Journal of Agricultural Sciences and Natural Resources
Year:2007 | Volume:14 | Issue:2|Papers Count:24

In this research, the results of tensil testing on poly (vinyl chlorid) (PVC)- plup paper composite using a statical model in order to composite mechanical properties predication have been investigated. In preparation for pulp paper reinforced-PVC composites, two types of pulp paper (Chemical - Mechanical pulp (CMP) and Natural Sulphite Semi - Chemical pulp (NSSC)) were mixed with PVC at three different levels of wt% of 10, 20 and 30. g- aminopropeyl trimethoxy silane was used at 0, 1 and 2 wt% as a coupling agent. The effect of these variables on tensile strength, Young's modulus, elongation at yield was determined through 3*2*3 factorial design. The analysis of variance of the experimental and predicted data shows that the constricted models provide a fair approximation of actual experimental measurements. Finally, experimental details regarding of optimum composites predicted by empirical models are discussed.

Industrial activity may result in the accumulation of heavy metals in soils and increase the uptake of these metals by plants. This research was conducted to evaluate the map of soil contamination with Pb and Ni around the Isfahan Steel plant and Mobarakeh Steel complex, as the major industrial area of the Isfahan province. In this research, 208 soil samples were collected in a regularly spaced grid pattern with an interval of 4 km. The sampling distance was decreased to a minimum of 500 m as the sampling point got closer to the industrial plants. The plant available Pb and Ni concentration were determined using DTPA extracting solution. The results showed that the concentration of Pb increased around the Isfahan Steel plant and Ni around two factories. Variograms were best fitted by the spherical model. To determine the estimation accuracy, mean error (ME), mean of sum of square error (MSE) were calculated. The result of validation revealed that high accuracy of estimation for all of the heavy metals especially for Ni.

The application effects of organic residues, LECA (light expanded clay aggregates) and zeolite all as incorporation and mulch (except for zeolite which was only incorporated) were investigated on the bare soil evaporation, soil temperature and mechanical resistance in a pot experiment. It was concluded that compost and LECA both as mulch effectively conserved soil moisture and reduced evaporation. The surface application of LECA and compost were more effective on evaporation control relative to their incorporation. Surface application of LECA and compost reduced temperature fluctuation and mechanical resistance. Compost incorporation reduced dry bulk density and increased available soil water content, but LECA and zeolite incorporated to soil did not affect soil physical characteristics.

A split plot experiment with randomized complete block design in three replications was conducted in Zanjan Agricultural Research Center in 2003, to investigate the effects of full irrigation, irrigation until flowering, irrigation at flowering and without irrigation on growth and yield of three chickpea cultivars (Jam, Hashem and Pirouz). The results of plant growth analysis on the basis of growth degree days (GDD) showed that dry matter accumulation (DMA), crop growth rate (CGR), relative growth rate (RGR), leaf area index (LAI) and grain yield were considerably reduced, due to water deficit. DMA, CGR and LAI in Pirouz were lower than in Jam and Hashem, but there was no significant difference between Jam and Hashem in LAI. Grain yield of Jam was significantly higher than two other cultivars. Although Hashem produced higher yield than Pirouz, but yield difference between these two cultivars was not significant. Maximum DMA and CGR highly correlated with grain yield. These two growth indices did not show significant correlation with mean 100 grains weight, but correlation of these indices with the number of pods and grains per plant were positive and significant. This shows that indices such as maximum DMA and CGR increase crop yield by increasing the number of grain per plant.

In order to study the effects of leaf clipping on yield and yield component of three seed corn varieties a field experiment was conducted as factorial laid out in complete block design with three replications in 2005. Three varieties (700, 604 and 301) and four leaf defoliation levels (without defoliation, ear leaf clipping. Above ear leaf clipping, and below ear leaf clipping) were used in this experiment. The result showed that defoliation, varieties and their interaction significantly affected on ear length, seed abortion, ear seed row number and grain yield. Varieties had different seed number in row and also defoliation affected on it. 1000-grian weight was not affected by any of defoliation treatments. On the whole, without defoliation, ear leaf clipping, and below ear leaf clipping treatments had the same ear length. Above ear leaf clipping reduced ear length. Ear length reduction, seed abortion, seed number in row, and grain yield was observed in 700, 604 and 301 in descending order respectively. The most ear seed row number, seed number per row and grain yield was obtained from without defoliation treatment. Ear and below ear leaf clipping was rank in second order in aspect of three former traits. Above ear leaf clipping produced the lowest ear seed row number, seed number in row and grain yield. Below ear leaf clipping and without defoliation produced the same grain yield in early maturity variety, but grain yield was more in without leaf clipping than other treatments in medium and late maturity variety. Response of early maturity variety to leaf clipping was severely more than late maturity variety (700). Low and non-significant effects of below ear leaf clipping on corn grain yield show that medium and early maturity varieties can be cultivated in higher density than 7plant/m2. These two former varieties also can be used in intercropping (with legumes).

Two methods were applied to prepare meals from whole and dehulled seeds of three Canola varieties (Quantum, P.F 7045/91, and Hyolla 401). Hexane-Extracted meals and Two-phase solvent extraction (Methanol-Water\Hexane) meals. The effect of variety, dehulling and oil extraction method on the protein, glucosinolate and phytic acid was significant (P<0.01), reasonably, and the protein content of two-phase samples was higher (8.9-12.4 %) than hexane-extracted samples. The results showed a reduction between 4.0-60.8% in glucosinolate content of two-phase samples. Some functional properties (Protein dispersibility Index (PDI), Nitrogen solubility Index (NSI),Water and Fat absorption, Emulsifying properties, Whippability and Foam stability) of Hexane-Extracted and methanol-water\hexane-extracted meals were determined. Variety, dehulling and oil extraction method had reasonably significant effect (P<0.01) on PDI and NSI of all meals examined, so the average reduction in PDI of two-phase meals and flours was 47% and 48%, respectively. A linear relationship between PDI and NSI of meals with a high correlation coefficient (r =0.96) was found. Water absorption of laboratory samples exceeded 200% which compares favorably with that of soybean meal. Fat absorption of methanol-water\hexane-extracted meals was about 10 percent higher than that of Hexane-extracted meals. Oil extraction method and variety had no significant effect (P<0.05) on meals emulsifying activity. The effect of heating on the emulsifying activity was not significant (p<0.05). Our results showed variety, dehulling and oil extraction method had reasonably significant effect (P<0.01) on the samples whippability. The foam stability of two-phase samples (60-120 min) was higher than single-phase samples (20-40 min). The flour samples obtained from three Canola varieties would be suitable for incorporation into foods as binder or extender in meat industries.

This research was conducted to study the effects of water deficiency stress, nitrogen application rates, and plant population on kernel and dry matter yields, nitrogen agronomic efficiency, nitrogen use efficiency and nitrogen recovery fraction of grain com (hybrid SC.704) in 2003 in experimental field in Natural Resources and Agricultural Sciences University of Khuzestan, Ahvaz. This study was consisted of three separate split-plot experiments, using. Randomized Complete Block Design (RCBD). In each experiment, one of the following irrigation treatments was implemented; optimum irrigation, moderate stress and severe drought stress where irrigation was done after depletion of 30%, 40% and 50% of field capacity, respectively. Irrigation treatments implement at 4-5 leaf stage (seedling establishment) and continued until 10 days before physiological maturity. In each experiment three nitrogen lease consisting of 140, 180, and 220 Kg N ha-1 were considered as main plots and subplots consisted of three plant population of 6, 7.5, and 9 plant m-2. There were three replications in each experiment. The results of combined analysis indicated that the effect of drought stress, nitrogen and plant population on kernel and dry matter yields, leaf area index and relative water content was significant. The increase of drought stress severity caused significant decrease in kernel and dry matter yields, leaf area index and relative water content. Severe drought stress reduced the kernel yield by 40% compared to the optimum irrigation condition. This reduction was mainly due to reduction in kernel number per ear and kernel weight. Kernel and dry matter yields increased with nitrogen application rate. The response of kernel and dry matter yields to increase in plant population was positive. Increase in drought stress severity and nitrogen application rate, caused significant decrease in nitrogen agronomic efficiency, nitrogen use efficiency and nitrogen recovery fraction. The response of these efficiencies to plant population was positive. Results of this study indicated that nitrogen application rate and plant population should be adjusted accordingly with the availability of water in the soil to obtain highest input use efficiency and therefore, minimizing production costs.

This study was conducted to evaluate the effect of five blends of probiotic bacillus on the growth and survival of Acipenser persicus larvae via bioencapsulation of Artemia urmiana nauplii. This experiment was conducted in a completely random design in four treatments. The blends of probiotic bacillus such as Aqua-1, Aqua-2, Aqua-3 and Aqua-4, and are used in three concentrations of 1.09×105, 2.2×105 and 3.18×105 bacteries per ml in suspension of broth. Every day artemia nauplii by one of blends of probiotic bacillus was bioencapsulated for 10 hours and Persian sturgeon larvae were fed on it. The controlled treatments were fed on unbioencapsulated artemia nauplii. The larves were fed on 6 times a day, every4 hours with bioencapsulated nauplii. The results indicated that the probiotic bacillus according to the concentrations used in bacterial broth, were replaced in digestive system of Persian sturgeon larvae, and had positive significant effects on the growth factors, final weight, Specific Growth Rate (%), food convertion efficiency and survival rate (P<0.05). But food convertion Ratio showed significant decreas (P<0.05). No significant difference in the condition factor was observed (P>0.05). The increase of the growth factors indicated a positive significantly correlation with the number of probiotic bacteries (CFU/larvae).The experiment indicated that the ability of probiotic bacillus to influence the increase of the growth performance is relatively high.

The major objective of this research was to investigate plasma 17a-Hydroxyprogestrone (17-OHP) and oocyte maturation of grey mullet (Mugil cephalus) after stimulation with hormones. Two hormone injections, a primer and a resolver, were used to induce spawning in 12 grey mullet's combination of carp pituitary homogenate, HCG and LRH-A2 each used as a primer or resolver of a two-injection protocol. Another three fish received saline injections as controls. All fish were bled and checked for ovulation for 48 hours. During hormonally induced spawning, 67% of mullets spawned. Oocyte of this mullets in the onset of experiment, were in the later period of stage IV (yolk globule stage). Peak levels of 17-OHP in spawned fishes occurred 30 hour after first injection. These changes are coincident with oocyte undergoing hydration, germinal vesicle breakdown and ovulation. Plasma 17a- hydroxyprogesterone levels in unspawned mullets increase to the end of experiment. Oocytes of these mullets in the onset of experiment were in the middle period of stage IV that developed to onset of stage V (mature stage) in the end of experimental period. In contrast to female in the treatment groups, none of three females in the control group had significant changes in maturing stages of oocyte and levels of 17-OHP in experimental period. This suggests that 17-OHP is one of the most effective steroids in the final maturation- inducing for grey mullet.

This paper is presenting the results of four years biometric study on the growth rate ,the length–weight relationships and age composition of 194 male and 710 female stellate sturgeon fish in the the south-eastern part of Caspian sea during 1380-1384 years. The maximum age frequencies for male and female were 9-13 and 12-13 years, respectively. Brood fishes more than 15 years have made little proportion of total catch. The oldest and largest individuals for male were 17 years and 156 cm and for female 27 years and 178 cm. The growth model of sexes were negative allometric. The age-fork length and age- total weight relationships had high correlation .This results can be used in the monitoring of stellate sturgeon in the Caspian sea and trying to evaluate the stocks.

In order to evaluate the feeding habits of tiger-toothed croaker (Otolithes rubber) 239 specimens were collected during December to March, 2003 in coastal areas of Chabahar, Iran. Stomach contents were examined by using of the numerical method. The abundance and frequency percents and type of preys, along with the percentage of emptiness of stomach, and prey dominant were evaluated during different months and in different groups based on upon length, sex and maturity. Result showed that in tiger-toothed croaker prey fish was the dominant and specific food item. There were monthly changes in feeding intensity and the feeding was weak. The percentage of emptiness stomach in March and December were highest and lowest, respectively. The empty stomach index (CV) indicated that tiger toothed croaker belong to the fish group with medium food intake. Shrimp was the main food in immature fish and with increasing in length and maturity of fish; shrimps were replaced with fish prey as the main food.

The ability of Artemia urmiana nauplii as a carrier of oxolinic acid and its transfer to the Persian sturgeon larvae (Acipenser persicus), drug excertion in the nauplii of Artemia in the cold incubation (4oC) and fish larvae in the laboratory conditions (19-21oC) were studied. The correlation between drug excretion and time of nauplii storing in the cold incubation was significant. The oxolinic acid excretion in first 12 hours of experiment in 2 doses of 5% and 10% (w/w) were 23.16% and 13.05% and in 24 hours of experiment 58.86% and 41.09% comparable of t0 (time of transferring to cold incubation), respectively. This decrease was significant. In dose of 20% of experimental treatment excretion rate of oxolinic acid in 4, 8, 12 and 24 hours of experiment comparable of t0 were 10.89%, 14.8%, 18.48%, 55.51%, respectively. The correlation between oxolinic acid excretion from nauplii of Artemia urmiana and time of nauplii storing by passing the time was high (r>95%) and significant (p<0/05). The oxolinic acid excretion in fish larvae in first 12 hours of experiment in 3 doses of 5%, 10%, 20% were 5.7%, 43.58%, 70.51%, respectively. These decreases were significant in 2 doses 10% and 20%.

Fluidized bed drying method is one of the most important new drying methods of agricultural materials. In this study the rough rice drying process by fixed and fluidized methods was compared based on thermal efficiency, drying rate and kernel fissuring percent. The experiments were conducted by a laboratory fluidized bed dryer with ability of the inlet air temperature and airflow rate control to operate in fixed and fluidized conditions. The rough rice samples were dried from 17.7 initial moisture content to 11% final moisture content (dry basis) at three temperatures of 40, 60 and 80oC. The air velocity in fixed, semi-fluidized and fluidized bed conditions was 0.1, 1.1 and 3.5 m/s, respectively. The thermal efficiency of dryer was calculated based on the ratio of thermal energy utilized for evaporating water from the drying product to thermal energy supplied to the drying air. The maximum and minimum thermal efficiency of 22.84 and 3.3% were belonged to the fixed bed condition at 80oC and the fluidized bed condition at 40oC, respectively. The fixed bed condition was determined as the main factor influencing kernels fissuring, so that the maximum drying time of 280 minutes and the maximum kernel fissuring of 78% were measured in this condition at 80oC. The minimum drying time of 40 minutes and the minimum kernel fissuring of 17% were belonged to the semi-fluidized bed condition at 80 and 40oC, respectively.

This experiment was conducted to evaluate the effects of betaine supplement in diets with different quantities of protein on the performance, body temperature and blood proteins of broiler chicks at 21 to 42 days of age under heat stress. Broiler chicks of Ross 308 strain fed a common starter diet (2900 Kcal ME/kg and 20% CP) for three weeks. At 21days of age, four hundred and thirty two birds randomly assigned to four dietary treatments consisted of : 1- diet with sufficient quantity of protein recommended by NRC (1994), 2- a low protein diet with 0.85 quantity of protein recommended by NRC (1994), 3- diet 1 plus 0.15% betaine supplement, 4- diet 2 plus 0.15% betaine supplement. Each of 4 dietary treatments was fed to six replicate groups of 18 chicks. During the three weeks of experiment, birds exposed daily to 37oC for 8 hours. Six birds were wing banded in each experimental unit for determining of body temperature and protein blood before and after heat stress. Results of experiment indicated that broilers were fed the standard diet with supplementation of betaine had better performance than other treatments. Dietary protein level had no significant effect on body temperature (P>0.05), but supplementing of betaine increased body temperature at 32 days of age (P<0.05). Also, male birds had significantly higher body temperature than female at 38 days of age (P<0.05). Dietary treatments had not any significant effect on blood proteins (P>0.05) and hematocrite value was higher for the birds were fed sufficient quantity of protein diet (P<0.05). Heat stress significantly increased body temperature at 32 and 38 days of age and also total protein, albumin and hematocrite (P<0.05). Heat stress had no significant effect on body temperature at 28 days of age and blood globulin concentration.

In this study host stage preference and functional response of Diglyphus isaea (Walker) as one of the most important natural enemies of the larval stages of vegetable leafminer, Liriomyza sativae (Blanchard) were studied in a growth chamber at temperature of 25±1oC, RH 60±5% and a photoperiod of 16:8 (L:D) on Sunry bean bushes. Host stage preference was investigated using equal number of first larval instar and second-third larval instars in choice and no-choice preference tests. The results indicated that in no-choice experiment the mean number of first instar larvae and second–third instars larvae parasitized were 2.83±0.95, 11.83±0.95 and in choice experiment were 1.67±0.8, 7.83±1.0, respectively. There were significant differences between mean numbers of parasitized larvae in two stages of the host. The preference coefficient for young larva and old larva were 0.253±0.08, 6.61±2.3 in first experiment and 0.203±0.11, 5.81±1.5 in second experiment, respectively. There were significant differences between preference coefficients in two stages of the host. Consequently D. isaea preferred second-third larval instars for ovipositor. To study the functional response one pair of D. isaea were introduced to six density levels of 2, 4, 8, 16, 30 and 60 second-third larval instars. Each density was replicated 5 times. Analysis of data was conducted using Juliano method (1993) and SAS software. Logistic regression was used for determining type of functional response, and non linear regression was used for estimating searching efficiency (a) and handling time (Th) parameters. The results showed that the functional response was type III. The rates of searching efficiency and handling time by Rogers's model were 0.0048 and 1.789, respectively.

This study was carried out to isolate the causal agent of charcoal rot disease and determination of reaction mode in some safflower (Carthamus tinctorius L.) genotypes. Therefore, safflower plants that had symptoms of charcoal rot disease were sampled, in 2003. The disease symptoms were included, crown discoloration, root rot, lower stem rot and darkening of inner crown sections. The isolation of pathogen was performed by culture of some sections of root, crown and lower stem on acidified P.D.A. The fungus colonies were gray white that with producing sclerotia were changed to black. The sclerotia were black in color, smooth and hard with size of 58-63×158-163m in diameter. The single or clustered pycnidia were formed on sterilized stems and toothpicks, which were located on P.D.A. Pycnidia, had dark brown colorization, solitary or massive, opening by apical ostiole, and pycnidiospores were hyaline and ellipsoid with 9´21m in size that these characteristics were carefully similar to that described for Macrophomina phaseolina (Tassi) Goid. Pathogenecity of the fungus was studied by inoculation of three safflower genotypes at the 6 to 8 leaf stage using of stem-puncture method. At flowering stage, inoculated plants were evaluated and scored for amount and severity of charcoal rot disease symptoms. Results indicated that the safflower genotypes, IUTC129, Safire and AC-Stirling had resistant, semi-susceptible and susceptible reaction to charcoal rot disease, respectively.

The epiphytic population of the Pss strains causing red streak on weed species growing in and around sugarcane fields in Mazandaran in October and December 2001 and June 2002 were determined. The epiphytic population densities on Setaria viridis, Cynodon dactylon, Phalaris minor, Sorghum halopens, Zea mays and Amaranthus retroflexus were high, low and intermediate in December, June and October respectively. It seems that Setaria viridis and Cynodon dactylon are epiphytic hosts of Pss in sugarcane fields.

In order to identify Fusarium spp. associated with root and crown rot of wheat, several fields in different regions of Gorgan city were sampled during growing season (2003-2004).Samples with chlorosis, abnormal growth; decay root and foot were collected. For isolation of fungi, discolored segments (root and crown) were surface disinfected with 0.5% NaOCl. Then cultured on Potato Dextrose Agar with pH .For exact observation some characteristies of species were used from Carnation Leaf Agar medium. Among the 18 Fusarium isolates, 6 species were identified as: Fusarium moniliforme*, F. nygamai, F. solani *, F. oxysporium*, F. equiseti*, F. semitectum*. A Few isolates (*) were used for pathogenicity tests by mixing autoclaved soil with inoculum (colonized wheat seeds with on isolate) and spore suspension under lab and green house condition. F. equiseti and F. semitectum were only pathogenic and able to cause root and foot rot in wheat.

Bridges are the most important and usable river structures that they have been used since long back. In this research, effect of constructed bridges on depth and areas of flood in Ziyarat river of Gorgan city (Iran) has been investigated. To conduct the study, the topographic and land use maps, longitudinal profiles and cross sections were drawn. The river was divided into 9 reaches. Then flood hydrographs for different return periods were estimated by SCS and Muskingum-Cunge methods. Geometrical characteristics of river and bridges have been determined by field surveying. Water surface profile has been calculated using HEC-RAS software in two different conditions of considering and fictitious elimination of all bridges in the study area. Flood maps for study return periods have been prepared in ArcView GIS in two cases. Then flooded area and flood depth for any return periods in 2 cases were compared. Furthermore, in this research the effect of any bridges were assessed and the most effective bridges in flooded area were defined. Finally, according to the result of this research, suitable approaches were proposed.