جستجوی مقالات مرتبط با کلیدواژه « hamadan » در نشریات گروه « آب و خاک »

The objective of this study was to investigate the effect of wildfire in the rangelands of the Gonbad region of Hamedan on soil organic carbon storage in two control and fire areas after three years of fire, and the feasibility of using remote sensing in indirect estimation of soil carbon. Therefore, 20 soil surface (0-10cm depth) samples were collected from the burned area and 20 samples from the control area (40 samples in total) by the systematically random method after three years of fire time. Changes in organic carbon, total nitrogen, acidity, and salinity of surface soil were tested by independent t-test between control and fire areas. Then, to investigate the linear relationship between the storage of soil organic carbon with other parameters, the Pearson correlation was used in SPSS v. 26. The results of the independent t-test showed that there was no significant difference in EC, acidity, and soil organic carbon of the control and fire areas, but the amount of total soil nitrogen showed significantly different. The results showed a significant positive correlation was observed between soil organic carbon and total nitrogen at the level of one-hundredth of 0.830 (p< 0.01) in the fire area, and the BI index showed a significant negative correlation of 0.727 (p< 0.05). In the control area, a significant positive relationship was observed between organic carbon and total nitrogen at the rate of 0.627 (p <0.05). The results of processing Landsat 8 images (OLI-TIRS sensor) in the fire area showed that there was a statistically significant relationship between soil organic carbon and light and wetness index obtained from tasseled cap (-0.726 and 0.674, respectively) and PC1 component obtained from principal component analysis and -0.724 (p <.05). These results indicate that it is possible to use tasseled cap images to predict soil organic carbon in fire areas.

Due to the important role of irrigation water chemical composition in the yield of crops and its effects on the soil structure, it has been taken into consideration by the agricultural sector planners. In this regard, the sour and burning taste of water in some agricultural wells around the HamehKasi village in Hamedan province has caused concerns about their water composition and possible detrimental effects on soil stucture and plant growth. Therefore, the present study was conducted to evaluate the water quality and the trend of changes in its composition. In this study, 6 gaseous water-wells were identified and their salinity was measured 15 times in three years (5 times each year), and the trend of their electrical conductivity changes was evaluated by SPSS software. Also, from each well, one sample was taken in order to determine the electrical conductivity, cations and anions content, and their chemical indices were calculated and evaluated by means of different criteria and diagrams. The results showed that calcium and bicarbonate ions have the highest concentrations in these waters, and the water of the mentioned wells was considered as unconventional and was Ca-Mg-HCO3 type. The water salinity of these wells was high (from 2.96 to 6.07 dS/m), and had very high salinity and sodicity (C4S4) after correction of the sodium adsorption ratio. Due to high salinity of water, fine-textured soil and lack of sufficient water for leaching, it is expected that the soil will be salinized in the root zone by irrigation, and as a result, the yield of plants and especially perennial plants would decrease. However, the statistical analysis of the electric conductivity changes of gaseous water-wells in HamehKasi area indicated that the salinity of their water decreased significantly over time. Consequently, the quality of water in the HamehKasi area in terms of irrigation improved over time.

Despite the progress made in identifying the various materials that can be used to lining of irrigation canals, a large parts of the country's irrigation canals are still unlined. On the other hand, last researches indicates that in some linings the expected target is not achieved and the amount of water loss in them is not significantly different from unlined canal. Therefore, it is necessary to evaluate the rate of water seepage losses in different bedsoil textures from the bed of the unlined canals and then, if necessary, linings should be carried out. The rate of water seepage losses in unlined irrigation canals and its relationship with the bedsoil textures in the Bahar plain from Hamedan province have been evaluated. For this purpose 6 unlined irrigation canals were selected. The technical characteristics, geometric dimensions and hydraulic parameters of the water flow were determined and the amount of water seepage losses measured with input-output method, in the early, middle and final stages of the agricultural season. Based on the average results, water seepage losses in selected canals are between 0.88 to 3.84 and averagely 2.38 m3/m2/day. The average seepage losses in the early, middle and final stages of the crop season are 2.61, 2.18 and 2.35 m3/m2/day. The evaporation losses with averaged of 0.01 m3/m2/day(to 0.3 percent of the total losses), were very small compared with seepage losses, and the remaining losses were due to seepage. The relationship between the amount of seepage from the substrate of the studied channels and the percentage of fine particles of the bedding soil (particles with diameter less than 0.75 mm) were extracted and presented as Sloss=5.394*e-0.0299*Fine. According to this relation, if the fine particles of bedsoil of canals increases to 35 present, the water seepage losses from this canal decreases to less than 50 of the present value.

Soil is a finite natural resource and non-renewable under agricultural production without implementation of sustainable management practices. Ecological sustainability of agroecosystems can be comparatively assessed by soil quality evaluation, which in turn is assessed by soil quality indices. Soil quality is the general term used to refer to “the continued capacity of soil to function as a vital living system, within ecosystem and land-use boundaries, to sustain biological productivity, maintain the quality of air and water environments, and promote plant, animal, and human health”. Conservation tillage and use of cover crops are some of the sustainable agriculture practices that can improve the soil quality by adding organic matter and nutrients, and by acting as scavengers to trap leftover nutrients that otherwise might leach out. Cover crops are used as ground cover, mulches, green manure, nurse crops, smother crops, and forage and food for animals or humans. Given the significant role of tillage practices and crop residue management in soil quality improvement and crop production, a four-year field experiment was conducted to determine selected soil quality indices and Cucurbitapepo yield under different tillage and legume cover crop managements in Hamadan.
A four-year field experiment (2011-2014) was carried out at Bu-Ali Sina University experimental field in Dastjerd, Hamadan, as a factorial experiment in randomized complete block design with three replications. The area is located at 37 km of Hamadan, on 35◦ 01' N latitude and 48◦ 31' E langitude with 330 mm annual rainfall and 1690 m altitude. The treatments consisted of three levels of tillage practices (NT: no-till (direct seeding), MT: minimum tillage (chisel plowing disk) and CT: conventional tillage (moldboard plowing disk)) and two levels of cover cropping (C1: with legume cover crop (lathyrus sativus) and C0: without cover crop). These treatments were applied for four consecutive years in a way that lathyrus sativus as cover crop were planted in late winter for each year and returned to the soil surface with a trowel when 30% of the field was flowered. One week later, and prior to the cultivation of main crop, the mentioned tillage treatments were implemented. In the fourth year of the project,Cucurbita pepo was planted as the main crop. Soil and plant (Cucurbita pepo) were sampled early autumn (2014) and were analyzed for soil organic carbon, soil active carbon, macro and micro-aggregate carbon, mean weighted diameter of water stable aggregates, soil bulk density, basal microbial respiration and grain yield. Obtained data were analyzed using statistical software SAS 9.4 and the means were compared using LSD multiple range test at 5 percent level.
The results revealed that total organic carbon, active carbon, aggregate carbon, mean weighted diameter of water stable aggregates, bulk density, porosity and basal respiration were significantly affected by cover crop and tillage system so that the highest amount of these indicators were obtained in no-tillage system with cover crop treatment (NT-C1) and the lowest amounts were observed in the conventional tillage without cover crop (CT-C0). For instance, mean soil organic carbon increased from 0.4 percent in CT-C0 to about 0.7 percent in NT-C1. For majority of soil quality indices, no significant difference was observed between minimum and no-till; moreover, the application of cover crop in conventional tillage improved some aspects of soil quality. For instance, MWD was the highest (2.14 mm) in NT-C1, and was not significantly different with that of MT-C1 treatment. On the contrary, this index was significantly the lowest (0.48 mm) in CT-C0. The C. pepo grain yield was also significantly affected by tillage system, cover crop and their interactions. The highest grain yield (142.1 g.m¬-2) was obtained in MT-C1 treatment, which did not show significant difference with NT-C1 treatment. The lowest C. pepo grain yield (115.3 g.m¬-2) was observed in conventional tillage without cover crop (CT-C0) treatment, but it was in a same statistical group with NT-C0, MT-C0 and CT-C1 treatments. Cover crop increased organic carbon, active carbon, porosity, bulk density, microbial biomass activity and MWD by enhancing soil organic matter, probably; conservation tillage on its part further improved these effects by preventing the rapid decomposition of organic matter by reduced soil destruction, which eventually increased soil organic carbon, active carbon and production of stable aggregates.
Generally, after four years of applying different tillage practices and cover cropping, it was demonstrated that the integrated management of the conservation tillage (either no-tillage or minimum tillage) with legume cover cropping was the most appropriate management in the semi-arid region of Hamadan in view of selected soil quality indices and crop yield improvements.

In several fields of Isfahan and Hamadan provinces, due to lack of proper design and hydraulic shortcomings of sprinkler system, the efficiency system is unacceptable and causes ponding of water on the land and runoff from the field. Therefore, in this study, some of the existing sprinkler irrigation systems in Fereidan and Bahar regions were evaluated.
In this research, nine and ten potato fieldsin Isfahan (Fereidan Region) and Hamedan (Dashtebahar Region) Provinces respectively were evaluated for 2 years.Soil physical characteristics such as soil texture andsoil permeabilityat field sites were measured in the Isfahan and Hamedan Soil and Water Laboratory. Also sprinklerirrigation systems in these fields were investigated. From soil characteristics in Frieden region could be noted to medium soilpermeability(1.5 to 2.0 cm.hr-1) andsoil texture (medium to heavy). Thesprinkler irrigation was permanentclassic system.Soil texture (loam, clay loam, silty loam, silty clay loam)and the existing irrigation system were reported moveable classic and wheel move sprinkler irrigation. Irrigationsystems assessments weretaken place according to Merriam and Keller methodology (1978) (5).Uniformity coefficients, potential and actual application efficiency of low quarter (PELQ¡ AELQ¡ CU and DU) were determined.The hydraulic system parameters consists of H, Q and P were measured.First of all, soil moisture in the experimental sites to determine the soil moisture deficit (SMD) was measured.Pressureandflow ratesprinklersatthe beginning, middleandend of theirrigation experimentsas well as in fieldswere measured.Aftertwohours, sprinklers pressure,flow rateandvolume of waterinthecanswere measured.The uniformityandefficiencyof thesystemswere calculated as well.
Nine sprinkler irrigation systems were evaluated and DU, CU, AELQ and PELQ in the fields were equal 60.8%, 57.2%, 75.3% and 66.2% respectively. The results indicated that the poor PELQ was mostly due to lack of sufficient knowledge of the operators about optimal use of the irrigation system including control of inlet pressure, simultaneous operation of too many sprinklers and inappropriate duration of each sprinkler operation. All these factors led to deviation from the designed irrigation time and interval. The low values of DU and CU could be attributed to insufficient pressure and discharge of irrigation systems. In sprinkler irrigation system, the main difficulties in implementation of this system are lack of accuracy in design and insufficient knowledge of users. Ten sprinkler irrigation systems were evaluated in Bahar plain and PELQ, AELQ, CU and DU in the fields were equal 53.0%, 45.6%, 81.1% and 77.1% respectively. Average of PELQ, AELQ, CU and DU in the weel move systems were equal 55.1%, 51.1%, 66.7% and 81.4% and solid systems were equal 52.1%, 43.3%, 73.0%, 81.0% respectively.
Results show that the poor AELQ was mostly due to economics. Poor DU and CU were mostly due to Low pressure and sprinkler's discharge in fildes.

Climate change and its impacts on water recourses is known as one of the most important challenges which human would be faced with it in the future century. Although different studies are performed to consider the effects of climate change on the metrological and hydrological variables using climatic scenarios and General Circulation Models, but its effects on agricultural sectors such as water requirement are less investigated. The main objective of this study is to asses the effect of climate change on the net irrigation requirement changes of main crops in Hamadan-Bahar plain (winter wheat, barley, potato, sugar beet, maize (grain), maize (grass), peas and onion) in three next decades according to different scenarios using LARS-WG5 model compared with baseline period.
In this study daily metrological variables including precipitation, minimum and maximum temperature and relative humidity were collected from the Islamic Republic of Iran Meteorological Organization for 1981-2010. For main purpose, first of all, the capability of LARS-WG5 model was investigated and verified to simulate meteorological variables including minimum and maximum temperature, solar radiation and precipitation at Hamadan synoptic station in the baseline period (1981-2010). In the next step, meteorological variable values were stimulated by HadCM3 model based on A1B, A2 and B1 emission scenarios in the period of 2011-2040. Finally, the net irrigation requirement values of main crops were estimated for baseline and three future decades.
Based on the simulated results of LARS-WG5 model, the average values of air temperature and precipitation will increase by 0.77, 0.88 and 0.78 oC and 2.1, 5.9 and 10.2% for A1B, A2 and B1 scenarios, respectively.The results showed that average monthly precipitation will increase in October, December and February for three scenarios and decrease in March, April and May for A2 and B1 scenarios. Also, the total amount of net irrigation requirement of examined crops will increase between 2.6 to 28.2 mm for three future decades compared with baseline period. According to A2 scenario, the net irrigation requirements of wheat and barley have the lowest values of increasing change and sugar beet and potato have the highest increasing changes.
According to the A2 as a plausible scenario, the total net irrigation requirement of sugar beet, wheat, barley, potato, maize (grain), maize (grass), peas and onion in 30 next years will increase 267, 75, 57, 275, 250, 153, 145 and 224 cubic meters per hectares, respectively compared with baseline period. In general, considering increasing changes of the net irrigation requirements of different examined crops, the selection of appropriate cropping patterns consistent with climate change is required.

Estimation of groundwater in the aquifer water resources management is important. In this study for estimation of the spatial distribution of water table level in Hamadan-Bahar plain neural intelligent methods including Multy Layer Perseptron (MLP), Radial Basis Function (RBF), Co-Active Neuro-Fuzzy Inference System (CANFIS) and Adaptive Neural Network based Genetic Algorithm (ANNGA) were used. To estimate water table in locations without measurements values, point values were estimated from each neural intelligent methods zoned in geographic information system. Overall, accuracy of used method based minimum errors were related to ANNGS, MLP, RBF and CANFIS, respectively. So that in ANNGA model, Root Mean Square Error (RMSE) was 0.431 m and correlation coefficient (r) value was 0.996. Maximum errors were related to CANFIS and RBF models with RMSE=1.27 m and RMSE=0.81 m, respectively. Also, comparison of the spatial variation of water table estimated by ANNGA model with observational data showed that points distribution in 90% confidence limits were little. Therefore, with using the latitude and longitude as input data water table spatial changes and its zoning can be estimated.

Phosphorus (P) after nitrogen limits agricultural production in most region of the world. Information about P release rate is limited in Hamadan soils. The objective of this research was to study P release in 10 soils from Hamadan province by successive extraction with 0.5 M NaHCO over a period of 1752 h and the correlation of P release characteristics with soil properties and corn plant (Zea mays) indices. The results showed that soil P release began with a fast initial reaction, followed by a slow secondary reaction until 1752 h. The amounts of soil P released after 1752 h ranged from 309 to 586 mg kg-1. The cumulative P release was evaluated by six kinetics equations. Statistical analysis showed that phosphorus release kinetics were described by parabolic diffusion law, first order and power function equations. The correlation study indicated that soil P release coefficients such as rate constant of first order, parabolic diffusion law, power function equations, P released after 168 and 1752 h were significantly correlated with some soil properties such as Olsen-P, calcium carbonate equivalent, sand and silt. The correlation studies between plant indices and constants of kinetics equation showed that rate constant of first order equation was not significantly correlated with plant indices. Equation constants of parabolic diffusion law, power function and P release after 1752 h were significantly correlated with plant indices. The results of this research indicated that release rate of P is different in soils and is an important factor in supplying available P to plants.

Some of the field crops are severely affected by the Fusarium foot and root-rot in the west of Iran, Hamadan. Pathogenic Fusarium species are potentially severe destructive diseases and could be a major limiting factor for the cereals and potato production in this province. The purpose of this study was to determine the possible effect of soil solarization on the population dynamics of Fusarium spp. The propagules under Hamadan climatic conditions. Pre-tarping irrigation to achieve the field capacity was carried out prior to the various treatments including the black and transparent polyethylene plastic sheets. The experiment was performed in a completely randomized block design with three replicates, in a naturally infested soil. After three, five and eight weeks, soil samples were collected from different soil depths in appropriate plots. The propagule numbers of Fusaria were counted through dilution plate method using selective Nash & Synder and PDA media. The results indicated that the propagules of Fusarium in treated soils (five and eight weeks treatments) were significantly decreased as compared with the three week treated and untreated control plots. Better results obtained with the transparent sheets after eight weeks, followed by treatments with five weeks of mulching. Accordingly, the hydrothermal control of the Fusarium foot and the root-rot disease seem to be effective under the cool and temperate area of Hamadan.