Majid Afyuni - Academia.edu (original) (raw)

Papers by Majid Afyuni

Archives of Agronomy and Soil Science, Jun 24, 2015

The conventional application of nitrogen fertilizers via irrigation is likely to be responsible f... more The conventional application of nitrogen fertilizers via irrigation is likely to be responsible for the increased nitrate concentration in groundwater of areas dominated by irrigated agriculture. This requires appropriate water and nutrient management to minimize groundwater pollution and to maximize nutrient use efficiency and production. To fulfill these requirements, drip fertigation is an important alternative. Design and operation of drip fertigation system requires understanding of nutrient leaching behavior in cases of shallow rooted crops such as potatoes, which cannot extract nutrient from lower soil depth. This study deals with neuro-fuzzy modeling of nitrate leaching from a potato field under a drip fertigation system. In the first part of the study, a two-dimensional solute transport model (HYDRUS-2D) was used to simulate nitrate leaching from a sandy soil with varying emitter discharge rates and various amounts of fertilizer. The results from the modeling were used to train and validate an adaptive network-based fuzzy inference system (ANFIS) in order to estimate nitrate leaching. Radii of clusters in ANFIS were tuned and optimized by genetic algorithm. Relative mean absolute error percentage (RMAEP) and correlation coefficient (R) between measured and obtained data from HYDRUS were 0.64 and 0.99, respectively. Results showed that ANFIS can accurately predict nitrate leaching in soil. The proposed methodology can be used to reduce the effect of uncertainties in relation to field data.

Ecotoxicology and Environmental Safety, Nov 1, 2018

A total of 167 samples of agricultural soil, atmospheric dust and food crops (wheat and maize) we... more A total of 167 samples of agricultural soil, atmospheric dust and food crops (wheat and maize) were collected, and four heavy metals, including Zn, Cu, Ni, and Cr, were analyzed for their concentrations, pollution levels and human health risks. The mean heavy metal contents in the agricultural soil and atmospheric dust were exceeds background values and lower than their IEQS (Iranian Environmental Quality Standard) with an exception of Ni. A pollution assessment by Geo-accumulation Index (I) showed that the pollution levels were in the order of Ni> Cu> Cr> Zn for agricultural soils and Ni> Cu> Zn> Cr for atmospheric dust. The Ni levels can be considered "moderately to heavily contaminated" status. The human health risk assessment indicated that non-carcinogenic values were below the threshold values (1), and main exposure pathway of heavy metals to both children and adults are ingestion. The carcinogenic risks values for Ni and Cr were higher than the safe value (1 × 10), suggesting that all receptors (especially wheat) in Kermanshah province might have significant and acceptable potential health risk because of exposure to Ni and Cr. The carcinogenic risk for children and adults has a descending order of Ni> Cr, except for wheat. These results provide basic information on heavy metal contamination control and human health risk assessment management in the Kermanshah province.

علوم آب و خاک, May 1, 2021

Compost leachate is a liquid resulting from physical, chemical and biological decomposition of or... more Compost leachate is a liquid resulting from physical, chemical and biological decomposition of organic materials. The main objective of this study was to evaluate the influence of leachate compost on the physical, hydraulic and soil moisture characteristic curves. Also, the effect of leachate on the aerial organ fresh weight of corn was investigated. Leachate was added to clay loam and sandy clay loam soils at the rate of zero, 1.25 and 2.5 weight percent. The soil water characteristic curve and the estimation of the parameters of the van Gnuchten and Brooks and Corey models were performed using RETC software. Leachate increased the bulk density and decreased the available water of the clay loam soil. Only 1.25% of the leachate increased the available water in the sandy clay loam soil. Two levels of leachate decreased the bulk density of sandy clay loam soil. Leachate decreased the saturation hydraulic conductivity of the clay loam and increased this parameter of sandy clay loam soil. Leachate was more successful in increasing the aerial organ fresh weight of corn in the sandy clay loam soil. Therefore, leachate was more useful in sandy clay loam than in clay loam soil, and 1.25% treatment was better in the sandy clay loam soil. Also, the used leachate increased the repellency of both soils. Leachate caused the parameters of van Gnuchten and Brooks and Corey models to increase, as compared to the control in both soils.

International journal of recent scientific research, Apr 28, 2017

Lead and cadmium are heavy metals and are regarded as traffic generated pollutants scattered in t... more Lead and cadmium are heavy metals and are regarded as traffic generated pollutants scattered in the urban environment through vehicular traffic flow. A total of 13 roads in the city of Isfahan were used for studying the roadside soil pollution amount and determination of effective traffic parameters on soil lead and cadmium amounts. Soil samples were collected and analyzed from 13 sites. An empirical statistical approach was employed for the analysis and modeling purposes. Results suggest that Lead and Cadmium mean concentrations within the distance of 50 m from road curbside are more than background values. These values are well-above the maximum acceptable concentration of heavy metal contents of agricultural soil. Regression analysis of metal concentrations in gutter soil showed that the most effective traffic parameter which affects soil metal concentrations is total traffic volume. It was also observed that Lead and Cadmium concentrations (as independent variables) decreased logarithmically as distance increased from road curbs (as dependent variable), but they decreased exponentially with increment of total traffic volume (as another dependent variable). The regression models developed in this research are used for estimation of Lead and Cadmium concentrations in urban roadside soils on the basis of the distance from road and total traffic volume. The outcomes of this research can be used for mitigation of environmental impacts of roads by using them in urban land use planning, urban design, urban transportation and road traffic management and control.

Journal of Geochemical Exploration, Sep 1, 2017

The heavy metal content of particulate matter was investigated in the city of Guangzhou in southe... more The heavy metal content of particulate matter was investigated in the city of Guangzhou in southern China. Samples of urban foliage near 36 pedestrian bridges were analyzed to determine their Zn, Pb, Cu, Cr, V, Ni, and Co contents after digestion in a mixture of strong acids composed of HNO 3 , HCl, HF, and HClO 4. The results revealed a severe heavy metal pollution compared with the background levels in Chinese soils, except for Co and V. The mean concentrations of Zn (1,024 mg kg-1), Pb (233 mg kg-1), Cu (203 mg kg-1), Cr (118 mg kg-1), V (41.9 mg kg-1), Ni (41.4 mg kg-1), and Co (11.3 mg kg-1) in urban dust were higher than the reference levels, and were highest in samples located near high-traffic areas. Multivariate statistical methods (correlation analysis, principal-components analysis, and clustering analysis) were used to identify the possible sources of the metals. Three main pollutant sources are assigned: Zn, Cu and Ni levels were strongly correlated and were possibly related to combustion processes and vehicles; Pb, Cr and Co were mainly derived from traffic sources, combined with soil sources; and V mainly originated from natural sources.

Journal of Water and Wastewater; Ab va Fazilab ( in persian ), Jun 1, 2006

Natural degradation of cyanide is one of the oldest methods used to remove the cyanide present in... more Natural degradation of cyanide is one of the oldest methods used to remove the cyanide present in industrial wastewater of electroplating and extraction processes in gold and silver industries. The most important mechanism involved in the natural degradation of cyanide is volatilization which is affected by parameters such as impoundment surface, soil porosity and density, initial concentration, and atmospheric conditions. The objective of the present study was to determine the effects of those parameters involved in natural degradation that can be varied to optimize the design or operation of tailings impoundment. The experiments carried out in this study were of the completely random, statistical factorial, and time-split design using the four major variables of time, surface to depth ratio, tillage operations, and soil cyanide initial concentration. The experiments included 3 levels for surface-depth ratio, 2 levels for tillage operation, and 2 levels for initial concentration with three replications to yield a total number of 36 pilots. Cyanide measurements were performed at four intervals. Statistical analysis and variance of the data obtained on soil cyanide concentration showed that time had the highest effect on soil cyanide removal. Tillage and increased initial contamination both increased cyanide removal efficiency. For a given volume of cyanide contaminated soil, increased surface-depth ratio led to a faster reduction of soil cyanide residual. The regression analysis of the data obtained from this study resulted in the development of a model that can be used to predict soil cyanide concentration with respect to such parameters as time, initial contamination, and surface-depth ratio.

Catena, Dec 1, 2018

Carbon (C) sequestration in soil is recognized as a possible solution for climate change mitigati... more Carbon (C) sequestration in soil is recognized as a possible solution for climate change mitigation. Different land uses may alter carbon sequestration in soil. In the semiarid regions of central Iran, during the last decades, land use changes from native cover to farmlands have altered the C sink role of soil to a source of CO 2 emission to the atmosphere. This study was conducted to evaluate and compare changes and the potential of soil organic carbon (SOC) sequestration from 1988 to 2014, under different land uses, in western central Iran (Lordegan). The land uses included pasture, forest, rain-fed, and irrigated farmlands. Soil (450 samples) from 50 points across the study basin (390 km 2) was collected in three depth increments (0-5, 5-15 and 15-30 cm) during three sampling times (June and November 2014, and June 2015). Mean SOC concentrations in the pasture, forest, rain-fed and irrigated farmlands were 10.3, 20.2, 9.2 and 10.1 g kg −1 , respectively. The SOC concentration in the forest soil was significantly greater than the other land uses, and any reduction in forestland area would lead to the SOC stock decline. About 1390 Gg organic carbon was found to be stored in the top 0-30 cm depth of the study area. Comparing land use maps between 1988 and 2014 indicated an alteration in the relative contribution of each land use across the study area leading to SOC stock reduction by 100 Gg carbon during this period. The results showed that all studied soils comprised non-complexed clay, suggesting a considerable potential capacity for sequestering carbon. The results also indicated that the SOC controlling factors varied considerably among different land uses and soil depths. Mean weight diameter of aggregates (MWD), bulk density, clay and sand content, and altitude were identified as the important controlling variables by the stepwise multiple linear regression analysis. '4 per mille Soils for Food Security and Climate' was launched at the COP21 conference in Paris in December 2015. This program aims to compensate the global emissions of greenhouse gases through increasing soil organic carbon by 0.4% per year (Minasny et al., 2017). The amount of OC in soil at any given time depends on the longterm balance between the carbon inputs and the losses rate. These rates are controlled by factors including soil attributes (e.g., soil lithology and texture), climatic variables (e.g., mean annual temperature and precipitation), biotic characteristics (e.g., microbial population and biomass production), and anthropogenic factors (such as land use and management) (Albaladejo et al., 2013; Zdruli et al., 2017). These factors affect SOC stock through influencing the SOC decomposition rate,

علوم آب و خاک, Aug 1, 2015

Soil pollution and accumulation of heavy metals in soils and crops are the most important bioenvi... more Soil pollution and accumulation of heavy metals in soils and crops are the most important bioenvironmental problems that threaten the life of plants, animals and humans. This study was conducted to explore contamination of heavy metals in soils of Hamadan province. A total of 286 composite surface soil samples (0-20 cm) were collected thoroughout the province. After preparation of the samples, the total contents of Zn, Pb, Cu, and Ni in soil samples were extracted using HNO 3. Total contents of heavy metals were measured by ICP. Contamination factor results showed that most samples were moderately polluted and contamination factor for lead was highly polluted. Interpolated distribution map of contamination factors (CF) and pollution load index (PLI) of the heavy metals were prepared using GIS. The overlap of CF and PLI maps with geology and land use maps indicated that the concentrations of Ni, Pb, Zn, and Cu have been controlled by natural factors such as parent material, but agricultural activities according to excessive consumption of animal manure and chemical fertilizers can increase most of these elements in soil.

Pollution, 2020

The main objective of this study is to evaluate heavy metals contamination of highly consumed veg... more The main objective of this study is to evaluate heavy metals contamination of highly consumed vegetables and hazardous effects of consuming these vegetables. The study was conducted in vegetable fields in three different regions according to the level of environmental pollutions, including "Isfahan", "Flavarjan" and "Faridan, Golpayegan and Natanz". Six types of vegetables in each field with three replicates in each region were selected in the summer of 2017 by the random sampling method from vegetable fields. The level of heavy metals (Pb, Cu, Co, Cd and Cr) in vegetables has been measured for each sample. The result showed that in the Isfahan region, the highest daily intake of Pb, Cu, Co, Cd and Cr for the consumption of all the vegetables was obtained in the recipients. The highest target hazard quotient for non-cancerous diseases of contaminated vegetables was 28.9 and 21.1 in "Isfahan" for children and adults, respectively. The target hazard quotient for vegetable consumption was greater than one and at high hazard for both age groups. The principal component analysis showed that the contamination by the heavy metals in the "Isfahan" and "Falavarjan" regions overlapped and the risk of contamination of heavy metals in urban vegetables in both regions increased the hazard of non-cancerous diseases. It is highly recommended that the quality standards of foods that are imposed on the production of food crops.

JWSS - Isfahan University of Technology, 2017

CLEAN – Soil, Air, Water, 2019

The growing demand for environmental protection and sustainable food production requires the effi... more The growing demand for environmental protection and sustainable food production requires the efficient use of organic and slow‐release fertilizers in agriculture. In this study, co‐composting of municipal solid waste (MSW) + three different ratios of natural and Mg‐modified zeolites (5, 10, and 15% on a wet weight basis) is conducted to improve the MSW compost quality. The effects of soil amendment with MSW compost containing natural zeolite (CNZ) and Mg‐modified zeolite (CMZ) on the corn yield, moisture content, leaching volumes, and NO3‐N concentrations are investigated. Compared to the control (zeolite‐free compost), the CNZ15 and CMZ15 treatments show 39.9 and 49.3% reduction in electrical conductivity and an increase of 64.5 and 110% in NH4‐N retention, respectively. By using the composts containing zeolite, the moisture content in the surface layer of soil is increased up to 12.6%. Nitrogen uptake and water use efficiency in the CNZ treatment are enhanced by 34.6 and 40.0%, re...

Colloids and Surfaces B: Biointerfaces, 2018

Water protection and bioremediation strategies in the vadose zone require understanding the facto... more Water protection and bioremediation strategies in the vadose zone require understanding the factors controlling bacterial transport for different hydraulic conditions. Breakthrough experiments were made in two different flow conditions: i) an initial bacteria pulse under ponded infiltration into dry sand (-15000 cm); ii) a second bacteria pulse into the same columns during subsequent infiltration in constant water content and steady-state flow. Escherichia coli (E. coli) and Rhodococcus erythropolis (R. erythropolis) were used to represent hydrophilic and hydrophobic bacteria, respectively. Equilibrium and attachment/detachment models were tested to fit bromide (Br ) and bacteria transport data using HYDRUS-1D. Derjaguin-Landau-Verwey-Overbeek (DLVO) and extended DVLO (XDLVO) interaction energy profiles were calculated to predict bacteria sorption at particles. Adsorption of bacteria at air-water interfaces was estimated by a hydrophobic force approach. Results suggested greater retention of bacteria in water repellent sand compared with wettable sand. Inverse parameter optimization suggested that physico-chemical attachment of both E. coli and R. erythropolis was thousands of times lower in wettable than repellant sand and straining was 10-fold lower in E. coli for wettable vs repellant sand compared to the exact opposite by orders of magnitude with R. erythropolis. HYDRUS did not provide a clear priority of importance of solid-water or air-water interfaces in bacteria retention. Optimized model parameters did not show a clear relation to the (X)DLVO adsorption energies. This illustrated the ambivalence of (X)DLVO to predict bacterial attachment at solid soil particles of different wetting properties. Simultaneous analysis of mass recovery, numerical modeling, and interaction energy profiles thus suggested irreversible straining due to bacteria sizing as dominant compared to attachment to liquid-solid or liquid-air interfaces. Further studies are needed to distinguish straining mechanisms (i.e. pore structure or film straining) in different hydraulic conditions.