جستجوی مقالات مرتبط با کلیدواژه "اقتصادی" در نشریات گروه "آب و خاک"

Considering the lack of renewable water resources in the world and the high share of the agricultural sector in water consumption, makes increasing water productivity very important. Corn is an important type of fodder that is harvested for consumption as silage of the whole plant (Coors et al., 1997). Despite having one harvest stage, this plant has a high dry matter yield. Its silage is easily prepared and it is a tasty fodder with stable quality for livestock and has higher energy than other fodder (Curran and Posch, 2000). Research results in Hamedan province in two traditional and modern irrigation systems showed that the average physical water productivity for fodder corn in traditional and modern irrigation systems was 5.11 and 6.67 kg per cubic meter of water, respectively. The average economic water productivity for fodder corn in traditional and modern irrigation system was 7678 and 10068 rials per cubic meter of water, respectively (Seyedan and Mottaghi, 2019). The main purpose of this article was to measure the water received in the field of fodder corn fields in Behbahan city and to investigate their physical and economic water productivity. To do this, the applied irrigation water, physical and economic water productivity under different agricultural management and in irrigation networks and systems can be compared and evaluated.

This research was carried out in the field and in order to investigate the effects of independent variables on applied irrigation water, physical and economic water productivity in the cultivation of fodder corn in irrigation methods and networks under the management of farmers in the cropping season (2016-2017). It was implemented in Behbahan city. Thus, in 12 farms of the farmers, the applied fodder corn irrigation water was measured (without interfering in their irrigation program). The effective rainfall of the 2016-2017 crop year in Behbahan city was calculated using the United States Department of Agriculture (USDA) method. To determine the applied irrigation water, first, the inflow rate from the selected water source was measured with a suitable device (WSC flume, water meter and ultrasonic flow meter). The SPSS16 software was used for step-by-step linear multivariate regression analysis. Linear multivariate regression analysis was used to investigate the effects of independent variables on dependent parameters. One-way analysis of variance was performed with SPSS16 software. The purpose of using one-way analysis of variance was to statistically show a significant difference between the average of two or more "independent" groups. In order to compare the indicators of physical and economic water productivity , there was a need to resolve the difference. Therefore, to solve the scale difference, the common method of Z-Score standardization was used.

The results of the analysis of variance in the regression model showed that the growth period of the plant had the most significant positive effect on the amount of irrigation water with the t-statistic of 5.288. Performance with a t-statistic of 5.919 had the most significant positive effect on economic water productivity. Among the independent variables, yield and applied irrigation water had the most significant positive and negative effect on the physical productivity of water with the values of 6.419 and -6.381, respectively. The applied irrigation water varied from 4826 to 14733 cubic meters per hectare. The results of the analysis of variance and the descriptive results of the mean of the traits showed that the highest value of physical water productivity was equal to 10.128 kg/m3 in rain irrigation and the lowest value was 4.818 kg/m3 in surface irrigation in the traditional network. They had a significant difference. The calculated Z-Score values showed that 50 and 33% of the sprinkler and surface irrigation farms (modern network) had acceptable economic productivity, but 100% of the surface irrigation farms in the traditional network did not provide acceptable economic productivity.

The amount of irrigation water used in the fields with sprinkler irrigation method was 46 and 33% less than traditional and modern network fields that were irrigated by surface irrigation method. Also, the consumption of irrigation water in the surface irrigation method in the traditional network was 20% more than the surface irrigation in the modern irrigation network. This increase in water consumption was effective in reducing the irrigation efficiency of traditional networks compared to modern networks that irrigated with surface irrigation. The reason for the higher consumption of irrigation water in the surface irrigation method in the modern network compared to sprinkler irrigation can be attributed to the following factors: 1- The lack of irrigation management during the change of the irrigation shift of the fields, which sometimes happens due to the absence of the irrigation worker during the shift change. 2- lack of control of the incoming water of the fields due to the lack of meters or devices to measure the incoming flow. 3- Improper leveling of lands under the modern irrigation network, which increases the irrigation time of these fields. By covering the traditional irrigation canals with concrete or other coverings suitable for the climate of the region, water losses can be reduced. Also, the necessary training for the correct use and management of irrigation water according to the different stages of fodder corn growth will be effective in reducing water consumption. Water according to the stages of growth and development of the plant prevented the occurrence of under-irrigation stress in the stages of flowering and seed filling, which is the most important stage sensitive to water stress.

Even though dams have many social benefits, it also has caused social, economic, environmental and technical management risks along time. Due to the fact that the dam is considered a great phenomenon in nature, its effects on the environment are extensive. One of the issues that must be investigated during the operation of dams is the negative environmental effects in the dam construction area. The negative environmental effects of dams are including sedimentation in the dam's reservoir and lake, intensification of erosion in the downstream lands, inundation of agricultural lands due to rise of the underground water level. The effects of the mentioned risks for dam construction may be irreparable. The aim of this study is evaluating the effects of social, economic, technical management and environmental risks affected by the construction of dams on the watershed. Decisions related to the management of these dams require recognize the dangers and risks in the dam and prioritize them. Dam construction projects are more risky than other projects due to the high credits and time spent on their construction. Using multi-criteria decision-making methods is a suitable tool for evaluating different risks in these dams. In this study, the combined DEMATEL-ANP method is used to identify the relationships between risk criteria and sub-criteria and prioritize them. So, four criteria and 42 sub-criteria were determined to evaluate different risks in Mamloo, Taleghan and Lar dams and the network relationships between them were determined. The results show that the employment sub-criterion in economic criterion with a weight of 0.0720 has the highest risk and the land acquisition sub-criterion in management technical criterion with a weight of 0.0029 has the lowest risk compared to all sub-criteria.

With urban developments and the aging of urban water distribution pipes their demand  for repair and maintenance is rapidly grown. There are several factors that affect the performance and leakage in water and wastewater distribution networks (Ameyaw and Chan, 2016). By increasing the water leakage from pipes and wastewater depletion from houses to the injection wells, water level under the city ground is rising and saturation condition will be created near the underground infrastructures. In recent years, local uplifting of subsurface water level in metropolises created different challenges over water and wastewater systems with multiple damage effects (Baah et al., 2015;Qiu et al., 2016).İn recent two decades, the rising of groundwater table in Kerman city have caused several challanges over the water and wasetwaer infrustructures. İn the ancint zone of the Kerman city, water level come up to 3 meter under the groundsurface and is interacted with several underground structures and basment flooding. The rising water table have several destructive  effects over the urban infrastructures. The main purpose of the present study is to investigate the effects of rising subsurface water level  in Kerman city by using an AHP based damage prioritization to depict the relative importance or urgency of a damages of water level rising over infrastructures.

Water leakage from dam reservoir and body is one of the most concerning issues in establishment of such large projects, which in addition to wasting costs brings lots of negative social and environmental consequences. One of the dams of Urmia lake catchment area, which suffers leakage phenomenon being unusable, consequently, due to not doing exact geotechnical studies is Arbatan reservoir of Heris town. Investigation of the dam establishment site shows that the dam reservoir has been placed on evaporative sediments and water penetration has resulted in formation of some sinkholes and water escape channels in the lower substrates and the dam discharge. So the aim of the present research study is to evaluate use of clay blanket for covering the reservoir floor and its restoration. To do so, after identifying subterranean features of the reservoir using SEEP/W numerical model and bent method, leakage amount of water was determined under clay blanket application state. Results of the two numerical and bent methods indicated that leakage amount of the dam reservoir covered with clay blanket are 23569 and 584000 cubic meter, respectively, within 180 days. So, with huge amount of leakage, efficiency of the method will not be effective and a good solution for the dam restoration. In general, such amount of leakage might result in repeated rapture in the dam body and clay blanket. So under such conditions, success of every investment related to this dam will confront high level of uncertainty.

The aims of this study are evaluation of water use management and water use efficiency of Yamchi pressurized irrigation and Ghoorichay low pressurized (hydroflume) canals, with total area 3885 ha and located in Ardabil plain. Annual relative irrigation supply, Annaual relative water supply, relative rainfall supply, water productivity and irrigation water productivity, as physical water use efficiency and parameters pure and impure benefit of water use efficiency and pure and impure benefit of irrigation water use efficiency as economic parameters were calculated. Results showed that, for four years of 2011-12, 2012-13, 2013-14 and 2014-15 mean of irrigation deficit of Yamchi and Ghoorichay canals were calculated 28 and 43 percentage, respectively. For three years of 2012-13, 2013-14 and 2014-15 mean of water productivity in Yamchi and Ghoorichay canals was calculated 1.52 and 2.15 kg/m3 and mean of irrigation water productivity was calculated 2.16 and 4.08kg/m3, respectively. Mean of water pure and impure benefit for Yamchi canal were estimated 987.67 and 884.67 toman/m3 and for Ghoorichay canal were estimated 4028 and 9100 toman/m3 , respectively. Mean of irrigation water pure and impure benefit for Yamchi canal were estimated 12669, 1515.33 toman/m3 and for Ghoorichay were estimated 23988.33 and 6523.33 toman/m3, respectively.

Soil is a key resource that contributes to the earth system functioning as a control and manages the cycles of water, biota and geochemical and as an important carbon reservoir. Soil organic matter is one of the most important factors in soil quality assessment and having relationship with physical, chemical and biological properties of soil. Carbon sequestration in plant biomass and soils is the simplest and the most economically practical solution to reduce the risks of atmospheric carbon dioxide. Little information is available about the effects of grazing management on sequestration of carbon in Khuzestan Province pastures. Therefore, this study was conducted to evaluate the effects of grazing exclusion on the amount and forms of carbon management and carbon sequestration with economic view in some pasture soils from Peneti Plain of Izeh area and Dimeh regions of Ramhormoz in Khuzestan Province.
This study was conducted in two regions including Izeh and Ramhormoz representing different climates, vegetation and soil types of southwestern Iran. We selected two grazing treatments including ungrazed and grazed pastures in each region. The first area includes rangeland ecosystem in Izeh city between 31° 57ʹ 8ʺ to 31° 58ʹ 20ʺ N and 49° 41ʹ 11ʺ to 49° 42ʹ 33ʺ E. The region has a typical temperate continental climate, characterized by dry summers and cold winters. The mean annual rainfall is 623mm. The mean annual temperature (MAT) is 19.2 °C, and the mean monthly air temperature varies from -0.6 °C in January to 42.4 °C in July. The second area (Ramhormoz) is located between 31° 7ʹ 44ʺ to 31° 9ʹ 11ʺ N and 49° 29ʹ 13ʺ to 49° 28ʹ 52ʺ E. The mean annual rainfall is 200 mm and the mean annual temperature (MAT) is 27.2 °C, and the mean monthly air temperature varies from 4.2 °C in January to 51.6 °C in July. For each climate region, grazed and ungrazed sites were located on the same soil series with similar aspect and slope. Then, random soil samples were taken from the surface and subsurface in 15 points. After air drying the soil samples and passing them through a 2 mm sieve, physical, chemical properties of the soils were measured.
The soil of both studied regions are non-saline, calcareous, and alkaline and have relatively heavy texture. The results showed that the studied characteristics in four study areas had low and moderate coefficients of variation. This suggests that the contribution of edaphic and environmental factors to explain variation in the data is not high. Also, grazing management has increased soil organic matter of surface and subsurface soil, but despite the increase in organic matter contents of subsurface soils the difference was not statistically significant. The effect of management practices, in order to have a significant effect to lower parts of the soil, it requires a longer period management. Comparing the biomass upon non-grazing (405 and 42 gm-2 in Izeh and Ramhormoz respectively) and grazed (117 and 17 gm-2) areas, indicates a good condition of vegetation in the non-grazing and the effectiveness of enclosure in rehabilitation of pastures in the study area. However, due to more rainfall rates, the amount of biomass produced in Izeh is higher.
The carbon management index in the study areas, as well as the depths of the study is high, indicating recovery of soil carbon and improving its quality. Also, based on carbon sequestration in the study area, non-grazing was one of the most proper and efficient management practices, which improved soil quality. Accordingly, it seems that non-grazing practices should be considered as one of the major programs in renewable natural resources plans. On the other hand, estimation of the economic value of carbon sequestration in the pastures has been remarkable, and increased 17 and 12.7% of the value of carbon sequestration in Izeh and Ramhormoz regions under the management of the exclusion. Therefore, the management of rangelands should be directed to allow for their ecologic performance and capacity considering the environmental economy of rangelands so that in broad terms, the justification for the enhancement and maintenance of the economic equilibrium can be viewed as a guaranty of implementing the range managements resulting in sustained development.

Production and growth of plants in many parts of the world due to degradation and water scarcity have been limited and particularly, in recent decades, agriculture is faced with stress. In the most parts of Iran, especially in the Khorasan Razavi province, drought is a fact and water is very important. Due to melon cultivation in this province, and the conditions of quality and quantity of water resources and water used to produce the melon product in this province, any research done on the use of saline and brackish waters is statistically significant. To study the effects of different water salinity and water management on some of the agronomic traits of late summer melon with drip irrigation, an experiment with 7 treatments and 3 repetitions was conducted in a randomized complete block design, in Torogh station, Mashhad. The irrigation treatments were: 1- fresh water from planting to harvesting, 2- water (3 dS/m) from planting to harvesting, 3- water (6 dS/m) from planting to harvesting, 4- water (6 dS/m) from 20 days after plantation to harvesting, 5-water (6 dS/m) from 40 days after plantation to harvesting, 6-water (3 dS/m) from 20 days after plantation to harvesting, 7-water (6 dS/m) from 40 days after plantation to harvesting. Row spacing and plant spacing were 3 m and 60 cm, respectively and the pipe type had 6 liters per hour per unit of meters in the drip irrigation system. Finally, the amount of salinity water, number of male and female flowers, number of seed germination, dry leave's weight, leaf area, chlorophyll (with SPAD) etc. were measured and all data were analyzed by using MSTAT-C software and all averages of data, were compared by using the Duncan test. Results and Discussion The results of analysis of data showed the following: Number of seeds germination: Salinity in water irrigation had no significant effects on the number of seed germination. However, there was the most number of seed germinations in the fresh water treatments. However, with increased water salinity, the time of seed germination reduced. The maximum delay in germination of seeds was in the treatment that was irrigated with fresh water from the beginning of cultivation. Number of flowers: First, the male flowers appeared and after 5 to 7 days, the appearance of female flowers began. The effect of irrigation treatments on female flower appearance was significant. With increased water salinity, the number of male flowers decreased. There was the lowest male flower in the treatment that was irrigated with saline water from the beginning, but there was no significant difference among the other treatments. Root, steam and leaves: The effect of saline irrigation water on dried leaves’ weight and dry root weight was significant at 1% and 5% levels, respectively. Fresh treatment and salinity treatment have the least and the most root dries weight, respectively (irrigated from the beginning with fresh or saline water). Two treatments that were irrigated with fresh and brackish water from thebeginning of cultivation have the highest leaf growth. The same trend was true for steams. In general, in all treatments, after applying different quality water to the end of the growing season, the trend of plant growth was similar to the others. Chlorophyll: One of the most common measurements made by plant scientists is the determination of Chlorophyll concentration. The SPAD index was used for comparison of chlorophylls. With an increase of the salt in irrigation water, the SPAD index was also increased. The maximum and minimum SPAD was in the treatments that were irrigated with saline water (treatment A) and fresh water (treatment C) from the beginning of cultivation, respectively. Yield: With increasing the salinity of water, the total yield decreased. Salinity in irrigation water had a significant effect (at the 5% level) on total yield. The mean yield of brackish and salinity irrigation water treatments were 17.5% and 26% less than the fresh water irrigation treatment, respectively.These differences were significant. However, there was no significant difference between the yield of cases using brackish or salt water. The results showed the following: Salinity in irrigation water had no significant effect on the number of seed germinations. However, there was the most number of seed germinations in the fresh water treatments, but by raising the salinity of water, the time of seed germination was reduced. With increasing the salinity of water, the number of male flowers decreased. There was the lowest male flower in the treatment that were irrigated with salt water from the beginning, but there was no significant difference between the other treatments. The effect of salinity water on leaf dry weight and dry root was significant at 1% and 5% levels, respectively. Fresh and salinity treatments have the least and the most root dry weight, respectively (irrigated from the beginning with fresh or salt water). Two treatments that were irrigated with fresh and brackish water from the beginning of cultivation have the highest leaf growth. The same trend was true for steams. Two treatments that were irrigated with fresh and brackish water from the beginning of cultivation have the highest leaves areas. And they had significant difference with other irrigation treatments. With an increase in the salt in irrigation water, the SPAD index also increased. The mean yield of brackish and salinity water irrigation treatments were 17.5% and 26% less than that of fresh water irrigation treatment, respectively.These differences were significant. But there was no significant difference between the yield of brackish and salt water.

Sustainable development of pressurized irrigation systems is a key to mitigate the crises of water scarcity، mainly because of more demand for food، in Iran. However، despite the importance of the issue، little areas of lands are equipped with the pressurized irrigation systems and still there are long way to reach to the desired level. Moreover to the different technical، technological، and infrastructure problems and challenges associated with the sustainable development of pressurized irrigation systems in Iran، socio-economic and policy –institution issues and problems are among the important cases. Therefore، the objective of this research project was to systematically identify the socio-economic and policy–institution problems، issues، and challenges associated with the sustainable development of pressurized irrigation systems in Iran. The methodology of the program was fully participatory، with the participation of representatives of different stakeholders in the water and the agriculture in general، and the experts، and resource persons in pressurized irrigation enterprise of the country in specific. The ISNAR approach was used here. The experts were gathered and participated in the different brain storming meetings to identify the relevant problems، issues، and the challenges. The research outputs were mainly in the form of problem trees. However the identified problems were also prioritized، based on their importance، and some related strategic pivots were also developed finally. Based on the results، the main socio-economic and policy –institution problems hindering sustainable development of pressurized irrigation systems in Iran could be categorized in the following categories: Economic and finance problems (including national economy، costs to the beneficiaries، banking and finance and credit issues)، socio-cultural problems (including socio-cultural basis and capacity building، inefficiencies in adoption of the systems، and weaknesses in agricultural production systems)، policy and institutions issues (including organizational and human resource structures weaknesses، and problems associated with the policy and planning، inefficiencies in motivation of beneficiaries willingness toward the acceptance and adoption of the systems). Quantity basis، the economic-finance، socio-cultural، and policy-institution problems were totally 88 cases، and based technical discussions and comments of the stakeholders assigned into different selected categories. From the strategic aspects، results of this research indicated that the following strategies should be implemented in the country for the sustainable development of pressurized irrigation from socio-economic and policy institutions aspects: 1) More involvement of the private sector in pressurized irrigation systems development and hence disengagement from the government 2) More attention to energy savings in the systems، considering growing demand of energy and energy prices increase to happen in near future 3) Selection of economic criteria in prioritizing development of pressurized irrigation systems in different regions، and 4) More focus of research studies and plans on measures for economic justification of using pressurized irrigation systems in small farms.

Extension of cultivation areas becomes gradually impossible due to ever-increasing population growth and urban area development in Iran. Therefore, it is very important to use the existing cultivated lands more efficiently. Land suitability evaluation makes the sustainable use of the lands feasible. The objective of this study was qualitative, quantitative and economic suitability evaluation of irrigated croplands for wheat, maize and sesame in Mehran plain, Ilam Province. Soil survey in the field, laboratory analysis of the soil samples, qualitative, quantitative and economic evaluation were different successive stages of this research. In qualitative evaluation, climatic, topographic and soil suitability classes were determined according to the degree of the matching with plant requirements, by parametric (square root) method. Quantitative and economic evaluations were done based on observed, potential and marginal yield analysis. Results of the qualitative land evaluation showed that most of the land units were classified moderately suitable for given crops because of soil limitations. Qualitatively, most of the land units were classified in the same classes as, or in lower classes than quantitative suitability classes for wheat and maize production, due to high management level at the farms. Whereas quantitative classes of sesame were determined lower than qualitative classes induced by low management level for this crop. Economic land suitability classification showed that the wheat production was the most economic land utilization type. Results of the economic assessment suggested that the cultivation of wheat in rotation with sesame would produce the most income for different units and could be increased in future using improvement in management level in the study area for sesame cultivation.

Northern watershed of Kouhrang River with the area of 68437 hectares is located in northwestern Chahar Mahal and Bakhtiary province within 49 54 to 50 9 E longitude and 32 83 to 32 36 N latitude.Making a balance and equilibrium between the number of ranchers, the rangeland production potential and appropriate flock size in each utilization unit is a necessary task. It is a matter of importance to determine suitable ranch size based on pastoral household but suitable household livelihood as well. The main goal of this study is to determine utilization unit size based on ecologic and socioeconomic factors for each household. Along with detecting the ranch allotments, the range capacity and its productivity potential were studied. Then, based on expenses and the revenues resulting from herdship,(on ranges), the suitable flock size for fulfillment of the household expenses regarding the range utilization periods, the suitable range size per household was determined. 10 vegetation types with 0.91 AUM per hectares grazing capacity were detected in studied area. There are 46 range allotments and some parts of other 6 range allotments in studied area with average area at 1510 hectares. Average pastoral household is 36.8 per unit range allotments. Pastoral households share at rangelands is 41 hectares now. The minimum and suitable ranch area for each pastoral household which can provide annual needs and costs is 520 hectares and 142 animal unit at a mix flock at 3 to 2 ratio of sheep to goat for a 100 – dayes grazing season. The result of this study showed that production potential at each range unit is influenced by flock size, household share on farming lands, and the household numbers on each ranch unit. Ranch unit and the livelihood level, have significant influence at 5% level on suitable ranch size per household.

In Iran, the development of cultivated areas becomes gradually impossible due to ever-increasing population growth and urban area development. Therefore, it is very important to use the existing cultivated lands more efficiently. Land suitability evaluation makes the sustainable use of the lands feasible. The objective of this study was qualitative, quantitative and economic assessment of land suitability in Talandahst area for rainfed wheat, barley and chickpea. Talandasht plain with a surface area of 4500 ha is located southwest of Kermanshah city. The climate is semi-arid with cold winter and moderate summer. The successive stages of this research included soil survey in the field, soil analysis, qualitative and quantitative and economic evaluations of land suitability. In qualitative evaluation of land, climatic, topographic and soil suitability classes were determined according to the degree of the matching. Limitation and parametric methods were used in qualitative evaluation. Quantitative and economic evaluations made based on the observed yield and gross benefit, respectively. Based on qualitative evaluation, the studied area is marginally suitable for rainfed farming of wheat, barley and chickpea. This is due to water deficiency occurring during some stages of the growing cycle. The solution for this problem is supplementary irrigation. In addition to climate limitation, there are also topographic and soil restriction for the growth of the studied crops. On the basis of observed yield, the land units are moderately to highly suitable for rainfed wheat and barley production. Among the three named crops, the most and least profitable ones are chickpea and barley, respectively, and wheat ranks between them.