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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.
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Sara bulukazari; Hossein Babazadeh; Nyazali Ebrahimipak; Seyed Habib Mousavi-Jahromi; Hadi Ramezani_etedali
Abstract
In exploitation of low-quality water in arid and semi-arid regions, irrigation management is essential to increase water use efficiency. Determination of crop-water-salinity production function is an essential tool for proper irrigation management. In this study, the AquaCrop model was first evaluated ...
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In exploitation of low-quality water in arid and semi-arid regions, irrigation management is essential to increase water use efficiency. Determination of crop-water-salinity production function is an essential tool for proper irrigation management. In this study, the AquaCrop model was first evaluated by considering 4 soil and water salinity levels and 4 deficit irrigation levels for the major cereal crops including wheat, barley, and corn in Qazvin Plain. The results showed that the coefficients of determination for wheat, barley, and corn yield were 0.97, 0.86 and 0.91, respectively. Therefore, the model can evaluate the performance in salinity and deficit irrigation conditions with a good approximation. To determine the optimal production functions of each crop, the results of the plant model were compared with three models of linear and nonlinear regression, and artificial neural network. The neural network model was able to estimate the performance compared to the AquaCrop model with lower error and higher correlation (0.99). These values in the linear function for wheat, barley, and corn were 0.98, 0.95, and 0.78 and in the nonlinear function as 0.92, 0.86 and 0.81, respectively. Also, the error calculated in the neural network method for wheat, barley, and maize was 40.16, 62.09, and 57.08 kg, respectively, which were less than the linear model by 75 %, 70 %, and 95 %; and less than the exponential model by 90 %, 85 %, and 93%, respectively. The best trained network for determining the water-salt production function for barley and wheat 5 Nero and for corn 7 Nero was introduced in the single layer structure. Sensitivity analysis on wheat and barley showed that this model had low sensitivity to irrigation and salinity parameters and only corn plant showed a moderate range sensitivity to salinity parameter.
Alireza Nouralinejad; Ebrahim Amiri; Hossein Babazadeh; Hosein Sedghi
Abstract
This research was conducted to determine the production function of common bean and cowpea and evaluation of water use efficiency in Astaneh Ashrafiyeh, in 2016 and 2017. The present study was conducted as split plot in a randomized complete block design with 3 replications. Main treatments consisted ...
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This research was conducted to determine the production function of common bean and cowpea and evaluation of water use efficiency in Astaneh Ashrafiyeh, in 2016 and 2017. The present study was conducted as split plot in a randomized complete block design with 3 replications. Main treatments consisted of irrigation of 40%, 60%, 80%, and 100% of water requirement of the plant, and nitrogen treatments in sub plots consisting of no fertilizer, 30, 60, and 90 kg N ha-1 and two bean varieties (ordinary beans and cowpea). The results showed that the effects of irrigation and nitrogen fertilizer on seed yield and other agronomic traits were significant (P< 5%), in 2016 and 2017. Two-year average seed yield in 100% water requirement and 60 kg N ha-1 treatments in common bean and cowpea cultivars were 3446 and 3646 kg ha-1, respectively. The highest water productivity in 2016 and 2017 was obtained for the interaction of cultivar and irrigation on seed yield, and was 0.48 and 0.47 kg m-3, respectively. Water use productivity of the interaction between nitrogen fertilizer and bean cultivars in 2016 and 2017 in 100% water requirement treatment and 30 and 60 kg N/ha was between 0.42 and 0.46 kg m-3. The results of the estimation of production function indicated that the seed yield increased with nitrogen fertilizer application up to 30 kg ha-1, but with gradual increase in nitrogen fertilizer, the yield decreased. Based on the present study, 100% water requirement for seed yield can be recommended for both bean cultivars, however, the amount of fertilizer should be 60 kg N/ha for common bean and 30 kg N/ha for Cowpea.
Fereshteh Moeinifar; Fayaz Aghayari; Hossein Babazadeh
Abstract
To study the effect of different drip irrigation regimes and superabsorbent materials on the fruit quantity and quality characteristics of Zahedi date palms, a field experiment was carried out in split plot arrangement using randomized complete block design with three replications. Deficit irrigation ...
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To study the effect of different drip irrigation regimes and superabsorbent materials on the fruit quantity and quality characteristics of Zahedi date palms, a field experiment was carried out in split plot arrangement using randomized complete block design with three replications. Deficit irrigation treatments with three levels including 100%, 75%, and 50 percent crop water requirement based on the Ntional Water Document were in the main plots and superabsorbent treatments with three levels including without superabsorbent (control), use of Aquazorb superabsorbent (300 g per date palm), and use of Zeolit superabsorbent (4 kg per date palm) were in the sub plots. The results of analysis of variance showed that the effect of deficit irrigation on fruit weight, fruit length, water productivity, and potassium, and the effect of superabsorbent materials on fruit length, potassiom and total sugar was significant at 1% level. Also, intraction effects of deficit irrigation and superabsorbent materials on fruit weight and potassium content (at p<1%) and on the fruit length (at p< 5%) was significant. Use of superabsorbent materials in condition of irrigation with 100% crop water requirement did not have a positive effect on the quantity and quality characteristics of date fruit. But, under irrigation with 75% and 50% crop water requirement, superabsorbents significantly improved some quality characteristics of the fruit. Water productivity with 75% crop water requirement increased by 29.4% as compared with the 100% treatment, and use of Aquazorb and Zeolit superabsorbents increased water productivity (14.5% and 17.7 percent, respectively) as compared with the control. In general, irrigation with 75% crop water requirement (with consumption of 8052 m3 ha-1) and use of Zeolit superabsorbent for date palms (Zahedi cultivar) is suggested for Ghasreshirin area.
h a; h b; Hossain ebrahimi
Abstract
Salinity is considered as one of the main problems affecting the growth and yield of many plants. Salinity tolerance varies with the amount of nitrogen uptake. The aim of the study was modeling the response of tomato (Solanum lycopersicum) under simultaneous salinity and nitrogen deficiency stresses. ...
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Salinity is considered as one of the main problems affecting the growth and yield of many plants. Salinity tolerance varies with the amount of nitrogen uptake. The aim of the study was modeling the response of tomato (Solanum lycopersicum) under simultaneous salinity and nitrogen deficiency stresses. The indoor pot experiment was conducted in Damavand region, Iran, in 2015. The experiment was carried out on tomato plant in a factorial randomized complete block design with 3 replications. The treatments consisted of six levels of salinity (1, 2, 4, 6, 8 and 10 dS/m) and three levels of nitrogen including zero, 50 and 100 percent of the N-fertilizer needs. The maximum dry matter yield (25.8 gr) was obtained in the treatment with salinity of 1 dS/m and fertilizer consumption of 100%, while the minimum dry matter yield (5.8 gr) belonged to the treatment with salinity of 10 dS/m and no fertilizer application. Modified Liebig-Sprengel (LS) and Mitscherlich-Baule (MB) models were used to evaluate tomato response to nutrients. Comparison of statistics showed that for modeling tomato plants response to simultaneous salinity and nitrogen stresses, modified MB model (d=0.95) fitted better to the measured data compared to modified LS model (d=0.88). Therefore, modified MB model was recommended to estimate relative yield of tomato. Also, results showed that, at a fixed salinity level, by increasing amount of nitrogen application, the yield of dry matter was increased, while yield of dry matter decreased with increasing salinity. Threshold of yield decline in saline conditions is not fixed and depends on the amount of nitrogen in the soil. Decline of relative yield with increase in salinity wasn’t significant in zero-nitrogen treatment, which showed the influence of nitrogen deficiency relative to salinity. Therefore, threshold of tomato yield decline could be increased by nitrogen fertilizer management.
m m; h b; f k; n e
Abstract
The agricultural sector is known as the largest consumer of water. Due to limited water resources, water productivity needs to be enhanced in this sector. The concept of water productivity has attracted the attention of policy makers in food and water sector at large scale. Remote sensing is used in ...
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The agricultural sector is known as the largest consumer of water. Due to limited water resources, water productivity needs to be enhanced in this sector. The concept of water productivity has attracted the attention of policy makers in food and water sector at large scale. Remote sensing is used in the assessment and management of soil and water resources in recent decades. In the present research, this method was used to estimate water productivity. Evapotranspiration and actual production levels of dry matter were calculated using SEBAL algorithms and five images from the Landsat 5TM satellite in Qazvin Plain. The results of SEBAL algorithm in five images and lysimeter data were compared and evaluated in the region. The coefficient of determination ( 15R2"> ) and their mean absolute difference were 0.9948 and 0.446 mm/day, respectively, which demonstrated the accuracy of remote sensing methods in estimating agricultural water productivity at the basin level. The results showed that water productivity varied from 0.18 to 1.35 in the field. The wheat water productivity values from Landsat 5TM images and lysimeter data were 0.73 and 0.85 kg/m3, respectively, which are relatively close to each other.
m s; h b; m h; f k; m p
Abstract
Several mathematical models exist that represent plant response to salinity. These models consider salinity of the soil saturation extract (ECe) for plant response to salinity in the root zone. A considerable step would be taken towards applying such models, if irrigation water salinity can be used instead ...
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Several mathematical models exist that represent plant response to salinity. These models consider salinity of the soil saturation extract (ECe) for plant response to salinity in the root zone. A considerable step would be taken towards applying such models, if irrigation water salinity can be used instead of ECe, because under field conditions, irrigation water salinity measurement is much easier than determining soil salinity. The objectives of this study were to quantify basil response to irrigation water salinity, to estimate its yield salinity threshold value and to investigate efficiency of available mathematical models for estimating its yield based on irrigation water salinity. Consequently, a large experiment was conducted with 13 water salinity levels including 1.175 (control treatment), 1.8, 2, 2.2, 2.5, 2.8, 3, 3.5, 4, 5, 6, 8, and 10 dSm-1. The designated salinity treatments were performed by diluting the Shoor River saline water with adequate quantity of fresh water. In order to quantify the salinity effect on basil yield, seven mathematical models were selected. The results indicated that basil yield reduction threshold value based on irrigation water salinity was 1.7 dSm-1 with yield reduction gradient of 8.1% per dSm-1. The mathematical model of Homaee et al. (2002) provided more accuracy than the other models in simulating basil yield reduction function based on irrigation water salinity. Overall, the results of this research indicated that root water uptake models of Homaee et al. (2002), van Genuchten and Hoffman (1984) and two statistical models of Steppuhn et al. (2005) provide reasonable results for simulating basil yield response to irrigation water salinity, respectively (the least nRMSE and ME). The results further indicated that when enough leaching was applied, there would not be significant differences between the ECe-based models and those obtained based on irrigation water salinity.