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Solmaz Mokarram; Javad Behmanesh; Vahid Rezaverdinejad
Abstract
Biochar as a porous material is rich in biological carbon in a stable form. Its structure is capable to store water and nutrients. Therefore, it is used for retention of such materials, especially in sandy soils. Biochar can improve water productivity in the agricultural sector in drought stress condition ...
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Biochar as a porous material is rich in biological carbon in a stable form. Its structure is capable to store water and nutrients. Therefore, it is used for retention of such materials, especially in sandy soils. Biochar can improve water productivity in the agricultural sector in drought stress condition to achieve food security in the world. In order to study the effect of deficit irrigation and biochar on yield of coriander in a coarse-grained soil under water stress, this research was conducted using a factorial manner and a completely randomized design in the research greenhouse of Urmia University. The experimental treatments included three levels of irrigation: 100%, 75%, and 50% of the plant water requirement, and three levels of biochar application: 0, 2.5%, and 5% of the weight of each pot, which totally included 27 treatments. Irrigation was applied on the basis of plant requirement and soil water content below field capacity and the applied water was measured during the growing season. For each pot, quantitative parameters including weights of dry and wet plant, stem, leaf, and root were accurately measured. The results showed that the effects of irrigation levels and biochar on some measured parameters were significant at the probability level of 1% and 5%. The results demonstrate that by applying deficit irrigation, the measured quantitative parameters and plant yield decreased. The highest value of the parameters was obtained from the treatment of 100% water requirement and use of biochar up to the level of 2.5% of the soil. Therefore, applying suitable amount of the biochar as soil amendment improves coriander plant's growth and yield.
2
Faranak Baradaran-Hazaveh; Hossein Babazadeh; Ebrahim Amiri; Hossain ebrahimi
Abstract
Pulses have a special position, after wheat and rice, in the Iranian people diet. The growth of these plants is very fast and water stress has an important effect on their yield. The objective of this study was to evaluate the DSSAT Model in simulating the growth and yield of cowpea under different levels ...
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Pulses have a special position, after wheat and rice, in the Iranian people diet. The growth of these plants is very fast and water stress has an important effect on their yield. The objective of this study was to evaluate the DSSAT Model in simulating the growth and yield of cowpea under different levels of irrigation water. An experiment was conducted as a randomized complete block design (RCBD) with three replications in Kiashahr City, Iran, in the crop seasons of 2017 and 2018. The main treatments included irrigation with management of 40%, 60%, 80%, 100%, and 120% of plant water requirement and the three sub-treatments included irrigation at vegetative or reproductive stages, and full irrigation. In this experiment, the DSSAT simulation model was used to evaluate water efficiency and water balance components. Evaluation of simulated and measured values of grain yield was performed using the parameters of coefficient of determination, t-test, root mean square error (RMSE) and root mean square normalized error (nRMSE). The results showed that the difference between the predicted grain yield and the observed values was acceptable (RMSE=92 and nRMSE = 12.62%). Total biomass was also well simulated (RMSE=130 and nRMSE = 5.91%). Using the measured grain yield and water balance components simulated from the DSSAT model, the water productivity based on evapotranspiration (WPET) was about 33% lower than that based on transpiration (WPT). According to the results, irrigation with 100% water requirement at both vegetative and reproductive stages resulted in the highest transpiration (383mm), and was selected as the optimum irrigation management during the growing season.
7
Ali Abdzad Gohari
Abstract
Knowing the appropriate cultivars and proper irrigation management is one of the most important factors affecting the growth and yield of peanut plant. The present study was conducted as split split plots in the form of a randomized complete block design with three replications, in 2018 and 2019 ...
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Knowing the appropriate cultivars and proper irrigation management is one of the most important factors affecting the growth and yield of peanut plant. The present study was conducted as split split plots in the form of a randomized complete block design with three replications, in 2018 and 2019 in Guilan Province. The main plot consisted of two methods of drip and furrow irrigation, and the sub-plots included supplying 125%, 100%, 75%, 50%, and 25% of water requirement, and the sub-sub-plot included two peanut cultivars Guil and Jonobi. The results of the study showed significant effect of irrigation method on seed yield (at p<0.5) and the effect of water supply on all measured traits (at p<0.1). The highest seed yield in 2018 and 2019 was observed in Guil cultivar with 100% water requirement of the plant with an average of 3221 and 3161 kg.ha-1, respectively. In the two study years, annual averages of seed yields in drip irrigation (1808 and 1803 kg/ha) compared to the furrow method (1753 and 1754 kg/ha) showed an increase of 3.1% and 2.8%, respectively. The correlation between traits, showed a positive and significant effect between seed yield and number of pods per plant, number of seeds per plant, and 100-seed weight. Based on the results, for peanut cultivation in the study area, Guil cultivar with drip irrigation and providing 100% of water requirement (5481 m3 of water/ha in this research) is recommended.
Mohammad Ali Shahrokhnia; Hamid Zare
Abstract
Estahban region in Fars province is mostly covered with rainfed fig trees. Gardeners have applied over-irrigation because of drought in recent years. In this study, irrigations were scheduled based on different crop water stress indexes by measuring canopy temperature. The treatments included irrigation ...
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Estahban region in Fars province is mostly covered with rainfed fig trees. Gardeners have applied over-irrigation because of drought in recent years. In this study, irrigations were scheduled based on different crop water stress indexes by measuring canopy temperature. The treatments included irrigation at different Crop Water Stress Indexs (CWSI) of 0, 0.2, 0.4, 0.6, 0.8. A rain-fed treatment was also added as control. The trees were irrigated by hand using water tankers. During the two years of the research, the number of irrigations, yield, and water productivity were measured. Duncan test was used for statistical analysis of the treatments in a complete block test design with four replicates. Economical analyses were also done based on benefits and costs in 2017 and 2018. Results showed that the maximum observed CWSI was not more than 0.6. Irrigation increased the yield values from 3.1 kg/tree in rain-fed condition to 9.8 kg/tree in the fully irrigated treatment. However, water productivity decreased from a large value in the rainfed treatment to 0.65 kg/m3 in the fully irrigated treatment. The treatment that was irrigated once had amuch increase in yield and increase about 740000 and 1190000 Rials in net benefit compared to rain-fed treatment in the studied years. The net benefit of one irrigation in the two studied years was about 530000 and 990000 Rials/m3of applied water. These values decreased with increase in the irrigation times. The benefit cost ratio in the two studied years was 1.10 and 1.46 for rain-fed trees while it was 2.21 and 2.89 for single irrigation treatment, respectively. Therefore, by one supplemental irrigation of the rain-fed fig trees,the drought damages could be controlled, a significant economical benefit could be gained, and over-irrigation is avoided.
7
Saber Jamali; Hossein Ansari; Abbas Safarizadeh-sani
Abstract
Peppermint (Mentha piperita L.) is used for medicinal and food purposes. Its cultivation has economic importance, due to its ability to produce and store essential oil. This research was conducted to study the effect of deficit irrigation and magnetized water on yield and yield components of peppermint ...
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Peppermint (Mentha piperita L.) is used for medicinal and food purposes. Its cultivation has economic importance, due to its ability to produce and store essential oil. This research was conducted to study the effect of deficit irrigation and magnetized water on yield and yield components of peppermint in the experimental research greenhouse of Ferdowsi University of Mashhad, during 2018-19. We used a factorial experiment based on the completely randomized design with 3 replications. Irrigation levels consisted of 4 levels (100%, 85%, 70%, and 55% of plant water requirements) and magnetic field factors consisted of 3 levels (0, 0.3, and 0.6 teslas). The result showed that decrease of the water requirement by 15%, 30%, and 45% resulted in reduction of shoot fresh weights by 11.2%, 15.1%, and 36.5%, respectively. However, irrigation with magnetized water (0.3 teslas) under deficit irrigation levels (85%, 70%, and 55% of plant water requirements) resulted in the increase of shoot dry weights by 19.5%, 24.7%, and 66.4%, respectively. In general, the use of magnetic water under water stress enhanced plant growth and improved dry and wet shoot yield in peppermint compared to the control treatment under deficit irrigation conditions.
mahdi mokari; Meysam Abedinpour; hadi dehghan
Abstract
Presently, the main challenge of agricultural sector is improvement of crop water productivity (CWP). To evaluate the effect of water stress and planting date on grain yield, water productivity and yield components of wheat (Pishgam var.), an experiment was conducted as split plot based on complete ...
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Presently, the main challenge of agricultural sector is improvement of crop water productivity (CWP). To evaluate the effect of water stress and planting date on grain yield, water productivity and yield components of wheat (Pishgam var.), an experiment was conducted as split plot based on complete randomized design with three replications, at Kashmar Agricultural Research Station, in 2018-2019. Irrigation treatments included 100% of irrigation water requirement (IWR), 80% IWR, 60% IWR, and 40% IWR as the main treatments, and three planting dates including 23rd September, 23rd October and 23rd November as sub treatments. The results showed that water stress had significant effect on grain yield, water use efficiency (WUE), and harvest index (HI) at 1% probability level, such that with increasing water stress, the grain yield, HI and WUE was decreased. Also, the results showed that the effect of sowing date on grain yield, thousand kernel weight, and number of kernels per panicle, HI, and WUE was significant. The highest values of grain yield, HI, and WUE were 7227.33 kg/ha, 32.77 %, and 2.51 kg/m3, respectively, and belonged to 23rd October and 100% IWR treatment. The lowest of these values were 2000 kg/ha, 15.3%, and 1.14 kg/m3, respectively, related to 23rd November and 40% IWR treatment. The interaction between water stress and planting date had significant effect on all agronomic traits, except the number of kernels per panicle and WUE. According to the results of this study, irrigation treatment of 100% IWR and planting date of 23rd October can be considered for autumn wheat cultivar (Pishgam var.) in arid and semi-arid region of Kashmar.
fatemaeh hajiabadi; Farzad Hassan Pour; Mostafa Yaghoubzadeh; Hossin Homami; Seyed Mohsen seyedi
Abstract
Salinity and drought stress are the most important factors that limit plant growth, especially in dry and semi-arid regions. To investigate the effects of irrigation water levels and salinity on yield and yield components of wheat cultivar Sirvan, a factorial experiment was conducted in a complete randomized ...
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Salinity and drought stress are the most important factors that limit plant growth, especially in dry and semi-arid regions. To investigate the effects of irrigation water levels and salinity on yield and yield components of wheat cultivar Sirvan, a factorial experiment was conducted in a complete randomized block design with three replications in the research field of agricultural faculty of the University of Birjand during the growing season of 2017-18. The treatments included irrigation at four levels (125%, 100%, 75%, and 50% water requirement) and water salinity in three levels (1.6 dS.m-1, 6 dS.m-1, and 7.8 dS.m-1). The results showed that yield components, biological yield, and grain yield of wheat were affected by water irrigation levels and water salinity. Moreover, these treatment significantly reduced the yield components, harvest index, and water use efficiency (WUE). In biological and grain yield of wheat, the highest and the lowest amounts belonged to 125% water requirement × salinity of 1.6 dS m-1 by 1535and 588.76 g m-2, respectively. In biological yield and grain yield, there was no significant difference observed between 125% wheat water requirement × salinity’s of 1.6% dS.m-1 and 100% water requirement × salinity of 1.6% dS.m-1 treatments. Biological and grain yield of wheat decreased to 65% in 50% water requirement × salinity of 7.8 dS m-1 compared with 125% water requirement × salinity of 1.6% dS.m-1. According to results of this experiment, 125% and 100% water requirement treatments had the highest biological and grain yield. Although 125% wheat water requirement had the highest value in all traits but they were not significant compared to 100% water requirement treatment. In water salinity treatments, non-stress levels had the best performance. According to the results of this study, to avoid salt accumulation in the root zone under saline water irrigation and to decrease negative salinity effects, irrigation must be applied based on wheat water requirement.
Hadi Dehghan; mahdi mokari; Meysam Abedinpour
Abstract
Due to the quantitative and qualitative decline of groundwater resources, it is essential to optimize the water use in agriculture. One of the methods to optimize water use in agriculture, especially in arid and semi-arid regions, is to use yield-water-salinity functions. Therefore, this study was performed ...
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Due to the quantitative and qualitative decline of groundwater resources, it is essential to optimize the water use in agriculture. One of the methods to optimize water use in agriculture, especially in arid and semi-arid regions, is to use yield-water-salinity functions. Therefore, this study was performed for prediction of spinach yield and yield components and determination of optimal production function under salinity and water stress conditions in Kashmar region, Iran. A factorial experiment was performed in a completely randomized block design with four replications including three salinity levels (i.e. S1= 0.75, S2=4, S3= 8 dS/m) and three levels of irrigation (including full irrigation (100% of water requirement)) = I1, I2=75% I1, and I3= 50% I1). Yield and yield components data of spinach (including leaf area, plant height, stem height, root length, plant dry weight, and root dry weight) were fitted to different production functions including simple linear, Cobb-Douglas, quadratic, and transient models. Optimal production function of spinach was determined after determining the coefficients of different functions. To evaluate different functions, the statistical indices of normalized mean square error, mean absolute error, modeling efficiency, agreement index and explanation coefficient were used. The results showed that the coefficient of determination (R2) for estimation of the biomass weight by quadratic, transcendental, simple linear, and Cobb-Douglas functions were 0.938, 0.890, 0.888 and 0.867, respectively. Most of the values of normalized mean square error and mean absolute error belonged to the simple linear functions and Cobb- Douglas. According to the results of this research, the quadratic production function is recommended as the optimal production function for yield and yield components of spinach.
halime piri; Abolfazl Bameri
Abstract
In this research, the effect of different levels of irrigation water, nitrogen fertilizer, and cow manure on garlic was investigated. The experiments were carried out in a split-spilt plot design, with four levels of irrigation water depths (40%, 60%, 80% and 100% of the plant water requirement) in the ...
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In this research, the effect of different levels of irrigation water, nitrogen fertilizer, and cow manure on garlic was investigated. The experiments were carried out in a split-spilt plot design, with four levels of irrigation water depths (40%, 60%, 80% and 100% of the plant water requirement) in the main plots, three levels of nitrogen (50, 75 and 100% nitrogen) in the sub- plots, and three levels of manure (25, 32.5 and 50 ton/ha cow manure) in the sub-plots. Nitrogen was applied in two stages and cow manure in one stage before planting. At the end of the experiment, parameters such as plant height, weight, and number of garlic, yield, and irrigation water productivities were measured. The results showed that the effects of irrigation water, nitrogen fertilizer, and manure were significant (p< 1% and <5%) on all parameters. The highest yield was obtained from 100% fertilizer application and 100% water requirement, but no significant effect was observed between treatments of 100 and 80% of water requirement. The highest amount of irrigation water utilization was obtained at irrigation level of 60% and fertilizer level of 100% (1.48 kg/m3/ha). In this regard, there was no significant difference between treatments of 60% and 80% of water requirements. The amount of allicin was reduced by reducing irrigation water and reducing fertilizer use. Increasing nitrogen fertilizer up to 75% of fertilizer requirement, amounting to 150 kg/ha, resulted in increase of allicin, but higher amounts resulted in decrease of allicin content. Therefore, due to shortage of water in the region, irrigation of this crop can be done with 80% of the plant's water requirement, without a significant effect on the yield.
Hooshang Khosravi
Abstract
A wide range of Iranian agricultural lands is located in arid and semi-arid regions and, hence, crops face some drought stress. Therefore, sustained agricultural production is important in these circumstances. Azotobacter is a molecular-nitrogen-fixing bacterium, which promotes plant growth by various ...
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A wide range of Iranian agricultural lands is located in arid and semi-arid regions and, hence, crops face some drought stress. Therefore, sustained agricultural production is important in these circumstances. Azotobacter is a molecular-nitrogen-fixing bacterium, which promotes plant growth by various mechanisms and may provide drought resistance. Inoculation of crops with superior bacterial isolates compatible with dry areas may increase plant tolerance to drought stress. In this study, the effect of inoculation of native isolates of Azotobacter isolated from arid and semi-arid regions of Iran under drought stress conditions was investigated on the growth of maizesilage cultivar i.e. Single Cross 704, in greenhouse conditions. The experiment was conducted as a completely randomized block design (RCBD) with three replications including inoculations with 15 Azotobacter isolates, blank (no inoculation and no drought stress), control (no inoculation but with drought stress). In order to apply drought stress by weighing method, soil moisture content in the vegetative stage was allowed to drop to 40-50% of allowable moisture depletion, and at flowering stage to harvesting, a range of 50-60% was maintained. The results showed that drought stress significantly decreased shoot dry weight, plant height, and dry weight of corncob compared to non-stress control. Inoculation with Azc10 resulted in a significant increase in the shoot dry weight compared to the control. This isolate increased the shoot yield by about 20% compared to non-inoculated treatment under drought stress conditions.
Ali Beyki; Abbas Khashei
Abstract
This research was conducted with the aim of studying the effect of interaction of water stress and different levels of zeolite on growth and yield characteristics of black cumin (Nigella sativa L)plant during cropping season of 2018. The study was based on completely randomized block design as split ...
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This research was conducted with the aim of studying the effect of interaction of water stress and different levels of zeolite on growth and yield characteristics of black cumin (Nigella sativa L)plant during cropping season of 2018. The study was based on completely randomized block design as split plots, with irrigation at two levels (I1 and I2: irrigation with 100% and 50% water requirement, respectively) and zeolite treatment at three levels (Z0: without Z1 and Z2: using potassium zeolite at 2 and 4 gr.kg-1 soil, respectively), with three replications at Research Farm of Faculty of Agriculture, University of Birjand. Under the influence of interaction between zeolite and irrigation management, the highest plant height was 16.88 cm, and weight of fresh and dry yield and 1000-seed were, respectively, 11.96, 9.33, and 13.19 g. Also the number of capsules per plant and seeds per capsules were, respectively, 10.11 and 52.44. The maximum grain yield was 874.77 kg.ha-1 and water use efficiency (WUE) was 0.135 kg.m-3, respectively. The lowest values for the corresponding parameters were 13.13 cm, 7.4, 5.05, and 11.95 g, respectively, and 8.33 and 44.44 for the number of capsules per plant and seeds per capsule, yield of 748 kg.ha-1 and WUE of 0.118 kg.m-3,. Water stress led to a decrease in the characteristics of growth and yield of black cumin. Therefore, application of zeolite at high levels (15 tons per hectare), especially under full irrigation of the plant, could lead to maximum yield and characteristics of black cumin growth.
fatemeh abbaspour; hamidreza asghari; P Rezvani Moghaddam; hamid abbasdokht; javad shabahang; adel baig babaei
Abstract
A field experiment was conducted which focused on the effects of walnut wood biochar and chemical fertilizers on quality characteristics of Black Seed (Nigella sativa) under water deficit conditions. The experiment was carried out in a split plots factorial layout based on a randomized ...
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A field experiment was conducted which focused on the effects of walnut wood biochar and chemical fertilizers on quality characteristics of Black Seed (Nigella sativa) under water deficit conditions. The experiment was carried out in a split plots factorial layout based on a randomized complete block design with three factors and three replications. Three levels of irrigation (I1: 100%, I2: 70% and I3: 40% of crop water requirement) were assigned as the main plots and the combination of three levels of biochar (B1: 0, B2: 10 and B3: 20 t.ha-1) and two levels of chemical fertilizers (F1: without and F2: with chemical fertilizer) were allocated to sub plots. Recommended dose for nitrogen, phosphorus, and potassium was 150 kg N.ha-1, 75 kg P2O5.ha-1 and 100 kg K2SO4.ha-1, respectively. Results showed that irrigation had no effect on soil properties, but application of 20 t ha-1 of biochar improved soil saturation percentage, soil organic carbon, and total nitrogen. Irrigation significantly influenced the seed yield, oil yield, oil percentage, and fatty acids, except oleic acid. The 70% water requirement treatment increased the amount of fatty acids, except stearic acid. Plant quality characteristics significantly increased by 10 t ha-1 biochar application. Application of 10 t ha-1 biochar plus 70% irrigation water requirement and using chemical fertilizer (I2B2F2) produced the highest seed yield (1158.4 kg ha-1). Based on the results, it seems that application of 10 t ha-1 biochar is suitable for black seed production under water deficit condition.
khadije fattahi dolatabadi; hosin babazadeh; payam najafi; hossin sedghi
Abstract
To prevent water stress in plants and have sustainable water management in the field, fast and accurate determination of irrigation time is one of the most important issues. Measuring soil moisture and leaf surface temperature are two methods of determining time of irrigation. In this research, by combination ...
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To prevent water stress in plants and have sustainable water management in the field, fast and accurate determination of irrigation time is one of the most important issues. Measuring soil moisture and leaf surface temperature are two methods of determining time of irrigation. In this research, by combination of these two methods, a model for planning and management of forage maize irrigation (cultivar SC-701) is presented. The air relative humidity (RH) and temperature (Ta), leaf surface temperature (TL), and soil moisture content (SM) were measured in 2013 and, by using artificial neural network model and multiple stepwise method, a regression model was developed. Experiments were carried out in 2014 with five treatments including 100%, 85%, 75%, 65%, and 35% total available water (TAW), with four replications, Irrigation was carried out when soil moisture content reached the treatments moisture level. Measurements of the previous year were repeated and the model was calibrated. The results of the first year showed a correlation (R2=0.87) between the parameters RH, Ta, TL, Ta-TL as independent variable and SM as the dependent variable. Then, using three input parameters of air temperature, leaf surface temperature, and relative humidity, Determination Coefficient of soil moisture content model was calculated as R2= 0.92. In this model, soil moisture has an inverse relation with (Ta) and (TL-Ta) variables, but a direct relation with RH. Soil moisture content was compared using the model for the second year treatments and compared with the measured values. The difference in soil moisture content measured and estimated by the model at the peak solar radiation time (at noon) was less than ±10%. The model estimated 75% TAW treatment data well, with very small difference compared to the measured value.
Sajad Azimi; mojtaba khoshravesh; abdolah darzi; Meysam Abedinpour
Abstract
Kashmar plain is located in an arid region and recent consecutive drought events have attracted serious attention to water use management. In this research, the effects of four levels of super absorbent polymer A200 (0(V0), 0.1% (V1), 0.2% (V2) and 0.3% (V3) wt%), four levels of vermicompost (0(V0), ...
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Kashmar plain is located in an arid region and recent consecutive drought events have attracted serious attention to water use management. In this research, the effects of four levels of super absorbent polymer A200 (0(V0), 0.1% (V1), 0.2% (V2) and 0.3% (V3) wt%), four levels of vermicompost (0(V0), 7(V1), 10(V2) and 15(V3) tons per hectare), and three levels of irrigation (60%(W1), 80%(W2) and 100%(W3) of water requirement) were evaluated on water use efficiency (Irrigation water and rain) (WUE) and irrigation water use (WUEi) of wheat. The study was conducted in research farm of Kashmar Higher Education Institute. Factorial experiment was performed using a completely randomized design with 144 pots. The results showed the highest WUE and WUEi in S3V3W3 treatment as 1.49 kg/m3/ha and 2.26 kg/m3/ha, respectively. The lowest WUE and WUEi were observed in S0V0W1 treatment and were 1.03 kg/m3/ha and 1.56 kg/m3/ha, respectively. Totally, it can be concluded that superabsorbent and vermicompost increased the WUE and WUEi. Under the conditions of this experiment, according to the analysis of variance, the combined application of superabsorbent and vermicompost was not significant. Also, according to the comparison of means at 5% significance level, in separate application of superabsorbent and vermicompost, the best value for achieving maximum WUE and WUEi is 0.2% (weight percent) superabsorbent or 10 ton/ha of vermicompost. By using the maximum superabsorbent and vermicompost and increasing water application from 60% to 80% and from 80% to 100%, WUEi increased by 6.5 percent and 19.7 percent, respectively.
ali dehghan moroozeh; Bahman Farhadi Bansouleh; mokhtar ghobadi
Abstract
In order to evaluate the effect of irrigation amounts on soybean yield and quality, an expriment was conducted as randomized complete block design with three replications in Kermanshah, during summer of 2015. Irrigation treatments were in eight levels including T1=100%, T2=120%, T3= 80%, and T4=60% of ...
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In order to evaluate the effect of irrigation amounts on soybean yield and quality, an expriment was conducted as randomized complete block design with three replications in Kermanshah, during summer of 2015. Irrigation treatments were in eight levels including T1=100%, T2=120%, T3= 80%, and T4=60% of crop water requirement in all growth periods, and T5= 80% and T6=60% in vegetative stage, and for T7= 80% and T8=60% water requirement was applied at flowering stage. During other stages of plant growth in T5, T6, T7, and T8, plants received 100% of water requirement. In this study, some geometric and gravity properties of seeds including length, width, area, perimeter, length to width ratio, circulatory coifficent, distance from the center of gravity to the junction of length and width, and leaf area index by using SmartGrain model and yield components, the number of pods, seed weight, dry weight, and plant height were measured and evaluated. The results showed that irrigation significantly affected all traits, except for the distance between the center of the intersection of width and length grain and circulatory coifficent. So, the most sensetive stage to water stress wass flowering, followed by the 60% water requirement treatment in the whole growth period. The highest water use efficiency for grain and oil yield was obtained in 120% treatment, followed by the 80% treatments in vegetative growth stage. In general, the results showed that, if deficit irrigation is to be carried out on soybean, it is better to have 20% irrigation deficit (80% water requirement) at the vegetative stage.
Habib Karimi Avargani; Ali Rahimikhoob; Mohammad Hadi Nazarifar
Abstract
Crop Simulation models are used for water management in farms and are widely used for optimization of water use efficiency. AquaCrop model, developed by FAO, is based on yield response to water. Compared to other similar models, AquaCrop requires fewer input parameters. The objective of this study was ...
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Crop Simulation models are used for water management in farms and are widely used for optimization of water use efficiency. AquaCrop model, developed by FAO, is based on yield response to water. Compared to other similar models, AquaCrop requires fewer input parameters. The objective of this study was evaluation of this model for barley under deficit irrigation in Pakdasht region. The experiment was done in 2014-15 growing season and included three irrigation treatments and three sowing dates. The irrigation treatments included full irrigation and two treatments of 80% and 60 percent of full irrigation. Sowing dates included early, normal, and late planting. Comparing the estimated values of AquaCrop model and measured values showed that the model is well capable of simulating the barley biomass production. Average R2, RMSE and MBE for the comparison between measured and estimated values were calculated to be 0.96, 8.4 %, and 2.6 %, respectively.
Nader Kouhi Chellehkaran; h d
Abstract
Crop growth models facilitate management of irrigation water and fertilizer because less on-site (filed) visits and direct measurements are required. On the other hand, these models are complex and difficult to be understood and require input data that is not available, thus, using them in management ...
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Crop growth models facilitate management of irrigation water and fertilizer because less on-site (filed) visits and direct measurements are required. On the other hand, these models are complex and difficult to be understood and require input data that is not available, thus, using them in management decisions, which should be done before cultivating season, will be difficult. The objective of this study was to develop a model for grain yield prediction of Corn (Zea maize) based on simulated leaf area index (LAI) under water stress conditions. In this study, corn LAI was simulated based on cumulative degree-days and water stress index. The model used crop and soil as well as meteorological data including daily maximum and minimum air temperature (oC), precipitation (mm), and solar radiation (MJ.m-2d-1). The model was developed based on the 2013 growing season data for single cross 704 cultivar under full irrigation and water stress conditions, and was validated with 2014 growing season data. The highest values of simulated LAI in the 100% water requirement (WR) treatment were between 6.14 and 5.78, in the 80% WR between 5.63 and 5.4, and in the 60% WR was between 4.11 and 3.47, which varied by 0.13 (2%), 0.14 (2.5%) and 0.29 (6.6%), respectively. In the mid- stage of growth, the estimated LAI was more consistent with measured values (2%). In treatments under stress (except for the fourth stage of sampling), the LAI estimated by the model was 6.6% higher than the values observed. In all treatments, the high correlations (R2) between the values of the simulated LAI and observed LAI in both years of the experiment were between 0.9 and 0.99.
halimeh piri; Hossein Ansari; m p
Abstract
Water stress and salinity are among the problems of agricultural production in many parts of the world. In this study, the effect of salinity (2, 5 and 8 dS/m), different irrigation levels (120%, 100%, 75%, and 50% of water requirement) and three harvesting times (cuttings) were investigated on some ...
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Water stress and salinity are among the problems of agricultural production in many parts of the world. In this study, the effect of salinity (2, 5 and 8 dS/m), different irrigation levels (120%, 100%, 75%, and 50% of water requirement) and three harvesting times (cuttings) were investigated on some qualitative and quantitative parameters of sorghum silage in the Sistan region. The study was carried out using a factorial split plot design with 12 treatments and 3 replications. The results showed that increasing salinity and irrigation water depth decreased fresh and dry matter yield. However, no significant difference was observed between 100% and 75% crop water requirement treatments. Also, treatments with 2 and 5 dS/m salinity were not significantly different in feed production. Furthermore, the fresh and dry forage yields were higher in the second cutting than in the first and third harvesting. Decrease in irrigation water and increase in salinity decreased protein but increased carbohydrate and proline. The highest amount of protein (16.79 percent) was obtained in the second harvesting and at the salinity of 2 dS/m, while the highest amount of carbohydrates (10.79 mg/gFW) and proline (0.42 mg/gFW) belonged to the third harvesting with salinity of 8 dS/m. By increasing salinity in irrigation water and with the passage of time during the growing season, soil salinity increased and distribution of salinity in the soil profile was more uniform in the treatments that had no water stress. Thus, according to the results, 25% of the plant water consumption can be saved and irrigation with 75% of water requirement and salinity of 5 dS/m would have no significant effect on the amount of forage produced. The best forage quality for livestock consumption was obtained in the second harvesting. However, this experiment was done in one growing season and in the long time reduction in the amount of water and the use of salt water can cause soil salinization and accumulation of salts in the soil. Therefore, it is recommended that the experiment be repeated in the future, before making a final decision about reducing irrigation water.
r a; a a; h a; m k; e a
Abstract
Rice cultivation in Iran is dominantly under submerged condition, which requires plenty of water, nitrogen fertilizer application, very difficult and laborious land preparation, along with high labor costs. In order to assess the effects of different rice cultivation methods on increasing water productivity ...
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Rice cultivation in Iran is dominantly under submerged condition, which requires plenty of water, nitrogen fertilizer application, very difficult and laborious land preparation, along with high labor costs. In order to assess the effects of different rice cultivation methods on increasing water productivity and to find a suitable method of water and nitrogen application, an experiment was carried out in Rice Research Institute of Iran, Amol (RRII), in 2014. The experimental layout was split-split plot with 3 replications, using Keshvari rice variety. Two land preparation methods i.e. with and without puddling, were the main factors, while four levels of irrigation application were the sub-factors, with sub-sub plots allocated to four levels of nitrogen application (N0, N80, N120, N160 kg/ha) . The results showed that the effect of rice cultivation method on water use and water productivity (WP), and the effects of irrigation and nitrogen on yield-related traits, water use and WP were statistically significant at %1 level. The new cultivation technique -aerobic cultivation method- saves water use and increases WP, respectively, as much as 27.95% and 29.11%.With the increasing The application of nitrogen, increased yield and WP, in the form of linear equation. Applying 130% of Class A pan evaporation and nitrogen 120 kg was optimal yield and saving water and nitrogen, respectively 8.9% and 33%.
e g; a m; a k
Abstract
Drought and its resulting stress is one of the most important common environmental stresses that limit agricultural productions. In order to evaluate the effect of cattle manure biochar on the growth, yield, and water use efficiency of spinach at different soil moisture status, a factorial completely ...
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Drought and its resulting stress is one of the most important common environmental stresses that limit agricultural productions. In order to evaluate the effect of cattle manure biochar on the growth, yield, and water use efficiency of spinach at different soil moisture status, a factorial completely randomized design with 3 replications was conducted under greenhouse conditions during October 2014 to January 2015. Treatments consisted of four biochar levels (0, 1.25, 2.5 and 5% wt of initial soil) and three soil moisture levels (FC (without stress), 0.7FC, and 0.55FC). To compensate the water losses via evapotranspiration, the pots were weighted every day and water stress was imposed by adding the water required in each treatment. Total water consumption during the growing season was also determined. Results indicated that application of both soil water stress levels resulted in significant reduction in leaf area, stomatal conductance, water consumption, and fresh and dry weight as compared to those of the controls (without water stress and biochar application). The greenness index significantly increased by 14%, 14%, and 11 % as compared to that of the control when soil moisture level of 0.55 FC was applied at the first, second, and third growth stages (40, 55 and 70 days after planting), respectively. Application of biochar also significantly increased greenness index, leaf area, and stomatal conductance as compared to that of the control. Soil moisture stress up to 0.7FC decreased the plant water consumption; however, it did not affect the water use efficiency, significantly; while water stress level of 0.55 FC decreased water use efficiency significantly. In general, application of 1.25 biochar (25 ton/ha) as compared to the control decreased the negative effects of water stress on plant (reducing leaf area, fresh and dry weight, etc.) and improved plant growth indices and increased the growth of plant at all of the applied water stress levels. Therefore, in order to reduce water consumption and improve the growth and yield of plants, biochar application, especially under drought stress conditions or in greenhouse conditions, is recommended. Meanwhile, performing such an experiment under field conditions is also suggested.
A GH; A SH; M R; H Z
Abstract
Deficit irrigation, as a limiting factor for growth, will affect physiological characteristics of plants. In order to investigate the effects of deficit irrigation on yield, chlorophyll fluorescence, dry weight of stems and leaves, and leaf area index of sunflower, this study was performed at the research ...
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Deficit irrigation, as a limiting factor for growth, will affect physiological characteristics of plants. In order to investigate the effects of deficit irrigation on yield, chlorophyll fluorescence, dry weight of stems and leaves, and leaf area index of sunflower, this study was performed at the research farm of Agriculture and Natural Resources University of, Sari, Iran, in 2013. The experimental treatments were arranged as randomized complete block design with three replications. The irrigation regimes consisted of full irrigation (FI), regulated deficit (DI75, DI55), and partial root-zone drying irrigation (PRD75, PRD55). The results indicated that the effect of irrigation treatments on yield, photosynthetic efficiency, maximum fluorescence (Fm), minimum fluorescence (Fo), leaf area index, shoot dry weight, leaf dry weight, and head dry weight was significant. Comparison showed that water stress significantly decreased grain yield, photosynthetic efficiency index and maximum fluorescence (Fm), whereas the minimum fluorescence (Fo) was increased. The maximum seed yield (5148 kg ha-1) was attained in full irrigation treatment and had no difference with PRD75 treatment. The maximum leaf area index at the end of the growing season was 4.3 and recorded in FI and had no difference with PRD75, DI75 and PRD55. Overall, treatment PRD75 is recommended since it reduced water consumption by 16.8 percent relative to FI treatment and had no significant difference with full irrigation treatments (FI) in terms of seed yield, quantum yield, and other growth parameters.
Masoud Mohammadi; Hossin Molavi; Abdolmajid Liaghat; Masoud Parsinejad
Abstract
Salinity and water stress are the main problems of agricultural production in many parts of the world, especially in arid and semi-arid areas. Therefore, this study was conducted to investigate the effects of Zeolite application under salinity and ...
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Salinity and water stress are the main problems of agricultural production in many parts of the world, especially in arid and semi-arid areas. Therefore, this study was conducted to investigate the effects of Zeolite application under salinity and water stress conditions on yield and yield components of Corn in Karaj, Iran. A factorial design with randomized complete block arrangement was used with three replications including three factors: salinity, irrigation water, and Zeolite application. Irrigation water, salinity and Zeolite application factors consisted of two levels each:W1=100% and W2=50% of crop water requirement; S1=0.7, S2=5 dS/m, and Z1=0 and Z2=10 t/ha, respectively. The soil texture was clay loam. Results showed that salinity and water stresses reduced yield and yield components, while Zeolite application increased them. Simultaneous impact of salinity, deficit irrigation, and Zeolite application had significant effect on corn yield, the 1000 kernels weight, number of grains per ear, and plant height. The maximum corn yield, 1000 seeds weight, number of grains per ear, and plant height were, respectively, 7233.3 kg/ha, 309 g, 504, and 220.7 cm and corresponded to W1S1Z2 treatment, while the minimum corn yield, 1000 seeds weight, number of grains per ear and plant height were 2296 kg/ha, 101.7 g, 159, and 146.3 cm, respectively, and belonged to W2S2Z1 treatment. The maximum water use efficiency (1.41 kg/m3) and its minimum (0.68 kg/m3) were observed in W2S1Z2 and W1S2Z1 treatments, respectively.
Sara Mardaninejad; Hamid zare; Hasan Tabatabaei; Abdorahman Mohammadkhani
Abstract
Water stress and the limitation of plants water requirement have different effects on the underground organs growth indices. In this research, the effects of water stress on the growth of long green pepper root were studied in comparison with the regular method of irrigation in the greenhouse conditions. ...
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Water stress and the limitation of plants water requirement have different effects on the underground organs growth indices. In this research, the effects of water stress on the growth of long green pepper root were studied in comparison with the regular method of irrigation in the greenhouse conditions. Irrigation treatments included 4 levels, viz. 40%, 60%, 80%, and 100 percent of the crop water requirement (CWR). At the end of the growing season, the root sampling was done and some of the root indices such as fresh and dry weight, root surface area and volume, length and root length density, and surface area to fresh weight ratio were measured for each treatment and compared with those of the control (100 percent CWR). Duncan's multiple range test showed that, with increasing irrigation water, the weight, volume, surface and root length increased. Therefore, all the studied indices in the 40 % CWR treatment were the lowest in comparison with the control treatment. Besides, in the 80 % CWR, decrease in fresh and dry weight of root was, respectively, 4.7 % and 31 %; in the 60 %CWR, fresh and dry weight decreased 10.5% and 47.7 %, respectively; and in the 40 % CWR treatment, fresh and dry weight of root decreased 25.7 % and 62.5 %, respectively, in comparison to the control treatment. Also, root surface and volume in the 80 %CWR decreased by 9% and 19.8 percent; in the 60% CWR treatment by 16.1% and33.8%; and in the 40 % CWR treatment by 25.8% and 47.3%, respectively, in comparison to the control treatment. The results showed that the root average growth in the control, 80%, 60%, and 40% CWR treatments reached the depth of 50, 48, 43, and 39 cm at the rate of 0.35, 0.33, 0.3, and 0.27 cm/day, respectively. The results of the three stress treatments showed that the reduction ratio of root traits in the 80% CWR was more appropriate compared with the other treatments. These results show savings in water consumption, which is important in terms of economic. Also, in all of the treatments, the amount of root length density decreased with soil depth penetration. In other word, most of the roots density was observed in the surface layer of soil.
r alimohammadi; a mousavi; m tatari; a.r fatahi
Abstract
In order to investigate the effects of deficit irrigation during phenological stages of fruit growth and development on almond (cv. “Mamaei”) production, an experiment was carried out in split plot and complete randomized block design with three replicates in 2000-2003.The main plots were ...
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In order to investigate the effects of deficit irrigation during phenological stages of fruit growth and development on almond (cv. “Mamaei”) production, an experiment was carried out in split plot and complete randomized block design with three replicates in 2000-2003.The main plots were three different stages of fruit growth consisting of: stage I (fruit growth), stage II (kernel growth) and stage III (pre-harvest period). The subplots were different irrigation regimes including T1=100% ETC (Full irrigation), T2= 80% ETC (deficit irrigation), T3=40 % ETC (deficit irrigation), and T4=0 % ETC (without irrigation). Parameters such as fruit size (length, width, and diameter), fresh and dry fruit weight, fresh and dry kernel weight, fruit drop, kernel percentage and yield were measured. The results showed that deficit irritations and water stress during stage-I decreased fruit size (length, width and diameter of fruit), fresh and dry weight of fruit and increased fruit drop percentage; but it did not have significant effect on mineral elements in leaf and fruit. The deficit irrigation and water stress during stage-II decreased fresh fruit weight, fresh and dry kernel weight, N in leaf and B in fruit. However, there was no significant effect on the measured parameters during stage-III. According to the results, deficit irrigation during all phenological stages of fruit growth significantly decreased yield, kernel dry weight and kernel percentage. The results showed that the effects of phenological fruit stages on N, K, Ca and B in leaf and on N, K, P, Mg, Ca, Zn, Fe, Mn, Cu and B in the fruits were significant, but the effects of irrigation regimes were not significant on mineral elements in leaf and fruits.
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r a; r asadi
Abstract
Deficit (or regulated deficit) irrigation is one way to improve efficiency of water use when crop is exposed to a certain level of water stress during a particular growth period. In order to optimizing water use under tape irrigation system, a field experiment was carried out ...
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Deficit (or regulated deficit) irrigation is one way to improve efficiency of water use when crop is exposed to a certain level of water stress during a particular growth period. In order to optimizing water use under tape irrigation system, a field experiment was carried out during 2010 growing season at the experimental farm of Agriculture and Natural Resources Research Center of Orzoueyeh, located in Kerman province. The treatments were laid out in completely randomized block design with three replications., Four water potential thresholds for starting the irrigation treatments were selected by using tensiometers (net water requirement (control) and suctions of 1/2 FC, 1/5 FC and 1/8FC). The crop studied was corn, single cross 704 cultivar. The results showed that water use volumes saved in the three suction treatments consisting of treatments 1/2 FC, 1/5 FC and 1/8FC were 11%, 13% and 17 percent, respectively, in comparison with the control treatment. But, compared to the control, yield of the mentioned treatments decreased by 4 %, 28%, and 34 percent, respectively. However, water use efficiency increased in the 1/2 FC treatment by 6.5% over the control treatment. Statistical analysis of yield components in the control and 1/2 FC treatments demonstrated that these two treatments were in the same group. Among the evaluated treatments, the control and 1/2 FC treatments were economically satisfactory.