Irrigation
A.R. Kiani; M.R. Yazdani; M.T. Feyzbakhsh
Abstract
Introduction: In Golestan province, despite the lack of water resources, traditional rice cultivation, a crop with high water consumption, is increasing due to economic justification. This issue has become one of the main problems of the province's agricultural sector in recent years. In order to prepare ...
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Introduction: In Golestan province, despite the lack of water resources, traditional rice cultivation, a crop with high water consumption, is increasing due to economic justification. This issue has become one of the main problems of the province's agricultural sector in recent years. In order to prepare the planting bed (puddled transplanting) in the traditional method of rice production, a significant amount of irrigation water is used before planting the seedlings in the main land. Moreover, the plant is in the water during the growing season, which causes high water losses by surface water evaporation and deep penetration. Rice direct seeding cultivation is a method that has been considered in the world for various reasons, including higher water productivity. Currently, reports indicate that more than 50% of groundwater resources are extracted and allocated annually for rice cultivation in the region investigated. In general, field information and observations indicate that the level of paddy cultivation is increasing in the province. In the past few decades, agricultural policymakers have sought to restrict and ban rice cultivation in the country, except in Gilan and Mazandaran provinces. The rationale behind this decision is high water consumption, declining groundwater aquifers and long-term instability of water resources. The developed strategy did not work effectively, as it did not consider the benefits of the farmers in the short run. The increasing trend in the area under paddy fields from 1995 to 1500 hectares per year shows the unsuccessfulness of this up-to-down strategy.Materials and Methods: A field experiment was conducted to investigate the effect of rice cultivation and irrigation methods on yield, water consumption and water productivity over two rice cropping seasons (2019–2020) in northern Iran (Gorgan Agricultural Research Station). Irrigation method as the main factor in four levels (permanent flooding, intermittent as wet and dry, sprinkler, tape) and cultivation method in three levels (direct seed in dry bed, non-puddled transplanting and traditional transplanting) in the form of a strip design. The plot was based on a randomized complete block design with three replications. The applied water, yield and some yield components and water productivity were measured and calculated during the growing seasons.Results and Discussion: The results showed that in all irrigation methods, yield was significantly reduced by changing the traditional seeding transplanting to dry seed. The amount of water applied in sprinkler and drip irrigation methods from traditional seedlings was significantly reduced as compared to direct seed seeding. Dry seed cultivation, however, consumed more water than traditional transplanting in the flood irrigation treatments (wet and dry and permanent). The highest yield (8206 kg/ha) was obtained for traditional seedling cultivation by flood irrigation, and no significant difference was observed between the yields for the other irrigation methods. In general, changing the irrigation systems had a greater effect on water consumption than changing the rice cultivation method. In addition, changing the cultivation method had a greater effect on changing the type of irrigation systems. In traditional transplanting cultivation, the yield decreased by about 14, 9 and 11%, respectively, by changing the irrigation systems from permanent flood irrigation to sprinkler, wet and dry, and drip irrigation. The highest water use was observed for flood irrigation method in direct seeding (12490 m3/ha) and direct transplanting (11967 m3/ha).Conclusion: Currently, farmers cultivate rice by transplanting in padded land irrigated by flooding techniques in Golestan province, which results in high water consumption (about 13,000 m3/ha). By changing the irrigation method from flood irrigation to drip for traditional transplanting cultivation, water consumption decreased by about 39% and as a result water productivity increased by about 22%, albeit a 11% reduction in yield occurred. With the conversion of traditional transplanting seedling by flood irrigation to non-puddled transplanting by drip irrigation, the yield decreased by about 24% and the amount of water by about 45%, and water productivity in this case reached 0.9 kg/m3. This can be considered as the best alternative for conserving both water resources and production. If only reducing water consumption is the main priority (regardless of yield reduction), the best treatments are drip irrigation with direct seeding, non-puddled transplanting and then traditional seedling, respectively. If there is a sprinkler irrigation system in the field, this option is given priority in the direct seeding and non-puddled transplanting. If changing the irrigation system is not considered, the use of intermittent irrigation (as a wet and dry) with non-puddled transplanting, traditional methods and direct seeding are preferred, respectively.
M. Karimi Fard; M. Zakerinia; A.R. Kiani; Mohammadtaghi Feyzbakhsh
Abstract
Introduction: Rice is the second most important edible grain after wheat in Iran. The most important factor for sustainable production in rice production lands, is water. Almost 75 percent of the world's rice is produced from paddy fields and rice is the largest consumer of water among all crops. Its ...
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Introduction: Rice is the second most important edible grain after wheat in Iran. The most important factor for sustainable production in rice production lands, is water. Almost 75 percent of the world's rice is produced from paddy fields and rice is the largest consumer of water among all crops. Its growth is significantly affected by climate change and water scarcity. This research was carried out to compare the direct cultivation and transplanting of rice under different irrigation methods from the point of view of water productivity. Material and Methods: The current work was designed as split plot based on randomized complete block design with 6 treatments and three replications in 18 plots with 6 m wide and 12 m length (72 m 2) in area of approximately 1500 m2 at the Agricultural Research Station of Golestan province in spring and the summer of 2018. Treatments including three levels of basin irrigation, sprinkler and drip (tape) irrigation were considered as main factors and two methods of direct cultivation and transplanting were considered as sub-factors. Results and Discussion: The results of analysis of variance showed that the effect of irrigation and sowing method on the yield of rice were significant at 0.01 level probability. The highest amount of biological yield in transplanting was obtained by basin irrigation (8177 kg/ha) and in direct seeding in basin irrigation and taper irrigation (7375 and 6836 kg/ha, respectively). The highest 1000-grain weight in transplanting method was obtained in basin irrigation and direct seeding method in traditional irrigation and tape irrigation. The highest number of filled grains in the panicle was observed in the basin irrigation treatment in transplanting, with significant difference compared to the amount observed in direct seeding. Traditional irrigation between planting methods had not significant effect on the number of hollow grains; while in sprinkler and tape irrigation (with an average of 51 and 56 for sprinkler and tape irrigation, respectively), the number of hollow grains had a higher rate in direct seeding (with an average of 41 and 45 for sprinkler and tape irrigation). The results showed that basin irrigation with 8177 kg/ha grain yield in transplanting method and basin and tape irrigations with 7375 and 6836 kg/ha in direct seeding method had the highest grain yield. Sprinkler irrigation had the lowest paddy yields in transplanting (4188 kg/ha) and direct seeding (5712 kg/ha). Tape irrigation with 7390 and 6840 m3 of consumed water, resulted in lower water consumption compared to traditional irrigation (10700 and 1693 m3), respectively. The highest amount of water use efficiency was obtained in direct and tape irrigation (0.99 kg/m3) and in traditional and tape irrigation (0.76 and 0.66 kg/m3, respectively). Conclusion: Adjusting water consumption both through lower water consumption and reduced water wastage can lead higher water productivity of rice production systems creating sustainable rice production systems. In transplanting method, tape irrigation and traditional irrigation had higher water use efficiency than sprinkler irrigation, although a significant water use reduction in tape irrigation rather than basin irrigation should be analyzed economically at real water prices. Overall, in this study, the tape irrigation method, by reducing water consumption, was able to increase water productivity and maintain the yield of rice in direct cultivation. Sprinkler irrigation had the lowest yield of rice in transplanting and direct cultivation. Problems such as lack of uniformity of spraying and waste water through the wind as well as poor quality of sprinklers are the main reasons for the decrease of the efficiency of sprinkler irrigation.
Ali Reza Kiani; Afshin Mosavat
Abstract
Introduction: Lack of water and deterioration in the quality of soil and water resources are considered to be the prime cause of reduced crop yield in arid and semi-arid regions ‘More crop per drop’ by trickle irrigation, deficit irrigation, and uncommon water are the best strategies for mitigating ...
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Introduction: Lack of water and deterioration in the quality of soil and water resources are considered to be the prime cause of reduced crop yield in arid and semi-arid regions ‘More crop per drop’ by trickle irrigation, deficit irrigation, and uncommon water are the best strategies for mitigating water crises. Different irrigation management strategies are needed to increase production in different areas. In areas where sufficient water is available, a full irrigation strategy could be a suitable option, while in areas where water is limited, deficit irrigation would be an appropriate method, and finally in areas where water resources are saline, management strategies for achieving sustainable production as well as economic yields would be suitable. Maize is the third most important grain crop in the world following wheat and rice and it is the main source of nutrition for humans and animals. Because of the importance of maize in the world, increasing maize production under environmental stresses is a big challenge for agricultural scientists. Different methods of irrigation and the use of saline water that had satisfactory results for increasing agricultural production have been studied by several investigators . The main objective of this study was to establish an efficient use of limited water resources as well as to explore the possibility of replacing saline water with fresh water using different management techniques.
Materials and Methods: A field experiment was conducted over two maize cropping seasons (2012–2013) in northern Iran (Gorgan Agricultural Research Station) to compare different alternate irrigation scenarios using saline water on corn yield, salinity and soil moisture distribution in a randomized complete block design with three replications. Treatments were: T1 and T2 = 100 and 50 % of crop water requirement with non-saline water, respectively; T3 and T4 = variable and fixed full irrigation with saline and non-saline water in every other row, respectively; T5 and T6= fixed and variable deficit irrigation with non-saline water in every other rows, respectively and T7= full irrigation with saline water. To create the desired water salinity (8 dS/m), non-saline well water (1.5 dS/m) and drainage water (20–35 dS/m) were blended in different proportions. A T-tape drip irrigation system (20 m in length) was used in the field experiment.
Results and Discussion: In general, corn yield in 2013 was about 1270 kg ha-1 higher than in 2012. From the weather records it can be seen that the second year was drier than the first year. Yield analysis showed that deficit irrigation treatments (T2, T5 & T6) and also alternate salinity treatments (T3 & T4) did not significantly difference. In other words, the deficit irrigation management had no effect on yield. Corn yield in T3 and T4 with 50% of saved fresh water was just reduced to 7 and 1 % of T1, respectively. As a result, comparing treatments T3 and T4 with full irrigation have shown that treatments T3 and T4 are the best option. Comparison of moisture distribution in deficit irrigation treatments showed the highest water content in surface and deep layers was related to the treatments T6 and T2, respectively. The distribution of salinity in the soil profile for treatments T3 and T4 showed that after two years of irrigation with saline water, there is the possibility of use saline water for corn production, but drainage and leaching of soil will need to maintain sustainability.
Conclusion: Naturally, in water scarce areas that use some strategic management such as deficit irrigation or saline water use, there is available arable farmland to further develop the irrigated area, and thereby increase total production. According to the results of the two-years where there was a shortage of water to meet crop water requirement and saline water was not available, the use of deficit irrigation managements as described in this study can save fresh water resources and increase total production and farmer's income. If the region is facing a shortage of water resources and saline water is available nearby agricultural land, it is suggested to use alternate furrow irrigation with saline and non-saline water; with the crop water requirement being met by the saline water, the total output will be higher than using deficit irrigation management with non-saline water. Comparision of the distribution of moisture in deficit irrigation treatments showed that surface soil moisture was lower in the treatment of T5 because it was more lateral distribution. In the deeper layers, soil moisture of the treatment T2 was more than others, because it was the predominant infiltration. The two treatments T3 and T4 because of the combined matric and osmotic potential and the movement of water along the sides and deep percolation, resulting widely distributed in soil moisture and thus remaining lower moisture in the soil compare to full irrigation treatments. Consequently, this finding indicates that after two years of corn irrigation using saline (8 dS/m) and non-saline water in every other row (treatments T3 and T4) production can be increased, and in case of proper leaching and drainage management, agricultural sustainability will also preserve.
A. Kiani; A. Hezarjaribi; T. Dehghan; M. Khoshravesh
Abstract
Introduction: Water scarcity is one of the major problems for crop production. Using drip irrigation as an effective method in the efficient use of water is expanding in arid and semi-arid regions. One of the problems in under pressure irrigation during use of saline, unconventional and waste is emitters ...
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Introduction: Water scarcity is one of the major problems for crop production. Using drip irrigation as an effective method in the efficient use of water is expanding in arid and semi-arid regions. One of the problems in under pressure irrigation during use of saline, unconventional and waste is emitters clogging. There are several ways to prevent particle deposits in pipes and clogging of emitters. Generally, conventional methods are divided into two categories: physical and chemical methods. In physical method, suspended solids and inorganic materials are removed using particles sediment sand and disc filters. In the chemical method the pH drops by adding acid to water resulting in the dissolution of carbonate sediments. With chlorine handling, organisms (i.e. algae, fungi and bacteria) that are the main causes of biological clogging are destroyed. However, the application of these methods is not successful in all cases. It has been observed that the emitters have gradually become obstructed. Magnetic water is obtained by passing water through permanent magnets or through the electromagnets installed in or on a feed pipeline. When a fluid passes through the magnetized field, its structure and some physical characteristic such as density, salt solution capacity, and deposition ratio of solid particles will be changed. An experimental study showed that a relatively weak magnetic influence increases the viscosity of water and consequently causes stronger hydrogen bonds under the magnetic field.There exist very few documented research projects related to the magnetization of water technology and its application to agricultural issues in general and emitter clogging in drip irrigation method, in particular. This technology is already used in some countries, especially in the Persian Gulf states. This research was designed and implemented aimed at increasing knowledge about the application of magnetic technology and its effects on emitters clogging in the drip irrigation system.
Materials and Methods: A field experiment was carried out in 2011 in Gorgan Agricultural Research Station to study emitter clogging in drip irrigation using magnetic, non-magnetic and acidic water under salinity condition. The geographical location of the farm was 36° 55′ N, 54° 25′ E and 13.3 m above mean sea level with annual rainfall 400-450 mm. The experiment was laid out with a split plot in a complete randomized block design with three replications. The treatments included three treatments of the management of emitters clogging including, magnetized water (M), non-magnetized water (N) and acidic water (A) plus using three water quality levels namely, well water (S1), saline waters 7 (S2) and 14 (S3) dS m-1. Two methods were simultaneously used to magnetize water. In the first method, an electromagnet was installed around the sub-main pipe before the flow of water to the laterals. The amount of power required to magnetize the irrigation water was 0.03 kW-h of electricity per m3 of water. In the second method, the permanent magnets (ceramic magnets) were installed around the sub-main pipe before the laterals. In the second method the power requirement was 0.3 Tesla. To assess the emitter clogging, discharge and its variations as a function of time, emission uniformity, uniformity coefficient, and coefficient of variation were estimated and analyzed.
Results and Discussion: The results of variance analysis showed that the effect of different irrigation management in irrigation system (N, M and A treatments) and different levels of water quality on all parameters were significant. Statistical comparison showed that in all cases there were no significant differences between magnetized water and non-magnetized water treatments. However, acidic water was statistically different from the two types of water mentioned. Both magnetic and conventional indices were examined in this study. However, no significant difference was observed. But in all cases, using magnetic water is advantageous compared with using non-magnetized water. The overall results have shown that the use of magnetized water in this study, in the non-saline water condition, does not offer a relatively higher advantage compared to the use of non-magnetized water.
Conclusion: For saline water, insignificant differences were observed between magnetic and non-magnetic water treatments, however magnetic water was slightly preferable. Most of the indicators that were assessed showed that acid water treatment was significantly different from magnetic and non-magnetic water treatments. Thus, acid water treatment is not preferable. Emitter clogging with increase of time and the salinity level of irrigation water increased; the greatest difference between the treatments occurred in S3 and the last irrigation treatments. Magnetic water up to salinity level of 7 dS m-1, had no effect on the flow rate and thus on the emitter clogging. However, when using saline irrigation water and also with the increase of time, emitter clogging in magnetic water treatment was lower compared with non-magnetic treatment.
Keywords: Emitters clogging, Magnetized water, Saline water
M. Salehi; M. Kafi; A.R. Kiani
Abstract
Abstract
In order to optimize the water management in agriculture in semi arid and arid conditions water-salinity function should be evaluated. In order to evaluate salinity and deficit irrigation two experiments were conducted in 2008 and 2009. Kochia was grown with six levels of saline water (1.5, ...
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Abstract
In order to optimize the water management in agriculture in semi arid and arid conditions water-salinity function should be evaluated. In order to evaluate salinity and deficit irrigation two experiments were conducted in 2008 and 2009. Kochia was grown with six levels of saline water (1.5, 7, 14, 21, 28, and 35 dS/m) and three levels of applied water (25, 75, and 125 percent of the water requirement) in 2008 and four levels of applied water (50, 75, 100, and 125 percent) in 2009. Data were analyzed using linear, quadratic, Cobb-Douglas and transcendental functions. Results showed that quadratic function estimated yield better under salinity and water stress. Marginal rate of technical substitution showed that water salinity and water supply can be substituted with the other in a wide range in order to achieve equal amount of yield. Marginal production of water quantity and quality were 6.7 and 154 kg.ha-1 in 2008 and 4.8 and -511 kg.ha-1 in 2009, respectively.
Keywords: Production function, Halophyte, Water quality, Water quantity
