جستجوی مقالات مرتبط با کلیدواژه "سامانه های آبیاری" در نشریات گروه "آب و خاک"

To monitor and compare the changes of salts in the soil profile around the roots of the corn plant, the plant yield, and the productivity of corn water, an Experimental was conducted in a completely randomized block of three repetitions in two crop years 2017-2018 and 2018-2019 at Ahvaz Agricultural Research Station. Experimental treatments included two subsurface drip irrigation systems with a working depth of 30 cm from the soil surface and tape irrigation and two irrigation intervals of 2 and 4 days. The results of monitoring soil solutes obtained from sampling depths (0-25, 25-50, and 75-50 cm) showed that soil salinity in the second year in both systems as a result of improving the quality of irrigation water from 3.61 dS/m to 2.01 dS/m, it was reduced by two times. The results of soil salinity monitoring showed the highest ratio of salinity reduction with a 2-day irrigation interval in both irrigation systems. The most leaching was done at the irrigation depth of 25-50 cm in the subsurface drip irrigation system and at the depth of 0-25 cm in the tape system. The highest yield of corn dry fodder was 9.13 and 7.13 tons per hectare, respectively, and the best water efficiency based on dry corn fodder at the rate of 13.74 kg/m was obtained in the strip drip irrigation system (tape) with a two-day irrigation interval and in the second crop year. Also, the results of the soil salinity measurement showed that the implementation and exploitation of the drip irrigation system can be the basis for improving the quality of the soil as the most important non-renewable resource of agriculture.

One of the major consumers of water and energy sources is agriculture and evaluating the performance of irrigation systems to determine the efficient use of these two sources is one of the priorities of sustainable agriculture. In this regard, the present study has conducted a spatial analysis of water and energy consumption in Qazvin irrigation network. For this purpose, first, the dominant cropping pattern of the study area was extracted and then the water requirement was estimated for the products in the cropping pattern using CropWat 8.0 software. To estimate energy consumption, energy consumption in the sprinkler and drip irrigation systems, groundwater pumping, diesel fuel, labor, seeds, machinery (tractors and combines), chemical fertilizers, and pesticides for each available secondary field in the irrigation network was calculated. The results showed that the highest energy consumption in all secondary farms indirect energy consumption is related to diesel fuel with 40% of total energy consumption and in indirect energy consumption belongs to nitrogen fertilizer with 20% of total energy consumption. Also, in the energy used to pump water in irrigation systems at different heads required for pumping for crops in the dominant cropping pattern, alfalfa consumed the most energy with a value of 4811.44 Kwh / ha and corn consumed the least energy with a value of 1194.19 Kwh / ha. According to the results, the impact of diesel fuel, chemical fertilizers, and water pumping on energy consumption are high, thus controlling the consumption of these inputs would significantly reduce energy consumption.

Today, the increase in food demand has led to an increase in energy use, which has some environmental consequences such as air pollution and global warming. Irrigation is one of the energy-intensive operations in agriculture, which consumes great part of energy inputs and has harmful environmental effects. Applications of modern methods of irrigation in agriculture can be considered from different aspects. So, the aim of this study was to evaluate the energy and environmental indicators of walnut orchards under surface and pressured irrigation methods. The required data, including information about inputs and energy consumed in walnut orchards, were collected using questionnaires and face-to-face interviews in Shahr-e Kord and Saman region of Chaharmahal and Bakhtiari province. The collected data belonged to the production period of 2021–2022. The averages of total energy consumed for walnuts production in pressured and surface irrigation systems were 29573.53 and 25058.46 MJ ha−1, respectively. This shows that despite less water consumption in the pressured irrigation system, the total energy input in this irrigation system is more than the surface irrigation system. No significant difference was observed regarding the performance of walnut in the two mentioned irrigation systems. The inputs energy consumption in the walnut production with the pressurized irrigation system were highest for plastic and farmyard manure (about 32% and 15%, respectively); while in surface irrigation system, the share of nitrogen fertilizer and farmyard manure were highest (about 30% and 25%, respectively). Energy ratio of walnut production in surface irrigation systems was computed as 3.58, while the corresponding value in pressured system was 2.77. In other words, surface irrigation had better conditions in terms of energy indicators. The LCA results of walnut production showed that in the two irrigation systems, the greatest effects in human health and the ecosystems are from on-farm emissions. In general, the investigation of the environmental indicators of walnut production in the two irrigation systems showed that the use of the pressured irrigation system reduces the environmental damage.

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.

Soil quality is an essential indicator for sustainable land management that generally depends on soil physical, chemical and biological properties. Due to the multiplicity of soil properties, the number of variables is usually reduced to a minimum set by statistical methods, which reduces study time, decreases monitoring cost for sustainable use of agricultural lands. The aim of this study was to introduce the most effective soil characteristics of agricultural lands in Mohammadshahr plain, Karaj, to prevent the descending trend of soil quality.
In this study, four farms and orchards which were different in terms of crop type and irrigation system were selected and evaluated with Integrated Quality Index (IQI) and Nemero Quality Index (NQI). In both indicators, the characteristics affecting soil quality are combined in the form of a mathematical model and presented as a numerical quantity. For this purpose, first 12 soil profiles were described, followed by sampling from topsoil (surface layer) and sublayers (weighting average for the depths) and testing 17 soil characteristics affecting its quality. In the next step, both indicators were calculated using two different sets of soil properties. The first category, the Total Data Set (TDS), included all measured soil characteristics, and the second group, the Minimum Data Set (MDS), included the most important properties affecting soil quality. The Principle Component Analysis was implemented to select the MDS. Soil properties were scored to calculate IQI and NQI. For this purpose, a function was defined for each soil feature to standardize all scores between zero and one. Weighting various soil quality properties was also performed by calculating the common variance of the variables, which was obtained by factor analysis method.
Calculation of IQI and NQI indices showed that the topsoil samples were in grade III and sublayer samples belonged to grade IV with major limitations due to lack of profile development, organic carbon deficiency, salinity and high gravel. Four and six items out of 16 variables were identified effective for topsoil and sublayers, respectively. The IQI index based on TDS was more accurate and sensitive than the NQI index for soil quality assessment, as more features are considered for TDS. In the IQI index, both the weight of attributes and their scores are effective, while in the NQI index, only the attribute score is considered. On the other hand, the coefficient of determination between the TDS and MDS for topsoil and sublayer samples was 0.55 and 0.56% for IQI model, respectively, and 0.48 and 0.16% for NQI model, respectively. In other words, the determination coefficients showed the reliability of using the MDS instead of TDS in both IQI and NQI models. In the MDS, mean weight diameter (MWD) showed the highest effect on the surface layer and percentage of gravel had the greatest impact on the soil quality of the sublayer.
Although TDS took into account all soil properties and showed a slightly higher coefficient of determinations with both soil quality indicators, the MDS obtained similar results to the TDS with only about half of the properties. In the MDS, the features with an internal correlation is eliminated rendering it more cost effective. The results of this study assist decision-makers to choose better quality management and soil sustainability strategies while decreasing the monitoring cost.

Facing to drought in recent years has lead to focus on promoting the use of localized irrigation in the country. Due to the shortage of available water resources, farmers have also realized the need to use a drip irrigation system. Monitoring and evaluation of existing and operating systems is of particular importance that can prevent the waste of capital and achieve the main goals of the application of pressurized irrigation systems. Date is one of the garden products that play an important role in food security and national economy. Hence the purpose of this research is technical and hydraulic evaluation of the performance of localized irrigation system (bubbler) on palm trees located in Bastak city in Hormozgan province and also comparing water productivity of this method with the basin irrigation system, which is common in this area. For this purpose, two farms were selected and evaluation parameters were determinrd by measuring the flow rate and pressure of the bubblers in two stages. According to the results of this study, the potential application efficiency of low quarter (PELQ) and actual efficiency application of low quarter (AELQ), which represent the overall performance of the localized irrigation system (bubbler), were 29.21% and 32.44% on March 2019, and 32.64% and 36.26% on June 2019, respectively. Therefore, the performance of proposed irrigation system was evaluated to be in a poor condition. By training the operator to wash the filtration system properly and timely and to contorol the semi-main pipe valves adjustment, the performance of the localized irrigation system can improve. Water productivity of the date cultivar Khanizi was 0.18 kg/m3 for the garden irrigated with basin surface irrigation method. However, it was 0.33 kg/m3 for the garden irrigated with bubbler system. Therefore, the bubbler irrigation system had a higher water efficiency in comparison to the surface irrigation. The results showed due to lack of training to operator, absence of design engineer at the project site, lack of accurate information from the project site and also the lack of proper supervision over the implementation of the drip irrigation system, the performance of the system has not been at an acceptable level.

This study was donein three phases; “Determination of water productivity gap”, “Systematic analysis of water productivity improvement strategies” and “Presentation of water productivity improvement plan”. Irrigation water productivity in plain scale was estimated 40 to 50% of water productivity potential. In Wheat, Barley and Corn crops 47, 52 and 30 % of yield gap was related to inappropriate water supply (amount, time and distribution uniformity) and 31, 32, and 52% of yield gap was related to inappropriate application of fertilizers in the fields. In Qazvin plain, irrigation water productivity in agronomy sector in the ten year period, from 2006 to 2016, has increased by an average of 4.9 % annually (from 1.17 to 1.74 kg/m3). With irrigation systems and crop pattern modification, there is ability to upgrade water economic productivity and increasing the farmer's incomewith reducing water harvesting. The aquifer status can be improved if modern pressurized irrigation systems be developed with cultivation level control or water harvesting control. Investigation the conceivability of strategies also showed that institutional barriers and social constraints are the main barriers to productivity growth. Based on strategic mapping method, presented strategies for improving water productivity were categorized in three groups; initiation, mediation and termination strategies. The most important threats to productivity improvement were quantitative and qualitative degradation of Qazvin aquifer and soil degradation due to improper use of plastics in farms. Initiation strategies for improving water productivity are farmer’s education on irrigation and productivity, and attracting their participation in the formation of water conservation and exploitation associations. By improving water productivity over a 15-year period groundwater abstraction in the agricultural sector can be reduced to programmable water levels (877million cubic meters). without harming the livelihoods of the farmers and the agricultural economy. Using this productivity improvement potential requires multispectral planning and control on water abstraction.

Precise estimation of the amount of water consumed, irrigation efficiency and water productivity of crops are the most important key indicators in agricultural sector planning of Iran. The figures given for the volume of water used in the agricultural sector are very different and there are serious doubts as to their accuracy. The average of water use efficiency in the country is 1.32 kg/m3 and its annual growth in the last 11 years has been reported to be 0.041 kg/m3 (Abbasi et al., 2017). Therefore, it is necessary to carry out an exploratory work that can be used to quantify the volume of water consumed by various products. Therefore, the main objective of this paper is to measure water consumption of wheat directly and to compare wheat water productivity in different irrigation systems under farmers management in Behbahan.

The volume of application water for wheat in different farms during one season (2016-2017) was measured and compared. The measured values were compared with the crop water requirement estimated by the Penman-Monteith and the national document. To determine the volume of water consumed, firstly, the flow rate of the selected water sources was measured, with the appropriate devices (flumes, meter and micro molina). Farm information including cultivated area, soil texture, soil electrical conductivity, electrical conductivity of the irrigation water used, and farm location with GPS were recorded. Other field information such as irrigation method, irrigation water sources (surface, underground), type of irrigation network (modern, traditional) were also recorded. Effective rainfall was calculated by the SCS method. Crop water requirement using the Penman-Monteith method was determined from data of current year and 10-year data for Behbahan city from the nearest meteorological station.

 32 wheat farms were selected and evaluated, of which 15 farms were irrigated with surface irrigation, 10 farms with sprinkler and 7 farms with drip irrigation systems. The results showed that the yield of wheat varied from 2000 to 6854 kg per hectare. The most water productivity of wheat occurred in a farm with drip irrigation being 2.79 kg/m3. Irrigation application efficiency varied from 22.7 to 99.7%. Updated crop water requirement changed from 373.4 to 517.0 mm. The highest water consumption was measured to be 4626 m3/ha in the farms receiving water from springs. The results of the t-Test analyses showed that the yield in drip irrigation farms (average being 5169 kg/ha) was significantly different as compared to sprinkler and surface irrigation systems with 3574 and 3795 kg/ha, respectively. The results of the comparison of the mean water productivity in the t-Test indicated that drip system with 1.51 kg/m3 of water productivity had the highest values and there was a significant difference with the two sprinkler and surface systems, which respectively had water productivity of 0.90 and 0.88 kg/m3. The Pearson correlation coefficients showed that the trend of changes in the amount of water consumed with the trend of changes in the application efficiency index and water productivity proved uncoordinated and it was significant at 1% level.

 The results of measurements in 32 farms showed that half of the drip irrigation fields were not cultivated on the recommended date range. Therefore, the growth period in this half was less than 140 days. Despite the decline in growing season and the non-observance of planting dates, yield in these farms was over 4000 kg ha-1. Application efficiency in sprinkler irrigation method was more than other irrigation methods. The reason for the high application efficiency in sprinkler irrigation was the backwardness of sowing date on one side and the late harvest of wheat on the other. The surface system with a growth period of 158 days had the highest growth period and has a significant difference with two dripping and sprinkler systems. The surface water system with the volume of water consumed at 4398.7 m3/ha had the highest volume of water consumed and showed a significant difference with the drip system, but this difference was not meaningful compared with the sprinkler system. The volume of water consumed by two systems of drip and sprinkler was measured at 3490.5 and 3863.6 m3/ha, respectively. The backwardness of wheat harvesting time in sprinkler irrigation fields caused the major filling time of the grains to be adjusted to April, which coincided with a higher increase in the air temperature. This led to increased water consumption at this particular time point and caused a significant decrease in water consumption despite the lower consumption of water in the sprinkler system.

Considering water productivity in different products is one of the basic parameters in optimizing the optimal use of inputs and performance. In this regard, water as one of the most important inputs should be given special attention. This study was conducted to evaluate irrigation water productivity in wheat, tobacco, watermelon and tomato as the main products of Bushehr Province. The most irrigation water productivity for these products was 0.45, 0.19, 7.73 and 12.77 kg / ha, respectively. The results showed that the use of drip irrigation system increases water productivity. In all cases, water utilization in the drip irrigation system was higher than the surface irrigation system. The drip irrigation system increased the productivity of water by 3 to 5 times, and reduced water consumption by 2 times, and increased the yield by 2 time in products such as tomato and watermelon. The failure of the drip irrigation system in the saline water resources use was due to inappropriate design and utilization, in particular the lack of proper utilization of water filtration filters. In the agricultural sector of the province, despite the existence of various deficiencies, valuable knowledge is available in the farmers of the region, especially in areas such as tomato cultivation, which can be used for these capacities.

Simulation of water movement in soil profile and recognition of the effect of irrigation systems on soil moisture dynamics is of great importance. For this purpose, one-dimensional LEACHW numerical model was used in selected agricultural areas of Mohammadshahr plain of Karaj. By describing 9 profiles the soil in 3 selected fields and gardens and taking into account the initial moisture conditions and monitoring their changes during the crop season or simulation period, the LEACHW model was implemented and the estimated moisture values of the model were measured with measured moisture values. The results were compared by means comparison test, sensitivity analysis of the model, and the model was again run on the basis of calibrated parameters and the amount of water lost and remaining in the soil profile during the growing season. At the output of the model, the amount of water lost and remaining in the soil profile was estimated. The results showed that modern irrigation systems were not effective in aquifer nutrition; therefore, one of the ways to increase water productivity is to reform traditional irrigation systems and move towards the development of new irrigation systems. Undoubtedly, the main task of developing new irrigation systems to ensure the country's food security is to optimize water use in the agricultural sector as the main consumer of water resources in the country.

Due to specific climate conditions in Iran and impossibility of increasing new resources of water for agricultural sector, agricultural water management is essential for improving water productivity. Assessment of low irrigation efficiency in the Country and providing appropriate solutions to improve irrigation efficiency and water productivity at the national level can be a great help for modifying irrigation efficiency. For this purpose, available data on irrigation efficiencies in different irrigation systems and differnet irrigation networks (traditional and modern) were analyzed. Analysis was based on results obtained from about 200 field scale studies including 1900 measured irrigation events across Iran from 1991 to 2015. The finding showed that application irrigation efficiency (Ea) ranged between 22.5 and 85.5% having meant of 56%. The averages of Ea in the basin, border and furrow irrigation systems were 55.3, 52.9 and 52.5%, respectively. Although, Ea in sprinkler irrigation systems for example wheelmove and solid set systems were 66.9 and 52.1%, respectively. Average of Ea in pressurized and surface irrigation systems were 66.6 and 53.6%, respectively. As well as, Ea in sprinkler and drip irrigation systems were 62.1 and 71.1%, in order. Results also indicated that Ea over three decades (1992-2001, 2002-2011, and 2012-2015) were 52, 58.4, and 58.8%, respectively. However, network irrigation efficiency for three decades was in order of 67, 68.5 and 74.2%. As a result, total irrigation efficincey (Ep) was 34.8, 40 and 43.6% in these decaceds, respectively. This means that, Ep had annully increased about 1% from 1996 to 2013. An important reason for increase of irrigation efficiency over these decades are improvment of knowledge of users and beneficiars with regards to water and soil issues, improvment of new irrigation systems and extension of research findings to operators and beneficiars.

The energy crisis has led the world toward the reduction of energy consumption. More than 70 percent of the energy in agriculture sector is used by pumps. In our country, there is no clear standard and guideline and also no adequate supervision for the design, selection, installation and operation of pumping systems appropriate to the circumstances and needs. Consequently, these systems operate with low efficiency and high losses of energy. While more than 20 percent of the world's electricity is consumed by pumps, average pumping efficiency is less than 40%. So evaluation of pumping stations and providing some solutions to increase efficiency and pumping system’s life time and to reduce energy consumption can be an effective in optimization of energy consumption in the country. The main reasons for the low efficiency of pumping systems comparing to potential efficiency are using unsuitable techniques for flow control, hydraulic and physical changes of pumping system during the time, using pumps or motors with low efficiency and poor maintenance. Normally the amount of flow is not constant over the time in a pumping system and needed flow rate is changed at different times. Designing of pumping system should be responsible for peak requirements as well as it must suggest the suitable flow control method to achieve least energy losses for minimum flow requirements. Also one of the main capabilities to reduce energy consumption in pumping stations is improving the flow control method. Using the flow control valves and bypass line with high energy losses is very common. While the use of variable speed pumps (VSPs) that supply water requirement with sufficient pressure and minimum amount of energy, is limited due to lack of awareness of designers and (or) high initial costs.
In this study, the operation of the pumping stations under four scenarios (for discharge control) in a drip irrigation system was analyzed and evaluated: A) Pumping station equipped with VSPs, in this case it is possible to regulate energy consumption due to the required discharge and pressure for irrigation system , B) Pumping stations equipped with constant speed pumps (CSPs) and flow control valve maneuver in every decade of irrigation, C) Pumping stations equipped with CSPs without any flow control and D) Pumping stations equipped with CSPs and flow control valve maneuver per month of irrigation. Pumping stations equipped with CSPs was designed for a 100 hectares irrigation area for peach and apple trees in the South West of Isfahan province. The produced pressure under four types of flow control were determined. Then pump performance and energy consumption were evaluated under three operation scenarios (B, C and D) and afterward compared with the performance of VSP stations that was designed for this irrigation system.
The most important point in the design of pumping stations is energy consumption, because the cost of energy supply is high and the operation should be able to save more energy. Using the output values of pressure and flow rate from developed model, the amount of energy consumption for each pump was calculated. It was observed that the energy consumed in pumping stations equipped with VSPs is significantly less than other stations. Regarding to the total energy consumption and the amount of energy that each scenario can save, the percentage of energy savings were calculated. The results show that the highest percentage of energy savings are belonging to scenario (a) (using VSPs).
The results of this study show that application of VSPs at pumping stations than commonly pumping stations with CPSs, depending on the type of CSP operation, saves 44 to 54 percent of energy. Using VSPs, which save a lot of energy compare to other methods, can be an important phase in optimizing energy consumption and minimizing the cost operation of the agriculture pumping station. So the type of operation that discussed in the present study and also the type of irrigation system, pump selection, cultivated area and irrigation scheduling are effective at saving energy during VSPs employment. In a recent case, reduction in energy cost should be independently calculated for each irrigation system and be considered in the lifetime costs of pumping system. Regarding the results of this research and also latest studies, it can be said that the study design and implementation of variable speed pumps in irrigation projects should be considered in national scale. Because development of pressurized irrigation schemes that inevitably need to pump, is the country's main policies for efficient use of water.