Irrigation
E. Farrokhi; M. Nassiri Mahallati; A. Koocheki; alireza beheshti
Abstract
Introduction: Predicting yield is increasingly important to optimize irrigation under limited available water to enhance sustainable production. Calibrated crop simulation models therefore increasingly are being used an alternative means for rapid assessment of water-limited crop yield over a wide range ...
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Introduction: Predicting yield is increasingly important to optimize irrigation under limited available water to enhance sustainable production. Calibrated crop simulation models therefore increasingly are being used an alternative means for rapid assessment of water-limited crop yield over a wide range of environmental and management conditions. AquaCrop is a multi-crop model that simulates the water-limited yield of herbaceous crop types under different biophysical and management conditions. It requires a relatively small number of explicit and mostly-intuitive parameters to be defined compared to other crop models, and has been validated and applied successfully for multiple crop types across a wide range of environmental and agronomic setting. This study was conducted as a two-year field experiment with the aim of the simulation of water productivity, above ground biomass and fresh and dry yield of tomato using AquaCrop model under different irrigation regimes applied at two growth stages in Mashhad climate conditions.Materials and Methods: A two-year field experiment was conducted during 2016-2017 growing seasons in the experimental field of Ferdowsi University of Mashhad located in Khorasan Razavi province, North East of Iran. The water-driven AquaCrop model developed by FAO was calibrated and validated to simulate water productivity, above-ground biomass and yield of tomato crop under varying irrigation regimes. AquaCrop was calibrated and validated for tomato under full (100% of water requirements) and deficit (75 and 50% of water requirements) irrigation regimes at vegetative (100V, 75V, and 50V) and reproductive stages (100R, 75R, and 50R). Model performance was evaluated in terms of the normalized root mean squared error (NRSME), the Nash–Sutcliffe model efficiency coefficient (EF), Willmott’s index of agreement (d) and coefficient of determination (R2). The drip irrigation method was used for irrigation. The tomato water requirement was calculated using CROPWAT 8.0 software. The irrigation water was supplied based on total gross irrigation and obtained irrigation schedule of CROPWAT. The 2016 and 2017 measured data sets were used for calibration and validation of AquaCrop model, respectively.Results and Discussion: Calibration results showed good agreement between simulated and observed data for water productivity in all treatments with high R2 value (0.93), good ME (0.23), low estimation errors (RMSE=0.09 kgm3) and high d value (0.85). The goodness of fit results showed that measured WP values were closer to simulated WP values for the validation season (2017) than for the calibration season (2016). During calibration, (2016), the model simulated the biomass with good accuracy. The simulated above ground biomass values were close to the observed values during calibration (2016) for all treatments with R2 ranging from 0.92 to 0.99, NRMSE in range of 7.4 to 23%, d varying from 0.94 to 1, and ME ranging from 0.71 to 0.98. Validation results indicated good performance of model in simulating above ground biomass for most of the treatments (0.92 < R2 < 0.98, 6.5% < NRMSE < 21.3%, 0.76 < ME < 0.99). During validation (2017 growing season), overall, the trend of biomass growth (or accumulation) was captured well by model. However, the range of biomass of simulation errors was high, especially in treatments with higher stress. Accurate simulation of the response of yield to water is important for agricultural production, especially in an arid region where agriculture depends closely heavily on irrigation. During validation, the model predicted dry and fresh yield satisfactorily (NRMSE = 15.64% and 11.80% for dry and fresh yield, respectively).Conclusion: In general, the AquaCrop model was able to simulate the observed water productivity, above ground biomass and yield of tomato satisfactorily in both calibration and validation stage. However, the model performance was more accurate in non- and/or moderate stress conditions than in sever water-stress environments. In conclusion, the AquaCrop model could be calibrated to simulate growth and yield of tomato under temperate condition, reasonably well, and become a very useful tool to support decision on when and how much irrigate. This study provides the first estimate of the soil and plant parameter values of AquaCrop for simulation of tomato growth in Iran. Model parameterization is site specific, and thus the applicability of key calibrated parameters must be tested under different climate, soil, variety, irrigation methods, and field management.
Irrigation
E. Farrokhi; M. Nassiri Mahallati; A. Koocheki; alireza beheshti
Abstract
Introduction: The modeling approach for the simulation of the growth and development of tomatoes in Iran has been overlooked. Calibrated crop simulation models, therefore, are increasingly being used as an alternative means for the rapid assessment of water-limited crop yield over a wide range of environmental ...
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Introduction: The modeling approach for the simulation of the growth and development of tomatoes in Iran has been overlooked. Calibrated crop simulation models, therefore, are increasingly being used as an alternative means for the rapid assessment of water-limited crop yield over a wide range of environmental and management conditions. AquaCrop is a multi-crop model that simulates the water-limited yield of herbaceous crop types under different biophysical and management conditions. It requires a relatively small number of explicit and mostly intuitive parameters to be defined compared to other crop models and has been validated and applied successfully for multiple crop types across a wide range of environmental and agronomic settings. This study was conducted as a two-year field experiment with the aim of the simulation of soil water content, evapotranspiration, and green canopy cover of tomato using AquaCrop model under different irrigation regimes at two growth stages in Mashhad climate conditions. Materials and Methods: A field experiment was conducted over two consecutive seasons (2016-2017) in the experimental field of Ferdowsi University of Mashhad, located in Khorasan Razavi province, North East of Iran. The experiment was laid out in a split-plot design with different irrigation regimes at the vegetative and at the reproductive stage as the main and subplot factors, replicated thrice. In total, 27 plots of 4.5×3 m (13.5 m2) were used at a planting density of 2.7 plants per m2. Seedlings were planted in a zigzag pattern into twin rows, with a distance of 1.5 m between them, so there were four twin rows of three meters in each plot. The distance between tomato plants within each twin-row was 0.5 meters. A buffer zone spacing of 3 and 1.5 m was provided between the main plots and subplots, respectively. The following experimental factors were studied: three irrigation regimes (100= 100% of water requirement, 75= 75% of water requirement, 50= 50% of water requirement) and two crop growth stages (V= vegetative stage and R= Reproductive stage). The drip irrigation method was used for irrigation. The tomato water requirement was calculated using CROPWAT 8.0 software. The irrigation water was supplied based on total gross irrigation and obtained irrigation schedule of CROPWAT. Model accuracy was evaluated using statistical measures, e.g., R2, normalized root means square error (NRMSE), model efficiency (E.F.), and d-Willmott. The 2016 and 2017 measured soil and canopy data sets were used for calibration and validation of the AquaCrop model, respectively. Results and Discussion: For a water-driven model, such as AquaCrop, it is important to evaluate its effectiveness in simulating soil water content. During calibration (2016), the model simulated the soil water content with good accuracy. The simulated soil water content values were close to the observed values during calibration (2016) for all treatments with R2 ranging from 0.90 to 0.97, NRMSE in range of 8.47 to 17.96%, d varying from 0.76 to 0.99, and M.E. ranging from 0.87 to 0.96. Validation results indicated the good performance of the model in simulating soil water content for most of the treatments (0.79<R2<0.99, 10.04%<NRMSE<18.65%, 0.77<ME<0.92). Appropriate parameterization of canopy cover curve is critical for the model to provide accurate estimates of soil evaporation, crop transpiration, biomass, and yield. In general, the calibration results showed good agreement between simulated and observed data for canopy cover development in all treatments with high R2 values (>0.87), good E.F. (>0.61), low estimation errors (RMSE, ranging from only 4.5 to 9.2) and high d values (>0.92). Conclusion: The AquaCrop model (version 6.1) was calibrated and validated for modeling soil water content, evapotranspiration, and green canopy cover for tomatoes under drought stress conditions. In general, soil water content, evapotranspiration, and green canopy cover of tomato were simulated by AquaCrop model with acceptable accuracy in both calibration and validation stages. However, the model performance was more accurate in no and/or moderate stress conditions than in severe water stress environments. In conclusion, the AquaCrop model could be calibrated to simulate the growth and soil water content of tomatoes under temperate conditions reasonably well and become a very useful tool to support the decision on when and how much irrigate. For R2, values > 0.90 were considered very well, while values between 0.70 and 0.90 were considered good. Values between 0.50 and 0.70 were considered moderately well, while values less than 0.50 were considered poor. Root mean square error ranges from 0 to positive infinity and expresses in the units of the studied variable. An RMSE approaching 0 indicates good model performance.
M.H. Rad; M.H. Asareh; M.R. Vazifeshenas; A.R. Kavand; M. Soltani Gerdeframarzi
Abstract
Introduction: Although jujube (Ziziphus jujuba Mill.) is known as a medicinal plant and is less important than other fruit trees, it has received more attention in recent years due to its significance in traditional Iranian medicine. There is no study on the actual water need for jujube trees and the ...
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Introduction: Although jujube (Ziziphus jujuba Mill.) is known as a medicinal plant and is less important than other fruit trees, it has received more attention in recent years due to its significance in traditional Iranian medicine. There is no study on the actual water need for jujube trees and the impact of irrigation on yield and water use efficiency in the country. However, some studies emphasized on the need of regular watering and irrigation to improve the quality and quantity of jujube fruit. Given the importance of jujube in China, extensive researches have been conducted on water requirements, plant strategies to save water, impact of drought stress on plant morpho-physiological behaviors, impact of appropriate water distribution on soil quantity and quality of plant development, root distribution patterns and its impact on the amount of water consumed. In all cases, it has been emphasized that the mechanisms of water consumption in jujube differ by climate, genotype, irrigation method and management. In order to improve the quantity and quality of jujube fruit, it is necessary to balance the soil moisture condition and keep the plant away from stress. However, dehydration in jujube is a serious issue that should be addressed with the aim of saving water and improving fruit quality. In this study, the actual water requirement of the plant, the effect of different levels of deficit irrigation on evapotranspiration (ET) and crop coefficient (Kc) rate, yield and water use efficiency (WUE) in jujube trees were investigated. The moisture stress was applied through all stages of plant growth by deficit irrigation. Materials and Methods: In this study, the lysimeter experiment site of Yazd (Shahid Sadoghi Desertification Research Station) with 20 weighing drainage lysimeters (170 cm in height and 121 cm in diameter) was used. To measure evaporation from the soil surface, one lysimeter without plant was used. Note that the moisture content in this lysimeter was always maintained at the field capacity. For the measurement of reference ET (ET0), one lysimeter was used and it compared with ET0 calculated by Penman-Monteith-FAO. After preparing the lysimeters and providing the conditions for planting seedlings, we planted one tree per lysimeter. Trees collected from the villages of Alqoor, Flarg and Gyuk (South Khorasan Province). The suckers were two-years-old with the same size and shape. Trees were irrigated with 50 liters water on a weekly basis for six months. At the beginning of autumn of 2018, treatments including complete irrigation (field capacity), 30% and 60% of deficit irrigation were conducted in a completely randomized design with six replications. Soil moisture measurement during the experiment was performed by TDR. Soil moisture was recorded at 4 depths (0-30, 30-60, 60-90 and 90-120 cm) and their mean was considered as an index of soil moisture status to compensate the irrigation fraction. During the experiment and at the end, indices such as different stages of plant growth, ET, ET0, Kc, yield and WUE were determined. The data were analyzed by analysis of variance (ANOVA) using the statistical package SPSS ver. 16.0, and the mean values were also compared using LSD multiple range test (α = 0.05). Results and Discussion: The results showed that the jujube trees began their vegetative growth from late March (leaves appear) until the end of November (leaves fall) over 2017-2018 agronomic year in Yazd. During this time, which lasted about 235 days, four major and important stages were evident. The steps cited were in FAO's recommendation for deciduous fruit trees (in Issue 122 of the Iranian Irrigation and Drainage National Committee). The results of these studies showed that the length of different growth periods of jujube trees (including early stage, plant development stage, mid stage and end stage) was different with another deciduous fruit trees. ET values in three irrigation regimes showed that the highest ET was observed in July and the lowest in March. Annual ET in control, 30% and 60% of deficit irrigation treatments were 828.06, 514.04 and 386.04 mm, respectively, with 0.45, 0.28 and 0.21, annual Kc, respectively. The results of ET and Kc computed at different growth stages showed that the reproductive growth development period (flowering, fruit set beginning of fruit growth) had the highest ET. In control treatment, the lowest ET (60.81 mm) and Kc (0.27) were observed in early growth period with less than 10% of crown cover. The highest ET (316.22 mm) and Kc (0.60) were found in growth development period with full crown cover. Analysis of variance showed that there was a significant difference (P <0.0001) between the different irrigation treatments in terms of dry matter yield. There was a significant difference for WUE (P <0.001) between different irrigation treatments. Each of different irrigation regimes had a significant difference in yield. The highest yield for each tree was found for the control treatment with 229.36 g and the lowest yield with 57.90 g was observed for 60% deficit irrigation regime. There was no significant difference between control and 30% deficit irrigation treatment in WUE. The value of WUE decreased with increasing the drought stress. In 60% deficit irrigation treatment, WUE was 0.366 g fruit dry weight per liter denoting the significant difference between this irrigation treatment and the others. Conclusion: The results of this study showed that jujube trees were susceptible to drought stress in all four stages of growth, especially the period of growth coinciding with flowering, fruit set and early fruit growth. Hence, jujube trees yield and WUE seem to decrease under drought.
S. Jamali; H. Ansari; S.M. Zeynodin
Abstract
Introduction: Since the agriculture is the main water consumer, it is necessary to increase water use efficiency. As a management practice, deficit irrigation strategy is applied to cope with water shortages, especially during drought periods. A greenhouse experiment was conducted to investigate the ...
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Introduction: Since the agriculture is the main water consumer, it is necessary to increase water use efficiency. As a management practice, deficit irrigation strategy is applied to cope with water shortages, especially during drought periods. A greenhouse experiment was conducted to investigate the impact of water and salt stress on Quinoa plants (Chenopodium quinoa Willd.), Aly et al (2) showed that quinoa plants can tolerate water stress (50% FC) when irrigated with moderately saline water (T1 and T2, respectively). The results of some studies showed that Amaranth was the most responsive plant to water. Quinoa showed the best performance in the treatment with the upper-middle water level among the other evaluated species. Millet showed thermal sensitivity for cultivation in the winter, making grain production unfeasible; however, it showed exceptional ability to produce biomass even in the treatment with higher water deficit. Water stress can affect plants by reducing the plant height, relative growth rate, cell growth, photosynthetic rate, and the respiration activation. Cultivated plants have several mechanisms of adaptation to water deficit, but the responses are complex and adaptation is attributed to the ability of plants to control water losses by transpiration, which depends on the stomatal sensitivity and greater capacity of water absorption by the root system, among other factors. In PRD method, half of the root zone is watered and the other half is kept dry intermittently. The objective of this research was to study yield and yield components of Quinoa (Chenopodium quinoa Willd.) Titicaca cultivar, using PRD irrigation method in three growing bed, under greenhouse conditions.
Materials and Methods: This research was conducted to study the effects of water stress on yield and its components of Quinoa under the different growing beds in the experimental research greenhouse of Ferdowsi University of Mashhad during 2018. Titicaca cultivar of Quinoa was planted and experimental design was factorial, based on complete randomized design and three replications, included two irrigation managements (FI, full irrigation and PRD, partial root-zone drying method) and three levels of growing bed (S1, silty clay, S2 clay loam and, S3 sandy loam). Research station is located in north-east Iran at 36° 16' N latitude and 59° 36' E longitude and its height from sea level is 985 meters. The seeds of Quinoa were planted at a depth of 1.5 centimeters in the soil of each pot and were irrigated with tap water. Plants were harvested after 4 months and plant height, branches number, panicle number, thousand kernel weights, grain yield, biomass; steam, leaf, and panicle dry weight panicles were measured. Physical and chemical properties of irrigation water and soil were determined before the beginning of the experiment. The obtained data analyzed using the statistical software of SAS (Ver. 9.4) and the means were compared using LSD test at 5 % percent levels.
Results and Discussion: Results showed that the highest plant height (84.4 cm) was in FI treatment and the shortest plant height (82.5 cm) was in PRD treatment. The highest and the lowest 1000 kernel weights and grain yield were measured in FI (4.0 and 19.7 g per plant) and PRD (3.6 and 17.7 g per plant) treatments, respectively. With a 50 % reduction of water in PRD compared to FI treatment, 1000 kernel weights were decreased by 9.1%. Grain yield was decreased by 10.2% (changing from FI to PRD). The highest and the least grain yield (20.2 and 18.4 g per plant) were obtained in S1 and S2,3 soils, respectively. Silty clay soil with 1000 kernel yield of 4.12 g had higher than clay loam and sandy loam soil, which produced 3.78 g and 3.78 g, respectively.
Conclusion: In general, the effect of the PRD irrigation method on reducing water use in the greenhouse production of Quinoa was positive and recommendable. Silty clay soil with 1000 kernel yield of 4.12 g had higher than clay loam and sandy loam soil, which produced 3.78 g and 3.78 g, respectively.
R. Najafipour; H. Ramezani Etedali; B. Nazari
Abstract
Introduction: Greenhouses have a key role in agriculture productions. Given the ability of controlling production factors, there is the possibility of out-of-season cultivation in greenhouses, which is important in terms of food security, economics, and agricultural marketing. Estimation of water requirement ...
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Introduction: Greenhouses have a key role in agriculture productions. Given the ability of controlling production factors, there is the possibility of out-of-season cultivation in greenhouses, which is important in terms of food security, economics, and agricultural marketing. Estimation of water requirement for planning the development of greenhouses and their operation is very important. Awareness of the exact amount of water requirement is important both in terms of production and growth. Many studies have shown the usefulness of greenhouses in improving yield, physical and economical productivity. So far, comprehensive studies have not been carried out on the productivity of greenhouse cucumber cultivation and its effects on water resources in Qazvin province. Therefore, the goal of this study was to determine the greenhouse cucumber water requirement and provide a model for estimating evapotranspiration of cucumber under greenhouse condition. Also, determining greenhouse cucumber productivity in Qazvin province and evaluating the effect of this improvement on water resources were other objectives.
Materials and Methods: This research was carried out in a greenhouse near Qazvin city. The height of the greenhouse from the ground was 4 meters, and its plastic cover was made of polyethylene. Experiments were carried out in greenhouse with greenhouse seedling on 20-3-2015 in two rows of pot. The greenhouse was equipped with the necessary tools to measure temperature, maximum and minimum temperature, relative humidity, and solar radiation. Soil texture in this research was clay loam with 30, 32 and 38 percent of sand, silt and clay, respectively. The water content was, , 31% and 16 percent at field capacity (FC) and permanent wiling point (PWP) respectively. An irrigation interval of two days (a favorable condition) was considered. In this experiment, the seeds of the Royal cucumber were used to coincide with the planting time and harvesting length. The plastic pots with a diameter of 18 cm and a height of 23 cm were utilized. The pots were filled with equal quantities of fine and fine gravel (for drainage) and then with the agricultural soil prepared for cucumber cultivation. In order to provide conditions similar to the actual cucumber planting in the flower bed, the pots were placed close to the greenhouse. The irrigation of the plants was carried out manually for 83 days. The relative humidity, temperature and radiation were measured hourly. Further, the effects of irrigation on different characteristics of the test plants were observed and recorded. The moisture content was measured by weight and soil moisture reduction in full irrigation was compensated for the FC moisture content in each irrigation interval. Until 30 days after planting (Stages 4-6), the pots were irrigated with equal amounts. In order to evaluate the effects of deficit irrigation, four treatments were considered. These treatment were as follows: first treatment (FI): irrigation depth equal to 100% of the plant evapotranspiration with five replications, treatment (DI20): irrigation depth equal to 80% of the plant evapotranspiration with five replicates, treatment 3: (DI40) irrigation depth equal to 60% of the plant evapotranspiration with five replicates and the fourth treatment (DI60): irrigation depth equal to 40% of the plant evapotranspiration with five replications.
Results and Discussion: The maximum and minimum evapotranspiration was 8.7 and 1.06 mm/day in 61 and 13 days after transplanting, respectively. By investigation different mathematical models, the best models for estimation of cucumber evapotranspiration in greenhouse was the power model based temperature, humidity and height of crop with R2 of 0.86. The FAO-Penman-Monteith and Blaney-Criddle models exhibited the best and worst performance with R2 of 0.42 and 0.24, respectively. The cucumber water productivities in greenhouses ranged from 9.23 to 22.44 Kilograms per cubic meter. This wide water productivity range shows the importance of management and operation in water productivity improvement in greenhouses.
Conclusion: Estimation of greenhouses cucumber water requirement and water productivity are very important. The best model for estimating cucumber evapotranspiration in greenhouse was the power model based on temperature, humidity and height of crop with R2 of 0.86. In this study, cucumber water productivity was estimated in Qazvin greenhouses. The results showed that cucumber water productivities ranged from 9.23 to 22.44 Kilograms per cubic meter. Consequently, 117 ha greenhouse is required for producing the present value of cucumber in the province. This option would save 15 millions of cubic meter water in this area. Development of greenhouses with regarding to various economic and social aspects can help decision-makers in solving water shortage problems.
P. Daneshpazhoh; A. R. Ghasemi; Mohamad reza Nori Emamzadeie; R. Barzegar
Abstract
Introduction: Optimal water utilization is one of the most important challenges of the present century. Due to limited water resources and the existence of alternate droughts in the country, optimal use of it is necessary. The deficit irrigation technique is one of the most effective and practical ways ...
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Introduction: Optimal water utilization is one of the most important challenges of the present century. Due to limited water resources and the existence of alternate droughts in the country, optimal use of it is necessary. The deficit irrigation technique is one of the most effective and practical ways in which it can determine and justify the minimum water consumption with acceptable economic performance. Its use in reducing water consumption for biomass production and for irrigation of annual and perennial crops. To effectively apply water deficit management, an understanding of the effects of irrigation at different stages of vine growth is required. Partial Root-zone Drying (PRD) is also one of the new irrigation techniques over the past years. The results of many studies indicate that water use efficiency has increased and there is no significant reduction in the yield in this irrigation method. In this technique, only half of the roots are irrigated at each turn and the remaining half remains dry. On the other hand, in recent years, the use of natural minerals has improved in order to improve the physical and chemical composition of the soil, which leads to an increase in water holding capacity in the soil. One of the methods for increasing the water use efficiency is the application of water absorbent materials in soil. Super absorbent polymer increases the water saving in soil and decreases the amount of water used for irrigation. Zeolite is one of these minerals that increases the soil water holding capacity. So far, many studies have been carried out on the use of PRD, as well as the use of zeolite, but none has examined the effect of these two simultaneously. Therefore, in the present study, the efficiency of both above method and deficit irrigation on yield and water use efficiency of sweet pepper were investigated.
Materials and Methods: This research was carried out in a completely randomized design with 9 treatments and 4 replications in a greenhouse in Shahrekord University. This study was carried out at three levels of irrigation of 100%, 75% and 50% of the water requirement of the plant by Partial Root-zone Drying and zeolite in two levels of 2 and 4% by weight in the soil, in one and two sides of the pots with a height of 30 and diameter 28 cm. After preparing the culture medium, the F1 type Lummus seedlings were transferred to the pots. During the transfer of transplants into the pot, careful attention was paid to the fact that the roots were developed on both sides. Physiological parameters such as leaf area, total fresh and dry weight of the whole organ, total fresh weight of fruit, diameter and number of fruits and chemical indices including vitamin C, pH, total soluble solids and chlorophyll a, b and total chlorophyll with water use efficiency were measured and evaluated. In order to analyze the results, SAS software (version 1/9) was used. Mean comparison was also performed by LSD test.
Results and Discussion: The results of this study showed that there was a significant difference in the 1% level for fresh and dry weight, fresh weight of fruit and chemical indices of vitamin C, pH and soluble solids, and a significant difference at 5% for diameter fruit and chlorophyll. The results of comparing the meanings showed that fresh weight and fruit diameter were significantly decreased in all treatments than control. The number of fruits in severe irrigation (50%) and in both levels of zeolite showed a significant decrease compared to control. Vitamin C value as an important indicator of fruit quality in all treatments was significantly higher than control, in other words water stress causes an increase in the amount of vitamin C in the fruit, and the amount of pH in the most treatments has decreased significantly compared to the control treatment.
Conclusion: Given that all important processes such as photosynthesis, nutrition, opening and closing of stomatal and plant growth and development are under the influence of water, most of the studied traits in this research (except chlorophyll) in zeolite-containing treatments, showed a significant advantage over non-consumption of zeolite. The results also showed that application of PRD method with zeolite in deficit irrigation resulted in significant increase in water use efficiency in all treatments.
M. J.Fereidooni; H. Farajee
Abstract
Introduction: In Iran, due to reduction of water resources and increasing of water losses in the various methods of the surface irrigation pressurized irrigation methods, especially drip irrigation have got many attentions. Application of the plastic mulch method is used in cultivation of early sweet ...
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Introduction: In Iran, due to reduction of water resources and increasing of water losses in the various methods of the surface irrigation pressurized irrigation methods, especially drip irrigation have got many attentions. Application of the plastic mulch method is used in cultivation of early sweet corn. Application of this technique due to its temperature provides both plant growth and early maturity and then causes the on-time delivery of product to the target market. Additionally, to reduce water consumption, the use of germinated seedlings in the greenhouse and move it under plastic on the farm, productivity will increase. The aim of this study was to evaluate irrigation levels on yield of sweet corn by using plastic mulch, and the feasibility of seedling cultivation to early crop.
Materials and Methods: In order to evaluate the effect of different irrigation levels and cultivation techniques on water use efficiency and quality and quantity yield of sweet corn, an experimental program was carried out as split plot in randomize complete blocks design with three replication in Faculty of Agriculture, Research Field Station of Yasouj University in 2015. The main factor consisted of three levels of irrigation: 100 (I1), 75 (I2) and 50 percentage of water requirement (I3) and the sub-factor was including cultivation techniques of sweet corn in six levels: seed cultivation of sweet corn under plastic mulch on 4 April (CT1), seedling cultivation under plastic mulch on 4 April (CT2), seed cultivation to conventional method of sweet corn on 5 May (CT3), seed cultivation of sweet corn under plastic mulch on 5 May (CT4), seedling cultivation of sweet corn under plastic mulch on 5 May (CT5) and seedling cultivation to conventional method of sweet corn on 5 May (CT6).
In order to establish plastic mulch, after seed and seedling cultivation of sweet corn with installation of irrigation tape tubes, steel bars which were made in a semi-circular shape, were placed on rows and plastics were laid on it. After the establishment of the seedling on the farm, the irrigation levels were applied by volumetric counters. When the plant height was equal to the height of plastic tunnels, it was tried to pierce the plastic to grow suitability. During the time of maturity product, a 2 m2 plot in the middle of farm was selected and the ears were separated and weighed, and the forage yield was weighted. The grains of sweet corn were separated and canned yield was measured. The content of grain sugar, sucrose and fructose were measured by means of HPLC method, and the content of grain nitrogen with using of micro Kjeldahl’s method achieved. Statistical analysis was performed using SAS software. The mean values were compared by using LSD multiple range tests at 5% level. Figures were depicted by using of Excel software.
Results and Discussion: The results indicated that irrigation interaction and cultivation techniques were significant on ear yield, the canned yield, water use efficiency, and forage yield. The maximum ear yield obtained in treatments of I2CT1, I1CT1, I2CT2 and I1CT2 were equal to 14420, 14414.4, 13691.7 and 13513.5 kg ha-1, respectively and the maximum water consumption content for mentioned treatments were equal to 2521, 3362, 2385 and 3180 m3 ha-1, respectively. The minimum ear yield obtained in treatment of I3CT3 was equal to 706 gm-2. Water stress delayed the physiological processes including silk rating and tassel emergence, so that, it reduced growth and plant height and finally leaded to the reduction of grain yield. The maximum canned yield were obtained in treatment of I1CT1, I2CT1, I1CT2 and I2CT2 equal to 558.7, 551.1, 536.2 and 527.4 gm-2, respectively. Higher grain yield of sweet corn under plastic mulch in comparison with non plastic mulch, was due to increasing of dry matter accumulation before the silk production. It seems that increasing temperature and water content under plastic mulch resulted in an increase in grain dry matter accumulation. The maximum water use efficiencyfresh grain was obtained in treatment of I2CT2, I2CT1, I3CT2 and I3CT1 equal to 2.21, 2.18, 2.16 and 2.14 kgm-3, respectively. With increasing of water consumption water use efficiencyfresh grain decreased. Maximum forage yield was obtained in I1CT1 equal 2008 gm-2 and minimum forage yield was obtained in I3CT6 equal 1237 gm-2. Available water under plastic mulch, increased plant growth by increasing of leaf area index and shoot biomass due to stomata opening.
The effect of irrigation were significant on grain sucrose percentage, and content of protein. Moreover cultivation techniques effect was also significant on content of grain sugar, sucrose percentage and subsequently the content of grain protein. The maximum grain sucrose percentage was for treatment of 100% water requirement of sweet corn which was equal to 4.92%. Treatment of 75 percentage water requirement, also, the minimum grain sucrose percentage equal to 4.11% was obtained in treatment of 50 percentage water requirement. Retaining of moisture increased the amount of sugar and grain sucrose content. The maximum content of grain protein was equal to 11.41% in treatment of 100 percentage water requirements; also the minimum content of grain protein equal 8.58% was obtained in treatment of 50 percentage water requirement.
By reducing soil moisture, the content of protein and sugar grain increased, so the maximum content of grain protein and sugar were obtained in treatment of 50 percentage water requirement, although the maximum levels of irrigation reduced the content of protein and sugar. Under stress conditions, the plant material requirement is not enough, so by reducing nutrient transport, the leaf and stem cell development delayed, resulting in reduced plant height, leaf area, the content of grain protein, sugar. Finally, dry matter accumulation in the grain decreases with the transfer of nutrients from the leaves, and then it caused early death the leaf.
Conclusions: Application of seedling and plastic mulch accelerated plant growth, its development and then it was out of season production. If there are not water restrictions, application of treatment of 100 percentage water requirement of sweet corn with plastic mulch is desirable to maximum yield produce. Average of water consumption was in treatments of plastic mulch and non-plastic mulch equal to 2735 and 3411 m3 respectively. Maximum content of grain protein and sucrose percentage were obtained in treatments contains plastic mulch. Seedling cultivation in comparison with seed cultivation showed minimum content of grain sugar and grain sucrose percentage. In order to achieve the maximum quality and quantity yield in areas that are faced to water restriction, it is possible to use treatment of 75 percentage of water requirement and seeding cultivation under plastic mulch.
Mehdi Mohammad khani; mohammad karimi; afshin Gomrokchi
Abstract
Introduction: Evaluations show the necessity of using optimization models in order to determine optimal allocation of water in different water conditions. Its use can be proposed according to developed model abilities in this study in order to optimize water productivity and provide sustainable management ...
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Introduction: Evaluations show the necessity of using optimization models in order to determine optimal allocation of water in different water conditions. Its use can be proposed according to developed model abilities in this study in order to optimize water productivity and provide sustainable management and development of water resources over irrigation and drainage networks. Basic needs of the earth growing population and limitation of water and soil resources remindnecessity of optimal use of resources. World’s more than 280 million hectare lands are covered by irrigation networks (Khalkhali et al., 2006). The efficiency of most projects is between 30-50 percent and studies show that performance of most irrigation and drainage networks is not desirable and they have not achieved their aims. Hirich et al. (2014) Used deficit irrigation to improve crop water productivity of sweet corn, chickpea, faba bean and quinoa. For all crops, the highest water productivity and yield were obtained when deficit irrigation was applied during the vegetative growth stage. During the second season 2011 two cultivars of quinoa, faba bean and sweet corn have been cultivated applying 6 deficit irrigation treatments (rainfed, 0, 25, 50, 75 and 100% of full irrigation) only during the vegetative growth stage, while in the rest of a crop cycle full irrigation was provided except for rainfed treatment. For quinoa and faba bean, treatment receiving 50% of the full irrigation during the vegetative growth stage recorded the highest yield and water productivity, while for sweet corn applying 75% of full irrigation was the optimal treatment in terms of yield and water productivity. Moghaddasi et al. (2010) worked examines and compares this approach with that based on the optimization method to manage agricultural water demand during drought to minimize damage. The results show that the optimization method resulted in 42% more income for the agricultural sector using the same amount of water allocated in the 1999 drought. This difference emphasizes the importance of water allocation with respect to growth stages rather than simply cutting allocations on an equitable basis to combat water scarcity. However, managing the system using the optimization method is more complex and requires a new framework and planning to make it operational.
Materials and Methods: Qazvin irrigation network in Qazvin province is located in 150 km West of Tehran, between 36˚ 20΄ north latitude and 49˚ 40΄ east longitude and 36˚ 00΄ north latitude and 50˚ 35΄ east longitude. Net water requirement of cultivated crops in the irrigation network is 109.798 million m3. According to the total efficiency of the irrigation network, an impure water requirement of cultivated crops will be 304.994 million m3. The inlet water from Taleghan dam into irrigation network is 274.8 million m3 that compared to impure water requirement decrease 10%. The current study was conducted in 5 options, including: option 1 (current conditions and supplied water volume of 274.8 million m3), option 2 (optimized current conditions using LINGO software and supplied water volume of 274.8 million m3), option 3 (30% water deficit and supplied water volume of 192.36 million m3), option 5 (40% water deficit and supplied water volume of 274.8 million m3). Water requirement of crops is determined using meteorological data with 30 years long term statistics and CROPWAT8 software.
Results Discussion: Studying different scenarios of water deficit in network shows that products such as tomatoes, potatoes and alfalfa have the least changes in real production to potential production and yield ration in barely did not show significant difference in all options. In all of the options, tomatoes with water productivity indicator of 3029 rials/m3 have the maximum productivity index and sugar beets with water productivity indicator in options 2 to 5 as 479, 310, 307 and 268rials/m3, respectively has the minimum productivity index. Therefore, in water deficit conditions, the priority of water distribution in all options is for tomatoes and the last priority for sugar beets. In all of the options, wheat, barley and canola ascend in productivity index and corn and sugar beets descend in productivity index.
Conclusion: Studying water- production index shows that considering instructions will result in optimal productivity that in turn will increase production and network total income. Optimal model results show that drought effects can be satisfied with optimal and targeted management in allocating water, so that network total income has not reduced in stress occurrences compared to network net income. Optimization method in model development has been selected according to aim of model and it is proposed that model results to be assessed by non- linear optimization methods. It is proposed that, different scenarios of climate are studied in region according to climate changes and optimal allocation of water is prepared according to the effect of these scenarios on temperature increase, raining decrease and products water need increase in present cultivation method. For model efficiency increase, it is proposed that using neural networks capabilities, intelligent prediction of the input discharge to the network is done and the possibility of comprehensive management and timely combining of network with water allocation optimal model is provided.
Ali Reza Kiani; Afshin Mosavat
Abstract
Introduction: Lack of water and deterioration in the quality of soil and water resources are considered to be the prime cause of reduced crop yield in arid and semi-arid regions ‘More crop per drop’ by trickle irrigation, deficit irrigation, and uncommon water are the best strategies for mitigating ...
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Introduction: Lack of water and deterioration in the quality of soil and water resources are considered to be the prime cause of reduced crop yield in arid and semi-arid regions ‘More crop per drop’ by trickle irrigation, deficit irrigation, and uncommon water are the best strategies for mitigating water crises. Different irrigation management strategies are needed to increase production in different areas. In areas where sufficient water is available, a full irrigation strategy could be a suitable option, while in areas where water is limited, deficit irrigation would be an appropriate method, and finally in areas where water resources are saline, management strategies for achieving sustainable production as well as economic yields would be suitable. Maize is the third most important grain crop in the world following wheat and rice and it is the main source of nutrition for humans and animals. Because of the importance of maize in the world, increasing maize production under environmental stresses is a big challenge for agricultural scientists. Different methods of irrigation and the use of saline water that had satisfactory results for increasing agricultural production have been studied by several investigators . The main objective of this study was to establish an efficient use of limited water resources as well as to explore the possibility of replacing saline water with fresh water using different management techniques.
Materials and Methods: A field experiment was conducted over two maize cropping seasons (2012–2013) in northern Iran (Gorgan Agricultural Research Station) to compare different alternate irrigation scenarios using saline water on corn yield, salinity and soil moisture distribution in a randomized complete block design with three replications. Treatments were: T1 and T2 = 100 and 50 % of crop water requirement with non-saline water, respectively; T3 and T4 = variable and fixed full irrigation with saline and non-saline water in every other row, respectively; T5 and T6= fixed and variable deficit irrigation with non-saline water in every other rows, respectively and T7= full irrigation with saline water. To create the desired water salinity (8 dS/m), non-saline well water (1.5 dS/m) and drainage water (20–35 dS/m) were blended in different proportions. A T-tape drip irrigation system (20 m in length) was used in the field experiment.
Results and Discussion: In general, corn yield in 2013 was about 1270 kg ha-1 higher than in 2012. From the weather records it can be seen that the second year was drier than the first year. Yield analysis showed that deficit irrigation treatments (T2, T5 & T6) and also alternate salinity treatments (T3 & T4) did not significantly difference. In other words, the deficit irrigation management had no effect on yield. Corn yield in T3 and T4 with 50% of saved fresh water was just reduced to 7 and 1 % of T1, respectively. As a result, comparing treatments T3 and T4 with full irrigation have shown that treatments T3 and T4 are the best option. Comparison of moisture distribution in deficit irrigation treatments showed the highest water content in surface and deep layers was related to the treatments T6 and T2, respectively. The distribution of salinity in the soil profile for treatments T3 and T4 showed that after two years of irrigation with saline water, there is the possibility of use saline water for corn production, but drainage and leaching of soil will need to maintain sustainability.
Conclusion: Naturally, in water scarce areas that use some strategic management such as deficit irrigation or saline water use, there is available arable farmland to further develop the irrigated area, and thereby increase total production. According to the results of the two-years where there was a shortage of water to meet crop water requirement and saline water was not available, the use of deficit irrigation managements as described in this study can save fresh water resources and increase total production and farmer's income. If the region is facing a shortage of water resources and saline water is available nearby agricultural land, it is suggested to use alternate furrow irrigation with saline and non-saline water; with the crop water requirement being met by the saline water, the total output will be higher than using deficit irrigation management with non-saline water. Comparision of the distribution of moisture in deficit irrigation treatments showed that surface soil moisture was lower in the treatment of T5 because it was more lateral distribution. In the deeper layers, soil moisture of the treatment T2 was more than others, because it was the predominant infiltration. The two treatments T3 and T4 because of the combined matric and osmotic potential and the movement of water along the sides and deep percolation, resulting widely distributed in soil moisture and thus remaining lower moisture in the soil compare to full irrigation treatments. Consequently, this finding indicates that after two years of corn irrigation using saline (8 dS/m) and non-saline water in every other row (treatments T3 and T4) production can be increased, and in case of proper leaching and drainage management, agricultural sustainability will also preserve.
Zeyneb Fathi Tilko; Parviz Fathi; Farzad Hosseinpanahi
Abstract
Introduction: water scarcity is one of the primary problems in arid and semi-arid regions such as Iran. In these regions, increasing water productivity in agriculture sector is inevitable. Water productivity can be increased using the drip irrigation method and application of irrigation strategies such ...
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Introduction: water scarcity is one of the primary problems in arid and semi-arid regions such as Iran. In these regions, increasing water productivity in agriculture sector is inevitable. Water productivity can be increased using the drip irrigation method and application of irrigation strategies such as deficit irrigation. Potato is the major crop in Dehgolan plain. Researches have shown that the potato crops very sensitive to water stress. Sprinkler and furrow irrigation systems are common methods for irrigation of potato crop in Dehgolan plain. In this plain, the main supply for irrigation water is groundwater resources. Due to the falling water table in this plain, high sensitivity of the potato crop to water stress and low efficiency of current irrigation systems in the plain, the use of modern methods such as drip-tape irrigation system is inevitable. Drip tape irrigation is one of the efficient methods to increase water productivity of agricultural crops. In this method, determining the optimal drip tape placement in the soil and irrigation water depth are the important factors for obtaining maximum yield and irrigation water productivity of potato crop. The purpose of this study was to investigate the effect of drip tape placement depth and irrigation level on water productivity of the potato crop (Agria cultivar) in Dehgolan plain of Kurdistan province.
Materials and Methods: A field experiment was conducted to evaluate the effect of drip tape placement depth and irrigation water level on water productivity of the potato crop (Agria cultivar) in Dehgolan plain of Kurdistan province in spring season of 2014. The results of water quality analysis showed that the irrigation water has not any limitation to plant growth. The soil texture of the field was silty clay. The experiment was arranged in split plot design based on randomized complete blocks Design with three replications. The main plots and subplots included the irrigation water levels (60, 80, 100 and 120 percent of the potato water requirement) and drip tape placement depth (0, 5, 10 and 15 centimeters), respectively. At the end of the growing season, tuber yield of potato was measured. Measured data were analyzed using statistical software, R.Also, mean comparisons were done using Duncan's test.
Results Discussion: The results showed that the effect of irrigation water and drip tape placement on yield and water productivity was significant (P= 0.01%). The maximum yield and water productivity of this crop were related to 120 and 60 percent of crop water requirement, respectively. The results also showed that drip tape placement depth equal 15 cm was the depth when using drip tape irrigation system in Dehgolan plain. Economic analysis of different treatments showed that irrigation water depth equal 120 percent of the potato water requirement has higher Benefit–cost ratio than other treatments, but the water produced related to it is minimized. Since the Dehgolan plain faced with an intense water deficit and groundwater level of this plain has lost, so maximizing the amount of water produced in Dehgolan plain is inevitable. The results showed that the applied irrigation water depth equal 60 percent of potato water requirement and installation of irrigation tape at a depth of 15 cm can be achieved highest irrigation water use efficiency of potato in Dehgolan plain.
The result of this research indicated that tuber yield and water productivity of the potato crop under subsurface drip irrigation systems is higher than surface drip irrigation. The ability of subsurface drip irrigation in the improving of tuber yield could be attributed to the less water lost from the soil surface through evaporation. Subsurface drip irrigation allows maintenance of optimum soil moisture content in the root zone, which improved the water productivity.
Conclusion: The results show that the maximum tuber yield of potato was related to 120 percent of the potato water requirement. But the maximum irrigation water use efficiency was related to treatment water equal 60 percent of water requirement and drips tape placement depth equal 15 cm. As a result, recommended to increase the irrigation water use efficiency in Dehgolan plain, deficit irrigation strategies applied. The results also showed that the yield and water productivity of the potato crop in subsurface drip irrigation method is more than surface drip irrigation method. In this way the growth of weed and water loss through evaporation was very low and therefore the plant uses the greater amount of irrigation water.
borhan sohrabi
Abstract
Introduction: Iran is a vast country with limited water resources. Iran is located in arid areas and average precipitation is estimated to be 250 mm. In recent years, water shortage has created many problems for Iranian farmers. In these conditions, surface and ground water use is excessive. High consumption, ...
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Introduction: Iran is a vast country with limited water resources. Iran is located in arid areas and average precipitation is estimated to be 250 mm. In recent years, water shortage has created many problems for Iranian farmers. In these conditions, surface and ground water use is excessive. High consumption, low irrigation efficiency, bad time and geographical distribution of precipitation, population growth and increasing agricultural land are one of the main reasons for the irrigation water crisis. Therefore, the main problem of drought and water shortages still remains. The area of agricultural land in Golestan province is high, but most of them are rain-fed cultivation or left fallow. Due to the loss of irrigation water in traditional agriculture, development of pressurized irrigation as a solution to increase productivity and reduction of strain on water resources was raised. With government support, the use of pressurized irrigation systems is increasing.
Materials and Methods: To evaluate the effect of different amounts of water on new variety of cotton-Sepid, a two-year study was conducted using drip irrigation at Hashemabad Cotton Research Station, Gorgan, Iran.The Hashemabad Cotton Research Station is located in north of Iran at 36° 51' N latitude and 54° 16' E longitude at the south-east corner of Caspian Sea and its height from sea level is 13.3 meters. That station has a Mediterranean climate with relatively mild winters and relatively dry summers. The station's annual evaporation, precipitation and relative humidity are 1311mm, 525 mm and 71%, respectively. Soil texture of Hashem Abad station is silty clay loam. In this study, four levels of irrigation water: 0%, 40%, 70% and 100% evaporation of class A pan were studied in a randomized complete block design. Land was plowed in autumn last year and was ready for planting in April with the disc. During tillage, manure fertilizer on the soil surface was sprayed based on the soil test recommendations. At this stage, for combating weeds, herbicide trifluralin (2.5 liters per hectare) was used. Planting new varieties of cotton - Sepid was in the first decade of May. Each plot consists of 8 lines which was ten meters. After evaporation of 50 mm from Class A evaporation pan, irrigation is done. Irrigation tapes were placed just alternate between planting rows. Water consumption was measured using a volumetric water meter. To measure the product, cotton-seed of four rows of each plot were harvested. Yield components were measured in the same four rows. Product wastaken in October and early November during two harvesting.
Results and Discussion: Cotton as thermophilic plants, especially in humid areas, is strongly influenced by farm management. Among the controllable factors, irrigation management had very effective role in the balance between vegetative and reproductive growth. In other words, water stress control in cotton fields is essential for economic output. Through advanced techniques, drip irrigation despite high initial cost, will be the first choice. Because in addition to irrigation efficiency, with earliness management, mechanization harvesting is done better. According to the analysis of variance, the effect of different amounts of water on the total yield was significant at the level of one percent. The lack of statistical significant differences between treatments in terms of total yield of I100 and I70, the second treatment due to a 30% saving in water consumption and earliness as the best in the normal condition. One of the parameters that are usually affected by irrigation management is earliness. Average comparison shows in term of earliness, three treatments of I70، I40 and I0 in group A and treatment I100 are in the latter group. Thus, from this aspect I70 can be recommended. In terms of water use efficiency I40 and I70 with 1.44 and 1.17 kg per cubic meter had the highest WUE, respectively.
Conclusions: The results shown that irrigation water had significantly effects on first pic, second pic and total yield. But irrigation water treatments had no significant effect on earliness and boll weight. According to the combined analysis table (two years data), as much as % 70 of cumulative evaporation from class A pan, will be recommended for cotton farming in north of Iran in normal weather. In dry years, % 100 of cumulative evaporation from class Apan is suggested.
A Rezaei Estakhroeih; S. Khoshghadam; M. Ebrahimi Serizi; A. Badiehneshin
Abstract
Water shortage is the most important factors on crop production in the world. Several methods of deficit irrigation are solutions for reduction of irrigation water. To understand the effects of conventional deficit irrigation and partial root zone drying treatments on yield, yield components and water ...
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Water shortage is the most important factors on crop production in the world. Several methods of deficit irrigation are solutions for reduction of irrigation water. To understand the effects of conventional deficit irrigation and partial root zone drying treatments on yield, yield components and water use efficiency of sunflower (Farrokh cultivar), one study was carried out. The research was conducted on Shahid Bahonar University of Kerman in the spring of 2011. A factorial experiment in a randomized complete block design with one control (full irrigation) and 18 deficit irrigation treatments in three replications was considered. Deficit irrigation treatments were: conventional deficit irrigation (irrigation with %80, %60 and %40 ETP) and partial root zone drying (irrigation with %80, %60 and %40 ETP). Every deficit irrigation treatment was conducted in three growth stage of sunflower (all periods of growth, vegetative growth stage and reproductive growth stage).The results showed that the conventional deficit irrigation treatments (irrigation with 80% ETP) in vegetative growth had the highest plant height, leaf area, leaf area index and head diameter. Also, the maximum biological yield equal to49054, maximum grain yield is equal to 9934/3 and maximum oil yield is equal to 2441/2 kg per hectare in the conventional deficit irrigation treatments (irrigation with 80% ETP) in vegetative growth occurred.The highest water use efficiency for grain yield is equal to 1/46,forbiological yield equal to7/21 and for dry forage yield is equal 5/7 kilograms per cubic meter of water. According to results,conventional deficit irrigation (irrigation with %80, %60 and %40 ETP) is recommended on based.
ali asghar ghaemi; B. Zamani
Abstract
Introduction: Barley is very important to feed humans, livestock, medical, industrial uses, especially in fermentation industries. In Iran, barley crop cultivation was nearly 1.4 million hectares withits production of 1.3 million tons in 2003 (2). Barelyis the oldest crops to environmental stresses such ...
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Introduction: Barley is very important to feed humans, livestock, medical, industrial uses, especially in fermentation industries. In Iran, barley crop cultivation was nearly 1.4 million hectares withits production of 1.3 million tons in 2003 (2). Barelyis the oldest crops to environmental stresses such as drought and salinity resistance (3).The different barely growth stages with extreme water requirement can benoted in germination stage, stem elongation, heading the production stage, the stage of flowering and seed production. Typically, for spring and autumn barely respectively 3 and 4 to 5 times irrigation is done during the growing season. The barley water requirement over its life is between 4 and 7 thousand cubic meters and 518 liters of water is needed to produce one kilogram of dry matter. Due to limited water resources and low rainfall in Iran, efficient use of water is absolutely essential and the maximum water utilization must be achieved by applying a minimum amount of water in agriculture. One of the ways to increase productivity in agricultural water is deficit irrigation.Deficit irrigation is an optimization strategy for water use efficiency in irrigation.The purpose of this study was to evaluate the simultaneous effect of fertilizer treatments (150, 225 and 75 kg/ ha) and water at three different levels (100%, 75% and 50% of crop water requirement) at different growth stages on leaf area index, weight fresh and dried herb and plant nitrogen concentration and the effect of irrigation and nitrogen fertilizer on yield, yield components and productivity of water use.
Materials and Method: This research was conducted in Shiraz University in fall 2012 to study the effect of interaction of deficit irrigation and nitrogen fertilizer on yield, yield component and water use efficiency and nitrogen concentration in different stages of barley (Bahman species) growth. This experiment were evaluated using a randomized complete block design with s plit-plot layout with three deficit irrigation treatments ( consisted of irrigation with 100% ,75% and 50% of crop water consumption use) and three nitrogen fertilizer treatments (included 75 kg/ha, 150 kg/ha and 225 kg/ha) with three replication. A total of 27 experimental plots were carried out. In each plot, 11-row barley with 30 cm spacing apart and 5 cm depth were planted by hand. Barley seeding rates on the basis of 200 kg per hectare were planted in each experimental plots in the first half of November.Nitrogen requirement was applied in three stages of the growth: 30% before cultivation, 40% in shooting stage and 30% in barleyclusterstage.Irrigation treatments included 100% = W1, in this treatment 100% treatment crop water requirement was estimated by neutron meter (this was the control treatment which received muchwater as neededand no water stress in all growth stages),75% = W2: in this treatment 75% of the crop water requirement was applied, and 50% = W3: the 50% of the crop water requirement plant was applied. During differentgrowth stages plant required data were collected and the parametersinclude: grain yield, biological yield, straw yield, number of grains per spike, spike per unit area, grain protein, harvest index, 1000 grain weight, number of unfilled and filled grain per spike and efficiency of water use were determined . Tests to determine the percentage of leaf nitrogen and protein was measured by kjeldahldevice(6405UV / VIS). The software SAS (version.9.1) was used to analyze data and graphs were drawn in Excel.
Results and Discussion: results showed that the highest yield,yield component was obtained on 100% irrigation and 225 kg/ha fertilizer treatments. Also it was observed that at the certain level of irrigation treatment by increasing the amount of nitrogen fertilizer the amount of this parameters will be increased.Result also showed that at the certain level of nitrogen fertilizer by decreasing water, the maximum plant response to the nitrogen fertilizer consumption will be decreased gradually in most cases, 225 kg/ha nitrogen fertilizer treatment caused most of crop yield parametersbut the differences of crop yield at this treatment with 150kg/ha nitrogen fertilizer treatment wasnot significant. Water use efficiency for 50% deficit irrigation treatment was 0.77 and for 100% irrigation treatment was 0.55. Regarding the results obtained from this study andexisting water crisis problem in Iran, it can be noted that the irrigation ofbarley should not be exceeded more than the 100% of crop water consumption use but using 75% of water requirement is suggestive. Also using 150kg/ha nitrogen fertilizer treatment is more suitable for the area.
Conclusion: This study was conducted in order to determinethe yield performance of barley (Bahmanspecies)inBadjgah (Fars Provience)using three different irrigation treatments of 100, 75 and 50 percent of crop water requirement (based on the total available water plant) and three nitrogen treatments include 225, 150 and 75 kg/ ha in the spring and autumn cultivation. In terms of deficit irrigation, during the growing season crop will interface with different intensities and durations of water stress. This tension changes in response to nitrogen fertilizer by plant that creates unpredictable and in some cases is not always the same.Statistical analysis showed that there are significant differencesbetweenthe different treatments of irrigation, nitrogen fertilizer and their interaction.Applying 75% of barley water requirement is suggestive. Also using 150kg/ha nitrogen fertilizer treatment is more suitable for the study area.
M. Esmaeili; Bahman Farhadi Bansouleh; M. Ghobadi
Abstract
Introduction: Expansion of the area of oilseed crops such as soybean is one of the policies of Iranian agricultural policy makers as Iran is one of the major oilseed importers in the world. However, the area of this crop in Kermanshah province is negligible, but it could be cultivated in most parts ...
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Introduction: Expansion of the area of oilseed crops such as soybean is one of the policies of Iranian agricultural policy makers as Iran is one of the major oilseed importers in the world. However, the area of this crop in Kermanshah province is negligible, but it could be cultivated in most parts of this province. The quantity and quality of the produced grain could be affected by environmental factors such as weather parameters and water availability. The aim of the current study was to investigate the effects of levels of deficit irrigation on the quantity and quality of soybean crop yield in Kermanshah, Iran.
Materials and Methods: For this purpose, a field study was conducted as randomized complete block design with four replications and four irrigation treatments at the research farm of Razi University, Kermanshah in 2012. The size of each plot was 4 * 4 m. Irrigation treatments consisted of four irrigation levels: 20% over irrigation (T4), full irrigation (T3 as control), 20% less irrigation (T2) and 40% less irrigation (T1). The reason to choose T4 treatment was the lack of confidence in estimated crop evapotranspiration as there was no local calibration of crop coefficient (Kc) for this crop. The required water for T3 treatment was calculated based on daily weather data using FAO-Penman-Montith equation. Daily weather data was recorded in a weather station which was located in the research farm and is available in the www.fieldclimate.com. As there was no rainfall during the crop season, all of the required water was supplied through irrigation. The required water for treatments of T1, T2 and T4 was considered as 60%, 80% and 120% of T3 treatment. The required water was applied using a hose connected to a volumetric flow meter with a liter precision. Total amount of applied water during the crop season was 4399, 5865, 7331 and 8797 m3.ha-1 in the treatments. Fertilizers were applied based on the recommendations of soil fertility experts. Weeds were controlled manually. Finally, the area of two square meters in the middle of each plot was harvested in order to determine crop yield in terms of grain, biomass, stem, pod, seed protein content and fat percentage and also water productivity index. Dry weights of the samples were measured after drying samples in the oven for48hours at 70° C. The percentage of fat and protein in the grains are also measured in the laboratory. Water productivity index was calculated for each treatment by dividing crop yield (in terms of grain, biomass, protein and fat) over seasonal water use. Statistical analysis of the results is also done using MSTATC software.
Results and Discussion: The highest and lowest crop yields were measured respectively in the treatments T4 and T1.The mean value of grain yield was 1084, 1367, 1716 and 1940 kg.ha-1,respectively in the treatments T1, T2, T3 and T4. These results showed a 36% decrease in the grain yield by decreasing 40% in the amount of supplied water. However, biological yield was decreasedby the level of irrigation, but the rate of reduction was lower than that of grain yield. By reducing irrigation application, thepercentage of grain protein content increased while the percentage of fat in the grain decreased. Considering simultaneous reduction in grain yield and fat content in the grain, severe reductions in fat yield (oil content) were observed under water stress conditions. Crop yield in terms of fat was reduced by 26.2 and 50.1 %, respectively in treatments T2 and T1 in comparison with T3 (control treatment). The maximum and minimum percentages of protein in the treatments were 31% and 27%, respectively in the treatments T1 and T4. Maximum water productivity in terms of grain, biomass and protein was achieved in T1 treatment respectively with the amounts of 0.24, 0.81 and 0.077 kg.m-3. Maximum and minimum fat percentage was 0.052 and 0.040 kg.m-3, respectively in the T4 and T1 treatments. In addition,the results indicated that water productivity index in terms of grain, biomass and protein increased while they decreased in terms of fat yield.The results of statistical analysis indicated that water productivity index in all terms except protein had significant differences (at 5%) with T3 treatment.
Conclusion: Crop yield and water productivity (except in terms of fat) was increased by increasing applied water. Considering all indices of treatment T2 (20% deficit irrigation), itwas suggested as the best treatment.
S.S. Nurbakhsh; M. Ghobadinia; A. Danesh-Shahraki; mohammad reza Nori Emamzadeie; R. Fatahi
Abstract
Introduction: Nowadays, due to lack of water resources and increasing demand for water, agricultural water planning issues need further consideration. With proper planning and determination of irrigation depth and time, the effects of stress and yield loss on the plants are reduced. Irrigation scheduling ...
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Introduction: Nowadays, due to lack of water resources and increasing demand for water, agricultural water planning issues need further consideration. With proper planning and determination of irrigation depth and time, the effects of stress and yield loss on the plants are reduced. Irrigation scheduling is one of the most important factors in crop’s quality and quantity. The main objective of irrigation scheduling is to control crop’s water conditions in order to achieve its optimum yield level. So irrigation timing is the vital factor on which crop water stress and eventually yield's level are dependent upon. Moreover, irrigation timing is used in irrigation scheduling. The aim of this study was to evaluate the effect of irrigation time on water consumption, water use efficiency and yield of beans.
Materials and Methods: In order to observe the effect of the amount and the time of the irrigation on water consumption, yields rate and water use efficiency, the current research was carried out at the University of Shahrekord during the summer of 2012. The experiment was done as a completely randomized design with 4 repetitions consisting of irrigation time and the amount of irrigation in 4 and 2 levels (at 6, 8, 14 and 18) and (deficit irrigation, full irrigation), respectively. Beans seeds were planted in 32 similar vases with a diameter of 45 cm and height of 60 cm, in each experiment. Treatments were begun after 37 days from planting. Treatments were irrigated when the average moisture in the root zone was equal to the lower border of readily available water of full irrigation. At the end of the experiments, plants were completely harvested. Then the plant’s height, number of branches, numbers of pods per plant, pod and seed weight were measured.
Results and Discussion: Results showed that irrigating at different times during the day influenced water use efficiency, water consumption, seeds yield and number of pods in the bush. The water consumption was affected by irrigation time. Among full irrigation treatments, irrigation at 2 p.m. and 6 a.m. had the highest and lowest water consumption, respectively. The total amount of water used in irrigation at 8 a.m., 2:00 p.m. and 6 p.m. compared to 6:00 a.m. was increased by1.6, 9.5 and 4.1 percent, respectively. The results showed that irrigation at 2:00 p.m., caused a significant reduction in yield. Moreover, water use efficiency in 6 a.m. treatments had increased 18.5 percent more than that of the 2:00 p.m. irrigation treatment. The time of irrigation did not have a meaningful effect on bush height, the number of minor branches, the pod's length. The effect of the amount of irrigation water was meaningful on bush height, number of minor branches, seeds yield, the number of pods in the bush, pods length and seed weight. Seed yield at 8:00 a.m., 2:00 p.m. and 6:00 p.m. treatments has shown 0.29, 17.1 and 7.6 percent decrease in comparison with 6:00 a.m. irrigation treatment, respectively. Moreover, 100-seed weights were significantly affected by the irrigation time. The maximum and minimum weights of 100-seed weights were obtained at 6:00 a.m. and 6:00 p.m. irrigation, respectively. Analysis of variance showed that the number of pods per plant was affected by irrigation time. The maximum number of pods per plant was 101 which belong to the 6:00 a.m. treatment. In this experiment in the case of irrigation at 2:00 p.m., the number of pods per plant was significantly decreased in full and deficit irrigation. The results showed that although the irrigation frequency was the same, irrigation at maximum evapo-transpiration caused the plant to be under stress and the yield was reduced. In other word, it can be said that time of irrigation had no meaningful effect on the appearance and shape of the plant while it was effective in terms of the yield. Overall assessments showed that maximum of the measured features were obtained in the case of 6:00 a.m. treatment.
Conclusion: The results showed that irrigation at different times of the day and the applied water stress, reduced water use efficiency. These caused traits such as plant height; number of branches; number of pods per plant; pod and seed weight to be affected by the irrigation depth. Based on the results of this experiment it can be stated that, when there is no limit of water supply, it is recommended to irrigate in the early morning, before the steep slope of the temperature rise. However, in the situations with water shortage problems, is better to manage the water and the product.
Keywords: Bean, Deficit irrigation, Irrigation time, Water use efficiency
Saeid Boroomand Nasab; Mohammad javad khangani
Abstract
Deficit irrigation is an optimization strategy for water use efficiency in irrigation. This research was conducted to evaluation effect of deficit irrigation (DI) and partial root zone drying (PRD) on yield, yield components and water use efficiency of corn. Research was conducted on Shahid Bahonar University ...
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Deficit irrigation is an optimization strategy for water use efficiency in irrigation. This research was conducted to evaluation effect of deficit irrigation (DI) and partial root zone drying (PRD) on yield, yield components and water use efficiency of corn. Research was conducted on Shahid Bahonar University of Kerman in the spring of 2010 using a completely randomized block design with one control, 18 deficit irrigation treatment and three blocks. Deficit irrigation treatments were included: mild water stress (irrigation with درصد75 ETP), high water stress (irrigation with %50 ETP), fixed every other furrow irrigation and three partial root zone drying (Change the wet furrows in every irrigation, Change the wet furrows in every other irrigation and change the wet furrows in every second irrigations). Every treatment was applied at three growth stages of corn (all periods of growth, vegetative growth stage and reproductive growth stage). The highest biological yield obtained 32431 and the lowest was 17654 kg per hectare. The highest grain yield was 12115 kg per hectare and the lowest was 7163. Water use efficiency (km grain yield per cubic meter of water) for the control treatment was equal to 1.16 and for partial root zone drying with change the wet furrows in every irrigation (14 days) in all periods of growth treatment was equal to 2.13. Results showed that partial root zone drying with one interval irrigation (14-day) was the best choice to apply deficit irrigation on corn.
M.H. Najafi Mood; A. Alizadeh; K. Davari; M. Kafi; A. Shahidi
Abstract
This experiment was conducted based upon a factorial split plot design consisting of three factors: salinity with three levels (2.2, 5.5 and 8.3 dS/m), irrigation with four levels (50%, 75%, 100% and 125%), cultivars with two levels (Varamin and Khordad). There were three replicates for each treatment ...
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This experiment was conducted based upon a factorial split plot design consisting of three factors: salinity with three levels (2.2, 5.5 and 8.3 dS/m), irrigation with four levels (50%, 75%, 100% and 125%), cultivars with two levels (Varamin and Khordad). There were three replicates for each treatment combination. Salinity was considered as main plot while the other factors were arranged as sub plots in the experiment. Effects salinity and deficit irrigation on yield for cultivars of cotton studied with Marginal Production(MP), Marginal Rate of Technical Substitution(MRTS) and Value of Marginal Production(VMP) indexes. Also for economics analysis, optimum depth of irrigation for deficit irrigation and complete irrigation depth were determined for tow cultivar. MPI showed That in deficit irrigation condition, yield of Khordad less than Varamin, for 1 centimeter of irrigation depth. But in over irrigation level , decreasing yield of Khordad rather than Varamin. Also MPECw showed, That yield decreased 31.8 Kg/ha on Varamin and 76.5 Kg/ha on Khordad cultivars, by increasing 1 dS/m salinity of irrigation water. MRTS index showed for instant yield, when salinity of irrigation water decrease 1 dS/m, must be increase depth of irrigation, 1.68, 3.85 cm for Varamin and Khordad respectively. So that, in equal situation of irrigation water salinity, optimum irrigation depth for Khordad was rather than Varamin.Also in all of salinity levels, optimum irrigation depth, for Khordad was rather than Varamin.
