Research Article
Irrigation
E. Rezaei; M. Montaseri; H. Rezaei
Abstract
Introduction: Prioritization of optimal water allocation of surface flow storage dams for different applications (drinking, agriculture, industry, environment, etc.) in arid and semi-arid regions such as Iran due to the range of changes, high flow uncertainty Reservoir inlets, and the occurrence of intermittent ...
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Introduction: Prioritization of optimal water allocation of surface flow storage dams for different applications (drinking, agriculture, industry, environment, etc.) in arid and semi-arid regions such as Iran due to the range of changes, high flow uncertainty Reservoir inlets, and the occurrence of intermittent droughts are of great importance. For this purpose, the Fuzzy Hierarchy Process (FAHP) is proposed and used as a suitable formulation method in prioritizing water allocation in the water resources system. Therefore, in this study, prioritization of water allocation for different purposes of Shahrchai reservoir dam located upstream of Urmia metropolis has been done in a field study using fuzzy hierarchical method.Materials and Methods: A fuzzy hierarchical process based on quantitative and qualitative effective factors has been developed. In the first stage, the problem structure was designed by determining the priority of water allocation of users, criteria, sub-criteria, and other factors. Then the decision-making hierarchy based on the problem structure (purpose, criteria, sub-criteria, factors, and options in the first to fifth levels, respectively) was defined. In the mentioned prioritization structure, the goal was determined at the first level, ie the optimal or appropriate allocation of Shahrchay reservoir dam water for different operators, and at the second level, three economic, social and environmental criteria were considered as the main criteria. At the third level, " cultivation area and gross income" and "employment and population" were considered as sub-criteria of two economic and social criteria, respectively. The main beneficiaries, namely agriculture, urban drinking, recreation and tourism, industry, environmental needs of Lake Urmia and groundwater fourth level (options) have formed the problem structure. At the next step, based on the field data or questionnaires, criteria, sub-criteria, and factors were compared in pairs using the proposed linguistic and fuzzy comparisons, and the priority of water consumption over each criterion or sub-criterion or factor were compared based on fuzzy triangular numbers. The weights were determined and ranked each using the Chang development method. At the third stage of the final ranking, the priority of water allocation was determined based on the final weight of criteria or priorities at the previous stage and the superior option was determined. Finally, a sensitivity analysis of the weight change of the criteria and the decision-making process of the problem has been performed.Results and Discussion: A decision model based on a fuzzy approach is presented to rank the different options using Shahrchay dam water. For this purpose, firstly, using the opinions of experts and researchers, the results of a questionnaire, criteria and sub-criteria and important options in allocating water to Shahrchai Dam were determined. Secondly, using Chang's development analysis, different options were evaluated based on the mentioned criteria, sub-criteria, and factors. From a scientific point of view, because the questionnaires were presented to experts, the economic criterion is a high priority, so it is possible to attach great importance to the general conclusion about the criteria in economic attitudes and related issues. In addition, the allocation of water to the urban drinking sector with a weight of 0.33 was as the top priority, agriculture, Lake Urmia, industry, groundwater, and recreation were in the next priorities, respectively. Therefore, economic criteria and drinking water supply were recognized as the main objectives of planning and managing water resources in the metropolis of Urmia. The drinking sector is a vital factor for the survival of a community and because the drinking water of Urmia city is supplied through Shahrchai dam, so the allocation of water to this sector should be considered as the top priority. The agricultural sector was also given the second priority with less importance. The supply of water to this sector has a significant direct effect on the economy of the agricultural sector and indirectly on the entire economy of the region, which indicates the importance of the agricultural sector in the economy, living conditions of the region and the allocation of water to this sector. Comparing agricultural and industrial activities in Shahrchai catchment area, the most activity in the region is agriculture and industry is in a lower priority, which is also shown by the hierarchical results. Since Shahrchai River is one of the suppliers of water to Lake Urmia, the allocation of water to this section improves the condition of the lake and, consequently, it improves the environmental, economic, and social conditions of the region. The results also indicate the importance of Lake Urmia in relation to industry and its higher status indicates the attention of officials to the drying crisis of the Lake Urmia.
Research Article
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.
Research Article
Irrigation
H. Sarvi Sadrabad; A. Zare Chahouki
Abstract
Introduction: Inter-basin water transfer affects the environment, culture and economy of donor and recipient basin. In this regard, one of the most important aspects are the positive and negative effects on the quality of groundwater in the recipient basin. Spatio-temporal changes of groundwater ...
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Introduction: Inter-basin water transfer affects the environment, culture and economy of donor and recipient basin. In this regard, one of the most important aspects are the positive and negative effects on the quality of groundwater in the recipient basin. Spatio-temporal changes of groundwater quality as the results of inter-basin water transfer, plays an important role in water resources management. Thus, this study attempts to investigate the temporal trends of groundwater quality parameters using Mann-Kendall test and Sen's slope estimator. In addition, spatial changes of groundwater quality and the effects of inter-basin water transfer were studied.Materials and Methods: In this study, non-parametric methods and interpolation models were used to evaluate the spatio-temporal patterns of groundwater quality parameters in the Yazd-Ardakan plain. Mann-Kendall nonparametric test and Sen's slope were used to examine the temporal trends in the span of 2000 to 2020. The interpolation models and groundwater quality index (GQI) were used to study the spatial patterns and classify the quality of groundwater. The assessment of quality parameters of all studied wells including Ca2+, Mg2+, Cl-, Na+, SO42- and TDS were studied in equal time periods. Groundwater quality measurements were performed twice a year using a volumetric method, one in spring and the other one in autumn. The World Health Organization (WHO) standard was considered to compare values of different parameters in the plain.Results and Discussion: A decreasing trend was observed in SO42-, Na+ and TDS parameters in most wells and there was an increasing trend for Ca2+, Mg2+ and Cl- parameters. Considering WHO classification standard, all the studied parameters were in the allowable ranges except TDS. The parameter ranking showed that TDS, Cl- and Mg2+ had the greatest impact on the quality of aquifer groundwater. The Mg and TDS parameters had the highest and the lowest changes, respectively during 2000 to 2020. Results of the GQI showed that the total quality of the Yazd-Ardakan aquifer was in the moderate class and acceptable because of relatively large decrease in the groundwater in the span of the studied period. However, the decrease in groundwater quality was negligible. Changes of the quality map showed that the most negative quality changes were related to the Yazd, Taft, Meybod, Ardakan and northern regions (Chah-Afzal desert). This indicates high groundwater pumping in these areas and being located near the desert area. The most positive quality changes belonged to the central and southern part of the aquifer.Conclusion: Comparison of the interpolation models showed that the geostatistical methods can show better results than the definitive methods in zoning groundwater quality parameters. The Kriging and IDW models were the best models and consistent with the results of the research. The quality of groundwater was acceptable, while the reduction in quality was very low and negligible in the Yazd-Ardakan aquifer during the studied period. The temporal trends of SO42-, Na+ and TDS had either a negative significant trend or no trend in the Yazd area. Considering ranking maps, TDS, Cl- and Mg2+ had high impacts on determining the GQI. These trends were positive in Yazd city and consequently the GQI maps could not confirm the negative temporal trend and zoning maps. This finding showed that the use of qualitative indicators could neutralize the effects of the parameters on each other and provide a better and acceptable result. In all, the transfer water with appropriate quality could control the increase of the TDS, SO42-, Na and caused an increase in Cl- in these areas. There are many effective factors to study water quality, so its description seems to be difficult. Therefore, using water quality indicators can provide total water quality conditions in a concise and understandable way.
Research Article
Irrigation
A.A. Khosravi; A. Parvaresh Rizi; R. Barati
Abstract
Introduction: In many cases, after a flood, some information is needed about the flood characteristics at the upstream of a specific location where there is no hydrometric station on the river or flow discharge, and water surface level was not measured at the time of the flood. In reverse flood routing, ...
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Introduction: In many cases, after a flood, some information is needed about the flood characteristics at the upstream of a specific location where there is no hydrometric station on the river or flow discharge, and water surface level was not measured at the time of the flood. In reverse flood routing, calculations are performed from the downstream section step by step to the upstream section of the river and inlet hydrograph is produced based on river hydraulic characteristics and downstream hydrograph. During floods in rivers, the volume of floods gradually decreases due to infiltration into the bed and sides. This reduction in flood volume, called transmission losses, is significant in arid areas. Therefore, developed models for flood routing in seasonal rivers in arid and semi-arid regions should provide an appropriate estimate of transmission losses. In the routing process, the governing equations are combined with an equation to account for infiltration or seepage losses into the riverbed or canal. Then, by routing the flood along the interval and examining the resulting hydrographs at different points, the amount of transmission losses is determined. In the present study, which deals with the reverse hydraulic routing of floods in arid areas, the infiltration losses along the river estimated by the Green-Ampt relationship was considered in numerical models so as to perform reverse flood routing with appropriate accuracy and under hydraulic conditions of ephemeral rivers. To the best of our knowledge, so far no study has analyzed transmission losses in reverse hydraulic flood routing.Materials and Methods: The equations governing gradual variable flows are known as the Saint-Venant equations, which include the continuity and the momentum equations. In hydraulic flow routing models, the complete form of the continuity equation is used, but the momentum equation is applied in various forms obtained by removing some components. The simplest hydraulic routing model is the kinematic wave model in which the components related to inertial forces and pressure force in the momentum equation are omitted. In the diffusion wave model, the components related to inertial forces are omitted, but the pressure force is taken into account and finally, in the dynamic wave model, the momentum equation is considered completely without simplification. In the present study, separate programs were prepared in MATLAB 2013 software for reverse hydraulic flood routing by Kinematic and dynamic wave methods. In these numerical models, by coupling the Green-Ampt infiltration equation with the continuity equation, the depth and flow rate in different places and times are calculated in the upstream direction of the flow.Results and Discussion: In order to validate the results of the developed numerical models and to evaluate its applicability, a set of measured data known as Lane hydrograph and Bambeichi hydrograph was used. The results showed that both reverse hydraulic flood routing models produced the upstream hydrograph with appropriate accuracy. The results of the Bambeichi hydrograph data were more accurate than the Lane hydrograph due to its shorter length of the interval between upstream and downstream sections. For example, the peak discharge of inlet hydrograph calculated by the dynamic wave method for the Lane hydrograph data had an error of 7% compared to the observed value, while the error obtained for Bambeichi hydrograph data was 2%. Therefore, the accuracy of inverse routing models in estimating the volume of upstream hydrograph and consequently the amount of transmission losses was desirable especially for the Bambeichi hydrograph data. The highest error in estimating losses was 25% for the reverse kinematic model and the data related to the Lane hydrograph.Between the two reverse hydraulic flood routing methods, the performance of the dynamic wave method was more accurate for the most numerical experiments, as the governing equations are completely solved in this method. This difference is more pronounced in the Lane hydrograph, which represents the actual conditions of an ephemeral river.Conclusion: The accuracy of the developed numerical models was 90% in estimating the peak flow rate of the upstream hydrograph, and between 85% and 97% in estimating the time related to this discharge. The volume of the upstream hydrograph, which indicates the model performance in estimating the infiltration in the flow path, was also modeled with 75 to 98% accuracy. These results show that the numerical models simulate reverse flood routing with acceptable accuracy in ephemeral rivers, where transmission or seepage losses are significant. Due to different approaches in calculating infiltration losses, these methods can make differences for the hydrograph output of numerical models.
Research Article
Soil science
E. Mirparizi; M. Barani Motlagh; S.A. Movahedi Naeini; R. Ghorbani Nasrabadi; S. Bakhtiary
Abstract
Introduction: Iron deficiency is one of the most common nutritional problems of plants in arid and semi-arid soils especially in calcareous soils. Iron is essential to many cellular activities, required for optimum growth and development, however it is insoluble in aerated soils at neutral or basic pH, ...
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Introduction: Iron deficiency is one of the most common nutritional problems of plants in arid and semi-arid soils especially in calcareous soils. Iron is essential to many cellular activities, required for optimum growth and development, however it is insoluble in aerated soils at neutral or basic pH, therefore, iron deficiency is common in these soils. The problem is usually solved by using iron synthetic chelates which is a very expensive option. There is, therefore, a need for cheaper and more effective alternatives to traditional Fe fertilizers. Several reports have shown that application of Fe factory by-product to soil tends to raise the availability of Fe and reduce Fe deficiency in plants. Application of organic compounds to soil may improve the solubility of the minerals containing micronutrients and correct their deficiencies in alkaline and calcareous soils. A large amount of slag is produced annually at the Sarcheshmeh Copper Complex, Kerman Province, Iran. So far, the copper slag, however, has not been tested as an Fe fertilizer in calcareous soils. Since about 53.8% of slag obtained from copper concentrate melting is composed of iron oxides, we, thus, examined the effect of copper slag along with organic compounds on the level of upper leaf iron, photosynthetic pigments, SPAD index, the activity of plant enzymes and the level of active iron in the upper leaves of sorghum by performing a factorial experiment in a completely randomized design.Materials and Methods: In order to study the effect of copper slag (one of by-products of melting copper concentrate in Sarcheshmeh Copper Complex, Kerman Province) and organic compounds (cow manure and pistachio skin) on total leaf iron content, photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll), antioxidant enzymes activity (Guiacol Peroxidase, Glutathione peroxidase) and concentration of active iron of young leaves developed of sorghum, a pot experiment was conducted in the greenhouse with three replicates per treatment. We applied experimental treatments including 5 levels of organic matter (pistachio skin, cow manure at 2 and 4 wt. % and control sample), and 11 levels of iron (copper slag, copper slag with sulfur, copper slag with sulfur and thiobacillus, acidic slag (each 2 levels each), sequesterine, foliar application of EDTA, and control sample) to a soil sample with low iron content. At the end of the incubation period, sorghum bicolor was cultured in the above treatments. Ten seeds were sown in each pot. Seedlings were thinned to 4 when they were about 10 cm high. During the growth period, pots were irrigated with distilled water as needed. Before harvesting, SPAD, the concentration of photosynthetic pigments, level of active iron and activity of plant enzymes were also measured in fresh plant samples. Furthermore, the concentration of Fe in the leaves was measured. Analysis of variance was performed using software SAS and significant differences were determined based on LSD (Least Significant Difference Test) at p < 0.05 level.Results and Discussion: The interaction between slag treatments and organic compounds showed that treatments of 4 wt. % of cow manure with slag of 4 times of recommended soil test value (C4S4, and 4 wt. % of cow manure with slag of 4 times of recommended soil test value with sulfur and thiobacillus (C4S4S°T), had significant effects on increasing photosynthetic pigments pigments (chlorophyll a, chlorophyll b, total chlorophyll), SPAD index, activity of plant enzymes (Guiacol peroxidase, Glutathione peroxidase) and active iron. The highest active iron level in the young leaves developed (54.06 mg / kg) was observed in (C4S4S°T) treatment which showed a significant increase compared to the control treatment (17.14). Increased concentration of active iron was also observed due to application of treatments (slag, organic compounds and the interaction between treatments) in sorghum young leaves. The photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll), SPAD index and activity of plant enzymes (Guiacol peroxidase, Glutathione peroxidase) were more correlated with active iron in young leaves developed compared to total iron concentration in these leaves. This indicates that active iron can be used as an index to detect iron deficiency.Conclusion: The higher level of active iron in the young leaves developed was more associated with physiological indices of sorghum as compared with total Fe concentration in these leaves. Therefore, this parameter can be used as an index to detect iron deficiency. In this study, increasing the level of slag consumed and consequently increasing Fe concentration in the leaf resulted in a significant increase in chlorophyll a, chlorophyll b, total chlorophyll, carotenoids and activation of the plant enzymes.
Research Article
Soil science
S. Balandeh; A. Lakzian; A. Javadmanesh
Abstract
Introduction: Silver nanoparticles (AgNPs) have a broad spectrum of uses, therefore, AgNPs will be released from those products into many different ecosystems. In the last decades, AgNPs have received substantial attention due to their distinctive physical and chemical properties such as high thermal ...
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Introduction: Silver nanoparticles (AgNPs) have a broad spectrum of uses, therefore, AgNPs will be released from those products into many different ecosystems. In the last decades, AgNPs have received substantial attention due to their distinctive physical and chemical properties such as high thermal and electrical conductivity, chemical stability, catalytic activity and antimicrobial properties against microbes such as bacteria, fungi, and viruses. There are many parameters for assessment effect of toxicity due to AgNPs but soil microbial community is one of which considered being an important target for assessing the impact of manufactured nano-materials on the terrestrial environment. Toxicity of AgNPs is due to the physical interaction of AgNPs with microorganisms and the production of reactive oxygen species (ROS). Although as we have been known harmful effects of AgNPs on the soil bacterial community, but the most information about antimicrobial properties of AgNPs come from the routine lab instructions such as soil respiration, substrate induced respiration and microbial biomass and colony forming unite. So, the objective of this paper was to study the effects of silver nanoparticles on microbial activity using the routine lab instructions and compare with the obtained data from the molecular genetic techniques. In this paper, the quantitate population of soil bacterial was estimated using Real time qPCR with the MIQE guidelines. Materials and Methods: In order to study the effect of silver nanoparticles on microbial activity and bacterial population in a calcareous soil, an experiment was conducted as a completely randomized design based on factorial arrangement with three replications. Experimental factors included silver slat forms (AgNPs and AgNO3), Ag concentrations (0, 0.5, 5, 10, 50, and 100 mg Ag kg-1 dry soil) and incubation time (7 and 42 days). Soil samples (Typic Haplicambids) with clay loam texture and seven percent of calcium carbonate was collected from Research Field of Ferdowsi University of Mashhad, Mashhad, Khorasan Razavi, Iran. The soil samples were amended with different concentrations of AgNPs and incubated at 25oC for 42 days. The water content of soil samples was adjusted at 70% WHC during the incubation time. After 7 and 42 days of incubation, the soil substrate-induced respiration (SIR), heterotrophic plate count (HPC), and soil urease and dehydrogenase activities were measured. Finally, based on the obtained data, the soil biological quality index was estimated using the soil biological parameters. In order to quantify the total bacterial population, DNA was extracted from soil samples and was estimated using the relative concentration of 16S rDNA gene by a quantitative Polymerase Chain Reaction (qPCR), with a minimum information for publication of quantitative real-time PCR experiments (MIQE) guidelines. Results and Discussion: The results showed that with increasing the concentration of both AgNPs and AgNO3, the activity of dehydrogenase and urease in soil samples decreased during the incubation times. Microbial substrate induced respiration (SIR) and the total bacterial population in soil samples considerably declined at the end of experiment. Bacterial population in AgNPs treatments decreased compared to AgNO3 treatments but the reduction was not statistically significant. Over time, soil dehydrogenase activity and soil SIR decreased in both AgNPs and AgNO3 treatments, while soil urease activity and heterotrophic bacterial populations improved but again in heterotrophic bacterial populations was not statistically significant. The soil biological quality index was estimated from the soil biological data. AgNO3 treatments reduced the soil biological quality index compared to AgNPs treatments. In other words, the results showed that AgNO3 was more toxic to soil bacteria activity compared to AgNPs. The lowest soil urease and dehydrogenase enzyme activity and soil biological quality index were observed in the treatment of 100 mg kg-1 dry soil AgNO3 after 7 days of incubation. The application of 0.5, 5, 10, 50, and 100 mg Ag kg-1 dry soil decreased relative soil bacterial population by 22%, 40%, 59%, 73%, and 82% in AgNO3 treatment and 10%, 30%, 68%, 76%, and 86% in AgNO3 treatment compared to control after 42 days of incubation, respectively. Conclusion: The results of this study showed that silver nanoparticles can negatively affect the enzymes involved in the nitrogen and carbon cycle. The AgNPs had less toxicity effect on the soil microbial activity compared to AgNO3. However, AgNPs was more toxic to soil bacteria populations compared to AgNO3. Different behavior AgNPs and AgNO3 in calcareous soil needs more investigations but there is no doubt that AgNPs is as an emerging contaminant and it has high toxicity potential for soil microbial community.
Research Article
Irrigation
S.F. Mousavizadeh; H. Ansari; A. R. Faridhoseini
Abstract
Introduction: In the last decade, satellite-based methods, including remote sensing and microwave methods, have been used in many studies to detect soil surface moisture regionally. Thermal remote sensing method is quite effective for checking moisture for bare soil but shows poor correlation for vegetated ...
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Introduction: In the last decade, satellite-based methods, including remote sensing and microwave methods, have been used in many studies to detect soil surface moisture regionally. Thermal remote sensing method is quite effective for checking moisture for bare soil but shows poor correlation for vegetated surfaces. In addition, there is a widespread use of this method in the presence of temperature differences during the day. Satellite imagery enables the ability to measure humidity according to the environmental conditions at the surface. Thus, compared to field measurements, remote sensing techniques are promising because they are capable of spatial measurements at a relatively low cost. Water supply is one of the main causes of evapotranspiration, which can affect it. Soil moisture can be considered as the most direct and important variable describing drought and is the main parameter describing water circulation and energy exchange between the surface and the atmosphere. Scale reduction methods for soil moisture can be divided into three main groups including satellite-based method, GIS data and model-based methods. The same methods have been used extensively in monitoring soil moisture for different spectral patterns at different wavelengths, from visible to microwave remote sensing data. Spectral reflectance decreases with increasing soil moisture in the visible and near-infrared (NIR) range. Therefore, these methods can be used to estimate soil moisture using satellite data for water budgeting and other meteorological and agricultural applications.Materials and Methods: In this study, using the information provided by Zaki (2013), the measured humidity by the sensor was compared with the humidity obtained from the satellite. The soil moisture were measured in 16 points from an area of 13 hectares from Neyshabour plain of Khorasan Razavi province. The novelty of this study is to provide a simple method for using Landsat 7 satellite imagery to estimate the surface moisture of areas of the Earth to eliminate field sampling and optimal use for agriculture. One of the advantages of this method is the reduction of information obtained from the field as input values for crop modeling that can be used to estimate crop yield, so the moisture measured during the winter wheat crop period from November 2012 to March 2013 was used.Results and Discussion: The placement of band numbers 3 and 4 opposite each other to calculate M, the line equation was fitted. Since satellite imagery is not performed daily by satellite, six images were extracted during the growing season. On November 12, which is actually 12 days after planting, the plant is entering the germination stage and the soil is mostly bare. Because the satellite does not receive enough reflected green light, the accuracy of the image in measuring soil moisture decreases, but after the plant grows, the green light is reflected and the amount of digital digit of band 4 is affected, as a result, the amount of moisture in the plant leaves and stem is involved in measuring soil moisture, which is consistent with the results obtained by Petropoulos et al.Conclusion: In general, the results of this study showed that the simple and efficient Red-NIR spatial geometry model has a great ability to estimate soil surface moisture in favorable weather conditions and this method can be used for plant modeling as input data.
Research Article
Soil science
F. Ebrahimi Meymand; H. Ramezanpour; N. Yaghmaeian Mahabadi; K. Eftekhari
Abstract
Introduction: Delineating landscape into homogenous units is fundamental to managing resources and delivering sustainable development. The importance of this has long been recognized as a critical issue in various studies and it has been examined from different aspects. In soil mapping, the geopedologic ...
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Introduction: Delineating landscape into homogenous units is fundamental to managing resources and delivering sustainable development. The importance of this has long been recognized as a critical issue in various studies and it has been examined from different aspects. In soil mapping, the geopedologic approach is used for landscape classification, which was defined by Zinck (1989). This approach differentiates landscapes into landforms to increase the purity of soil map units. Therefore, the aim of this study was preparing geopedologic maps of the study area on the level of landform phases intending to make more homogeneous soil units.Materials and Methods: Honam sub-basin in Lorestan province is one of the most important agricultural areas in the Karkheh River watershed. Soil moisture and temperature regimes of the area were Xeric and Mesic, respectively. After a primary interpretation, a geopedology map of the study area at the landform level was prepared according to the geopedologic approach. After soil surveying, 31 profiles were excavated, described, and sampled in the largest delineation of this map. Ultimately, this landform unit was differentiated to the landform phase units using morphometric features and normalized difference vegetation index. Pedodiversity index was computed for each landform phase unit to investigate the credibility of the geopedological approach for this unit. The conditional probability of each soil family was also measured in each landform phase unit to compare statistical differences between landform phase units. Furthermore, statistical comparisons were made between the Shannon indices of each unit.Results and Discussion: The soils of the study area were classified into seven soil families according to Soil Survey Staff (2014). Based on the geopedology map, this area includes two landscapes of Piedmont plains and valleys. These two landscapes were differentiated to 6 and 3 relief/molding, respectively. Geologically, the study area has 5 lithologic units. Finally, 22 landform units were identified in this area. The area of the widest landform with the code of Pi461 was 1223.35 ha. With individual use of NDVI, TRI, and aspect map, this landform unit was differentiated into 3 phases, and with the use of these 3 maps collectively, 11 phases were differentiated. The results showed landform map unit of Pi641 with 31 soil profiles and 7 soil families has the highest value of diversity indices, such as 1.59 for the Shannon index. In addition, this map unit is a compound map unit consisting of several soils, where the highest probability of observing soils is related to soils A and B with 32.5% probability. By differentiating this landform unit into phases, the Pi461 map unit is separated into smaller units that are more homogeneous. For example, when it is separated according to the vegetation characteristics, the three phases Pi4611 (N), Pi4612 (N), and Pi4613 (N) were differentiated that have medium, low, and high vegetation, respectively. In this case, Pi4612 (N) map unit with 75% probability of soil C observation and Pi4613 (N) map unit with 87.50% probability of soil B observation are two homogeneous map units. The Shannon index of these two units is 0.56 and 0.37, respectively, which indicates the purity of these map units. The results also showed that diversity indices and conditional probabilities, respectively, were decreased and increased in most of the landform phase map unit compared to the landform map unit. The use of normalized difference vegetation index compared to other environmental features has been effective in separating the landform phase units and preparation of homogeneous map units. So, the most probability of observing the dominant soils of the study area increased from 32.25% in the landform unit to 52.63, 75.75, and 87.50% in the landform phase unit, and the Shannon index decreased from 1.59 in the landform unit to 1.36, 0.56, and 0.37 in the landform phase units. The use of other environmental features to increase the purity of the landform phase map unit is suggested in future studies.Conclusion: Results of using geopedological approach at landform level in the study area showed that this level is useful at highest levels of soil classification (from order to great group), but due to the complex nature of soils at lower levels of classification (family and soil series) does not have enough efficiency. Therefore, for improving the geopedology method accuracy and to present more uniform map units at lower levels of classification, landform phase maps were presented according to the environmental characteristics of the selected landform. The statistical comparisons between Shannon indices calculated for each map unit in the landform phase map showed a significant difference at the 90% probability level between most of the units, which indicates an increase in the purity of these units at the soil family level.
Research Article
Irrigation
M. Mohammadi; M. Akbary
Abstract
Introduction: Sistan and Baluchestan Province, in southeast of Iran, is covering about 11 percent of the whole space of the country but is one of the driest provinces in Iran and its average annual rainfall is about 110 mm. The purpose of this study was to identify large-scale atmospheric circulation ...
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Introduction: Sistan and Baluchestan Province, in southeast of Iran, is covering about 11 percent of the whole space of the country but is one of the driest provinces in Iran and its average annual rainfall is about 110 mm. The purpose of this study was to identify large-scale atmospheric circulation patterns causing extreme and widespread rainfalls during the warm seasons (spring and summer) in southeast of Iran (Sistan and Baluchestan province).Data and Methodology: Precipitation data of 6 synoptic stations of Sistan and Baluchestan province during a 30-year statistical period (1979-1998) were obtained from Meteorological Organization of Iran (IRIMO). The intensity of precipitation based on 90th percentile threshold and widespread precipitation index of at least ≥50% of the studied area were calculated. To identify the synoptic patterns of the upper atmosphere, the ERA5 data of the ECMWF European Center of Med-Latitude Weather Forecast with spatial resolution of 0.25° × 0.25° were obtained. The collected atmospheric parameters included mean sea level pressure (mslp), geopotential height (z), specific humidity (q), zonal (U) and meridional (V) wind components, relative vorticity (rv) and omega (w) and maps of the upper atmosphere were drawn at different levels using Gards software in the domain of 10 to 70E and 10 to 90N. Regarding the two selected characteristics, three events of heavy and widespread precipitation were determined.Results and Discussion: By analyzing the daily rainfall data over a period of 30 years (2018-1988) during the warm months of the year, the number of days with torrential and widespread rainfall in Sistan and Baluchestan province were determined. According to the index the previously defined floods and mudslides were obtained for 3 days with torrential and widespread floods that often occur in the spring, which are categorized to three main patterns including: 1- Gono Tropical Storm 2- Omega Blocking and 3 – 500 hpa trough system. The results showed that during the maximum 24-hour precipitation, in the first synoptic pattern, the southern cities of the province received the maximum precipitation due to the proximity of the storm’s core, but gradually from southern to northern latitudes, the rainfall declined considerably so that Chahbahar station had the maximum rainfall and Zabol station recorded zero rainfall. The storm is expected to move eastward as it moves to higher latitudes, but the high pressure formed on the Indian subcontinent acted as a barrier and directed the storm to the west, thus affecting the southern regions of Iran. In the second and third pattern, the location of Sistan and Baluchestan province in front of the trough axis and advection of cold weather of the northern latitudes were the main causes of instability that lead to heavy rainfall. The moisture of these rainfalls was obtained from Oman, Arabian Sea and Indian Ocean respectively. In the second pattern, the anticyclonic clockwise motions of the Arabian Sea has provided the moisture for extreme precipitation events. Common points of all three precipitation patterns are atmospheric moisture reduction in all three levels of the earth, 850 and 700 hectopascals from south to north of the province. This is mainly due to the distance from moisture sources as well as the arrangement and height of the roughness of Sistan and Baluchestan province, which has caused moisture trapping and prevented the transfer of sufficient moisture for the occurrence of torrential rains. In the second model, the amount of moisture reduction from south to north is less, which indicates the activity of the Arabian Sea high pressure and the power of this high pressure in moisture transfer. In general, with increasing altitude towards the northern regions, mainly rainfall systems have lost their moisture and unevenness has prevented the proper distribution of moisture in the province.Conclusion: In southeastern Iran, the spatial distribution of precipitation is strongly influenced by the proximity to the sea and the location of the topographic features. Upper air levels turbulences are the most common cause of air mass rise. The main factor in reducing heavy rainfalls in northern areas of Sistan and Baluchestan is the lack of sufficient water vapor to reach these areas. Extreme rainfall is more likely to occur in spring than in summer due to the appropriate thermal gradient in southeastern Iran. Finally, the results of the study showed that the possibility of precipitation in spring compared to summer due to the appropriate temperature gradient in southeastern Iran and the activity of Siberian and Northern European high pressure, the conditions for fronting in these areas are provided. Since the humidity of the southern oceans through atmospheric rivers has been effective in the occurrence of heavy rainfall in southeastern Iran, rising temperatures in the southern oceans due to global warming can strengthen moisture flows in the future and from this route to affect the intensity of rainfall in southeastern Iran.
Research Article
Agricultural Meteorology
S.M. Afzali; J. Khoshhal Dastjerdi; A. Torahi
Abstract
Introduction: One of the most critical human issues globally is producing more food for the world's growing population. The climate of each region is an effective factor in the agricultural sector and the amount of its production. Iran is one of the world's date-producing countries, which ranks second ...
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Introduction: One of the most critical human issues globally is producing more food for the world's growing population. The climate of each region is an effective factor in the agricultural sector and the amount of its production. Iran is one of the world's date-producing countries, which ranks second in terms of date production and exports. This plant has 200 genera and 4000 species, each of which can adapt to arid regions and can have the highest production and economic efficiency in its proper place. It is a monocotyledonous plant from the Palmaceae family that needs at least 10 degrees Celsius for continued growth. Growth will stop at temperatures below 10 degrees Celsius, and temperatures below 4 degrees Celsius will encounter cold stress. This plant is sensitive to environmental conditions and cannot live qualitatively and quantitatively in all hot and dry regions. On the other hand, the palm tree is a plant that lives up to several hundred years, and some of its varieties bear fruit up to 200 years old, but their valuable and economic life is on average about 50 years. It is noteworthy that this tree did not produce an economic crop until ten years ago. Dates have an important role in currency exchange, job creation, food security, and strengthening global competitiveness by providing income from non-oil exports. Therefore, the construction of a palm tree is a risky long-term investment in the country. Dates have different varieties, each capable of adapting to a region of arid regions and can produce the most production and economic efficiency in its proper location. Global warming, its impact on different regions of the earth in the future, and the response of the living creatures of these regions in the last century have led planners and scientists of many disciplines, especially climatology researchers, and in particular agricultural climatologists, to understand climate conditions and design long-lived sustainable plants that can survive in future environmental conditions and have good economic returns, design programs, and awareness algorithms.Materials and Methods: One of the best is the maximum entropy model (MaxEnt). By applying this algorithm, it can be predicted how the species will exist in different regions based on the presence of the species. The present study was conducted by field method, descriptive, and library statistics. The data used included WordClim site data (bioclimatic variables), presence data of two cultivars of date palm, Gantar and Halawi, daily meteorological data, elevation, and land slope based on the suitable land slope for palm tree cultivation, high and low temperatures, and phonological data. CCSM4 model with quadratic scenarios of 2.6, 4.5, 6.0, and 8.5 was used to predict and estimate different country regions in terms of talent for cultivation of two selected date varieties. Due to the higher value of AUC in Scenario 4.5, this scenario was considered as the selected scenario. This study is different from previous studies using the CCSM4 climatic model, new diffusion scenarios (RCP), and prediction of date distribution concerning its cultivars, while previous studies on prediction of date distribution have not paid any attention to it.Results and Discussion: The results showed that the distribution and cultivation area of Gantar and Halawi are different, and in the future, the suitable area of cultivation of Gantar cultivar will decrease, and the suitable area of cultivation of Halawi cultivar will increase. Jacknife test showed that the model successfully predicted the potential of cultivation area based on the AUC criterion and temperature-related biological variables (Bio 1, Bio 6, Bio 8, and Bio 10) had the most significant impact on the distribution modeling of cultivars. Therefore, with the rising temperature, parts of the country, especially the foothills of the plains, become more susceptible to cultivation. So that at present, when the maximum height for the optimal growth of cultivars is about 700 meters, it will reach about 1200 meters in the coming decades. At present, Iranshahr city in Sistan and Baluchestan province has the most desirable area of Gantar and Halawi cultivar cultivation. However, in the next decade, the most desirable cultivation area will be the Gontar cultivar in Ahvaz city and Halawi cultivar in Jask city. It was also found that using WorldClim site data for perennial and especially long-lived plants was not sufficient. Because in these data, high and low temperatures that can destroy the plant during its life or shorten its life and reduce the economic fruit of cultivation are not included, and of course gardening and fruit trees are a long-term investment. The risk of investing should not be increased.
