فهرست مطالب

Agricultural Science and Technology - Volume:17 Issue: 4, 2015
  • Volume:17 Issue: 4, 2015
  • تاریخ انتشار: 1394/05/02
  • تعداد عناوین: 23
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  • M. Safa, S. Samarasinghe, M. Nejat Pages 791-803
    An artificial neural network (ANN) approach was used to model the wheat production. From an extensive data collection involving 40 farms in Canterbury, New Zealand, the average wheat production was estimated at 9.9 t ha-1. The final ANN model developed was capable of predicting wheat production under different conditions and farming systems using direct and indirect technical factors. After examining more than 140 different factors, 6 factors were selected as influential input into the model. The final ANN model can predict wheat production based on farm conditions (wheat area and irrigation frequency), machinery condition (tractor hp ha-1 and number of passes of sprayer) and farm inputs (N and fungicides consumption) in Canterbury with an error margin of ±9% (±0.89 t ha-1).
    Keywords: Agricultural Production, Agricultural Systems, Modelling
  • J. Tomic, A. Torbica, L. Popovic, I. Strelec, Z. Vastag, M. Pojic, S. Rakita Pages 805-816
    The aim of this study was to characterize albumin fractions of four different wheat varieties grown in a local climatic context, as well as to find the relationship between the particular albumin fractions and enzyme activity of the tested wheat flours and dough rheological properties. The determined content of albumin fractions ranged from 2.64 to 17.50% of total proteins. More than 50% of the albumins total amount was in the range of 5-15 kDa of molecular weight. The obtained results indicated that albumin fraction 15-30 kDa was related to certain rheological properties of dough, especially those related to water absorption and uniaxial and biaxial resistance to extension. Regarding the enzymatic status of flour, no strong relationship was found among the 5-15, 30-50 and 30-60 kDa albumin fractions and proteolytic and a-amylolytic activity. However, the albumin fraction 15-30 kDa showed significant correlation with proteolytic activity.
    Keywords: α amylolitic activity, Lab, on, chip electrophoresis, Proteins, Proteolytic activity
  • R. Sharafati Chaleshtori, N. Rokni, M. Rafieian, Kopaei, F. Drees, E. Salehi Pages 817-826
    The aim of this study was evaluation of phytochemical components, antioxidant activity, and antibacterial effects of basil (Ocimum basilicum L.) essential oil (BEO) in vitro. The lipid oxidation of the meat and antibacterial effects of BEO were also evaluated in beef burger product. In this empirical study, essential oil of the basil was isolated by hydrodistillation. Then, BEO was analyzed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography/mass spectrometry (GC-MS). The effect of different concentrations of BEO (0.00, 0.062, 0.125, and 0.25%) at 4±1ºC temperature and storage time of up to 12 days was evaluated on lipid oxidation, anti Staphylococcus aureus activity, and organoleptic effects in beef burger. The main compounds in BEO were methyl chavicol (85.19%), 1,8 cineol (3.96%), trans-alpha bergamotene (1.18%) and linalool (1.03%). In the storage temperature (4±1ºC), the BEO decreased the growth rate of S. aureus in beef burger (P< 0.05). Also, overall acceptance rate in the beef burger containing 0.125% BEO created a better sense in the product (P< 0.05). No significant differences were observed after adding different concentrations of essential oil to decrease lipid oxidation in raw beef burger (P> 0.05). Therefore, this essential oil might be used as antibacterial agent and flavor enhancer in meat products such as beef burger.
    Keywords: Flavor enhancer, Gas chromatography, Ocimum basilicum, Phytochemical components
  • L. Dzadz, M. Markowski, P. Sadowski, A. Jakobczak, M. Janulin Pages 827-835
    The effect of temperature on the viscoelastic behavior of chicken meat frankfurters was assessed by creep recovery tests. Compression creep-recovery tests were performed at room temperature (20°C) and refrigeration (5°C) on samples of cylindrical shape. The viscoelastic behavior of samples was characterized based on the parameters of the four-element Burgers Model. During the compression phase, greater deformation was observed in samples analyzed at higher temperature, and it was demonstrated by a drop in elastic modulus and internal viscosity values of Kelvin–Voigt elements with an increase in temperature. The final percentage recovery of frankfurter samples decreased with an increase in temperature. The differences in compliance between samples analyzed at different temperatures can be attributed to temperature-induced changes in the properties of frankfurter fat.
    Keywords: Burgers Model, Compliance, Viscoelastic behavior
  • B. Hosseinzadeh Samani, M. H. Khoshtaghaza, S. Minaee, S. Abbasi Pages 837-846
    This study aimed to examine the effectiveness of combined microwave-ultrasonic pasteurization system on Escherichia coli and vitamin C content in sour cherry juice (SCJ). Based on the findings, microwave output power, ultrasound power, and ultrasonic exposure time as well as the microwave-induced temperature were the most effective factors in reducing E. coli and vitamin C content. In addition, the microwave-induced temperature and ultrasonic exposure time, as independent variables, were both effective on E. coli removal. At higher temperatures, the effectiveness of ultrasonic waves as well as cavitation intensity declined. However, their combined effect (ultrasound and temperature) was more significant than their individual effect. It was also found that any increase in ultrasound power, ultrasonic exposure time, and microwave output power led to a significant reduction in vitamin C content, while the ultrasound power was the most effective. On the basis of RSM modeling, the optimum processing condition was: 352.21W microwave output power, 49.94˚C temperature, 475.13W ultrasound power and 6 minutes of exposure time. On the basis of response surface methodology (RSM) modelling, the maximum vitamin C content was 142.5 mg per 100 mL with no remaining E. coli.
    Keywords: Cavitation, Microwave output power, Pasteurization, Ultrasound power
  • V. Najafi, M. Barzegar *, M. A. Sahari Pages 847-858

    This study investigated the fatty acids profile, oxidative stability indices, and bioactive compounds of virgin and processed olive oils (Leccino and Frantoio cultivars). Results showed that fatty acid profile of the studied oils contained mostly oleic acid followed by palmitic and linoleic acid. Acid values of virgin Frantoio and processed Leccino were 0.78 and 0.18 mg KOH/g oil, with peroxide values (PV) of 8.74 and 6.03 meq O2/kg oil, respectively. Virgin Leccino had the highest oxidative stability index with induction period of 18.83 h. The highest contents of phenolics, 321.14 mg/kg, tocopherols, 455.25 mg/kg, and sterols, 2189.1 mg/kg, were recorded in virgin Leccino oil. Laboratory processing of virgin olive oil decreased the phenolics to 70%, tocopherols to 50%, and sterols to 25%. Finally, based on the higher content of antioxidant compounds, the virgin Leccino oil had higher oxidative stability and bioactivity than Frantoio oil.

    Keywords: Bleaching, Deodorization, Rancimat test, Phenolic compounds
  • F. Javadi, M. M. Ahmadi, K. Qaderi Pages 859-868
    Movement of sediment in the river causes many changes in the river bed. These changes are called bedform. River bedform has significant and direct effects on bed roughness, flow resistance, and water surface profile. Thus, having adequate knowledge of the bedform is of special importance in river engineering. Several methods have been developed by researchers for estimation of bed form dimensions. In this investigation, bedform has been estimated using Artificial Neural Network (ANN) and Support Vector Machine (SVM) methods. The results obtained from these two methods were compared with empirical formulas of Van Rijn. The accuracy of the model was evaluated using (RMSE), (MSRE), (CE), (R2) and (RB) statistical parameters. Higher values of statistical parameters indicated that the SVM model with RBF kernel function predicted the bedform more accurately than the other method. The values calculated for R2, RMSE, MSRE, CE and RB parameters were 0.79, 0.024, 0.066, 0.786, -0.081, respectively. Comparison of the results of the SVM model with RBF kernel with other models indicated that SVM had a higher capability for estimating and simulating height of the bedform than Artificial Neural Networks.
    Keywords: Bed roughness, RBF kernel function, River engineering
  • P. Attarod, F. Kheirkhah, Sh. Khalighi Sigaroodi, S. M. M. Sadeghi Pages 869-883
    The goal of this study was to estimate the sensitivity of reference evapotranspiration (ET0) to changes in meteorological parameters in the Caspian region. Long-term meteorological data (1961-2008) were obtained from three synoptic meteorological stations. The region was primarily classified into three climatic zones, based on De Martonne climate classification. The Penman–Monteith equation was applied to calculate the ET0 and the sensitivity of ET0was studied in terms of changes in air temperature, solar radiation, wind speed and vapor pressure within a possible range of ±20% from the normal long-term meteorological parameters. The results indicated that the Caspian region could be classified into the three climatic classes: Mediterranean, humid, and extremely humid. During the last half century, meteorological parameters and, in particular, temperature of the Caspian region has changed dramatically and the ET0 has increased as a result of climate change. The study suggests that an increase in temperature by 20% (approximately 3.3 ºC) will result in ET0 demand increase by 16%. Changes in vapor pressure (20%) represented the highest inverse effect on annual ET0throughout the Caspian region (-19% in the Mediterranean, and -30% in other climates). The Mediterranean and extremely humid climates of the Caspian region showed an increase of 2 and 5% of the total ET0, respectively, in response to 20% change in the wind speed. It is quite essential for managers to take into consideration the expected change in evapotranspiration owing to global warming while planning for development of artificial and natural ecosystems in the Caspian region.
    Keywords: Climate change, Meteorological parameters, Penman, Monteith
  • M. Saeidi, M. Abdoli Pages 885-898
    Terminal drought stress during grain filling period has recently become more common in the semiarid Mediterranean regions, where wheat (Triticum aestivum) is grown as an important winter cereal crop. The objective of this experiment was to study the effect of terminal drought stress on grain yield, gas exchange variables, and some physiological traits of nine bread wheat cultivars. An experiment was carried out in a split-plot arrangement using randomized complete blocks design with three replications during the 2010-2011 season at the research farm of Razi University, Iran. Based on the results obtained, post anthesis water deficit significantly decreased grain yield, biomass, 1,000 grain weight, and harvest index of wheat cultivars. Under terminal drought stress and control treatments, there were significant differences between cultivars in terms of all traits studied. Also, terminal drought stress decreased leaf net photosynthesis rate (Pn), stomatal conductance (gs), transpiration rate, Chlorophyll a, b, and a/b, and increased leaf temperature and sub-stomatal CO2 concentration. Cultivars differed in their response to water stress. In general, tolerant cultivars showed a higher Pn and gs and leaf water content under both moisture conditions compared with susceptible ones. A greater reduction in gs and transpiration rate and smaller reduction in Pn under stress condition led to a remarkably higher photosynthetic water use efficiency of the tolerant cultivars. Finally, it can be concluded that planting wheat variety DN-11 in areas with post-anthesis water stress was recommendable for maximizing grain yield.
    Keywords: Photosynthesis, Relative water content, Stress Susceptibility Index, Water use efficiency
  • O. Cetin, N. Uzen, M. G. Temiz Pages 909-920
    The objectives of this study were to evaluate the effects of nitrogen fertigation frequency on lint yield, lint properties, chlorophyll content (SPAD readings), and the photosynthesis rate (PR) of cotton. This study was carried out in the Southeastern Anatolia Region of Turkey in 2011 and 2012 with drip-irrigated cotton. The maximum lint yield (1,856 kg ha-1) was obtained with one lateral for every two rows and the application of equal doses every two irrigation cycles (10 days). Fertigation frequency of every two irrigation cycles (10 days) increased (P≤ 0.05) the fiber strength (32.3 g tex-1), the fiber elongation (6.5%), and the fiber length (28.9 mm). The SPAD readings ranged from 40.1 to 54.9, depending on the treatment and experimental year. There was no significant difference (P≤ 0.05) among the SPAD readings. The PR ranged from 35.9 to 74.7 µmol m-2 s-1, and there was no significant difference between the treatments. One possible reason for the lack of difference in PR, or SPAD, was that there was no difference in the total amount of nitrogen applied in the different treatments. The PR measured in cotton leaves may also change depending on the environmental conditions during measurement, prevailing ecological conditions, age, and location of the leaf on a plant.
    Keywords: Cotton, Chlorophyll (SPAD), Drip irrigation, Nitrogen, Photosynthesis rate
  • X. Wang, Ch. Xu, J. Cang, Y. Zeng, J. Yu, L. Liu, D. Zhang, J. Wang Pages 921-934
    To clarify the underlying physiological mechanism of gibberellic acid (GA) in cold tolerance, the effects of exogenous GA3 on malondialdehyde (MDA), osmoregulation substances and endogenous hormones levels in the tiller nodes of two wheat cultivars, namely, Dongnongdongmai 1 (a cold insensitive cultivar) and Jimai 22 (a cold sensitive cultivar), were investigated at three periods of cold winter (0, -10, -25°C). The results showed that low concentrations of GA3 (0.1 and 1 µM) decreased the endogenous GA concentration in both cultivars, but only increased the abscisic acid (ABA)/GA ratio in Dongnongdongmai 1. High concentrations of GA3 (10 and 100 µM) increased the MDA level, retarded the accumulation of soluble protein and sugar in both cultivars, but decreased the content of ABA and the ratio of ABA/GA only in Dongnongdongmai 1 and had no influence on those in Jimai 22. The re-greening rate of Dongnongdongmai 1 decreased as the concentration of exogenous GA3 increased. Correlation analyses showed that MDA was negatively correlated with re-greening rate, while soluble protein, sugar ABA content, and ABA/GA ratio were positively correlated with re-greening rate. In conclusion, low exogenous GA3 level could decrease endogenous GA content and elevate ABA/GA ratio and soluble protein content, which help to improve cold tolerance. However, high exogenous GA3 level decreased the ABA content and ABA/GA ratio, resulting in lower soluble sugar and protein content and aggravated oxidative damage, and finally weakened cold tolerance. The endogenous GA metabolism and ABA/GA balance play central roles in exogenous GA3 mediated cold tolerance.
    Keywords: Cold stress, Physiological mechanism, Phytohormone, Tiller node, Winter wheat
  • J. I. Ruiz De Galarreta, R. Lopez, Pardo, R. Tierno, N. Alor, L. Barandalla, N. Haase, E. Ritter Pages 935-947
    Certain potato cultivars such as native potato species (NPS) from the Andes are known to have resistances to different pests and diseases. Some accessions are also interesting from a nutritional and culinary perspective. A collection of 35 NPS and 11 old Spanish accessions were analysed for Streptomyces scabies, Rhizoctonia solani and Globodera rostochiensis, as well as dry matter, reducing sugars, minerals, glycoalkaloid concentrations, and total antioxidant capacity. A wide variability was found between and also within the species. Most accessions showed favourable characteristics, while high concentrations values of glycoalkaloids were observed in certain accessions. The results suggest that some NPS and old Spanish accessions have a great potential for exploitation in potato breeding programmes as a source of resistances and nutritional variability.
    Keywords: Antioxidant capacity, Breeding, Glycoalkaloids, Pathogens
  • A. Mirshekari, Ph. Ding, H. M. Ghazali Pages 949-962
    Berangan banana were treated with hot water at 50 ºC for 0 (control), 10, and 20 min and then kept at room temperature (25±2 ºC), 75-80% RH to observe the ripening progress. Firmness and activity of cell wall degradation enzymes such as polygalacturonase (PG), pectin methylesterase (PME), and pectate lyase (PL) were determined for treated and untreated banana. The microstructure of banana peel cell wall was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Treated fruit was firmer than the control fruit during ripening process. PG, PME, and PL activities were reduced in the treated bananas when compared with the control treatment. Hot water treatment disturbed cell wall degrading enzymes activity and delayed the disassembling of pectin fraction of Berangan banana. The micrographs of SEM and TEM exhibited lower changes in cell compartment and less loosening of cell wall fibril fractions in treated fruits. The electrolyte leakage in Berangan banana decreased with the increase of exposure time. The results of this study indicated that hot water treatment at 50 ºC slowed down the ripening process and extended shelf lifeof banana.
    Keywords: Berangan, Cell wall, Fruit firmness, Heat treatment, Shelf life
  • T. Oztekin, S. Oztekin, N. Gebologlu Pages 963-976
    This experiment aimed to determine evapotranspiration, and responses of some yield and quality parameters of subsurface drip irrigated broccoli (Brassica oleraceae L.). Treatments included water application when available soil moistures were depleted 30, 40, and 50% during both spring and autumn cultivations. Under a semi-arid climatic condition of Tokat, Turkey, the experiment was carried out with a randomized complete block design in clay and clay loam soils during, respectively, 2011 and 2012. The mean measured soil-water depletion levels of 39, 49, and 59% (irrigation treatments) yielded statistically significant results among the seasonal actual evapotranspirations with a range from 210 to 294 mm. The determined crop coefficients (Kc) during the initial growth stage of broccoli for the autumn cultivations did not follow those of standard recommendations. Furthermore, we could not find any statistically significant difference in the yield and quality components among the irrigation treatments, but among the cultivation seasons.
    Keywords: Crop coefficient, Modified Penman equation, Vitamin C, Water use efficiency
  • R. Karim, F. Ahmed, U. Krishna Roy, T. Ara, R. Islam, M. Hossain Pages 977-986
    Strawberry is a valuable, nutritious, and economically important fruit all over the world including Bangladesh. Therefore, there is a demand to develop a suitable variety of strawberry. For this purpose, leaf explants from in vitro grown strawberry plantlets were cultured onto MS medium supplemented with different concentrations and combinations of 2,4-D, NAA and BA for callus induction. The most effective combination was 2.0 mg/L NAA with 0.5 mg/L BA. Then, the calli proliferated in this medium were cultured in MS medium containing different concentrations and combinations of BA, BA + NAA and BA + KIN + NAA for shoot regeneration. The best media combination was 1.5 mg/L BA + 0.75 mg/L NAA + 0.5 mg/L KIN. The regenerated shoots were cultured onto MS medium with different combinations of auxins or in MS and ½ MS medium without plant growth regulators (PGRs). The highest rooting performance was recorded in MS medium without PGRs. The plantlets were then gradually acclimated and successfully transferred to the field for evaluation. Somaclonal variations in different morphological characters such as plant height, no. of leaves/plant, petiole length, no. of stolon/plant, stolon length, no. of nodes/stolon, canopy size, no. of clusters/plant, fruit shape, no. of fruits/plant, average fruit wt. (g), fruit wt/plant (g), were noticed. Some of the somaclones exhibited better performances of the above mentioned characteristics than those of micropropagated mother plants and were well adapted to Bangladesh agro-climatic condition and were cultivated commercially in the winter season by many farmers.
    Keywords: Acclimatization, Callus, Micropropagation, Plantlets, Regeneration
  • X. L. Tan, Q. Huang, R. K. Tan, L. Wu, Zh. Y. Zhang, Zh. Wang, Ch. M. Lu, X. F. Li Pages 987-997
    Plant fatty acyl-acyl carrier protein thioesterase (FAT) is a major enzyme regulating the amount and composition of fatty acids in lipids. In this study, one type of cDNA, corresponding to the fatty acyl-acyl carrier protein (acyl-ACP) thioesterase (Fat) enzyme, was isolated from the seed of Brassica napus cv. Ningyou12. BLAST results revealed that the cDNA identified highly with the FatB class of plant thioesterases. The cDNA contained a 1,245 bp open reading frame (ORF), encoding a protein that contained 414 amino acid residues. Subcellular localization results showed that the BnFatB protein was located in the chloroplast. The BnFatB (KC445243) gene was expressed in many tissues and was strongly expressed in seeds. Heterologous expression of the BnFatB gene in yeast cells was performed in order to ascertain the function of the BnFatB gene. Semi-quantitative RT-PCR results indicated that the expression level of the BnFatB gene in transformed yeast had significantly increased compared to the control. GC analysis of the fatty acid revealed that, when compared with the control, the content of C16:0 and C18:0 in yeast cells expressing BnFatB increased by 45.7 and 21.7%, respectively; while C16:1 and C18:1 decreased by 15.3 and 30.6%, respectively. This study demonstrated that the BnFatB gene had similar function as the FatB enzyme, preferentially releasing saturated fatty acid from the acyl carrier protein. It can therefore be used as a candidate target for fatty acid improvement in oilseed rape.
    Keywords: Fatty acid, GC analysis, Heterologous expression, Lipid, Yeast
  • B. Abdollahi Mandoulakani, P. Sadigh, H. Azizi, Y. Piri, Sh. Nasri, S. Arzhangh Pages 999-1010
    The effectiveness of IRAP, REMAP, SSR, and ISSR markers were investigated to assess genetic diversity among and within eight Medicago sativa L. populations. A total of 101, 119, 117 loci and 31 alleles were amplified using 10 IRAP, 14 REMAP, 16 ISSR and eight SSR primers, respectively. IRAP markers generated the maximum proportion of polymorphic loci per primer (PPLP) while the maximum value of percentage of polymorphic loci (PPL) was observed for SSR markers. ISSR markers showed the highest value of marker index (MI). The maximum amount of expected heterozygosity (He), effective number of alleles (Ne), and Shannon’s information index was produced by SSR markers. UPGMA cluster using Nei’s genetic distance coefficients and combined data of four markers separated the populations into three major groups. Correlation coefficients among pairwise genetic and geographic distance matrices, made on the basis of all studied markers, were calculated using Mantel's test. Regression and correlation analysis between genetic distance and geographic distance showed no significant correlations (p>0.05).
    Keywords: Cluster analysis, Marker index, Medicago sativa, Retrotransposon, based markers
  • E. Aryakia, M. R. Naghavi, Z. Farahmand, A. A. H. Shahzadeh Fazeli Pages 1011-1023
    Plant tissue culture technique could provide sterile and controllable condition in order to assay direct effect of different compounds on plant growth accurately. In this study, the effects of aqueous extracts prepared from roots and shoots of goosefoot (Chenopodium album L.), redroot pigweed (Amaranthus retroflexus L.), fennel (Foeniculum vulgare), and wormwood (Artemisia absinthium L.) were evaluated on the seed germination and growth criteria in tissue culture media. The fennel root extract, nearly without phenolic content and with low antioxidant activity, showed the most drastic allelopathic effect on goosefoot, especially at 100 mg mL-1 concentration, which might be due to the presence of some substance potentially useful for biological control of goosefoot, an invasive weed. Goosefoot was resistant to extract of fennel shoot, wormwood root, and shoot, while fennel and radish (Raphanus sativus L.), at high concentration (100 mg mL-1), were not resistant to the root and shoot extracts of both goosefoot and redroot pigweed. In response to allelopathic components, shoot:root ratio was increased, and more peroxidase and superoxide dismutase activity were detected in roots. There was no direct relationship between allelopathic effects with total phenolic content and antioxidant activity. In conclusion, our results showed that allelopathic effects of extracts on growth and biochemical criteria depended on both the concentration levels and the plant parts from which the aqueous extract was derived. Therefore, tissue culture media is an accurate and suitable tool to screen plants resistant to allelopathic components of weeds, and to identify high allelopathic plants as potential bioherbicide and invasive plant controller.
    Keywords: Aqueous extract, Growth criteria, Invasive plant, Total phenolic content, Antioxidant activity
  • H. Ghorbani, N. Hafezi Moghads, H. Kashi Pages 1025-1040
    Soil contamination significantly reduces environmental quality and affects human health. To investigate and assess the effects of land use on the concentrations of some heavy metals in surface soils of Golestan province, 227 soil samples (0-60 cm) were collected from three types of land uses including agricultural lands, natural, and industrial areas. The total metals and metalloids (Cr, Se, As, Cd, Ni, Pb, Zn, Cu, Fe) were extracted and their concentrations were measured in all samples. The results showed that heavy metals accumulations in soil samples of the industrial land uses were higher than agricultural and natural land uses. There was significant correlation among the soils heavy metals (more than 30% for most samples) and also between soil heavy metals and organic carbon content in different types of land uses (average of 40%). Cluster analysis revealed that As and Se had the highest concentration values compared to their corresponding background in most samples and showed the evidence of anthropic effects. Various indices including pollution load index (PLI), modified contamination degree (mCd), and enrichment factor (EF) were used to determine the soil contamination level. The results of PLI and mCd,indicated the higher accumulation of heavy metals at industrial land uses. The enrichment factor of Se and As in soils were higher than the other metals, however, their values showed that anthropogenic activities had not serious effects on the environment quality in the studied area.
    Keywords: Enrichment factor, Modified contamination degree, Pollution load index
  • A. Heidari, P. Asadi Pages 1041-1055
    In this study, micromorphological properties of some samples collected from pedons polluted with petroleum refinery wastes and some adjacent unpolluted pedons were studied. After description of the studied pedons, disturbed and undisturbed samples were collected for physicochemical and micromorphological analyses. The results showed that the physicochemical properties (i.e. structure, bulk density, pH, EC and organic matter) of the soils polluted with petroleum wastes were strongly changed. Prolonged exposure of soils to the petroleum wastes resulted in the formation of specific and distinctive micromorphological features. Strongly developed granular microstructure and infillings of solid petroleum wastes alone or mixed with soil aggregates were some of the most important pedofeatures which were observed in deeper horizons. The existence of excrement belonging to different soil micro and macro fauna, coatings, hypocoatings, quasicoatings, and zones depleted from petroleum dissolvable materials at different depths were the other features throughout the pedons. The type of developed pedofeatures was correlated with the state of petroleum wastes and their fluidity in penetration, deposition, or dissolving and removal of soil compounds. This study demonstrated that micromorphology can be used as a powerful technique in characterization of petroleum polluted soils.
    Keywords: Oil contamination, Pedofeatures, Physico, chemical properties, Soil quality, Technosols
  • R. Rostamian, M. Heidarpour, S. F. Mousavi, M. Afyuni Pages 1057-1069
    Biochar and activated carbon, as carbon-rich porous materials, have wide environmental applications. In the present research, rice husk (RH) was used for preparation of biochar at 400, 600, and 800 °C under simple pyrolysis, physically-activated carbon with water steam, chemically-activated carbon with potassium hydroxide (KOH), and physiochemically-activated carbon with KOH and steam. Physical and chemical properties of biochar and activated carbons were characterized using nitrogen adsorption–desorption isotherm, Fourier transform, infra-red analysis, and Boehm method. The results showed that carbonization temperature and activation agents had significant effects on the characteristics of the samples. Activated carbon produced by KOH activation had the highest surface area (2201 m2 g-1) and total pore volume (0.96 cm3 g-1). High concentration of sodium (Na) is an important limiting factor to reuse poor quality water resources in arid and semiarid regions. The sorption capacity of biochars and activated carbons was investigated by performing batch sorption experiments using Na as adsorbate. Na sorption was increased with increasing surface area and pore volume. The highest Na sorption capacity of 134.2 mg g-1 was achieved by the KOH activated carbon, which has the highest surface area and pore volume. The kinetic data were well-fitted to pseudo-first order and intra-particle diffusion models.
    Keywords: Adsorbent, Diffusion models, Nitrogen isotherm, Physiochemical characteristics, Sorption isotherm
  • A. Rahman Pages 1071-1082
    Pressurized irrigation technologies of course have the potential to raise the productivity of land and water; but, these technologies could not popularize among the smallholders who own millions of farms worldwide. In developing pressurized irrigation technologies, particularly for field crops irrigation, researchers and manufacturers have developed more specialized and expensive technologies with sophisticated and intricate hardware. These new technologies have benefited only the large and wealthier farmers leaving the smallholders to remain confined with conventional methods of irrigation. This paper discusses the design, performance, and applicability of a low-pressure water sprinkling nozzle, named LERN. This nozzle can be operated satisfactorily over the operating pressure range of 79-117 kPa. The water application rate of LERN is reasonably high, i.e. 20-23 mm h-1; therefore, field crops such as rice, wheat, oil seed etc. can be irrigated quickly and efficiently even at small plots, where available options such as impact sprinklers are, in general, neither feasible nor applicable due to high pressure requirement (196 - 294 kPa), non-divisibility over small plots, and relatively high cost of pumping and system networking. Since the pressure requirement at the nozzle head reflects overall cost of a pressurised irrigation system, LERN holds greater promise in development of a cost effective pressurized irrigation system for irrigating field crop even at small plots.
    Keywords: Coriolis force, Developing world, Jet breaking, Operating pressure, Smallholders