Research Article
,fatmeh hashami; Ali Shahnazari; mahmood raeini; ali ghadami firouzabadi; Ebrahim Amiri
Abstract
The research as reported in related to simulation by WOFOST, predominately focused on traditional methods of deficit irrigation such as terms of percentage in full irrigation conditions or as evaluation of growth and development in certain days after irrigation. Also it should be noted that not only ...
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The research as reported in related to simulation by WOFOST, predominately focused on traditional methods of deficit irrigation such as terms of percentage in full irrigation conditions or as evaluation of growth and development in certain days after irrigation. Also it should be noted that not only these researches was based on a year plants, but also there isn’t any research of sunflower. So, in this research the ability of the last version of WOFOST in simulating of sunflower in DI and PRD in %75 and %55 levels is carried out in contrast to FI in two continued year so that crop coefficient of sunflower could be calculated and by this, the productivity of yield in Sari agricultural and natural resources research field could be achieved. The results of calibrations showed that crop coefficient which depends on weather, coordinates of region and physiologic and phonologic of plant is fixed among the simulation and irrigation coefficient are depend on irrigation treatment and their response in development of growth stages. Also the results showed that by decreasing the volume of water which given to plant, AMAXTB and KDIFTB decreased and adversely EFFTB is increase. Simulated seed yield and total biomass had normalized root mean square error (nRMSE) index less than 10%, coefficient of residual mass (CRM) index near zero, modeling efficiency (EF) about 0.98, correlation coefficient (R) about 0.96 and totally comparing the simulation and observation parameters showed that in the most statistical test done in the present study, the result in acceptable range which represented that WOFOST could be able to simulate the responses od sunflower in DI and PRD treatments by calibrated coefficient.
Research Article
abdolmajid liaghat; masoud Pourgholam amiji; pourya mashhouri nejad
Abstract
Introduction: With due attention to the limitation of water resources in Iran and specific geographical conditions of the country, using modern methods of irrigation with low water usage is inevitable. By applying suitable management in water system, soil and plant, while increasing product, we can establish ...
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Introduction: With due attention to the limitation of water resources in Iran and specific geographical conditions of the country, using modern methods of irrigation with low water usage is inevitable. By applying suitable management in water system, soil and plant, while increasing product, we can establish a sustainable agriculture. Today, subsurface irrigation systems are used in various methods around the world, especially in the countries encountering water shortage. One of the newest methods is applying sponge plastic pipes such as tuporex which is installed in the area of plant root. Then, water with the pressure of 0/6-2 atmosphere flows inside it and by exuding, it dampens the area.
Materials and Method: For this purpose, in this study number of 12 concrete lysimeters with the dimension of 2×2×1/25 m was used to investigate the effect of vegetation (mulch) on the efficiency of water consumption and product function for corn, salt accumulation as well as the amount of nitrate wash on soil profile under two permeable subsurface irrigation and surface irrigation. For irrigation, a body of water with salinity of 4 ds/m was used. The plan includes two main treatments (permeable subsurface and surface irrigation) and two sub-treatments (mulch and without mulch) withfactorial experiment in a randomized complete block design with three replications at the College of Agriculture Research Campus, Tehran Universityof technology Located in Karaj, Iran in 2010. Surface irrigation was performed based on the moisturein the soil and permeable subsurface irrigation was performed per dayas much water as was consumed.. Lysimeters soil is prepared from farm soil and through examination, its appearance special weight was registered to be 1.4 gr per cm3 equals to 1400 kg per m3. The amount of nitrogen fertilizer (Urea) was applied on the lysimeters according to the region convention, was 300 kg per hectare (120 gram per each lysimeter(. A half of this amount was used at the time of cultivation and another half was used for the plant 60 days after cultivation; because the amount of water given in this type of system is higher.On the other hand due to the lack of vegetation, the significant amount of evaporated water and water productivity have decreased.
Results and Discussion: Results disclosed that the subsurface irrigation system has important effect in decreasing consumed water (58% with mulch and 40% without mulch) and increasing crop yield (46% in seed corn yield, 50% in forge yield and 12% in weight of one thousands seed corn) in comparison with the surface irrigation system. As well as the subsurface irrigation has prevented lower soil layer from contamination and being salty by decrease salt and nitrate leaching. Besidespresence of mulch in lysimeterhas shown important role in decreasing water consumption and seed corn yield. The important thing is that the highest yield in two type of performance, was recorded in subsurface irrigation treatment with mulch (TM) and this subject is so important when we remind that (TM) treatment had the least amount of water uses. Itmeans that with the least amount of water consumed the highest amount of product was obtained among the treatments.On the other hand, surface and non-mulching (SO) irrigation is expected to have the lowest yield per unit water consumption.
Conclusions: Also in both subsurface irrigation with preamble tube and surface irrigation system, existence of mulch caused to decrease salt concentration to 40% and 30% in soil surface respectively which makes it suitable for the areas facing water shortage. It can be concluded that, existence of mulches in the both subsurface irrigation with permeable tube and surface irrigation system causing water saving 13 and 23 percent, respectively and the rate of saving water in surface irrigation system with presence of mulch has also increased. Thus, it is recommended that some of the plant residuals, like mulch remain on the ground after harvest. The subsurface irrigation with permeable tube system has been prevented from washing nitrate to the depths of the soil. As a result, the environmental pollution caused by nitrate losses in this system is minimal and this system saves fertilizer. Also the concentration of salt solution in the soil profile in subsurface irrigation system was significantly lower than the salt concentration in surface irrigation. As a result in areas that use the saline water for irrigation, the subsurface irrigation with preamble tube confirm better function than surface irrigation system and use mulch can increase yield and reduce leaching.
Research Article
P. Daneshpazhoh; A. R. Ghasemi; Mohamad reza Nori Emamzadeie; R. Barzegar
Abstract
Introduction: Optimal water utilization is one of the most important challenges of the present century. Due to limited water resources and the existence of alternate droughts in the country, optimal use of it is necessary. The deficit irrigation technique is one of the most effective and practical ways ...
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Introduction: Optimal water utilization is one of the most important challenges of the present century. Due to limited water resources and the existence of alternate droughts in the country, optimal use of it is necessary. The deficit irrigation technique is one of the most effective and practical ways in which it can determine and justify the minimum water consumption with acceptable economic performance. Its use in reducing water consumption for biomass production and for irrigation of annual and perennial crops. To effectively apply water deficit management, an understanding of the effects of irrigation at different stages of vine growth is required. Partial Root-zone Drying (PRD) is also one of the new irrigation techniques over the past years. The results of many studies indicate that water use efficiency has increased and there is no significant reduction in the yield in this irrigation method. In this technique, only half of the roots are irrigated at each turn and the remaining half remains dry. On the other hand, in recent years, the use of natural minerals has improved in order to improve the physical and chemical composition of the soil, which leads to an increase in water holding capacity in the soil. One of the methods for increasing the water use efficiency is the application of water absorbent materials in soil. Super absorbent polymer increases the water saving in soil and decreases the amount of water used for irrigation. Zeolite is one of these minerals that increases the soil water holding capacity. So far, many studies have been carried out on the use of PRD, as well as the use of zeolite, but none has examined the effect of these two simultaneously. Therefore, in the present study, the efficiency of both above method and deficit irrigation on yield and water use efficiency of sweet pepper were investigated.
Materials and Methods: This research was carried out in a completely randomized design with 9 treatments and 4 replications in a greenhouse in Shahrekord University. This study was carried out at three levels of irrigation of 100%, 75% and 50% of the water requirement of the plant by Partial Root-zone Drying and zeolite in two levels of 2 and 4% by weight in the soil, in one and two sides of the pots with a height of 30 and diameter 28 cm. After preparing the culture medium, the F1 type Lummus seedlings were transferred to the pots. During the transfer of transplants into the pot, careful attention was paid to the fact that the roots were developed on both sides. Physiological parameters such as leaf area, total fresh and dry weight of the whole organ, total fresh weight of fruit, diameter and number of fruits and chemical indices including vitamin C, pH, total soluble solids and chlorophyll a, b and total chlorophyll with water use efficiency were measured and evaluated. In order to analyze the results, SAS software (version 1/9) was used. Mean comparison was also performed by LSD test.
Results and Discussion: The results of this study showed that there was a significant difference in the 1% level for fresh and dry weight, fresh weight of fruit and chemical indices of vitamin C, pH and soluble solids, and a significant difference at 5% for diameter fruit and chlorophyll. The results of comparing the meanings showed that fresh weight and fruit diameter were significantly decreased in all treatments than control. The number of fruits in severe irrigation (50%) and in both levels of zeolite showed a significant decrease compared to control. Vitamin C value as an important indicator of fruit quality in all treatments was significantly higher than control, in other words water stress causes an increase in the amount of vitamin C in the fruit, and the amount of pH in the most treatments has decreased significantly compared to the control treatment.
Conclusion: Given that all important processes such as photosynthesis, nutrition, opening and closing of stomatal and plant growth and development are under the influence of water, most of the studied traits in this research (except chlorophyll) in zeolite-containing treatments, showed a significant advantage over non-consumption of zeolite. The results also showed that application of PRD method with zeolite in deficit irrigation resulted in significant increase in water use efficiency in all treatments.
Research Article
F. Mondani; B. Gholami; A.R. Bagheri; Gh.R. Mohammadi
Abstract
Introduction: The DSSAT model is one of the most general and extensively used process-based crop growth simulation models. This model has been used worldwide to simulate crop biomass, yield, and soil nitrogenleaching under different management practices and various climatic conditions. Among management ...
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Introduction: The DSSAT model is one of the most general and extensively used process-based crop growth simulation models. This model has been used worldwide to simulate crop biomass, yield, and soil nitrogenleaching under different management practices and various climatic conditions. Among management agronomic factors, nitrogen fertilizer has a major effect on crops production. However, nitrogen fertilizer limiting causes to decrease crops production, but, high application rates of nitrogen would led to strong environmental consequences. Thus, management of nitrogen fertilizer consumption causes to decrease environmental pollution in the agroecosystems. Therefore, the objectives of the present study were: (1) determination of genetic coefficients and calibration of the CERES-Wheat modelof DSSAT-CSM, (2) evaluation the performances of model forsimulating wheat growth, development and grain yield and (3) simulationof changesof soil and plant nitrogen in different fertilizer nitrogen application rates under Kermanshah climate condition.
Materials and Methods: Two experiments were established based on the randomized complete block design with three replications during 2015-2016. The treatments were included 4 levels of nitrogen fertilizer application (90, 180, 300 and 360 kg ha-1 urea). The required model inputs describe field management, daily weather condition, soil profile characteristics, and cultivar characteristics. The cultivar coefficients calibrated under optimum conditions (i.e., minimum stress in weather and nutrients). The genetic coefficients (P1V, P1D, P5, G1, G2, G3 and PHINT) of the Pishtaz wheat cultivar were derived using the GenCal software of DSSAT v 4.6 for 300 kg Urea ha-1 treatment (optimum condition of nitrogen fertilizer based on the results of soil library). After model calibration process, the CERES-Wheat model validated by comparing simulated and measured values of wheat cultivars phenologicaldevelopment stages (DVS), leaf area index, total dry weight and grain yield for treatments of 90, 180, 300 and 360 kg Urea ha-1 fertilizer by root mean square error (RMSE), normalized RMSE (nRMSE) and index of agreement (d) by results ofan independent experiment from calibration experiment.
Results and Discussion: The results indicated that the coefficient P1V was 54.45 °C day, the coefficient P1D was set 90.75 days hr-1, the value for P5 was 720 °C day, the value for G1 was 25, the values for G2 was 30 mg day-1, the value for G3 2 g, and the PHINT was 95°C day. The calibration results showed that the CERES-Wheat model was able to simulate growth, development stages and yield correctly, which indicate high accuracy in calculated genetic coefficients derived using the GenCal software of DSSAT v 4.6. In the simulated and measured conditions, leaf area index, total dry weight and grain yield improved by increasing of nitrogen fertilizer application. In the simulated and observed conditions, the highest grain yields were 7048 and 7874 kg ha-1 in the treatment of 360 kgnitrogen ha-1 and the lowest grain yields were 4006 and 4217 kg ha-1 in the treatment of 360 kgnitrogen ha-1, respectively. The validation results also indicated that the CERES-Wheat model had high ability to predictg growth, development stages and grain yield in the different fertilizer nitrogen application rates. So that, the RMSE fordevelopment stages were about 3 to 4 days and the nRMSEwere about 7 to 8% of measured average, respectively. The index of agreement (d) for development stages was about 0.99. The RMSE for total dry weight were about 360 to 720 kg ha-1 and the nRMSE were about 5% to 9% of measured average, respectively. The index of agreement (d) for total dry weight were about 0.94 to 0.99. The amount RMSE for grain yield were 304 to 630 kg ha-1 and the nRMSE were 11% to 17% of measured average, respectively. The index of agreement (d) for grain yield ranged from 0.98 to 0.99. The simulation result also indicated that amount of soil NO3 and NH4 increased with nitrogen fertilizer application. The highestsoil NO3 were 41.3, 54.5, 72.1 and 80.9 kg ha-1 in the treatments of 90, 180, 300 and 360 kg Urea ha-1, respectively. The amount of nitrogen leaching increased with rising of nitrogen fertilizer. The nitrogen leaching were 259.3, 276.2, 310.4 and 335.5 kg ha-1 in the treatments of 90, 180, 300 and 360 kg Urea ha-1, respectively. The amount of nitrogen in the wheat biomass improved by increasing nitrogen fertilizer application.
Conclusion: The results indicated that the CERES-Wheat calibrated correctly that confirm calculated genetic coefficient for Pishtaz cultivar under Kermanshah climate conditions. The results of validation also showed that the CERES-Wheat model was able to simulate all studied traits wheat cultivars except leaf area index accurately in different fertilizer nitrogen application rates. Excessive nitrogen consumption led to nitrogen leaching and groundwater pollution. Therefore, it is important to know the distribution of various forms of nitrogen and how they move in the soil.
Research Article
MirHassan Rasouli-Sadaghiani; Roghayeh Vahedi; Mohsen Barin
Abstract
Introduction: Millions of tons of trees pruning waste are produced annually in Iran, which can contribute to supplying soil organic matter. Soils in arid and semi-arid regions, due to lack of sufficient vegetation and the return of low amounts of plant residues to the soil, contain little organic matter. ...
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Introduction: Millions of tons of trees pruning waste are produced annually in Iran, which can contribute to supplying soil organic matter. Soils in arid and semi-arid regions, due to lack of sufficient vegetation and the return of low amounts of plant residues to the soil, contain little organic matter. These soils are often calcareous, and as a result, many plants in these soils are faced with nutritional problems, especially phosphorus deficiency. Phosphorus, as an essential element for plant growth, combines with soil components and changes into less soluble and insoluble compounds in calcareous soils with low amounts of organic matter. Organic matter and biological amendments can affect the solubility and mobility of nutrients in the rhizosphere and improve their bioavailability by creating different chemical and biological conditions. The pruning waste of trees can be used to produce biochar and compost and consequently improves soil physical and chemical properties and plays an important role in the dynamics and living of soil microorganisms. Biochar is a carbon-rich solid material produced during pyrolysis which is the thermal degradation of biomass under oxygen limited conditions. It has recently received much attention as a soil amendment which can be used to increase nutrient availability, improve the soil microbial diversity and biological activities such as enzyme activity in rhizosphere and sequester carbon in agricultural soils. In addition, compost is a chemical derived product from organic waste and contains many beneficial elements that are gradually released into soil and available to plants. Another approach to improve the bioavailability and mobility of phosphorus in the rhizosphere is the use of potential of phosphate-solubilizing microorganisms including arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR). Limiting the roots to examine the biological and chemical changes and the extent to which these properties have expanded in the rhizosphere are challenges that have been less addressed .Rhizobox is one of the systems used to study rhizosphere changes. The aim of this study was to investigate the effect of biochar and compost prepared from pruning waste of apples and grapes trees as well as microbial inoculation on phosphatase activity and phosphorus availability at wheat rhizosphere under rhizobox condition.
Materials and Methods: This study was carried out on a completely randomized design with a factorial arrangement in three replications, under greenhouse condition in rhizobox. The factors were organic matter (pruning waste biochar (PWB), pruning waste compost (PWC) and control (without organic matter)), microbial inoculation (AMF and PGPR) and soil type (rhizosphere and non-rhizosphere soil). For this purpose, a soil sample with light texture and low available phosphorus content was prepared. PWB used in the experiment was produced from mix pruning waste of apple and grape at the final temperature of approximately 350°C for 3 hours. Moreover, pruning waste compost of apple and grape trees was prepared from Department of Soil Science, Urmia University. The biochar and compost were ground and screened through a 0.5 mm sieve for the greenhouse experiment. The seeds of wheat were planted in 20 × 15 × 20 cm rhizobox (length, width and height). At greenhouse experiment, the biochar and compost were added to the boxes in terms of 1.5% pure organic carbon before planting (each box contained 5.8 kg of soil). In control treatments (without organic matter), sterile soil was used with microbial inoculation. Microbial strains used for inoculation included Pseudomonas aeruginosa, Pseudomonas fluorescens and Pseudomonas putida) and mycorrhizal fungus (Glomus fasciculatum). Wheat seeds (Triticum aestivum L. cv. Pishtaz) were grown in rhizobox. At the end of the vegetative growth period, acid phosphatase (ACP) and alkaline phosphatase (ALP) enzymes activities were asseyedassayed by spectrophotometry method. Soil available P was extracted with 0.5 M NaHCO3 (Olsen-P) in the rhizosphere and non-rhizosphere soils and phosphorus concentrations in the root and shoot were determined by the standard method.
Results and Discussion: The results showed that the application of PWC and microbial inoculation significantly increased ACP and ALP enzymes activity and the availability of phosphorus compared to the control. The highest increase in ALP enzyme activity and available phosphorus was observed in PWC treatment inoculated with PGPR. Furthermore, PWC increased the ACP and ALP enzymes activities in the rhizosphere soil by 1.39 and 1.33 times compared to non-rhizosphere soil, respectively. However, phosphorus availability in the non-rhizosphere soil of the PWC treatment was 21.19% higher than that in the rhizosphere soil. The lowest available phosphorus content was observed in rhizosphere soil of AMF treatment. In addition, the highest phosphorus concentrations in plant root and shoot were, respectively, found in the compost and biochar treatments inoculated with AMF. In PWB treatment, the inoculation of AMF increased shoot phosphorus concentration by 1.31 times relative to PGPR inoculation.
Conclusions: In general, applying organic matter and microbial inoculation had a significant positive effect on phosphorus availability and plant growth. Adding organic matter to the soil, such as compost and inoculation with microorganisms particularly PGPR bacteria in the root zone, led to increased soil available phosphorus. The activity of phosphatases in soil was influenced by using organic materials such as compost and microbial inoculation which enhance the bioavailability of inorganic phosphorus. More positive interaction of PWC and PWB with AMF than PGPR in the rhizosphere caused greater increase of phosphorus bioavailability in the root zone and plant phosphorus uptake. In general, according to the results of this study, it seems that the use of organic materials and biological potential of the microorganisms have a significant effect on phosphorus availability and improve plant growth.
Research Article
Jafar Sharifi Garmdareh; farhad khormali; Christian Rolf; Martin kehl; Ali shahriari; Manfred Frechen
Abstract
Introduction: The study of the northern Iranian loess is important since they are located in the middle of the Asian and European loess belt. In addition, presence of a climatic gradient i.e. increases in rainfall from north to south and from west to east, and the constant temperature, provide a unique ...
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Introduction: The study of the northern Iranian loess is important since they are located in the middle of the Asian and European loess belt. In addition, presence of a climatic gradient i.e. increases in rainfall from north to south and from west to east, and the constant temperature, provide a unique area to study climate change and environmental conditions. There are many recent studies on loess-palaeosol sequences in this region, that show the grain size variation and clay mineralogy changed with increasing precipitation. The purpose of this study was to investigate the trend of grain size variations and clay mineralogy in this climatic gradient to infer origin of the surface loess in this region.
Methods and Materials: Grain size and XRD analyses were carried out on six soil profiles extending from low precipitation in DashliBorun (200mm) to high precipitation in SeyyedMiran (670mm) regions. The grain size analysis was carried out with Beckman-Coulter LS 13320 PIDS. The device uses the principle of the forward scattering of monochromatic light and its diffraction under a certain angle. The angle of diffraction is inversely proportional to particle size. That means coarser particles cause a smaller angle of diffraction compared to finer particles. This method is quick, its results offer a good reproducibility and the data are digital and direct. Necessity for only small amounts of sample material, and covering a wide range from 0.4 to 2000 mm in diameter are other advantages of this method. Nevertheless, the amount of clay percentage may be subjected to certain underestimations because particles smaller than 0.4 μm diffract light in all directions that can cause problems with detecting the signal correctly. Hence the sum of particles with less than 5.5 mm in diameter were chosen as an estimate of clay percentage. Clay fractions were separated based on the methodology outlined by Kittrick and Hope (1963) and Jackson (1975). The carbonates were initially removed using 1 N sodium acetate buffered at pH 5. The organic matter was then oxidized by treating the carbonate-free soils with 30% H2O2, and digestion in a water bath. Free iron oxides were removed from samples by the citrate dithionate method of Mehra and Jackson (1960). The clay separates were removed by centrifuge and studied by a Bruker D8 Advance X-ray diffractometer. Clay minerals were estimated semi-quantitatively from the relative x-ray peak areas of glycol-treated samples.
Result and Discussion: The grain size analysis by laser diffraction method showed that the amount of clay (12.09 %) and fine silt (7.03%) in the soil located in Dashlibron (200 mm/yr) profile had the lowest amount and the U-ratio (6.35) and the medium grain-sized particle (48.28 µm) had the highest amount during this climatic gradient. Increasing precipitation had clear impact on theses parameters, so that the maximum amount of clay (36.56 %) and fine silt (28.02%) and the minimum amount of U-ratio (1.00) and the average medium grain size (8.78 µm) were observed in SayedMiran profile with the highest precipitation (670 mm/yr). Clay mineralogical study of soil parent material showed mica, chlorite, kaolinite and smectite as dominant minerals in the soils. As the amount of precipitation increases along the climate gradient, the amount of pedogenic vermiculite and smectite increase. Silt minerals included quartz, plagioclase, potassium feldspar, mica, chlorite and calcite. The amount of quartz, plagioclase or potassium feldspar minerals did not change in parent materials. The average medium grain size and U-ratio are function of the maximum wind speed and distance from the source. In addition, weathering can affect the size of the particles and cause changes in the mineralogy and amount of minerals in the size of the silt and clay fractions. On the other hand, understanding the changes of clay minerals can provide origin-dependent changes, transport processes, and climatic variations as they are recorded in these minerals.
Conclusion: In general, it can be concluded that the medium grain size and U-ratio decreased from low rainfall regions to higher rainfall and clay and fine silt contents showed a reverse trend. Clay minerals included mica, chlorite, and kaolinite and dominant silt minerals were quartz and plagioclase in all studied soil profiles along the climatic gradients. The results showed that changes in grain size reflect the distance from the loess material sources and also indicate intensity of pedogenic processes. Mineralogical analysis showed the similar mineral types in all loess parent materials of different regions, probably indicating the similar sources for the loess. The change in minerals abundances in the upper horizons indicate the pedogenic processes affected by climatic conditions along the climate gradient.
Research Article
Sheler Eskandari; kamal nabiollahi; Ruhollah Taghizade-Mehrjardi
Abstract
Introduction: Soil organic carbon is one of the most important soil properties which its spatial variability is essential to crop management, land degradation and environmental studies. Investigation of variability of soil organic carbon using traditional methods is expensive and time consuming. Therefore, ...
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Introduction: Soil organic carbon is one of the most important soil properties which its spatial variability is essential to crop management, land degradation and environmental studies. Investigation of variability of soil organic carbon using traditional methods is expensive and time consuming. Therefore, one of the ways to overcomethis challenge is using digital soil mapping whichcan predict soil characteristics using auxiliary data and data mining methods. Previous studies have shown that digital elevation model (DEM) and remotely sensed data are the most commonly useful ancillary data for soil organic carbon prediction. Artificial neural network (ANN) is a common technique of digital mapping. The region of Marivan in Kurdistan province is one of the forested areas inIran. In recent decades, due to population growth and the increased need for food, thisforested area has been threatened and some parts are now cultivated. Therefore, accurate mapping of soil organic carbon so as to improve land management and prevent land degradation is necessary. The purpose of this research wasusing ANN model and auxiliary data to mapsoil organic carbon.
Materials and Methods: The study area is located in Kurdistan Province, Marivan(cover 20000 ha). Soil moisture and temperature regimes are Xeric and Mesic, respectively. Elevation also varies between 1280 and 1980 m. The main land use typesarecropland, forestland and wetland. The major physiographic units are piedmont plain, mountain and hills with flat to steep slopes. Using stratified random soil sampling method, 137 soil samples (for the depth of 0-30 cm) were collectedand soil organic carbon were measured. In the current study,auxiliary data were terrain attributes and ETM+ data of Landsat 7. Terrain parameters (including 15 factors), bands 1, 2, 3, 4, 5, 6, 7, brightness index (BI) and normalized difference vegetative index (NDVI) were computed and extracted using SAGA and ArcGIS software, respectively. ANN model was applied to establish a relationship between soil organic carbon and auxiliary data. Finally, soil organic carbon weremappedusing ANN and validated based oncross validation method. Three different statistics were used for evaluating the performance of model in predicting soil organic carbon, namely the coefficient of determination (R2), mean error (ME) and root mean square error (RMSE).
Results and Discussion: Based on sensitive analysis of ANN model, auxiliary variables includingwetness index, index of valley bottom flatness (MrVBF), LS factor, NDVI index, and B3were the most important factors for prediction of soil organic carbon. The quantities of R2, ME and RMSE calculated for ANN model were0.80, 0.01 and 0.67, respectively.Soil organic carbon content ranged from0.26 to 8.45 % and the highest contentwasobserved in forestland with hill and mountain physiography and wetland around the lake. It is noteworthy that the differences fordifferent land uses were not statistically significant. Auxiliary data including wetness index, index of valley bottom flatness, LS factor, and B3 in different land uses had statistically significant difference (p
Research Article
S. Jafari; Ardavan Ghorbani; K. Hashemimajd; S. Ghafari
Abstract
Introduction: Soil is one of the important components of rangeland ecosystems. Soil is the natural and dynamic layer of the earth that act as an important component of rangeland ecosystems for the human food security and plants mechanical support which is the background for growth of them. Soil degradation ...
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Introduction: Soil is one of the important components of rangeland ecosystems. Soil is the natural and dynamic layer of the earth that act as an important component of rangeland ecosystems for the human food security and plants mechanical support which is the background for growth of them. Soil degradation decreases the potential of rangeland production; because soil is the primary factor for forage production in any rangelands with any kind of weather. Different grazing intensities change the chemical and physical properties of soil and plant composition of rangelands. It is important to know soil properties for the proper management of rangeland ecosystems. Therefore, this study was carried out with the objective of investigating the effects of grazing intensity on soil physical and chemical properties in Moghan rangelands using grazing gradient framework.
Materials and Methods: Three villages of Tolklo, Kolash and Panjalo were selected as the representatives of grass-shrubland in Moghan rangelands, in Parsabad county, Ardabil province, northwest of Iran. Samples were collected from three grazing intensities and three distances from the center of villages, as the critical center. Three soil samples were taken at each distance of village (three replications) from 0 to 30 cm (main root activity areas) depth (27 samples). Soil parameters including pH, electrical conductivity, saturated water content, dissolved sodium, potassium, calcium, magnesium, exchangeable potassium, available phosphorus, calcium carbonate equivalent, organic carbon, particulate organic carbon, dispersible clay, total nitrogen, aggregate mean weight diameter and soil texture were measured. To identify the trend of changing soil parameters in different grazing intensities including light, moderate and heavy, weighted average was taken for each three samples, which were collected from the three-grazing intensity at each village. Data statistically analyzed by using the Two-way analysis of variance and using Duncan’s multiple range test.
Results and Discussion: The results of the soil data analysis showed that except dissolved sodium and potassium, lime and soil silt percentage, there was no significant statistical difference between measured values of soil properties in different grazing intensities in Moghan rangelands. The result of the mean comparison for soluble sodium and potassium, lime and soil silt percentage showed that with increase of grazing intensity, the values of soluble sodium decreased. In addition, at the nearby of critical center and with the increase of grazing intensity, the values of soluble potassium increased. However, its highest and lowest amount was observed at the heavy grazing intensity and moderate grazing intensity, respectively. The highest and lowest amount of lime were also observed at the heavy and light grazing intensity, respectively. In other words, in nearby to critical center and with the increase of grazing intensity the value of these parameters increased. The results of the data analysis for soil texture showed that in both areas with the light and moderate grazing intensity, soil texture class was silty clay loam, but in the areas with heavy grazing intensity, soil texture class had gradually changed from silty clay loam to loamy texture. In other words, the soils had progressed to sandy soils, which is due to the change in their silty particles. With approaching to the critical center and with increase of grazing intensity the value of silt percentage decreased. The highest amounts of silt percentage were related to the light and moderate grazing intensities and its lowest amount was recorded in heavy grazing intensity. Results showed that the effects of heavy grazing on soil properties in the grazing gradient framework is detectable, and this framework can be sued for rangeland monitoring to detect the rangeland condition.
Conclusion: Heavy grazing and overall utilization of rangelands have caused soil degradation in most rangelands of Iran. This study revealed that heavy grazing jeopardized the sustainability of the rangeland ecosystem by creating unfavorable changes in soil and avalable minerals. Therefore, it recommended that soil parameters must be included in rangeland inventory and monitoring to use soil information for sustainable range management and, particularly in rangeland restoration and to select sustainable strategies for better and suitable management of these rangelands.
Research Article
Seyyedeh Zohreh Taghdisi heydarian; Reza Khorassani; Hojat Emami
Abstract
Introduction: The amount of soil nutrients and their availability for plants are the important aspects of soil fertility. Although micronutrients are used by plants in very small amounts, they play an active role in many plant-based processes and reactions influencing the plant growth and yield. The ...
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Introduction: The amount of soil nutrients and their availability for plants are the important aspects of soil fertility. Although micronutrients are used by plants in very small amounts, they play an active role in many plant-based processes and reactions influencing the plant growth and yield. The efficiency of absorption of micronutrient can be increased by adding some organic and mineral materials to soil. Saha et al. (41) observed an increase in micronutrient concentration of corn grain by adding organic materials to soil. Zeolite is one of the most commonly minerals used to increase agricultural production (17). The zeolites, due to their structure and porosity, are well-suited for retaining the nutrients and gradually releasing them into the root zone (40).Despite the positive effects of zeolite on some physical and chemical properties of soil, its application at high levels may adversely affect the absorption of nutrients and plant growth. Hamidpour et al. (18) who used zeolite for Zinnia flower, reported that zeolite reduced the yield of Zinnia flower. Basari et al. (4) reported that zeolite application increased soil pH and electrical conductivity (EC). Therefore, this research was carried out with the aim of assessing the influence of zeolite application, type (i.e. vermicompost and cow manure) and organic matter levels on the growth and the micronutrients uptake and determining the appropriate composition for corn.
Materials and Methods: A factorial experiment was conducted in a completely randomized design with three replications in greenhouse under controlled condition.The treatments consisted of raw zeolite (natural) in three levels (0, 6, 12% by weight), organic matter including vermicompost in three levels (0, 0.125, 0.25% or 0, 5, 10 t ha-1) and cow manure at three levels (0, 0.5, 1% by weight or 0, 20, 40 t ha-1).The soil was collected at a depth of 0-30 cm from the Mashhad Soil and Water Research Center. General soil characteristics and micronutrients concentration (iron, zinc and manganese) were determined according to standard methods (14, 27). For vermicompost and cow manure, some parameters such as pH and EC, organic carbon (46), available phosphorus and potassium (21), total nitrogen (7) and micronutrient (iron, zinc and manganese) were also measured (21). Further, pH, EC and micronutrient (iron, zinc, and manganese) were measured for natural zeolite (27). The pots were prepared by mixing 5 kg soil and experimental materials. N, P, and K were added according to soil testing. Irrigation with distilled water at field capacity level was done during the growth period. The plants were harvested75 days after sowing and after separating shoot and root, the plant materials were transferred to laboratory. Root and shoot dry weight were determined and after dry digesting of plant materials, the concentration of micronutrient were quantified by Atomic Absorption (21). The soil samples were also analyzed in order to determine the chemical properties of the soil after harvesting. Statistical analysis of the data was performed using JMP software and the mean comparison was carried out based on LSD test at 5% probability level.
Results and Discussion: The results of the experiment showed that increasing zeolite levels reduced dry weight, decreased height and uptake of zinc, iron and manganese and increased soil pH and iron and manganese concentrations. In addition, it was observed that the zeolite application had a negative effect on the plant growth and micronutrients uptake. Burriesci et al. (8) concluded that the zeolite application without fertilizing seems not to considerably increase plant growth. According to Kimberly and Nelson (24), the use of natural zeolite, without adding nutrients, leads to a competition between plant roots and zeolite for the nutrients absorption. Sarmetzidis et al. (42) showed that zeolite had no effect on the growth and yield of roses. Kolar et al. (25) reported that increasing the amount of zeolite in the geranium cultivar increased pH and the plants growth. At lower levels of zeolite, shoot fresh and dry weight was larger than that in higher levels of zeolite. Our results also denoted that the maximum amount of plant dry weight, plant height, the micronutrient (zinc, iron and manganese) uptake and the lowest soil pH were observed for the treatment of cow manure (1 %) in the absence of zeolite which had a significant difference relative to other treatments and also control. Shirani et al. (44) reported that the application of cow manure significantly increased corn dry matter. Ortiz and Alkaniz (36) showed that using organic fertilizers enhances the amount of absorbent metals such as iron, zinc and manganese as these metals are in a soluble and exchangeable form in these fertilizers. By releasing organic acids, the organic fertilizers, especially cow manure, reduce the localized pH of soil and increase the iron uptake by plants during the mineralization process.
Conclusion: According to the results, the use of zeolite increased soil pH, decreased corn growth and micronutrient uptake. Applying organic materials with zeolite can reduce the mentioned negative effect of zeolite. Cow manure at lowest level was more efficient than vermicompost at all levels. Overall, adding cow manure can improve the plant growth and micronutrient uptake by plant when the zeolite is intended to be used to modify soil physical characteristic.
Research Article
Parvin Kabiri; hamid reza motaghian; Alireza Hosseinpur
Abstract
Introduction: Anthropogenic activities have transformed the global geochemical cycling of heavy metals. Mine tailings are of great concern due to the detrimental effects of toxic inorganic elements causing environmental risks. Zinc (Zn) as an essential element is required in small amounts for various ...
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Introduction: Anthropogenic activities have transformed the global geochemical cycling of heavy metals. Mine tailings are of great concern due to the detrimental effects of toxic inorganic elements causing environmental risks. Zinc (Zn) as an essential element is required in small amounts for various biochemical reactions and physiological functions. However, high concentrations of Zn can induce oxidative stress. Applying an organic amendment is a promising, in situ phytostabilization approach to alleviate the phytotoxic effects of heavy metal in contaminated soils. The application of biochar as an amendment may be a solution to reduce the risk of pollutant diffusion. Biochars is a fine-grained biological residue combusted under low oxygen conditions, resulting in a porous, stable carbon-based material. The potential biochar applications include carbon sequestration, soil fertility improvement, and pollution remediation; therefore, it can reduce pollutants mobility and bioavailability.
Materials and Methods: Results of this research indicated that biochars decreased Zn concentration in maize shoots and roots. They reduced Zn concentration in the shoot/root of maize. Zinc concentration in shoots and roots of maize (Zea mays L.) harvested at 60 days after sowing, decreased with increasing thermochemical temperature and application rate of biochar. In treated soil with 2% (w/w) biochar prepared at 600 °C, Zn concentration in shoots and roots decreased by 21.6 and 33.0 % respectively (p
Research Article
shokrollah asghari; Mahmood Shahabi
Abstract
Introduction: Salinity and sodicity are the most important land degradation problems particularly in arid and semi-arid regions. Due to the depletion of Urmia Lake located in the northwest of Iran during recent years, the proportion of surrounding saline agricultural lands increased at a past pace. In ...
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Introduction: Salinity and sodicity are the most important land degradation problems particularly in arid and semi-arid regions. Due to the depletion of Urmia Lake located in the northwest of Iran during recent years, the proportion of surrounding saline agricultural lands increased at a past pace. In the salt-affected soils, aggregate stability is weak due to the high contents of sodium. The analysis of spatial variability of mean weight diameter of aggregates (MWD) and sodium adsorption ratio (SAR) is necessary to implement a site-specific soil management especially in the salt-affected soils. The main object of this study was evaluating the effects of different land uses (bare and agriculture) on the spatial variability of MWD and SAR in the salt-affected soils around Urmia Lake.
Materials and Methods: This study was conducted in the agricultural and bare lands of Shend Abad region located at the 15 km of Shabestar city, northwest of Iran (45° 36ʹ 34ʺ E and 38° 6ʹ 37ʺ N). Totally, 100 geo-referenced samples were taken from 0-10 cm soil depth with 100×100 m intervals (80 ha) in agricultural (n=49) and bare (n=51) land uses. Sand, silt, clay, organic carbon (OC), CaCO3, pHe, MWD, SAR and electrical conductivity (EC), were measured in the collected soil samples. Thewet sieving method was used to determine MWD of wet aggregates. The sieves were: 2, 1, 0.5, 0.25 and 0.106mm. The EC and SAR were measured in 1:2.5 (soil: distilled water) extra. The SAR was calculated from concentrations of Na+ and Ca+ + Mg+. The best fit semivariogram model (Gaussian, spherical and exponential) was chosen by considering the minimum residual sum of square (RSS) and maximum determination coefficient (R2). Ordinary kriging (OK) and inverse distance weighting (IDW) interpolation methods were used to analyze spatial variability of MWD and SAR. Spatial distribution maps of soil variables were provided by Arc GIS software. The accuracy of OK and IDW methods in estimating MWD and SAR was evaluated by mean error (ME), mean absolute error (MAE), root mean square error (RMSE) and concordance correlation coefficient (CCC) criteria. The CCC indicates the degree to which pairs of the measured and estimated parameter value fall on the 45° line through the origin.
Results and Discussion: According to the results of coefficient of variation (CV) from the study area, the most variable (CV=113.05%) soil indicator was SAR (bare land use), whereas the least variable (CV= 3.52%) was pHe (agricultural land use). The Pearson correlation coefficients (r value) indicated that there are significant (P
Research Article
Morteza Pouzesh Shirazi; Hassan Haghightnia; Rahim Khademi
Abstract
Introduction: Tomato is one of the most important vegetables that are used by human. High price of tomato due to its out of season production in Bushehr province has made a great tendency for farmers of this area to cultivate it in fall and winter in nearly 12000 hectares in the province. Mean annual ...
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Introduction: Tomato is one of the most important vegetables that are used by human. High price of tomato due to its out of season production in Bushehr province has made a great tendency for farmers of this area to cultivate it in fall and winter in nearly 12000 hectares in the province. Mean annual precipitation is about 250 mm per year. Maximum and minimum annual temperatures are 51 and -1 Celsius degrees. Mean annual evaporation is 3000 mm. Recent droughts and going down of water table because of over usage of underground water are main problems of this region that have enforced farmers to decrease irrigation water utilization and try to increase water use efficiency by using new technologies. Therefore, any new technical methods which can increase water use efficiency will help crop production quality and quantity and result in yield stability in the region. Many researchers have proved that mycorrhizal fungi can improve agricultural systems sustainability because of their ability to increase water absorption due to their long and expanded hyphae. Also they are known to increase nutrient uptake from soils even poor in minerals. Therefore, a greenhouse project was designed to determine the effect of Arbuscular mycorrhizal fungi on nutrients uptake and water use efficiency of tomato under drought stress in Bushehr province in southern Iran.
Materials and Methods: The experiment was carried out on completely randomized block design in factorial with three replications during 2016-2017 in the greenhouse of Bushehr agricultural and natural resources research organization located in Southern Iran. Factors were as follows: 1) four Arbuscularmycorrhizal fungi (Glomus mosseae ،Glomus intraradices، Glomus vsersiform and Glomus caledonium) and a control (without inoculation), 2) irrigation at three levels based on soil moisture depletion at I1=25, I2=50 and I3=70 percent of available water to show stress (from non-stress to low and high stress levels). Soil used for this experiment was dried in sunshine for one month to be evacuated from any native fungi. Soils of the region are calcareous ones with low salinity limitation (EC= 3.70 dS/m) and poor nutrition elements and slightly alkali (pH=7.9). Inoculation of roots by fungi was done by pouring one spoon of fungi near tomato roots while cultivating the transported seedlings in the pot. This would help the roots to be exposed to fungi directly while spreading through growing. Irrigation water used were 22.3, 20.1 and 17.7 liter for each pot filled with 10 kg soil during the season. The experiment lasted 100 days and tomato properties were measured such as yield, colonization percent, nutrition elements concentration and also, water use efficiency. Dried leaves were milled and put in furnace at 550 Celsius degrees. Roots were soaked in water for five minutes to be detached from soil and cleaned toughly. Detached roots were maintained in small glass jars filled with alcohol and were kept in refrigerator at 5 Celsius degrees. Roots were then colored by Try pan blue method and root colonization percent was measured by Grid line intersect method.
Results and Discussion: Results showed that interaction effect of mycorrhizal fungi and irrigation levels was significant at 1% level on tomato properties (except for N concentration in leaves). Mean comparison with Duncan`s test proved that increase in drought stress caused decrease in all tomato properties but fungi inoculation could mitigate water shortage in comparison to non-inoculated tomatoes Higher drought stress decreased colonization significantly. Drought stress caused significant deficiency in nutrition elements such as N, P and Fe, however some elements such as K, Zn and Mn were increased in medium drought stress. Inoculation with all mycorrhizal fungi improved nutrition elements concentration in tomato leaves. Water use efficiency was increased 67.9, 49.6 and 52.1 percent from non to medium and high stress respectively in tomatoes treated with Glomus intraradices.
Conclusion: Using of mycorrhizal fungi specially Glomus intraradices and Glomus caledonium increased tomato water use efficiency and improved growth properties due to the increment of water resistance ability in plant. This phenomenon is caused by higher nutrition elements uptake by roots and optimization of water relationship in tomato in the presence of mycorrhizal fungi. According to results, it is suggested tomato roots inoculation with mycorrhizal fungi especially in regions with high water stress potential.
Research Article
Jaafar Hosseinzadeh; Afsaneh Tongo; Ali Najafifar; Ahmad Hosseini
Abstract
Introduction: Direct monitoring of soil moisture and the extraction of moisture data by point method is not only costly and time-consuming, but in a large scale, is impractical; while drought is a regional phenomenon and requires extensive and regional data to monitor it. Therefore, providing a simple ...
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Introduction: Direct monitoring of soil moisture and the extraction of moisture data by point method is not only costly and time-consuming, but in a large scale, is impractical; while drought is a regional phenomenon and requires extensive and regional data to monitor it. Therefore, providing a simple method for monitoring soil moisture on a regional scale is of fundamental importance. Climatological or climatic indicators that are continuously measured and recorded at weather stations can be used as information that is readily available to determine soil surface properties such as temperature and soil moisture. The main objective of this study was to estimate soil moisture under forest cover, using climatic parameters that were recorded from a nearby station. Satellite imagery is currently used to estimate the temperature and moisture status of soil, but it must also be matched with accurate ground data and sufficient weather data stations, so it will not be applicable everywhere.
Materials and Methods: Mele-Siah forest habitat in the northwest of Ilam city was selected as the study area in this research. In this regard, in both the southern and northern slopes of Mele-Siah forest site, 18 pairs of humidity sensor at depths of 50, 70 and 110 cm were installed and soil moisture using TDR device was measured monthly. Monthly measurements of soil moisture were performed for three consecutive years and recorded as soil water content. In order to determine the relationship between soil moisture data and meteorological variables, the following 7 variables were extracted from the climatic data available at Ilam Weather Station: rainfall, relative humidity, average temperature, average maximum temperature, average minimum temperature, minimum absolute temperature and maximum absolute temperature. Multiple regression analysis and Pearson correlation coefficient in SPSS software were used to analyze the data and the relationship between soil moisture and climate indices.
Results and Discussion: The results indicated that the moisture variations at the soil surface, in comparison to the other depths, are more severe in all the months of the year. Therefore, the humidity drops at a distance of 20 cm between the depths of 70 to 50 cm, much more than 40 cm between the depths of 110 to 70 centimeters. The average moisture content in the months of the year in the direction of the north was more than that one was in the direction of the south. Climatic parameters of each month had high correlations with soil moisture levels of the same month. In this regard, average temperature and relative air humidity showed the highest correlations. Soil moisture in the area is minimized in September. The determination coefficient (R2) for the regression equation was about 0.93, which represented a very good estimation of soil moisture by the model. The highest average humidity was observed in early December and March and its lowest was observed in September. Correlation coefficients between soil moisture content and climatic indices of each month with two months before of them were not significant. However, the correlation coefficients between soil moisture content and climatic indices of the same month and previous month, except for rainfall, was significant. The results showed that we can use meteorological parameters to estimate soil moisture balance in the forests, which continuous and extensive measurement of soil moisture in them is difficult.
Conclusion: According to the study, the weather indicators such as average temperature and relative humidity of air whose data are available at weather stations or easy to measurable in remote areas, can be used to estimate soil moisture content under forests cover that do not have the possibility of continuous and extensive soil moisture measurement. Although rainfall was expected to be more strongly correlated with soil moisture content, but it should be noted that rainfall in some dry months is negligible or zero. Incidentally, we often want to estimate the moisture content of the soil, especially in dry months, through measurable parameters, thus the data of rainfall is not desirable. However, considering the topography of the study area, the distance from the meteorological station and the effect of elevation on soil moisture content may be effective on the accuracy of the results, but the use of data from meteorological stations near area provides the right comparison.
Research Article
Javad ramezani moghadam; Mostafa Yaghoubzadeh; Ahmad Jafarzadeh
Abstract
Introduction & Background: Assessment of climate change impacts on hydrology is relied on the information of climate changes in adequate scale. Due to outputs of GCMs (General Circulation Models) that are the most confident tools for simulating climate change impacts but are available in coarse resolution. ...
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Introduction & Background: Assessment of climate change impacts on hydrology is relied on the information of climate changes in adequate scale. Due to outputs of GCMs (General Circulation Models) that are the most confident tools for simulating climate change impacts but are available in coarse resolution. Downscaling process which is classified to several methods such as transfer function, weather generator and weather typing is performed for improving of GCMs projection and using them in local scale. Meanwhile feature selection is the main essential step in downscaling with transfer function. Because the main goal of downscaling is the improvement of GCMs projections, several researches examined vary approaches for feature selection. This study aims to assess performance of downscaling daily precipitation under four different selection methods such as PCA, CA, SRA and ParCA using comprehensive comparison tests.
Materials and Methods: Measured daily rainfall for Ardebil (with cold semi-arid climate) and Birjand (arid climates) were collected for the period from 1977 to 2004. The CanESM2 (Canadian Earth System Model) outputs were used as GCM for simulating of climate change impacts on precipitation pattern. So of CanESM2 outputs (large scale predictors) and measured daily precipitation (local scale predictants) were considered as input and target for downscaling respectively. The Artificial Neural Network (ANN) which widely has been used in climate change researches was selected as downscaling method. Despite of the most of literature have used only efficiency criteria for distinguishing from different approaches in downscaling, this study reveals performance of feature selection methods based on either them or statistical tests. The comparison tests between measured and downscaled rainfall such as assessment criteria, statistics characteristics comparison, contingency table event for wet and dry series diagnostics and Violin plot were used as tools for skill assessment of feature selection approaches.
Results and Discussion: Results showed that although different methods of predictor selection had includes various subsets, predictors such as relative humidity at surface and zonal velocity component at 500-hPa pressure levels in Birjand and mean temperature at 2m, mean sea level pressure and rotation of the air in Ardebil are the most descriptive features which have more relationship with measured daily precipitation. The efficiency criteria of comparing measured and downscaled precipitation indicated that CA method is superior to other in Birjand station and SRA’s results were better than those of other in Ardebil station. Value of RMSE, R and NSE was achieved 1.2 mm/day, 0.55 and 0.25 in Birjand and 1.75 mm/day, 0.14 and 0.013 in Ardebil respectively. The examination of measured and downscaled statistical characteristics reveals that CA has the better influence on downscaling than those of others in Birjand station. In this comparative test most of downscaled statistical components such as mean, median and skewness under CA have more similarity to measured values. But in Ardebil, with cold and arid climate, performance of SRA to downscale was the same as performance of CA to it. Also both SRA and CA were better than ParCA. The skill assessment of different methods to fit measured and downscaled variability by violin plot showed that generally ParCA outperformed other method in Birjand station. The comparison of violin plots, in Ardebil, revealed that no one of predictor selection methods has acceptable accuracy for fitting measured variability. Outcomes of contingency table event showed although all feature selection methods have not remarkable capability for distinguishing from the measured wet and dry series in Ardebil station, performance of ParCA and SRA were acceptable in Birjand station. The values of CSI for ParCA and SRA were calculated 0.25 and 0.22 in Birjand and it shows that more of 20 percent of ParCA and SRA’s diagnostics was correct.
Conclusions: By assessing of results, it can be inferred that generally downscaling of daily rainfall in Birjand station is outperforming Ardebil. In other expression daily downscaling of precipitation in arid climate has better results than cold and arid climate. Also different tests have various results about feature selection methods. In Ardebil, SRA in efficiency criteria test and both SRA and CA in statistics characteristics have better performance than others. But in this region no methods have remarkable performance in violin and dry and wet tests.
