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Mohammad Reza Yazdani; Ebrahim Asadi Oskouei; Asghar Rahmani; Naser Davatgar; Bahareh Delsouz Khaki
Abstract
In order to analyze the temporal and spatial changes in the amount of water required for puddling in rice fields of the Sapidroud Network, daily soil moisture data from the SMAP satellite was obtained and used in a seven-year period (2015 to 2021). The puddling stage (from April 20 to June 10) was analyzed ...
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In order to analyze the temporal and spatial changes in the amount of water required for puddling in rice fields of the Sapidroud Network, daily soil moisture data from the SMAP satellite was obtained and used in a seven-year period (2015 to 2021). The puddling stage (from April 20 to June 10) was analyzed after grouping based on different probability of occurrence (1%, 10%, 25%, 50%, 75%, 90% and 99%) and using raster calculations. In addition, in order to validate the calculations, the predicted values were compared with the saturated soil moisture values of 321 soil samples with specific geographic coordinates that had been measured by the Rice Research Institute of Iran. The comparison was conducted by using the mean absolute error (MAE), mean bias error (MBE), and normalized root mean square error (NRMSE). The results showed that in all moisture scenarios (from the wettest to driest), the foothills had less moisture than the plain and, especially, the low lands, and the soil moisture showed a decreasing trend during the growing period. The rate of this reduction increased gradually and in some areas it reached 2% per day at the end of the puddling period (May 22 to 31). The amount of gross water required for puddling increased from the wettest to the driest year and in the middle of the season (May 3 to 5) it was from 1693 to 2983 square meters per hectare and at the end of the season from 2496 to 3602 m3/ha, respectively. The validation results showed that the calculated MAE, MBE, and NRMSE values were 4.26%, 1.59%, and 15%, respectively, indicating that the accuracy is acceptable. The findings showed that the delay in the start of the puddling operation increases the water required for puddling operation (1.34 m3/ha for each day delay in a normal year). Therefore, in the lands of this network, in all circumstances, especially in dry years, to save water, it is better to release/supply water required for puddling from local reservoirs, wells, or from the Sepidroud Dam in early May.
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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.
Amir Hossein Yadollahi; Mojtaba Khoshravesh; Mohammad Ali Gholami Sefidkouhi
Abstract
The crisis of water scarcity is the main reason for the reduction of crops and the lack of human food needs in the countries located in arid and semi-arid regions. One of the methods used to increase the yield and water productivity is the use of low irrigation and magnetized water technology. The purpose ...
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The crisis of water scarcity is the main reason for the reduction of crops and the lack of human food needs in the countries located in arid and semi-arid regions. One of the methods used to increase the yield and water productivity is the use of low irrigation and magnetized water technology. The purpose of this study was to investigate the effect of regulated deficit irrigation with magnetized water on quantitative and qualitative characteristics of pea (Pisum sativum L.). The present research was performed on a farm located in Aghuzbon Village, Mazandaran Province, Iran. The experiment was performed as a factorial experiment in a randomized complete block design with three replications. The control treatment included full irrigation (FI) at all stages of the plant growth with normal water (non-magnetized). The main factor included non-magnetized water (W1) and magnetized water (W2), and the sub-factor included irrigation levels (I1=100%, I2=80%, and I3= 60% of crop water requirement). For irrigation, the trickle irrigation system with tape pipes was used. The results showed that the effect of irrigation water type and irrigation level as well as their interaction on parameters of pod per plant, seed per pod, grain yield, and water use efficiency were significant (p<1%). The highest pods per plant, seed per pod and grain yield in W2I1 treatment were 13.2, 7.5, and 8.472 t. ha-1, respectively, and the highest water use efficiency was observed in the W2I3 as 3.7 kg.m-3. On average, irrigation with the magnetized water increased grain yield and water productivity by 8.6% and 8.7%, respectively, compared to the non-magnetized water treatment. Also, the effect of type of irrigation water and irrigation level on oil, oil yield, protein, protein yield and germination time had a significant effect at 1% probability level, but had no significant effect on the ripening time. Also, 20% increase in irrigation level from I3 to I2 and from I2 to I1 in non-magnetized water treatment caused increase of the grain yield by 14.5% and 18%, respectively, while in magnetized water treatment, yield increased by 14.2% and 13.6%, respectively. The fastest germination time was related to W2I2 with 10.3 days after planting. In general, it can be concluded that irrigation with magnetized water can be a good way to increase yield, improve quality characteristics, and increase water use efficiency of green pea plant.
Farshad Khashaei; Javad Behmanesh; Vahid Rezaverdinejad; Nasrin Azad
Abstract
Use of subsurface drip irrigation (SDI) in row plants is increasing due to higher water and fertilizer efficiency. In order to investigate the effect of SDI levels and nitrogen fertilizer splitting on yield, yield components and water productivity of corn, a field study was conducted in 2018 as split ...
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Use of subsurface drip irrigation (SDI) in row plants is increasing due to higher water and fertilizer efficiency. In order to investigate the effect of SDI levels and nitrogen fertilizer splitting on yield, yield components and water productivity of corn, a field study was conducted in 2018 as split plot experiment based on a completely randomized block design with three replications at the research farm of Urmia University. The main plots of this experiment including three irrigation levels: 100%, 75% and 50% of net irrigation requirement and subplots included three nitrogen fertilizer split applications as: weekly, every other week and three times during growing season as urea fertilizer. Based on the results, the effect of irrigation levels treatment and number of fertilizer splitting on yield, yield components and water productivity were significant at 1% level. However, the effect of fertilizer splitting on water productivity was not significant. Interaction effects of the two variable treatments on plant height and leaf area index were significant at 1% level but did not significantly affect grain yield, biomass and water productivity. The highest grain yield and corn biomass were obtained with 22.39 and 39.85 ton/ha for complete irrigation, respectively. Also, the grain yield and biomass in the three- split treatments were highest with 18.47 and 32.56 ton/ha, respectively. The highest water productivity was obtained by irrigation application of 75% of net water requirement. It seems that in regions with water scarcity, applying deficit irrigation equal to 75% of the corn irrigation requirement, can be a good solution for saving water and achieving high water productivity. Also, fertilizer injection with higher amounts and less frequency especially at the sensitive growth stages, can be a more effective solution than using lower amounts with more frequent fertilizer application.
Hossin Badibarzin; Mhamood Hashemi tabar; S.Mehdi Hossini
Abstract
Since agricultural sector is the largest consumer of water, it is crucial to introduce effective policies to manage water resources in this sector. In the present study, the economic analysis of allocation and pricing of irrigation water on cropping pattern and water demand management in Sistan plain ...
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Since agricultural sector is the largest consumer of water, it is crucial to introduce effective policies to manage water resources in this sector. In the present study, the economic analysis of allocation and pricing of irrigation water on cropping pattern and water demand management in Sistan plain was investigated by use of a positive mathematical programming model (PMP). In this regard, an economic modeling system including a state wide agricultural production model (SWAP) was used. The GAMS software version 24.1 was used to solve the proposed modeling system. The results showed that the use of pricing and allocation policies for irrigation water led to a decrease in the total area of designated cropping products and a reduction in the farm gross margins in Sistan plain. However, the aforementioned policies resulted in savings of 4.594 to 46.256 and 7.123 to 29.484 million cubic meters of water consumed in the region as a result of applying allocation and pricing, respectively. Decrease in total area of cultivation of selected crops under different scenarios of irrigation water quotas policy, especially higher economical crops such as watermelon, melon, and onion. Total gross yield of Sistani farmers would be reduced from 1425694 to 1292677 million Rials, reducing the gross profit by 2.17% to 9.33% in the region's agricultural pattern. Thus, applying the policy of water allocation could save about 30 million cubic meters of water available to farmers. Compared to pricing policy, the use of water allocation policy is recommended due to its superior effect on preserving water resources in the Sistan plain.