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ali mokhtaran; Peyman Varjavand; Hossein Dehghanisanij; Shokrola Absalan; Azarakhsh Azizi; Alireza Jafarnejadi
Abstract
This study was conducted to compare and monitor drip and surface irrigation systems for corn and wheat crops in three planting seasons from summer 2016 to spring 2018 in one of the agricultural research stations in Khuzestan, located in Ahvaz. The source of irrigation water was Karun River with salinity ...
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This study was conducted to compare and monitor drip and surface irrigation systems for corn and wheat crops in three planting seasons from summer 2016 to spring 2018 in one of the agricultural research stations in Khuzestan, located in Ahvaz. The source of irrigation water was Karun River with salinity of 3 dS/m in Ahvaz section. This study was performed using randomized complete blocks design with three replications. The basis of blocking in corn cultivation was 2 and 4 days irrigation intervals, and in wheat cultivation, the distances between drip lines were 40, 60, and 75 cm. The results showed that the volume of water used in the drip system for corn and wheat was 24% and 32% lower than the surface irrigation system, respectively. Also, water productivity in the drip system was higher than surface irrigation system by 16% and 21%, for corn forage and grain, respectively, and by 35% for wheat. Wheat water productivity for different distances of drip lines was not significantly different. Therefore, in heavy-textured soils, drip irrigation lines at 75 cm spacing can be used for wheat cultivation. In soil monitoring analysis, the drip system reduced soil quality such that, after three planting seasons, the initial non-saline-sodic soil (ECe = 3.09dS / m, ESP = 6.18%) became saline (ECe = 7.63dS / m, ESP = 12.63%). Despite accumulation of salts at the periphery of the wetted soil under the drippers, the plants had a better growth and yield in the drip system than the surface irrigation, because of the high soil water potential around the roots and under the drippers, which reduced salt effects. The results of this study showed that if a drip system is used for the climate similar to the central and southern regions of Khuzestan, land drainage and leaching operations at the end of the growing season are necessary to protect the soil.
6
fereshteh batoukhteh; Mojtaba Khoshravesh; Hossein Dehghanisanij
Abstract
The main purpose of this study was to estimate the coefficients of different equations of water infiltration into soil, including Philip, Kostyakov, Kostyakov- Louise, Horton, and SCS to estimate the infiltration rate and potential for runoff in long-duration rainfall in two land uses (rangeland and ...
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The main purpose of this study was to estimate the coefficients of different equations of water infiltration into soil, including Philip, Kostyakov, Kostyakov- Louise, Horton, and SCS to estimate the infiltration rate and potential for runoff in long-duration rainfall in two land uses (rangeland and agricultural) and three soil textures (loam, clay loam ,and silty clay loam). These models were fitted to the measured infiltration data to estimate the model parameters and find a suitable model for this region. After estimating the parameters, the infiltration rates for 2, 4 and 24 hours were calculated using the infiltration rate equations of each model. For this purpose, the infiltration data were obtained by double rings method from 16 point of different regions in the basin. The parameters of these models were then obtained, using least square optimization method. In order to evaluate the accuracy of the models, the coefficient of determination (R2), Nash Sutcliffe (NSE) efficiency, root mean square error (RMSE) and mean error (ME) were calculated. Comparisons of the mean of evaluation statistics using the Tukey method showed that the method of estimating cumulative infiltration in the Kostyakov-Louise model had a more-stable trend compared to other models and was evaluated as the best in most soil texture classes and land uses. Means comparisons showed that despite the differences between the models in estimating the cumulative infiltration, the differences between the models in estimating the infiltration rate were not significant and were in the same group. Regardless of the model used, soil texture and land use are the two main factors affecting the final infiltration rate. According to the results, the rate of infiltration with time in agricultural use has significant changes, such that, in this use, it was initially high and decreased sharply with increasing time from 2 hours to 24 hours. In order to reduce the weakening effects of agricultural activities on soil quality and to increase the infiltration rate in long-duration rainfall and reduce runoff, management activities such as expansion of conservation agriculture, no-tillage, and minimum tillage farming operations will play a very effective role.
n s; h d; a d
Abstract
Application of advance irrigation methods to a proper utilization of water resources is inevitable. The effects of different amounts of irrigation water on yield and quality of two varieties of date palm under asubsurface drip irrigation were studied in Behbahan Agricultural Research Station during two ...
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Application of advance irrigation methods to a proper utilization of water resources is inevitable. The effects of different amounts of irrigation water on yield and quality of two varieties of date palm under asubsurface drip irrigation were studied in Behbahan Agricultural Research Station during two growing seasons (2014-2015). The study was conducted in a randomized complete block design with a split plot design with three replications where three levels of water application based on T1=75%, T2=100% and T3=125% of crop water requirement, were as the main plots and two variety of Khasi and Zahedi were as sub-plots. The results showed that different levels of irrigation have not had no significant effect on the quality and yield of fruit. However, there was a significant difference (p<0.01) between the levels of irrigation in terms of water use efficiency. Accordingly, T1 by 0.88 kg of dates per cubic meter of water showed higher water use efficiency. Comparison of mean interactions between the water application and varieties showed water use efficiency of Khasi and Zahedi varieties were 0.86 and 0.89 kg/m3, respectively. The applied irrigation water of palm trees based on T1 was of 7545 m3/ha which was 2515 m3/ha less compared to that under T2.
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.
M N; B GH; K D; A A; H D; A T
Abstract
In order to evaluate the role of a limited irrigation and agronomic management scenarios on improving yield and rain water productivity (WP) of rainfed wheat, a field study was conducted at multiple farms of Honam (Lorestan Province) in the upper Karkheh River Basin (KRB), Iran. The calibrated and validated ...
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In order to evaluate the role of a limited irrigation and agronomic management scenarios on improving yield and rain water productivity (WP) of rainfed wheat, a field study was conducted at multiple farms of Honam (Lorestan Province) in the upper Karkheh River Basin (KRB), Iran. The calibrated and validated AquaCrop model was used to define the best management scenario in order to enhance yield and WP of rainfed wheat in upper KRB in 2013-2014. In the next step, the best management scenarios were carried out in three research fields of rainfed wheat in 2014-2015. In field experiments, the treatments included two main management (traditional and advanced management) and two levels of limited irrigation (rainfed, single irrigation of 60 mm at spring time). According to the best scenario of AquaCrop model, spring single irrigation with constant depth of 60 mm was applied at three times (the first, middle and end of flowering period). The result shows that under rainfed conditions, by using the advanced management, rain water productivity of wheat increased by 36% as compared to traditional management. The results of this study showed that a single irrigation application at spring time (during flowering stage) increased the average total water productivity of wheat to 0.70 kg m-3, an increase of 74% as compared to the traditional management. The optimum program was obtained by a combination of advanced agronomic management package with single irrigation of 60 mm at the middle of flowering stage, which increased yield and WP of rainfed wheat to 176% and 134%, respectively, as compared to traditional management. Results of field experiments were in good agreement with the proposed scenarios by AquaCrop model.
a gh; h d; m kh; m s
Abstract
Limited water and energy resources in the world and the increasing demand for water and energy due to population growth and the development of human societies necessitate investigation of the water and energy consumption in irrigation systems. This study aimed to evaluate the water and energy consumption, ...
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Limited water and energy resources in the world and the increasing demand for water and energy due to population growth and the development of human societies necessitate investigation of the water and energy consumption in irrigation systems. This study aimed to evaluate the water and energy consumption, losses, and efficiency of diesel pumping stations and was conducted in Hamadan Province farms during the period 2009 to 2011. Nebraska Pumping Plant Performance Criteria was applied to compare the performance of irrigation pumping stations. The results showed that the total efficiency varied from 7.2% to 24.3 percent. The average of total efficiency and wasted energy of a diesel pump was calculated at about 14.7 percent and 4.84 liters per hour, respectively. The results showed that in many farms where sprinkler systems were used, the water applied was lower than crop water requirement. Average water use efficiency in alfalfa fields in the furrow and sprinkler systems was 1.7 and 2.7 kg/m3, respectively. The factors influencing decrease in energy efficiency were worn-out pump or motor, inappropriate implementation foundation for the pump engine, and inappropriate selection of engine for the pump.
Razieh Sarabadabani; Mohammadreza Bihamta; Zahra Shobar; Maryam Shahbazi; Amin Karami; Mohammadreza Naghavi; Hamidreza Nikkhah; Hossein Dehghanisanij
Abstract
To study the effects of terminal drought stress on yield and some physiological traits of barley (Hordeum vulgare L.), four cultivars, namely, Nosrat, Fajr 30, Yousef, and Moroco, and 2 advanced lines i.e. 17 and 67 were evaluated under terminal drought stress condition in Agriculture Biotechnology Research ...
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To study the effects of terminal drought stress on yield and some physiological traits of barley (Hordeum vulgare L.), four cultivars, namely, Nosrat, Fajr 30, Yousef, and Moroco, and 2 advanced lines i.e. 17 and 67 were evaluated under terminal drought stress condition in Agriculture Biotechnology Research Institute of Iran, in 2011. The glasshouse experiment was arranged as a split-plot in a randomized complete block design with three replications. The results of the experiment revealed that total biomass, grain yield, yield components, harvest index (HI), relative water content (RWC), leaf water potential (WP), stomatal conductance, and chlorophyll content significantly decreased while relative water loss (RWL), unfilled grains per spike, canopy temperature and electrolyte leakage significantly increased in drought condition. Yousef and Moroco could be considered as, respectively, drought-tolerant and drought-sensitive genotypes, with grain yield (575 and 142 g.m-2), relative water content (78.2% and 69 %) and decrease in rate of stomatal conductance (63% and 93 %) in drought stress, respectively. The results of principal component analysis suggested that some of the physiological traits such as RWC, stomatal conductance, and canopy temperature, as the first important component, could be used for genotype screening under terminal drought stress.