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ali mokhtaran; abdolali gilani; sami Jalali; Leila Behbahani; mojtaba Rezaei; Kobra Tajaddodi Talab
Abstract
Rice is one of the most important summer crops in Khuzestan Province. Due to the severe water limitation, the effect of using strip drip system in the method of direct seeded rice in dry bed was monitored on the yield of common rice cultivars of the province and changes in soil salinity. This research ...
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Rice is one of the most important summer crops in Khuzestan Province. Due to the severe water limitation, the effect of using strip drip system in the method of direct seeded rice in dry bed was monitored on the yield of common rice cultivars of the province and changes in soil salinity. This research was conducted during 2019-20 and 2020-21, at the Ahvaz Agricultural Research Station on three adjacent plots of land, using split-plot design and randomized complete blocks in three replications. The main factor was irrigation including three levels: daily irrigation, every two days, and three days; and the secondary factor included three cultivars (Red Anbori, Champa, and Daniyal) and one salt tolerant rice line (S2). In the first year, due to the allocation of water outside the cultivation date, the yield of the crop was very low, so, the analysis was done based on the second year. The average volume of irrigation water in the field was measured as 14,800, 15,200, 15,700 and 16,100 m3/ha for, respectively, line S2, Red Anburi, Daniyal, and Champa. The results showed that, in the daily irrigation, the "Red Anburi" local cultivar had the highest yield with 3767 kg/ha and S2 line had the lowest 2541 kg/ha, so that when the irrigation changed from every day to three days, the yield decreased by 56% on average. The highest water productivity was obtained by the "Red Anburi" cultivar (0.25 kg/m3) in the daily irrigation. The reason for this problem can be shown in the monitoring of soil salinity, so that with daily irrigation, the salinity of the saturated extract in all soil layers showed a decreasing trend from 3.77 to 1.8 dS/m. According to the results, use of drip irrigation system would significantly reduce the volume of irrigation water compared to "conventional puddled transplanted rice". This has been an effective strategy in reducing the stress on the water resources of the province and saving the available water to preserve the ecosystem, although significant reduction of rice cultivation area in this province is recommended.
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Norollah Jalali; Ali Shahnazari; MZ Ahamadi; Mojtaba Khoshravesh; Mojtaba Rezaie
Abstract
The purpose of this study was to investigate the effects of irrigation management on water requirement and crop coefficient of Hashemi and Kuhsar cultivars in the first crop. This experiment was carried out in Mahmoudabad District of Mazandaran Province in Iran in the form of factorial in a randomized ...
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The purpose of this study was to investigate the effects of irrigation management on water requirement and crop coefficient of Hashemi and Kuhsar cultivars in the first crop. This experiment was carried out in Mahmoudabad District of Mazandaran Province in Iran in the form of factorial in a randomized complete block design, in two growing seasons of 2016-2018. The water requirements for the fields (from transplanting to harvest) and the crop coefficient of these two cultivars were studied in two systems of traditional flooding and system of rice intensification (SRI). The results showed that, in the first crop, the two-year average water requirements of Kohsar and Hashemi in SRI were 534 and 556 mm and for the traditional flooding system 623 and 632 mm, respectively. The water required by the farm in traditional flooding decreased by 13.1% in the SRI. Based on reference evapotranspiration using pan evaporation method for the three stages of vegetative, reproductive, and maturing, crop coefficient values for the flooding system for Kuhsar were, respectively, 1.14, 1.29, and 0.92; and for Hashemi, they were 1.18, 1.32, and 0.92. According to the obtained results, SRI causes significant savings in paddy water consumption, therefore, it is suggested that, due to water shortage in the country, this method be used as one of the adaptation strategies in rice fields.
Pooya Aalaee Bazkiaei; Behnam Kamkar; Ebrahim Amiri; Hossin Kazemi; Mojtaba Rezaei
Abstract
This study was carried out to investigate the effects of irrigation intervals and different planting dates on the yield and yield components of rice. A split-plot design based on randomized complete block design was used with three replications, at Rice Research Institute of Iran (Rasht) in 2016 and ...
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This study was carried out to investigate the effects of irrigation intervals and different planting dates on the yield and yield components of rice. A split-plot design based on randomized complete block design was used with three replications, at Rice Research Institute of Iran (Rasht) in 2016 and 2017. The main factor was irrigation at four levels (full flooding, 5, 10 and 15 days irrigation intervals) and the secondary factor was planting date at three levels (April 21, May 11, and May 31). The results of analysis of variance showed that irrigation and planting date had a significant effect on the yield of rice at 1% probability level. The highest amount of biological yield was obtained in full flooding and 5-day irrigation interval, with an average of 10960 and 10238 kg/ha, respectively, and in May 11 and April 21 planting dates with an average of 10553 and 10397 kg/ha, respectively. The highest 100-grain weight was obtained in May 11 and May 31 planting dates, the maximum number of panicle per plant was observed in full flooding treatment, and in May 11 planting date and the highest number of filled grains was observed in full flooding treatment. The maximum number of hollow grains was observed in 15 and 10-day irrigation intervals and May 31 planting date. The results showed that the full flooding irrigation with a yield of 4271 kg/ha had the highest grain yield. The 10 and 15 days irrigation intervals had less grain yield than flood treatment and 5-day irrigation interval treatments. In two years of the experiment, the planting date of May 11 had the highest grain yield with an average of 3820 kg/ha. In this experiment, the May 11 planting date had the most favorable environmental conditions for growth and had a good yield-stability.
h a; m kh; a a; m r
Abstract
In recent years, the groundwater resources in Guilan province have played an important role in irrigating paddy fields. The goal of this study was to evaluate temporal and spatial variations of groundwater quality in a 4-year period using ordinal kriging. Water samples for this study ...
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In recent years, the groundwater resources in Guilan province have played an important role in irrigating paddy fields. The goal of this study was to evaluate temporal and spatial variations of groundwater quality in a 4-year period using ordinal kriging. Water samples for this study were collected from 130 wells across Guilan province, in September and March from 2003 to 2006. Maps of EC and TDS in the region were prepared using ArcGIS software. The maps showed that regarding TDS, western parts of Guilan province had no problem of groundwater TDS (less than 500 mg/L), whereas central and eastern parts had a moderate TDS (500-1000 mg/L). Results showed that salinity increased with time (except in 2005, due to more rainfall in 2004) and the highest EC was recorded in the central zone, particularly areas neighboring eastern parts of Guilan province. Delineated areas of EC and TDS classes were determined in each year. EC in the east and some other parts of Guilan province covering 23 to 34% of the studied area was between one to 1.5 dS/m which have a negative impact on the yield of sensitive plants such as rice. Uncontrolled digging of deep wells and over exploitation of groundwater can be regarded as the main cause of increasing salinity in paddy areas of Guilan province.
Mahboubeh Aghajani; Maryam Navabian; Majid Vazifehdost; Mojtaba Rezaee
Abstract
In recent years, discharge of Sefidroud River, which is the main source of agricultural water in Guilan province, has been decreasing because of construction of several dams in the upstream of Sefidroud basin. The future of rice production will depend on appropriate management strategy for optimization ...
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In recent years, discharge of Sefidroud River, which is the main source of agricultural water in Guilan province, has been decreasing because of construction of several dams in the upstream of Sefidroud basin. The future of rice production will depend on appropriate management strategy for optimization of water consumption in the paddy fields. In this research, to maximize water productivity in paddy fields, two optimal models were selected for irrigation management as fixed interval irrigation in the entire growing season and variable interval irrigation in different physiological growth stages of Hashemi variety, using SWAP model and Genetic Algorithm (GA). After validation of SWAP model, the chosen values were optimized by GA. In the optimal models, irrigation water depths and rice irrigation intervals were selected as the decision variables in different crop growth stages. Periodic irrigation management with fixed interval i.e. 7.33 days during the growing season, showed the maximum efficiency of irrigation water. However, the optimal variable intervals were 6.53, 4.60, 4.31 and 7.74 days during establishment, tillering stage, maturity, and harvest respectively. Finally, for saving of water, improvement of irrigation water productivity, reduction of evapotranspiration, proper irrigation interval in Sefidroud irrigation network, and ease of measurement of inflow water volume, a fixed irrigation interval of 8 days and irrigation depth of 52, 30, 40 and 12 mm in, respectively, establishment stage, tillering, maturity, and harvest stages was recommended. The highest water productivity obtained was 1.59 kg/ m3.
Z SAADATI; NADER PIRMORADIAN; E AMIRI; M REZARI
Abstract
In order to increase water productivity, a good understanding of crop response to water stress and tools which simplify the complex crop response to various environmental factors, especially to water, are needed.Simulation models that clarify the effects of water on crop yield are useful tools for improving ...
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In order to increase water productivity, a good understanding of crop response to water stress and tools which simplify the complex crop response to various environmental factors, especially to water, are needed.Simulation models that clarify the effects of water on crop yield are useful tools for improving farm level water management and optimizing water productivity. In this study, the WOFOST model was used to simulate two local rice varieties yield response under five irrigation treatments consisting of continuous flooding and irrigation at 0, 3, 6 and 9 days after disappearance of water from the soil surface. The experiment was conducted at Rasht region during two growing seasons of 2003 and 2004. The model was calibrated using the first year data and was validated using the second year data set. According to the results, the relative root mean square errors of grain yield simulation were 12.57% and 5.01% for Binam and Hasani cultivars in 2003, respectively. These values were 7.94% and 13.71% in 2004, respectively. The values of the observed and simulated water productivity based on precipitation and consumed water were close together. The results showed that the WOFOST model could simulate the effect of water on rice yield and water productivity in a humid region. Therefore, this model can be used to explore optimum management options to improve rice water productivity.