h. naghavi

Today, the reprocessing of mineral processing plant tailings is important from an economic point of view (as a secondary source of valuable elements) as well as environmental issues. The purpose of this research is to characterize the flotation tailings of iron concentrate lines 5, 6, and 7 in Golgohar and their pre-processing in order to maximally separate copper and iron minerals and increase their grade. Therefore, after preparing representative samples from flotation tailings, instrumental chemical analysis, particle size analysis, and microscopic studies were performed on them. Then, using magnetic separation and classification methods, iron and copper separation and enrichment were done. The characterization results of the tailings showed that its main minerals are pyrite, magnetite, and talc, and the iron and copper grades are about 30% and 0.11%, respectively. The results of the pre-processing tests showed that by performing magnetic separation at a field intensity of 2000 Gauss, the grade of iron in concentrate and copper in the tailings increased to 47.8 and 0.18%, respectively. By adding a classification step before magnetic separation and discarding the coarse-grained part of the sample and then performing magnetic separation on the fine-grained part (-38 microns) in the field intensity of 2000 Gauss, the grade of iron and copper in the concentrate and tailings, respectively, is 53.6 and improved by 0.21 percent. Therefore, pre-processing can return the iron in the flotation tailings as an intermediate product to the iron concentrate production circuit and prevent its wastage. On the other hand, by discarding more than half of the flotation tailings, increasing the copper grade, and reducing iron in the rest, this operation created many technical and economic benefits for the copper extraction process in the next stages. Classification and magnetic separation methods are operationally simple and cost-effective and can be implemented in lines 5, 6, and 7 of Golgohar with minimal changes and costs.

One way of developing sustainable agriculture is to increase crop Water Productivity (WP). In drought conditions, cultivation management should result in reducing water consumption as well as lowering the negative impacts on crop yield and quality. This experiment was conducted to determine the influence of irrigation levels (full and deficit irrigation, providing 100 and 75% of the irrigation water requirement, respectively) and soil water retaining materials (organic fertilizer, superabsorbent at depths of 30 and 40 cm, superabsorbent mixed with soil, band application of superabsorbent, plastic installation at depths of 30 and 40 cm and control) on WP, leaf Relative Water Content (RWC), Electrolyte Leakage (EL), photosynthetic pigments, yield and yield components of wheat during the growing seasons of 2017 and 2018. The deficit irrigation caused an increase in WP and EL and decreased yield, yield components, RWC, and photosynthetic pigments, while the soil water retaining materials improved these properties. The average yields in the organic fertilizer treatment and installation of plastic at a depth of 40 cm were 9.55 and 8.76 tons ha-1, respectively. The highest WP (1.89 kg m-3) was observed in the organic fertilizer treatment. Application of cow manure and installation of plastic membrane did not have significant effect on wheat properties in the two water conditions. Overall, utilizing organic fertilizer and nylon membranes under deficit irrigation, improved wheat characteristics and WP. However, to reach a comprehensive conclusion, it is necessary to evaluate these treatments for several consecutive years with different soil and water conditions.

In order to investigate the response of safflower cultivars to different levels of soil P for its optimum use, this study was carried out in Darab, Isfahan, Dezful, and Kerman regions as a factorial experiment with a randomized complete block design in three replications in two cropping seasons (2015-2016). The first factor was cultivar (Padideh and Goldasht cultivars for Isfahan and Darab and Goldasht and Soffe for Kerman and Dezful) and the second factor was different rates of triple super phosphate (TSP) including zero, 50, 100, 150, and 200 kg.ha-1. The soil available phosphorus in Isfahan was 10.2, Darab 11, Kerman 7 and Dezful 7.18 mg kg-1. Based on the results, the effect of cultivar on safflower seed yield in Isfahan and Dezful was significant (p<0.01) and (p<0.05), respectively, but in Darab and Kerman, the difference between the two cultivars was not significant. The effect of TSP rate on grain yield in all four regions was significant (p<0.01).  The interaction effect effects of cultivar-phosphorus on the grain yield was significant only in Isfahan region (p<0.05). In Isfahan and Dezful, the highest yield was obtained from the Goldasht at the rate of 50 kg.ha-1, significantly different than the control. In Kerman, the highest seed yield was obtained from Goldasht and at 150 kg ha-1 TSP, significantly different than other treatments. With the application of TSP in Darab, Dezful and Isfahan, 20%, 78%, and 28%, increase in grain yield was observed compared to the control, respectively. The best benefit-to-cost ratio in Darab and Kerman regions was obtained from Goldasht for 100 and 150 kg.ha-1 TSP, respectively, while in Dezful and Isfahan it was obtained for 150 kg ha-1 TSP in Soffeh and Padideh, respectively. In general, for safflower in warm regions with soil available P of 10 mg kg-1, 50 kg.ha-1 TSP and for areas with soil available P of 7 mg.kg-1, 150 kg ha-1 TSP can be recommended.

Protection and conservation of forests require access to information and awareness of structural features such as number per hectare and canopy cover of trees. This study aimed to select the optimal cluster sampling design in estimating the quantitative characteristics of the forest according to the three measures including accuracy, precision, and time required for the sampling. For this purpose, 30 hectares of watershed Olad Ghobad forests in the west of Lorestan province were selected. The Cartesian coordinates of all the trees in them were determined. In Matlab2014 software environment, the position of all trees was simulated. Then different cluster sampling designs (triangular, square, star 1, linear, L-shaped, star 2) were  defined in the research  by taking into account the number of samples (30, 60, and 90) and three distances (10, 20, and 30 meters). These processes repeated 10,000 times. The results showed that there was no significant difference between the estimated mean of different designs of cluster sampling methods of the study area. Based on the number of samples and the distance studied, it was found that sampling error for linear design has the highest accuracy compared to other designs. The results of estimating the E%2× T index for the characteristic number of trees per hectare and canopy cover showed the lowest values for the square (770.99) and linear (2347) designs, respectively. The results of accuracy estimation for both mentioned characteristics of Star 2 Design showed the lowest values (18.83) and (-5.54), respectively. The results of accuracy estimation for both mentioned characteristics of Star 2 Design showed the lowest values (18.83) and (-5.54), respectively.

Soil compactibility can be quantified using different indices such as maximum dry bulk density (BDmax) and critical water content (θcritical) in a compaction test. The objective of this study was to determine soil properties influencing soil compactibility by evaluate pedotranfer functions (PTFs) with respect to their accuracy and usefulness for the prediction of BDmax and θcritical using linear regression and ANN methods. 100 soil samples were collected from arable and virgin lands in southeast Iran. Primary particle size distribution, CaSO4, CaCO3, organic matter (OM) contents and natural bulk density were used as predictors. Two PTFs were developed using linear multiple stepwise regression: a PTF that estimates BDmax using clay and sand contents and natural bulk density as predictors (R2 = 0.45), the other one for the estimation of θcritical using clay and CaSO4 contents as predictors (R2 = 0.51). Furthermore, an attempt was made to construct PTFs for the prediction of the BDmax and θcritical using ANNs. High prediction efficiencies were achieved using the ANN models. Generally, when all of the easily-available soil properties were included as predictors, much more accurate estimates were obtained by the ANN models for the θcritical and BDmax as compared with the linear regression method. Sensitivity analysis showed that the most important variable in BDmax prediction using ANNs is the BDnatural followed by sand and clay, CaCO3 and CaSO4 contents. The θcritical had the highest sensitivity to clay content and the lowest sensitivity to OM content in the studied soils.

The present study tries to investigate the effect of composting process on some properties and heavy metals status of two municipal sewage sludge (MSS) as affected by three different organic bulking agents (BAs) at three levels (10%, 25%, and 45% V/V). According to the results, the composting process could reduce the fecal coliform to class A, a reduction more obvious in treatments with BAs than produced composts without them. Changes in the chemical properties of the composts vary according to the type of MSS and Bas. Based on the compost quality standard, most of the produced samples are classified in compost-class II. Examination of the total form of three heavy metals (HMs: Zn, Ni, Fe) of both MSS shows that composting process without BAs increases the HMs total concentration, but using of BAs have not been clear trends. In the contrary, BAs application reduced the available form of Fe and Ni, but increased the Zn available form. Examination of chemical forms of each studied HMs also shows that the composting process reduces the Ni and Fe mobility factor, but increases that of Zn. Generally, while, prepared composts can classify into the compost-class II, based on their properties, the high concentration of total Zn above the standard limit makes it extremely restrictive to be used as class II compost. However, according to EPA regulations, the composts with this concentration of Zn can be used as a relatively safe organic material on agricultural land.

Dendrochemistry is the science of analyzing the elements of tree rings that identify the biochemical changes of a tree under environmental changes. In order to investigate the change in the concentration of some of the chemical elements in the wood of declined trees compared to healthy ones, three healthy and declined Iranian oak trees (Quercus brantii Lindl.) in forests close to Khorramabad were cut and a disk was prepared from each tree. Then the vegetative rings of the last 35 years were cut into three five-years and two 10-years-old cuttings and extracted by the wet digestion method and the concentration chemical elements were measured using the atomic absorption apparatus. The results showed that potassium concentration in the wood of declined trees was higher than healthy ones while calcium and copper concentrations in the wood of healthy trees were less. Also, the ratio of sodium and calcium to potassium concentration in the trees of the two communities was significantly different. Correlation between elemental concentration and radial growth of healthy trees was not significant, whereas in declined trees there was a negative and significant correlation between calcium and lead content and radial growth. According to the results, the effect of climatic factors seems to be the most effective among several factors.

Knowing about the way water is distributed in the soil is essential for designing and managing the Subsurface Drip Irrigation systems (SDI). Since carrying out experiments to recognize the form of moisture distribution in the soil is too complicated and time-consuming، using numerical simulations can be an efficient، effective substitute method to design these systems. One of these models is HYDRUS-2D، which is able to simulate the movement of water، heat and solute in saturated and unsaturated conditions in soil. This research aims to figure out the extent to which the HYDRUS-2D model is able to estimate wetting pattern in soil around a dripper. The simulations’ findings were compared to the data gathered from the field، including SDI system in different irrigation times، and 72 hours after irrigation. Moreover، the rates of error were measured for all points and distances from the dripper in all times of irrigation and also beyond that. The results indicated that the model can simulate the changes، trend similar to what happened in the soil profile. However، it estimated the rate of soil moisture with higher errors in those points in which the wetting took place، with the maximum error rate being RMSE= 0. 05 per every 1. 5 hours after irrigation starting point in the depth of 30 centimeters where dripper is placed. Also، with an increase in the irrigation time، and soil moisture evening which resulted from redistribution of moisture، the model resulted in better estimations. 72 hours after finishing the irrigation، the estimates were closer to real figures with an average error estimate of RMSE= 0. 002.

The objective of this study was to evaluate effects of cow manure on soil hydraulic properties and bromide leaching in a sandy loam soil (coarse loamy mixed, Typic Torrifluvents). Manure was applied at 0, 30, and 60 tha-1 at three replications in a completely random design. Three months after manure application potassium bromide (KBr) at rate of 300 Kg ha-1 Br was uniformly applied on the surface. Soil bulk density, porosity, organic matter, and soil moisture at18 levels of matric potentials were determined. Soil samples to the depth of 105 cm at 15-cm increments were collected after 100, 200 and 400 mm of irrigation. Soil bulk density, porosity, organic matter content, and soil moisture at different levels of matric potential increased significantly with manure application. Manure application also significantly affected the hydraulic parameters. Bromide leaching was significantly lower in plots with manure application and the greatest leaching occurred at the zero manure application treatment. The center of mass evaluation indicated a relatively similar result with measured values.