mature tea bushes produced 3928 kg yield (made tea) ha-1 and water use efficiency of 7.2 kg ha-1 (made tea) for each mm of water used. The highest yield in rain-fed condition (1403 kg ha-1) and water use efficiency (6.1 kg ha-1 for each mm of rain water) were obtained with application of 200 kg N ha-1. The mean benefit/cost ratio for full irrigation and no irrigation were 1.75 and 1.17, respectively. According to this, although costs increased in full irrigation, but profit increased due to higher production and better quality of green leaf (first grade), compensating the costs.
Research Paper
r m; h t; h g; d m
Abstract
Limited water resources, especially in Iran, require most effective method of water use to avoid losses. One of the important parameters in irrigation is water distribution uniformity coefficient (CU) in sprinkler irrigation. CU in every irrigation depends on pressure heads (P), riser height (RH), distance ...
Read More
Limited water resources, especially in Iran, require most effective method of water use to avoid losses. One of the important parameters in irrigation is water distribution uniformity coefficient (CU) in sprinkler irrigation. CU in every irrigation depends on pressure heads (P), riser height (RH), distance between sprinklers on lateral pipes (Sl), and the distance between lateral pipes (Sm). The best combination of the above parameters for maximum CU is still unknown for users. In this research, CU values of zb model sprinkler (made in Iran) were measured at Hashemabad Cotton Research Station of Gorgan under 3 different pressure heads (2.5, 3, and 3.5 atm), 2 riser elevation (60 and 100 cm) and 7 sprinkler arrangements (Sl×Sm including 9×12, 9×15, 12×12, 15×12, 12×18, 15×15, 15×18m). By using differential evolution algorithm (DE), CU equation was optimized and the best optimized coefficient was obtained. In this algorithm, the coefficients F and CR were equal to 2 and 0.5, respectively, with a population of 100 members and 1000 number of generations (iterations), providing the best results. Absolute error between the results of this algorithm with the measured results was 2.2%. Also, Wilmot (d) and the root-mean square error (RMSE) values were equal to 0.919 and 2.126, respectively. The results showed that this algorithm had high accuracy to estimate water distribution uniformity coefficient.
Research Paper
h p; m kh; m.h b; p sh
Abstract
As irrigation system installation is expensive and time consuming, it would be better to have an estimate of the water content provided by the system in the active root zone before designing an irrigation system. In this study, HYDRUS-2D performance was assessed under a tape irrigating in-situ with a ...
Read More
As irrigation system installation is expensive and time consuming, it would be better to have an estimate of the water content provided by the system in the active root zone before designing an irrigation system. In this study, HYDRUS-2D performance was assessed under a tape irrigating in-situ with a heavy textured and relatively heterogeneous soil in Rasht region. Three different flows i.e. 2.5, 5, and 6 L/h/m and four irrigation times i.e. 1, 2, 3, and 4 hours were considered as the main treatments with three replications. Measured data were compared with the simulated results for both the whole soil profile and the part under the tape using two statistical indices, i.e. RMSE and efficiency factor (EF). The model performance was evaluated as good, with a low average RMSE of 0.0123 and 0.0236 cm3/cm3 for the whole soil profile and under the tape, respectively, with the corresponding average EF values of 77% and 76%, for this soil texture. Overall, the model could satisfactorily simulate soil moisture in a heavy textured and heterogeneous soil.
Research Paper
s r; a r; m n
Abstract
Soil hydraulic properties such as soil water characteristic curve are necessary prerequisite for modeling water movement and solute transport. Direct methods of estimating these hydraulic properties are time consuming and costly. Indirect methods, such as pedotransfer functions, estimate the hydraulic ...
Read More
Soil hydraulic properties such as soil water characteristic curve are necessary prerequisite for modeling water movement and solute transport. Direct methods of estimating these hydraulic properties are time consuming and costly. Indirect methods, such as pedotransfer functions, estimate the hydraulic parameters using easy-to-measure soil properties like particle size distributions, bulk density, or organic matter content. In this study, to estimate soil water characteristic curve, Rosetta pedotransfer function with artificial neural network approach, Soilpar-2, and different regression-based pedotransfer functions were compared and evaluated. For the purpose of comparison and evaluation of pedotransfer functions, statistical criteria of Root Mean Square Error (RMSE), Mean Absolute Error (MAE), Modified Efficiency Coefficient (E'), and Modified Index of Agreement (d') were used. The results show that Rosetta, with mean values of the statistical criteria RMSE, MAE, E' and d' equal to 0.0310, 0.0247, 0.7956, and 0.9037, respectively, enjoyed high accuracy compared to the rest of pedotransfer functions. The results of this study showed that, to estimate soil water characteristic curve, the artificial neural network was more preferable than the regression pedotransfer functions with higher number of input parameters for the study area. The results also indicated that the adjusted Campbell pedotransfer function with RMSE, MAE, E' and d' equal to 0.0685, 0.0530, 0.5561 and 0.8075, respectively, presented the next best estimate of soil water characteristic curve for soils of the study area, after Rosetta.
Research Paper
a s; e n; p d
Abstract
Pipe drain installation depth is one of the most important design parameters, which has a key role in the drained water volume and quality. In this research, the effect of pipe drain installation depth was investigated by using a physical laboratory model. Drains were installed at 0.25, 0.5 and 0.85 ...
Read More
Pipe drain installation depth is one of the most important design parameters, which has a key role in the drained water volume and quality. In this research, the effect of pipe drain installation depth was investigated by using a physical laboratory model. Drains were installed at 0.25, 0.5 and 0.85 m deep in a cubical box with dimensions of 1*0.5*1 meter filled with a sandy loam soil. Nitrate, nitrite, ammonium, and ammonia as well as drained water volume were measured. The results showed that maximum nitrate concentration increased with increase in installation depth. The observed nitrate concentrations for depths of 0.25, 0.5, and 0.85 m were 51.54, 105.45 and 296.42 mg/L, respectively. In addition, drained water volumes for depths of 0.5 and 0.85 m were 26% and 30% of the drained water volume of 0.25m depth, respectively. Therefore, it can be noted that decrease in installation depth caused a reduction in nitrate leaching amounts.
Research Paper
m t
Abstract
Field experiments were conducted on an existing subsurface drainage system in Roodasht region of Esfahan, Ian, to test the performance of drain spacing equations for transient flow. The water table profiles recorded from a series of observation wells indicated an essentially flat water surface. The effective ...
Read More
Field experiments were conducted on an existing subsurface drainage system in Roodasht region of Esfahan, Ian, to test the performance of drain spacing equations for transient flow. The water table profiles recorded from a series of observation wells indicated an essentially flat water surface. The effective hydraulic conductivity and the degree of anisotropy were calculated as 19.2 cm h-1 and 1.47, respectively. The variable drainable porosity as a function of water table height was computed by means of a two-dimensional flow concept. Twenty three drain spacings were computed by eight equations consisting of Glover, Luthin, Van Schilfgaarde, Hammad, Glover-Van Schilfgaarde, Dumm, Bouwer and Van Schilfgaarde, and Youngs. The results indicated that Youngs and Luthin equations had the best performance, contrasted to Glover and Hammad equations, which gave the most unreliable predictions. The other equations showed inferior performance. It follows that in other areas of Roodasht, where the impervious layer is shallow, either Youngs or Luthin equation may be used for design of drain spacing.
Research Paper
m sh; m m; m g
Abstract
Iran as an arid and semi-arid country always faces with the problem of soil water shortage due to insufficient precipitation and, especially in light soils, low water holding capacity and high deep percolation. Therefore, researchers have tried to use new methods for increasing this capacity to keep ...
Read More
Iran as an arid and semi-arid country always faces with the problem of soil water shortage due to insufficient precipitation and, especially in light soils, low water holding capacity and high deep percolation. Therefore, researchers have tried to use new methods for increasing this capacity to keep the water in the root zone and increase the amount of plant available water and water use efficiency of plants and reduce the stress of water scarcity. One of these methods is use of an impermeable barrier under the root zone such as asphalt layer, polyethylene membrane, and so on. The aim of this research was to use polyethylene membrane in sandy loam soil in two fields in Ardebil, with high amount of deep percolation. To study the effect of this membrane with two different methods of application on soil moisture and plant growth response. This project was conducted with two treatments, one with using membrane in one and two depths and the other one without membrane (control), with three replications and using a completely randomized design. Wheat was planted in two fields. During plant growth period, the soil moisture was measured by Time Domain Reflectometry (TDR). After harvesting, wheat growth indices were measured. The results in field No.1showed that using polyethylene membrane had significant effect on soil moisture and increased it up to five volumetric percent. Also, it increased grain yield by 0.6 ton per hectare: from 1.13 to 1.67 t/ha; while straw yield and total dry matter increased from 1.58 and 2.57 t/ha to 3.6 and 5.05 t/ha, compared to the control. But, in field No.2 with two depths of membranes, these indices did not show significant effects, the probable reason being that the 10 cm distance between the membranes allowed the water drainage from the root zone.
Research Paper
a r; a s; a.h n; r d; a f
Abstract
Use of the double ring infiltrometer to measure soil water infiltration in center pivot irrigation systems is not an accurate approach; because the real conditions of infiltration under center pivot sprinklers is different from what happens in the double ring. In this study, the infiltration parameters ...
Read More
Use of the double ring infiltrometer to measure soil water infiltration in center pivot irrigation systems is not an accurate approach; because the real conditions of infiltration under center pivot sprinklers is different from what happens in the double ring. In this study, the infiltration parameters were determined under real conditions of a center pivot system. For this purpose, a single ring with drainage equipment was used which could measure both infiltration and runoff rates during the experiments. Field tests were carried out at agricultural research station of Tabriz University, where soil texture was sandy loam. Treatments of the experiments were two types of sprinkler (Ldn, I-wob), three operation pressures (15, 20, and 25 psi), and two sprinkler heights (1.6 and 2 meter) with three replications. The results showed that the average amounts of infiltration rate and cumulative infiltration in the double ring method were double of the mentioned amounts in the single ring method. Therefore, use of the double-ring method data in design phase causes a significant runoff in operation. The maximum amounts of infiltration rate and cumulative infiltration were obtained in irrigation with operation pressure of 25 psi and sprinkler height of 1.6 meter. The model of Kostiakov had the maximum coefficient of determination (R2) and the model of Green and Ampt had the minimum amount of standard error (SE) in fitting with the measured infiltration data under real condition of a center pivot system in the field.
Research Paper
h a; m kh; a a; m r
Abstract
In recent years, the groundwater resources in Guilan province have played an important role in irrigating paddy fields. The goal of this study was to evaluate temporal and spatial variations of groundwater quality in a 4-year period using ordinal kriging. Water samples for this study ...
Read More
In recent years, the groundwater resources in Guilan province have played an important role in irrigating paddy fields. The goal of this study was to evaluate temporal and spatial variations of groundwater quality in a 4-year period using ordinal kriging. Water samples for this study were collected from 130 wells across Guilan province, in September and March from 2003 to 2006. Maps of EC and TDS in the region were prepared using ArcGIS software. The maps showed that regarding TDS, western parts of Guilan province had no problem of groundwater TDS (less than 500 mg/L), whereas central and eastern parts had a moderate TDS (500-1000 mg/L). Results showed that salinity increased with time (except in 2005, due to more rainfall in 2004) and the highest EC was recorded in the central zone, particularly areas neighboring eastern parts of Guilan province. Delineated areas of EC and TDS classes were determined in each year. EC in the east and some other parts of Guilan province covering 23 to 34% of the studied area was between one to 1.5 dS/m which have a negative impact on the yield of sensitive plants such as rice. Uncontrolled digging of deep wells and over exploitation of groundwater can be regarded as the main cause of increasing salinity in paddy areas of Guilan province.