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Showing 23 results for Development
S.a. Khatoonabadi, A.m. Amini, A. Mirzaali,
Volume 5, Issue 1 (4-2001)
Volume 5, Issue 1 (4-2001)
Abstract
Experience has shown that all centralized planning, policy-making and decision-making which presuppose exclusion of public participation have never been successful in achieving their objectives. The goal of this research is to determine the driving and preventive factors of herders’ participation in rehabilitation designs of Aghghala ranges in Gorgan Province. The research method was direct observation in which measurement techniques were used. A questionnaire was used to divide the sample society into two categories: the experts who design the range management system, and the local herders.
Results obtained from this investigation showed that according to the experts training, economic, planning and social parameters have the greatest effects on local herders’ participation while the herders maintained that planning, economic, training and social parameters have the greatest effect on decreasing their participation.
M.r. Khajehpour, F. Seyedi,
Volume 5, Issue 2 (7-2001)
Volume 5, Issue 2 (7-2001)
Abstract
Sensitivity of developmental stages of three sunflower cultivars to day length and temperature changes under field conditions were evaluated, and their development rates during various growth stages were modeled in a field experiment conducted in 1996 at the Agricultural Research Station, Isfahan University of Technology. Five dates of planting (April 27, May 12 and 27, and June 12 and 29) and three open pollinated sunflower cultivars (Record, Vnimik 8931 and Armavirec) were evaluated using a randomized complete block design with split-plot layout in three replications. Date of planting was considered to be the main plot and cultivars were randomized in sub-plots.
Number of days from planting (P) to head visible (HV) and P to first anther (FA) were significantly reduced with delay in planting as the result of increase in temperature during these periods. Number of days from P to physiological maturity (PM) was also significantly reduced with delay in P. This response, however, could not be explained by changes in temperature variables or day length. Number of days from HV to FA, in harmony with the partial stability of maximum and minimum temperatures during this period, was not affected by date of planting. Duration from FA to PM of the last planting date was significantly shorter than the other planting dates. This response was related to the persistence of the effect of high and stable maximum temperatures prevailing during HV to FA period of the last planting date. Armavirec was significantly earlier than Record and Vnimic 8931 for number of days from P to HV and from P to FA Cultivars showed significantly large differences for the FA to PM and P to PM durations. Armavirec was the earliest and Record was the latest cultivar. Based on the results obtained, it may be concluded that the cultivars under study were non-sensitive to photoperiod. Development rate (DR) of Armavirec responded linearly and DR of Record and Vnimic 8931 responded non-linearly to increases in temperature variables during P to HV and P to FA Development of Vnimic 8931 was faster than Record at high temperatures. DR of the cultivars decreased linearly during P to PM as day length increased. The relationship between DR and photoperiod could be used as a practical model for estimating P to PM duration of these sunflower cultivars.
H. Azadi, E. Karami,
Volume 5, Issue 3 (10-2001)
Volume 5, Issue 3 (10-2001)
Abstract
Cooperative have always been considered institutions capable of solving major problems in the process of development in different countries. These institutions has evolved along with theories of development from government dependent organization to independent, people centered with the objective of being equal-opportunity systems for all members in order to be responsive to current goals of development. The aim of the present research was to determine the level of success in mechanized companies in Fars Province (12 Mechanized Companies, 24 Rural Cooperatives and 8 Production Cooperatives) in achieving development goals through a survey research.
The findings indicated that production cooperatives were more successful in promoting farmers' income and participation of members in community activities, increasing equity and farmers' work related welfare while mechanized companies had more achievements in flexibility and participation of members in making decisions regarding farming activities and in terms of payment to farmers. In other words, production cooperatives have been more successful in achieving development goals (increasing income, participation, and work related welfare and decreasing inequity). Mechanized companies rank a position in the middle of the success scale, but rural cooperatives had the lowest success level in achieving development goals.
A. Azari, M.r. Khajehpour,
Volume 7, Issue 1 (4-2003)
Volume 7, Issue 1 (4-2003)
Abstract
Planting pattern through changing vegetative growth and utilization of environmental resourses affects yield components and seed yield. These effects were studied in the spring of 2000 at the Agricultural Research Station, Isfahan University of Technology, using a randomized complete block design with a split plot layout and three replications. Main plots consisted of three row distances (30 cm flat, and 45 and 60 cm on bed), and sub-plots included three planting densities (30, 40, and 50 plants m-2). The experiment was planted on March 13 using local safflower variety of Isfahan, named Koseh. Increase in row distance and plant density enhanced most developmental stages of safflower. Leaf area index was not significantly affected by row distance but increased as planting density increased. Up to the 50% flowering stage, 30 cm row distance produced highest plant dry weight, but had the least dry weight at the end of the growing season, probably due to the strong shedding of leaves. Up to the end of flowering stage, 50 plants m-2 treatment produced the highest plant dry weight, but ranked lower as compared to 30 plants m-2 treatment at the physiological maturity, probably due to the shedding of leaves. Row distance had no significant effect on number of branches per plant and per square meter, number of heads per branch, number of seeds per head, 1000-seed weight and harvest index. But number of heads per plant and per square meter as well as seed yield per plant and per square meter significantly decreased as planting distance increased. Plant density had no significant effect on number of branches per plant, number of heads per square meter, number of seeds per head, 1000-seed weight and seed yield. Increase in planting density increased number of branches per square meter, but reduced number of heads per branch and per plant, seed yield per plant and harvest index. The highest seed yield (4769 kg ha-1) was obtained with 30 cm row distance and 40 plants m-2 treatment. On average, 397 kg ha-1 petal was harvested, which has a large economic value. However, petal clipping, over all treatments, reduced seed yield by about 7.4%. Considering the advantages of uniform distribution of plants and adaptation of safflower to flat planting, 30 cm row distance with 40 plants m-2 might be appropriate for planting safflower under conditions similar to this experiment.
N. Dadashi, M. R. Khajehpour,
Volume 7, Issue 4 (1-2004)
Volume 7, Issue 4 (1-2004)
Abstract
A field experiment was conducted in 2000 at the Agricultural Research Station, Isfahan University of Technology, to model the response of four safflower genotypes to day length and temperature changes under field conditions. Five planting dates (March 12, April 12, May 10, June 8, and July 12) and four safflower genotypes (Arak 2811, local variety Koseh, Nebraska 10 and Varamin 295) were evaluated using a randomized complete block design with split-plot layout in three replications. Date of planting was considered as the main plot and cultivars were randomized in the sub-plots. Number of days from planting (P) to emergence (E), stem elongation (SE) to head visible (HV), and HV to flowering initiation (FI) significantly reduced with delay in planting as the result of increase in temperature during these periods. Number of days from P to SE, duration of flowering (DF) and termination of flowering (TF) to physiological maturity (PM) were significantly affected by planting date and reduced as day length increased. The same was observed in the case of number of days from P to 50% flowering (MF) and to PM. Large co-variation of day length with temperature may explain a portion of day length contribution to the variation in the above periods. Varamin 295 was later than other genotypes with respect to the duration from P to HV, and specially, for rosette duration. In addition and for unknown reasons, the rate of development (RD) of Varamin 295 at all developmental periods could not be explained by day length and/or temperature variables. Among other genotypes, Koseh with 125 days, and Nebrska 10 with 118 days from P to PM were the latest and the earliest genotypes, respectively. The response of Koseh to planting dates, as measured by the duration of various developmental stages, differed from Arak 2811 and Nebraska 10. This was attributed to the probable response of Koseh to day length. RD of Koseh, Arak 2811, and Nebraska 10 during P to MF was explained by a linear regression and RD of Koseh during P to PM by a polynomial regression with day length by mean temperature as an independent variable. RD of Arak 2811 and Nebraska 10 during P to PM was explained by minimum temperature. It seems that partial sensitivity of Koseh to day length has a considerable significance in its adaptation to environmental conditions prevailing in the summer under Isfahan climatic conditions.
R. Nikdokht, E. Karami, M. Ahmadvand,
Volume 11, Issue 41 (10-2007)
Volume 11, Issue 41 (10-2007)
Abstract
Sustainability of livestock production systems (LPSs) is of prime importance to the needs of human beings. From a sustainability point of view, an LPS is sustainable when it is environmentally nondestructive, economically viable and socially provides appropriate quality of life for producer and the whole community. Iran LPS is primarily based on traditional production systems. Therefore, an important issue for animal production in this country is the question of sustainability of traditional LPSs.The aim of this paper was to investigate and compare the sustainability of traditional LPSs in Firouzabad County. Three dimensions of sustainability were considered. Survey research was used to reach this purpose. Therefore, 300 livestock producers in “Nomadic”, “Semi-nomadic” and “Village- based” system were interviewed. Respondents were selected by a multi-stage cluster random sampling method. Face validity was confirmed by experts and the questionnaires were subjected to reliability testing using data collected in the pilot study. Findings showed that all three LPSs were unsustainable with regard to social, economical, and technico-environmental dimensions. Comparison of LPSs showed that Village-based LPS was from social dimension relatively sustainable and technically and environmentally unsustainable. While nomadic LPS was from social dimension relatively unsustainable and technically and environmentally sustainable.
P. Heydaryzadeh , M.r. Khajehpour,
Volume 11, Issue 42 (1-2008)
Volume 11, Issue 42 (1-2008)
Abstract
During the past years, safflower genotypes have been selected from local variety of Isfahan, named Kouseh. The response of these genotypes to planting date might be different. To determine this, performances of several genotypes selected from Kouseh plus Arak 2811 ) as check ( were studied at the Agricultural Research Station, Isfahan University of Technology in 2002-2004. The experiment was conducted using a split-plot arrangement within a randomized complete block design with three replications. Planting dates were considered as the main plots and subplots consisted of 22 genotypes of safflower. Number of days from planting to emergence was highest (18.0 days) in early spring planting and lowest (10.3 days) in late spring planting. Days from planting to head visible, flowering and physiological maturity were decreased with delay in planting from autumn to late spring. Days from planting to emergence, head visible and physiological maturity were not influenced by genotype. Genotypes C116 and DP29 had the highest (145.0) and genotype ISF28 the lowest (140.2) days from planting to flowering. Plant height, number of first and second degree branches, number of heads per first and second degree branches, number of seeds per head, 1000-seed weight and seed weight per plant reduced significantly with delay in planting from autumn to late spring. Genotypes C128 and DP7 had the highest (120.0 and 120.5 cm, respectively) and genotype DP9 the lowest (104.2 cm) plant height. Genotypes DP6 and DP9 had the highest (12.8) and the lowest (6.7) first degree branches per plant, respectively. Arak-2811 had the highest (16.9) and genotypes DP9 and DP5 the lowest (7.2 and 7.1, respectively) second degree branches per plant. Number of heads per first degree branches was not significantly affected by genotype. Arak-2811 and genotype C114 had the highest (12.8 and 12.2, respectively) and genotype DP9 the lowest (5.1) number of heads per second degree branches. Genotype DP7 had the highest (45.9) and genotype C111 had the lowest (28.0) number of seeds per head. Genotypes DP3 and C128 had the highest (34.2 g) and lowest (22.0 g) 1000-seed weight, respectively. Genotype DP25 had the highest (20.5 g) and genotypes DP29 and DP9 the lowest (9.9 and 10.0 g) seed weight per plant. Harvest index was not affected by planting date and genotype. The result of this study showed that safflower may yield more in fall planting under conditions similar to this experiment. Genotype DP25 might be recommended for this planting date, genotypes ISF66 and DP25 for early spring planting and genotypes DP7 and ISF14 for summer planting.
S.a.a. Hedayati, V. Yavari, M. Bahmani, M. Alizadeh, R. Kazemi, A. Hallajian,
Volume 11, Issue 42 (1-2008)
Volume 11, Issue 42 (1-2008)
Abstract
Great sturgeon is one of the most economically important species. However, in recent years overfishing, illegal fishing, etc., have resulted in severe declines in the stocks of this species. For conservation, stock of this species, determination of gonadal situation and its gonadal growth exchanges is very important. This paper is a histological approach to gonadal staging in 74 Huso huso in the 4 – and - 5 - year old classes. The fishes were reared in brackish water concert tanks under controlled conditions. A small section of the gonads of each fish was removed by biopsy. The gonadal tissue was fixed in buoin solution. They were dehydrated in different diluted solutions of alcohol and chloroform until they were clear. Then they were embedded in paraffin and sectioned at 7 µm and stained by hematoxylin and eosin method. Of the four-year old fish, %56 and %44 were males and females, respectively. %6 of males were at stage I %11 stage I-II %61 stage II %13 stage II-III %11 stage III-IV and %8 were at stage IV-V. %3 of the females were at unknown stage %3 stage I %11 stage I-II %60 stage II %14 stage II-III and 9% stage III. Of the 5 year old fish, %12.5 of males were at stage II % 25 stages II-III %50 stages III and %12.5 were at stage IV. %62.5 of females were at stage II and %37.5 were at stage II-III. Results of this study Compared with those obtained from fishes of the same age class studied in natural habitats as well as the results obtained for the farmed sturgeons from freshwater medium indicate that there is no similarly in the stage of gonadal development in different conditions. Longest stage in tow sexes was stage II that is longer in females, and passing of stage II in males is faster. Males showed more sexual maturity than females. Gonadic growth in culture medium is faster than wild condition, and it is faster in brackish water than fresh water. So, we can state that brackish water is a suitable medium for gonadic growth of Great sturgeon.
M. A. Ebrahimizade, A. M. Hassanli ,
Volume 12, Issue 44 (7-2008)
Volume 12, Issue 44 (7-2008)
Abstract
Root depth is one of the main parameters affecting soil moisture availability held within the plant root zone. This study was conducted to evaluate the trend of corn root development during the growing season in different irrigation methods with two water qualities, and distribution of roots in soil profile. The experiment was a split plot design with three main treatments (subsurface drip(SSD), surface drip(SD) and furrow irrigation(FI)) and two sub main treatments (municipal effluent and fresh water) in two consecutive years conducted in Korbal plain, Fars province. Root monitoring was carried out with the observation of soil profile root depth measurement. Samples were taken during the growing season 16 times, each with a 7 day interval. Measurement of root weight in different soil layers was carried out using monoliths of soil washed with water pressure using 50 mesh sieves. Although the longest roots were observed in plots irrigated with SSD and the shortest in FI, the final root length was not significantly affected by irrigation methods and water qualities. In this research, a model showing the trend of root length average growth was developed and tested in the experiment conditions. The average final main root depth for all treatments was 77 cm. Irrigation volume using root depth monitoring could be reduced compared to linear model, Borg & Grimes and CROPWAT model for root depth estimation. Irrigation water on the base of soil moisture deficit within the root zone in each irrigation event could be reduced when the real root depth is considered compared with the conventional general models giving a final root depth. Results showed the total dry root weight in SSD was more than that in SD and FI methods. However, water quality did not show a significant effect on dry root weight. The most root concentration in SSD was measured in depth of 20-40 cm, while in SD and FI the most concentration was in surface layer (0-20 cm). In the SSD, the roots were distributed more evenly compared with SD and FI methods. The concentration of roots in all treatments below 65 cm was not significant.
P. Heydarizadeh, M. Sabzalian, M.r. Khajehpour,
Volume 12, Issue 45 (10-2008)
Volume 12, Issue 45 (10-2008)
Abstract
During recent years, several genotypes have been selected from Isfahan land race Kouseh. The performance of safflower selected genotypes was studied in the field conditions, at Agriculture Research Station, Isfahan University of Technology during 2003. The experiment was carried out using a split plot arrangement according to a randomized complete block design with three replications. Planting dates (March 11, April 20, May 22 and June 23) were considered as the main plots and subplots consisted of 20 genotypes of safflower including 19 selections from Kouseh and Arak-2811 genotype. Days from planting to emergence and emergence to stem elongation were reduced as planting was delayed until the fourth planting date. Days from stem elongation to head visible was reduced with delay from the first to the third planting date, and then increased. Days from head visible to 50% flowering was reduced with delay from the first date to the third planting date, but increased in the fourth planting date. Days from 50 percent flowering to physiological maturity was increased with delay in planting. Days from planting to emergence, emergence to stem elongation, stem elongation to head visible and 50 percent flowering to physiological maturity were not influenced by genotypes. Genotype DP7 had the highest and genotype C111 and genotype DP25 had the lowest days from head visible to 50% flowering. The interaction between planting date and genotype in regard to days from stem elongation to head visible was also significant. Seed weight per plant was reduced with delay in planting date. Genotype ISF66 had the highest and genotype Arak-2811 had lowest seed weight per plant. The number of days from emergence to head visible in ISF66, DP5, C128 and Arak-2811 was affected by maximum temperature (Tmax), in genotype DP7 by Tmax2, in genotypes DP17, DP1 and C41100 by Tmin2 and in genotypes DP9, DP25, ISF28, ISF22, and C111 was affected by day length. It seems that development period from emergence to head visible was affected by temperature in the most genotypes. On March 11 planting date, genotypes had the maximum response to temperature and day length and the minimum response was observed in the fourth planting date. The genotype ISF66 had the highest seed yield on March 11 planting date. The result of this study showed that safflower should be planted in late March under condition similar to this experiment for maximum yield production.
H Owliaie, E Adhami, M Chakerhosseini, M Rajaee, A Kasraian,
Volume 12, Issue 46 (1-2009)
Volume 12, Issue 46 (1-2009)
Abstract
Magnetic susceptibility (χ) measurements are widely used for the evaluation of soil profile development. Fourteen soil profiles were studied in a relatively wide range of climatic conditions in Fars Province. Citrate-bicarbonate-dithionite (CBD) extraction and micro CT-Scan images were used to evaluate the source of magnetic susceptibility. The results showed that soil samples lost 23 to 91 percent of their magnetic susceptibility after CBD extraction (χCBD), reflecting differences in the source (pedogenic or lithogenic) of magnetic susceptibility. Greater values of the decrease were noticed mostly in well developed soil profiles as well as in soil surface. 22 to 89% of the decrease was observed in frequency dependence of magnetic susceptibility (χfd) after CBD extraction. A significant positive correlation (P<0.01) was obtained between χCBD and χfd in the soil studied. Micro CT-Scan images with a spatial resolution of 33 µm showed lithogenic magnetic Fe oxide (magnetite) grains.
S. Shamsi Mahmoodabadi, F. Khormali,
Volume 15, Issue 55 (4-2011)
Volume 15, Issue 55 (4-2011)
Abstract
In order to study the effects of different land uses on soil development, a loess hillslope was selected in Agh-Su area, eastern Golestan Province. Six profiles in four land uses including pasture, Quercuse natural forest, Cupressus artificial forest and a cultivated land, were dug and studied. Samples from different horizons were collected for physico-chemical and microscopic analyses. Important physical and chemical attributes such as bulk density (Bd), mean weight diameter (MWD), Organic carbon (SOC), cation exchange capacity (CEC), soil calcium carbonate (CCE) and available P were compared in land uses. Organic matter, CEC and MWD were significantly lower in the cultivated land use. Organic matter content in the forest and pasture area was considerably higher than that of cultivated land use. Soil profile development studies revealed that forest soils were highly developed. Quercus natural forest soils were classified as Calcic Argixerolls. Unlike cultivated soils which showed the minimum development and were classified as Typic Calcixerepts, formation of argillic horizon with dominant speckled b-fabric in the natural forest indicated the high landscape stability. Crystallitic b-fabric of horizons showed the absence of enough leaching of carbonate and the subsequent migration of clay particles. Intense erosion of the surface horizons of cultivated land use resulted in the outcropping of the subsurface carbonate rich horizon preventing soil development. The soils of pasture and Cuprecuse soils had mollic epipedon and were classified as Typic Calcixerolls with moderate development. Micromorphological properties of soils can help consider changes in pedogenic processes occurring under different land covers.
M. Zare, M. Soufi, M. Nejabat, L. Jokar,
Volume 18, Issue 67 (6-2014)
Volume 18, Issue 67 (6-2014)
Abstract
Gully erosion and sedimentation have high priority in Fars Province due to the losses from destruction of lands, roads and civil structures. In the present study, in order to evaluate the threshold for the development and initiation of gully topography in Fars province, two regions were selected including Allamarvdasht, Lamerd and Fedagh, Larestan. 30 gullies were selected in each mentioned area. Morphometric parameters were measured and topography threshold was drawn. To evaluate the effect of measured parameters on topography threshold, each gully was clustered based on parameters and cluster analysis. To determine the effect of dominant hydrologycal processes on gully initiation and development, the multivariate analysis was employed using SPSS (version 14) software. Using the power relationship between watershed area and slope of each gully, the dominant hydrological processes in gully initiation and development were determined by means of Excel software and were compared with coefficients of foreign regional studies. The results showed that in the two studied regions, the most effective hydrologycal process was surface runoff. Results also demonstrated that in these regions changing the shape of upstream basin topography to circle and their expansion have increased the threshold of watershed topography of gully erosion. Increasing the sodium absorbtion ratio and removing the ground cover reduce the threshold of gully erosion topography. Increasing the depth of gullies and soil organic matters resulted in greater relative threshold of topography.
A. Honarbakhsh, M. Pajoohesh, M. Zangiabadi, M. Heydari,
Volume 21, Issue 4 (2-2018)
Volume 21, Issue 4 (2-2018)
Abstract
Nowadays, human interferences in the natural resources cause the loss of these resources and lead to destructive floods, soil erosion and other various environmental, economic and social damages. Furthermore, increasing growth of population and climate change intensify the destructions. Thus management and planning through land use optimization is essential for the proper utilization, protection and revival of these resources. The purpose of this study is to couple the fuzzy goal programming and multi objective land allocation optimization approaches to develop a model for watershed management and planning in Chelgerd watershed. The proposed model is based on optimum area determination in various land uses and also their optimum local situation. In this research, a fuzzy model has been proposed. In this model, minimizing the amount of soil erosion and maximizing the amount of profit are priorities, respectively. Moreover, production resources including water and land as well as economic and social problems are limitations of the mentioned model. Results obtained show that the proposed model is an efficient model in land use optimization and sustainable area development and can increase profit to 37% and decrease sedimentation to 2.4%, respectively.
H. R. Moradi, M. Rahmati, H. Karimi,
Volume 22, Issue 1 (6-2018)
Volume 22, Issue 1 (6-2018)
Abstract
Groundwater is a major source of drought. Karstic aquifers are important sources of groundwater in the West and Kermanshah province. This study was performed to investigate the effects of the meteorological drought on the karstic aquifer with different conditions of development. The studied areas in this research included two karstic aquifers, Bistoon-Parau and Patagh mountain in Kermanshah province. In this study, we used monthly precipitation and springs discharge during a period of 20 years. Accordingly, the SPI and SDI indices were used to investigate the different states of meteorological and hydrological droughts, respectively. To determine the relationship between meteorological droughts and groundwater, Pearson correlation was used; aalso, to determine the time delay, the correlation between the different time conditions (no delay and delay 1 to 6 months) of the SDI index and the SPI index was investigated. The results of the relationship between the meteorological drought and groundwater showed that both had a significant correlation (p-value: 0.01). Also, based on the results of the correlation between different time conditions (no delay and delay 1 to 6 months) ,the SDI index was compared to the SPI index, showing that the time delay between the occurrence of meteorological drought and groundwater in the studied areas without time delay or a maximum one-month delay had happened. Based on the results, Pearson correlation coefficients between the SPI and SDI indices in the Bistoon-Parav region were more than those of the Patagh mountain region indicating the development of the Bistoon-Parav karst region, as compared with the Patagh Mountain.
B. Farid Giglou, R. Ghazavi,
Volume 22, Issue 3 (11-2018)
Volume 22, Issue 3 (11-2018)
Abstract
In this research, a regression model was introduced to study the mechanisms of the formation of gullies in the Quri Chay watershed, northern Ardebil province (Moghan Plain); this was done through investigating the effective factors of geo-environment and soil characteristics on the gully erosion. For this purpose, 17 gullies were randomly assigned through field surveys. Mapping and recording the morphometric of the selected gullies were performed by GPS positioning after seven rainfall events. The catchment-upper area of each gully was determined and its related physical parameters were calculated in order to investigate the effect of the physical characteristics of the catchment. Soil sampling was also done at the head of each gully at two different depths (30-30 and 60-30 cm) in order to determine the physical and chemical characteristics of the soil. According to measurement of the morphometric characteristics of the gully and soil characteristics through multivariate analysis of the data, a suitable regression model was developed for the longitudinal development of erosion after determining and calculating environmental factors related to the upper catchment of the gullies. The results of the correlation matrix between the longitudinal extension of the gully and the factors investigated indicated that the factors related to the physical characteristics of the beside watershed (area, perimeter, main stream length and average width of the catchment, main stream slope), gully morphometric characteristics (mean of gully cross section, the gully expansion area, and the gully average width) and soil characteristics (geometric mean of the aggregates diameter, lime, organic matter percentage) affected the formation and expansion of gully erosion in the Quri chay catchment. The results of regression analysis showed that the longitudinal expansion of the gully was mostly influenced by the area around each gully and the percentage of organic matter, which resulted in pressure on the rangeland and the loss of vegetation, which increased runoff and accelerated the lengthwise expansion of the gully. Also, the increase in the area of the beside catchment the gullies is known as one of the factors influencing the length of the gully, due to the high volume of runoff entering the head cut section; so it is necessary to manage runoff in the gully with the large beside catchment.
A. Khatoon Abadi, E. Parvizi, M. Ataie,
Volume 22, Issue 4 (3-2019)
Volume 22, Issue 4 (3-2019)
Abstract
In the recent decades, dams have paradoxically been considered as a constraint and or a driving force of surface water conservation. On the other hand, dams have had a number of socio-economic and environmental impacts, the main reason for conducting the current case study on Shah-Qasem Dam in Yasouj, Iran, was to employ the survey field research through a questionnaire to assess the rural peoples’ viewpoint; this was done in four villages of the Southern Sar’roud County. Based on the (Cochran) formula, 192 individuals were relatively selected from each village. According to the findings, the most important impact of the dam was mainly economical (the average impact was between 2.37 and 3.7), whereas the least one was environmental (the average impact was between 1.81 and 3.54). Also, the results of the hypotheses’ analyses by means of 2 and Wilcoxon showed the following results: rise of the villages’ income, increase of the cultivated farms, increase in the employed individuals, enhancement of the cultivated crops, the regions production rising, improved tourism, lack of people’s participation in the decision making process, and reaming of the same plant varieties in the area, as compared with the pre-dam era. It is worth considering, however, that based on the statistical population used, this study was concerned mainly with the short benefits of the dam, rather than its long-term destructive ones.
Z. Amiri, M. Gheysari, M. R. Mosaddeghi, M. S. Tabatabaei, M. Moradiannezhad,
Volume 23, Issue 2 (9-2019)
Volume 23, Issue 2 (9-2019)
Abstract
Location of soil moisture sampling in irrigation management is of special importance due to the spatial variability of soil hydraulic characteristics and the development of root system. The objective of this study was determination of the suitable location for soil moisture sampling in drip-tape irrigation management, which is representative of the average moisture in the soil profile (θavg) as well. For this purpose, soil moisture distribution (θij) at the tassel stage of maize and one irrigation interval (68-73 day after plant) were measured at the end of season. The results showed more than 70% length of the root of plant was located in 30 cm of the soil depth. By accepting ±10% error in relation to the averaged soil moisture, some region of soil profile was determined which was in the acceptable error range and also near the averaged soil moisture (0.9θavg<θRec<1.1θavg). By overlapping θRec in one irrigation interval, the appropriate location for soil moisture sampling was the horizontal distance from drip-tape line to 20 cm and the depth of 10-20 cm from the soil surface. To determine the appropriate place for soil moisture sampling, the development of root system and the maximum concentrated root length density in the soil profile extracting the maximal soil moisture should be taken in to account, parallel with the averaged soil moisture.
S.a.r Esmaili, A. Mosaedi,
Volume 26, Issue 1 (5-2022)
Volume 26, Issue 1 (5-2022)
Abstract
In recent decades, population growth, urban sprawl, urban environmental changes, and related issues are one of the significant issues in proper planning to manage the urban environment. One of the issues in urban development is the occurrence of floods and flooding due to heavy rains. In this research, flood modeling was studied in Mashhad Zarkash watercourses. The amount of rainfall for the return period of 10, 25, 50, 100, and 200 years were extracted by CumFreq software using the maximum 24-hour rainfall statistics of three rain gauge stations closer to the Zarkesh, Jagharq, Sar-e-Asyab, and Torqabeh watercourses basins during the statistical years 1364 to 1390. The peak discharge was calculated using the US Soil Protection Organization (SCS) rainfall-runoff method. Zarkesh watercourse is located on the outskirts of Mashhad. River and flood flow modeling was performed using Arc GIS, HEC-GEORAS, and HEC-RAS software in two conditions including structure (bridge) and no structure. Due to urban marginalization, urban development and land use change have greatly expanded in this region. The results of flood simulation showed that flood levels with a return period of 50 years increased by 50000 m2 equal to 22% in the presence of a structure compared to the state without a structure. The results of this research show that the construction of bridges on the river, the roughness coefficient by land use change, and the number of curves due to land permeability changes are effective in the flood zone.
M. Mehri, M. Hashemy, S. Javadi, M. Movahedinia,
Volume 27, Issue 3 (12-2023)
Volume 27, Issue 3 (12-2023)
Abstract
Rapid urbanization is responsible for impervious area increases and more runoff generation in urbanized catchments. Higher runoff volume in urbanized catchments leads to higher flood risk. One of the methods of runoff management is low impact development (LID). Bio-retention cell (BRC) is one of the infiltration-based LID practices that allows restoring the pre-development hydrologic cycle. However, the overall hydrologic performance of BRCs can vary depending on different urban environments. In this study, the hydrologic performance of BRC in terms of runoff and flood reduction was investigated in a highly urbanized area in the east of Tehran, Iran. The SWMM model was used to evaluate the performance of BRC. The results showed that BRC for rainfall with a return period of 2 to 50 years reduced the total runoff volume by 76.2% to 70.2% and the peak discharge by 65.9% to 36.4%, respectively. Also, for rainfall with a return period of 2 to 50 years, BRC resulted in 15.2% to 27.5% infiltration of rainfall in the study area, respectively. This study demonstrates that BRC can help restore the natural hydrologic cycle of urbanized catchments by reducing runoff and increasing infiltration.
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