Showing 8 results for Khaledi
S.s. Hosseini, M. Ghorbani, M. Khaledi, E. Hassanpour,
Volume 12, Issue 43 (spring 2008)
Abstract
This paper analyzed the effect of transaction costs on supply response of rice producers in Iran. Some of these producers participate in market as sellers or buyers and others remain self-sufficient. Farmers have different responses based on fixed and proportional transaction costs. The data used in this research consisted of information about 260 rice producers in Mazandaran province in 2004. The results indicated that lowering transactions costs would increase output by both increasing market participation and increasing production for market participants. Given that transaction costs affect market participation, aggregate supply will respond to changes in the transaction cost structure through its effect on market participation. It is recommended that policies reducing transaction costs be applied as a complementary policy to price policies to affect supply response.
A. Mohammadi, M. H. Biglouei, M. R. Khaledian, A. R. Moridnejad, J. Rajabi,
Volume 17, Issue 66 (winter 2014)
Abstract
To study the effects of irrigation durations and land slopes on wetting pattern dimensions, some experiments were performed using an emitter with constant discharge of 4 liters per hour by 2, 4, and 6 hours irrigation durations. Experiments were conducted on lands with the slopes of 0, 5, 15 an 25 percent, with silty loam soil texture in 3 replications in Fathali region, Mogan plain, Iran. Results showed that increasing the land slope caused an increment in wetting pattern dimensions and bulk, in constant irrigation durations. When slope increased, the depth of infiltrated water along the emitter had a little decrease which wasn’t significant. The upstream and downstream components of wetting pattern were symmetrical on 0 percent slope but not on steep lands. So, optimizing the water use, which is saved in the soil, depends on the land slope and the crop should be planted 10 to 25 centimeters away from the dripper. The investigation of soil moisture distribution on wetting pattern in slope lands showed that contrary to the flat lands the main part of the moisture is accumulated in lower part of the emitter, and wetting pattern in these sloping lands was larger than in flat lands.
F. Javadzadeh Shakhali, M. Khaledian, M. Navabian, P. Shahinrokhsar,
Volume 20, Issue 75 (Spring 2016)
Abstract
Soil moisture is one of the main input parameters in many models for monitoring and predicting crop yield. The ability of mathematical models has allowed correct application of brackish water and selection of management options. The purpose of this research was to evaluate the performance of HYDRUS-2D for simulating soil volumetric water content in a heterogeneous heavy soil under field conditions. Three volumes of irrigation water (10, 15 and 20 L) and three salinity levels of irrigation water (1.279, 2.5 and 5 dSm-1) were exerted in a linear drip irrigation system with three replications. In order to check the amount of soil volumetric water content, soil profiles were drilled to 40 cm depth and vertical wall of drip irrigation line was networked. Soil volumetric water content was measured with a TDR MiniTrase kit 6050X3K1B model. The observed soil moisture values were compared with the simulated ones using statistical indices (i.e. nRMSE and CRM). The results indicated that mean soil volumetric water content distribution in irrigation water with different levels of salinities was in the range of field capacity. The range of nRMSE values varied from 0.91 to 2.07 percent in different replications. According to calculated nRMSE values, performance of the simulation model, was ranked as excellent for simulation of soil volumetric water content. Range of CRM values was shown to be from -0.0080 to 0.0170 that was really low. Results of these two statistics indicate high ability of the model in simulating soil volumetric water content using estimating hydraulic parameters by inverse solution.
H. Khaledian, D. Nikkami,
Volume 21, Issue 1 (Spring 2017)
Abstract
Appropriate utilization of agricultural land and natural resources, decreased erosion and increased production occurs in watersheds. On the other hand, land use pattern due to increasing human activities on the ground to meet different needs, is changing. Optimization of land use is one of the management methods to achieve stability and reduce soil erosion. In this study, by using linear programming (simplex) and Geographic Information System(GIS), was investigated the land use optimization in three scenario option to: current condition, management condition, and standard condition.Erosion potential by using MPSIAC Model in irrigated land 1.65, dry lands 3.31, pasture 3.64, gardens 1.49 and 3.85 tons per hectare per year was estimated for Chehel-Gazi basin. The results of the sensitivity analysis for tree scenario showed that in the event optimize land use, erosion potential in the current Condition 0.85 percent increased, But in the land management Condition 16.92 percent and in a standard Condition 32 percent decreased. The results of sensitivity analysis showed that changes in the area of pasture all three options have the greatest impact in changing erosion potential of basin.
S. H. Roshun, Gh. Vahabzadeh, K. Solaimani, A. Khaledi Darvishan,
Volume 21, Issue 3 (Fall 2017)
Abstract
Sand and gravel mining from the most of our country rivers causes morphological, hydrological and geomorphological changes in these rivers. This study investigates the effects of removal of sand and gravel from the river bed on sedimentological features of Zaremrood River in Mazandaran province. For this purpose, by determining four sections before and four sections after the sand removing point, the river bed sediments sampling in combined approach and in a plot within the river were performed and sedimentology features such as the large, medium and small diameters (a, b and c), roundness (Rc), form factor (Sf), normal diameter (D), sphericity (S), and width ratio (W), were measured and calculated in the laboratory and analyzed by SPSS software. The results showed that the variations of sediment statistics a, b, c, Sf, D, S and W in the pre- and post- harvest location has a significant difference but the Rc statistic does not show any significant difference. The reduction of the triple diameters after the excavation site is caused by the fracture of the sediments in the mining area, so that the sphericity of grains also decreased in the mining area. Roundness of sediment particles after the excavation site is decreasing up to 600 meters reach and then it tends to increase.
N. Hasanzadeh, L. Gholami, A. Khaledi Darvishan, H. Yonesi,
Volume 25, Issue 1 (Spring 2021)
Abstract
Soil erosion is one of the most serious environmental issues in the world, causing soil degradation, reduction of land productivity, increasing flood, water pollution and pollutions transportation; it is also a serious threat to sustainable development in the world. Therefore, the soil conservation and the prevention of soil erosion and use of conditioners as the nanoclay can be considered as a solution to improve land productivity and protect environment. The present study was, therefore, conducted to address the effect of the application of montmorillonite nanoclay with three rates of 0.03, 0.06 and 0.09 t ha-1 on changing runoff and soil loss variables under laboratory conditions. The results showed that the nanoclay with the rate of 0.03 t ha-1 could decrease the runoff coefficient, soil loss and sediment concentration with the rate of 40.65, 88.38 and 82.19 percent, respectively. The average of soil loss in control treatment and conservation treatments of nanoclay with various rates was measured to be 3.76, 0.44, 1.33 and 3.16 g, respectively. Also, the results showed that the most sediment concentration was the control treatment with the rate of 5.84 g l-1 and the conservation treatments with nanoclay in the applied rates was 1.04, 3.47 and 2.96 g l-1, respectively. Also, the results showed that the nanoclay effect was significant on changing the soil loss and sediment concentration at the level of 99 percent. Finally, due to the effect, the use of this conditioner in natural conditions and investigation of the effects on environment and aggregates stability are recommended.
L. Gholami, A. Khaledi Darvisan, N. Karimi,
Volume 25, Issue 3 (Fall 2021)
Abstract
Soil loss can cause many intra-regional and extra-regional problems, on the other hand, the effect of soil moisture on processes of soil loss and sediment yield for the identification and simulation of soil hydrological response is necessary. Therefore, the application of soil conditioners is essential for soil and water conservation. The present study was conducted to investigate the effect of soil conditioners of vermicompost and nano-manure on variables of soil loss and sediment concentration at moistures of air-dried, 15 and 30%, and rainfall intensities of 50 and 90 mm h-1. The obtained results in addition to confirmation of the significant effect of each conservation treatment at the level of 99 percent on the intended components showed that the conservation treatment of vermicompost compared to nano-manure treatment had more effect on measured variables. Also, the conservation treatment of vermicompost could decrease the soil loss at soil moisture air-dried, 15, and 30 percent with rates of 72.15, 66.63, and 78.76 percent (50 mm h-1), respectively, and 45.01, 35.57, and 10.45 percent (of 90 mm h-1), respectively. The effect of conservation treatments, soil moistures, and rainfall intensity and the interaction effects of conservation treatments × rainfall intensity and rainfall intensity × soil moisture on changes of soil loss and sediment concentration were significant at the level of 99 percent. The application of vermicompost and nano-manure had acceptable results on studied parameters but the vermicompost effect was more than nano-manure. Therefore, due to the widespread use of different types of conditioners, nowadays, it is needed to move the application feasibility of conditioners such as vermicompost and nano-manure that these have not the adverse effects of environmental.
D. Khatibi Roudbarsara, A. Khaledi Darvishan, J. Alavi,
Volume 27, Issue 2 (Summer 2023)
Abstract
Soil erosion followed by sediment production is the most important phenomenon that causes soil and environment degradation in many areas and is increasing. Sediment fingerprinting is a method to identify sediment sources and determine the contribution of each source to sediment production. The present research was carried out to evaluate the relative erosion sensitivity of lithological units and to determine the contribution of each unit in bed sediment production using geochemical properties in the Vaz River located in Mazandaran province. The 33 soil samples were taken from the whole watershed and one sediment sample at the outlet of the watershed. Then, five tracers of B, Al, Sc, Mo, and Sn were selected as the optimal combination using three statistical tests range tests, Kruskal-Wallis, and discriminant function analysis. Finally, using optimal tracers and a combined multivariate model, the contribution of lithological units with very high (A), high (B), medium to high (C), and medium (D) sensitivity in bed sediment production were obtained using FingerPro statistical package and R software. The results showed that the contribution of lithological units with very high (A), high (B), medium to high (C), and medium (D) sensitivity in bed sediment production were 24.23, 50.77, 15.62, and 9.36%, respectively. Then, the specific contribution of each sensitivity class was also calculated to remove the effect of area on the results. The Qal lithological unit including the Quaternary sediments in the river bed and banks with very high sensitivity to erosion (A) and a specific contribution of 0.0807 % per hectare had the maximum contribution in bed sediment production in Vaz River.
