Journal of Agricultural Science and Technology
Volume:13 Issue: 2, Mar 2011

The population densities and spatial distribution patterns of Zetzellia pourmirzai Khanjani and Ueckermann and its preys Cenopalpus irani Dosse and Bryobia rubrioculus (Scheuten) were studied in a sprayed orchard in Kermanshah, a western province of Iran, from 31 May till 7 November, 2007. The interaction (density dependence) between the plant feeding mites and their predator was determined as well. Population density of the phytophagous mites and their predator were counted on 130 leaves (sampling unit) every 10 days. The mean population density of C. irani per leaf was significantly higher than that of the other mites. The population densities of C. irani, B. rubrioculus, and Z. pourmirzai were highest on 9 August (11.092 per leaf), 20 July (0.554 per leaf) and 30 July (1.385 per leaf), respectively. The index of dispersion, regression models (Taylor and Iwao), and Lloyd’s mean crowding to mean showed an aggregated distribution for all species. Some changes in the distribution from aggregated to random was indicated by Morisita’s index during different sampling dates. These changes showed that the spatial distribution of these mites can vary during the season. The smallest optimum sample sizes, calculated with Taylor's coefficients, were 20.806, 192.912, and 128.117 for C. irani, B. rubrioculus and Z. pourmirzai, respectively. Linear regression of predator to prey population densities showed a density-dependant predation by Z. pourmirzai on C. irani and on B. rubrioculus. In addition, a significant linear regression was obtained between temperature and the population fluctuations of these mites. The spatial distribution parameters of the tetranychoid mites and their predator could be used to improve sampling programs and to estimate the population densities of these mites and the efficacy of the predator being used in orchards IPM.

Drying characteristics of Quercus were determined experimentally as a function of temperature, air velocity, and variety (Quercus Persica and Quercus Libani). In order to estimate and select a suitable drying curve, five different thin layer drying models were fitted to the experimental data. Experiments were performed at the air temperatures of 50, 60 and 70°C. At each temperature level, two air velocities were adjusted: 0.5 and 1m/s. The effect of air temperature was found to be significant in comparison to air velocity for drying of fresh Quercus fruits. Increasing air velocity at constant air temperature resulted in the decrease of drying time. Among all the selected drying models, the Page model was found as the best mathematical model for describing the drying kinetics of Quercus fruits. Based on the results, drying temperature of 70 oC and air velocity of 1 m/s are the optimum values for drying Quercus fruit. Drying time and Page model constants were found to be dependent significantly on the variables studied.

This experiment was conducted to investigate the effects of Lactobacillus acidophilus on performance, carcass characteristics, blood parameters, and intestinal microflora of broiler chicks. The dietary treatments were: basal diet as control 1; basal diet plus 1g. kg-1 of a commercial probiotic Bioplus2; basal diet plus 10 and 20 g kg-1 fermented milk that contained 2×108 cfu g-1 Lactobacillus acidophilus. To evaluate the effect of water alone on chick performance, equal volume of water in 20 g fermented milk was added to each kg of the basal diet (control 2). A total of 280 one-day old male broiler chicks were randomly allocated to 5 experimental groups of 4 replicates of 14 chicks each. The chicks were grown to 42 d of age. The result of the experiment indicated that feed intake in chicks fed diet supplemented with commercial probiotic was significantly higher than L. acidophilus probiotic. Weight gain for the chicks fed with the diet that contained 20 g kg-1 fermented milk was higher than the control chicks, in the first 3 weeks. There was no significant difference in feed conversion and weight of organs. The number of Lactobacilli in ileum and colon were higher in L. acidophilus treated birds than the control group and also the number of Coliforms was lower, but the effects were not statistically significant. The levels of blood cholesterol, alanine aminotransferase, aspartate aminotrasferase and alkaline phosphatase were the highest in the control group, but the effect was statistically significant only for ALT measured at 21 d of age.

The objective of this study was to determine the efficacy of two procedures i.e. feeding and immersion followed by feeding, for masculinizing Blue Hap. Two experiments (experiments I and II) were conducted. In experiment I, feeding hormonal treatment was applied on post-yolk sac stage fry (10 days after fertilization at 27ºC). Dosages of 30mg (group A) and 60mg (group B) of 17α-methyltestosterone per kg of food were used during 60-day periods (40 fry per treatment). The control group i.e. group C, received no hormone. In experiment II, one day post hatching larvae were exposed to an immersion treatment in 17α-methyltestosterone at 1000 μg/l up to 2 h (16 larvae per treatment). Later, at the first day of post-yolk sac stage, the treatment was followed by oral procedure which was divided in 2 groups: group D and group E. In group D, 30 mg 17α-Methyltestosterone per kg of food was used during a 60-day period. In group E, fry received 60 mg of hormone per kg of food during the same period. The control group i.e. group F, did not receive any hormone. Change in sex proportion within each experiment as well as between experiments was analyzed by chi-square test (p<0.05). In experiment I, 60 mg feeding treatment significantly (p<0.05) increased the proportion of the males (85.7%) in comparison to the control group (46.67%). Lower male proportion (60%), but still significant (p<0.05), was evaluated in 30 mg feeding treatment. In experiment II, in both groups (D and E), although sex ratio was different from the theoretical 1:1 sex ratio, fish skewed toward sterility rather than masculinization because of high hormonal dozes. In conclusion, this study confirms that it is possible to achieve high rates of hormonal masculinization in Blue hap.

There has been a renewed interest in edible films made of renewable and natural polymers such as protein, polysaccharide and lipids. Natural polymers derived from natural sources like food protein, offer the greatest opportunities because of their biodegradability and their ability to supplement nutritional value of foods. Faba bean is a valuable source of protein and is cultivated in large quantities in Iran. Therefore, in this study, we investigated the potential of faba bean protein isolate (FPI) as a new protein source for preparation of an edible film and determined the effects of film forming solution pH and plasticizer concentration on the film properties. Results showed that increasing the pH improved mechanical properties (tensile strength and elongation) and solubility of the films, but, caused the water vapor permeability (WVP) and lightness of the films to decrease. Plasticizer concentration did not affect WVP over the studied range. Elongation and solubility of the films increased and the tensile strength decreased by increasing plasticizer content of the film forming solutions. The lowest WVP and the highest tensile strength were observed at pH 12 and 40% (w/w of FPI) glycerol concentration.

Wheat starch is the most common type of starch in Iran as well as many other parts of the world with enormous applications in food and non-food products. To improve its physicochemical properties or create new functionalities, starch can be modified by changing its molecular structure. Amongst different methods for starch modification, physical methods have received more attention recently. Pre-gelatinization of starch is a physical method to modify the properties of native starch. The main aim of this research was to study the physicochemical properties of pre-gelatinized wheat starch produced using a small scale industrial twin drum drier. The results indicated that drum drying destroyed native starch granules, degraded molecular structure and reduced the degree of crystallinity of starch. Pre-gelatinized starch (PGS) showed cold water viscosity at 25 ºC, while native wheat starch was not able to increase the viscosity under this condition. It also increased water absorption and swelling of the starch compared to its native counterpart. Pre-gelatinized wheat starch can be used as a thickening agent in instant food products to eliminate heating stage in their production or in manufacturing of the products sensitive to high temperature.

Gas chromatography (GC) and gas chromatography mass spectrometry (GC-MS) were employed to determine the chemical composition of essential oil obtained from dry fruits of Carum copticum. Thymol (36.7%), -terpinene (36.5%) and -cymene (21.1%) were found to be the major constituents of the oil. The anti-bacterial activities of the oil were mainly investigated against food poisoning bacteria (Salmonella thyphimorium, Pseudomonas aeruginosa, Entero-pathogenic Escherichia coli, and Staphylococcus aureus) by broth microdilution and agar diffusion methods. The oil exhibited significant anti-bacterial activities against all the examined bacteria. In conclusion, the results of this study showed that the oil of Ajowan is rich in monoterpenes and it may be used as a natural anti-bacterial agent in drug and food industries.

This paper reports the results of using three empirical methods (Makkink, Priestley-Taylor and Hargreaves) for estimating the reference evapotranspiration (ET0) in the semi-arid region of Tensift Al Haouz, Marrakech (center of Morocco). The Penman-Monteith equation, standardized by the Food and Agriculture Organization (FAO-PM), is used to evaluate the three empirical methods. The obtained ET0 data were used to estimate crop water requirement (ET) of winter wheat using the crop coefficient (Kc) approach and results were compared with ET measured by the Eddy Covariance technique. The result showed that using the original empirical coefficients a,  and Cm in Hargreaves, Priestley-Taylor and Makkink equations, respectively, the Hargreaves method agreed fairly well with FAO-PM method at the test site. Conversely, the Priestley-Taylor and Makkink methods underestimate the ET by about 20 and 18 %. After adjustment of the original values of two parameters  and Cm coefficients in Priestley-Taylor and Makkink equations, the underestimation of ET was reduced to 9% and 4% for the Priestley Taylor and Makkink methods, respectively, which led to an improvement of 55% and 76% of the obtained values compared with the original values.

An accurate determination of evapotranspiration is required for many studies that involve estimation of the water balance. One methodology is the use of lysimeters. Considering the semiarid climate of Kerman Province, in southeastern parts of Iran, the only operating electronic weighing lysimeter in the country was used for calculating daily ETo from April 2004 to March 2005 in three different periods, i.e. the entire year, and high and low evaporative demands periods. The measured error was equal to 1 kg mass, which is equivalent to 0.14 mm of water in the field. An automated weather station was used that provided 10-min recordings of the weather data to be used for predicting daily ETo with models. The lysimeter was installed in proximity of the automated weather station and both were located in a field with grass cover. The lysimeteric data were used for the evaluation of six grass evapotranspiration models, including FAO-56 Penman–Monteith, Penman-Kimberly 1996, FAO-24 Blaney-Criddle, FAO-24 Radiation, Makkink, and Hargreaves-Samani. The root mean square error (RMSE) and index of agreement (d) were used for assessing prediction accuracy of different models. Results indicated that for the entire year period, the FAO-24 Radiation equation was the most precise method for calculating ETo, with a RMSE of 1.63 mm day-1 and a d- index of 0.78. During the high evaporative demand period (April to September 2004) the FAO-24 radiation equation was superior compared to the other methods for calculating ETo with a low RMSE value of 1.86 mm day-1 and a d-index of 0.45. During the low evaporative demand period, again, FAO-24 radiation equation was superior compared to the other methods with RMSE of 1.30 mm day-1 and d-index of 0.46. In all of the three periods, the Makkink method showed poor performance and can not be recommended for the region.

DRASTIC model has been used to map groundwater vulnerability to pollution in many areas. Since this method is used in different places without any changes, it cannot consider the effects of pollution type and characteristics. Therefore, the method needs to be calibrated and corrected for a specific aquifer and pollution. In the present research, the rates of DRASTIC parameters have been corrected so that the vulnerability potential to pollution can be assessed more accurately. The new rates were computed using the relationships between each parameter and the nitrate concentration in the groundwater. The proposed methodology was applied to Astaneh aquifer located in north of Iran. Samples from groundwater wells were analyzed for nitrate content in thirteen locations. The measured nitrate concentration values were used to correlate the pollution potential in the aquifer to DRASTIC index. Pearson correlation was used to find the relationship between the index and the measured pollution in each point and, therefore, to modify the rates. The results showed that the modified DRASTIC is better than the original method for nonpoint source pollutions in agricultural areas. For the modified model, the correlation coefficient between vulnerability index and nitrate concentration was 68 percent that was substantially higher than 23 percent obtained for the original model

A subsurface drainage network mainly carries unsteady flow and data are not usually available for model parameters calibration in such networks. In the present research, the finite volume method using the time splitting scheme was employed to develop a computer code for solving the one dimensional unsteady flow equations. Using corrugated sub drainage pipes, an experimental prototype setup was constructed to examine the numerical model response in predicting the observed unsteady data in such circumstances. The experimental setup components and the model parameters were calibrated in place based on steady state flow condition. The results revealed satisfactory performance by the abovementioned method and the scheme employed and justified its validity for field application.

The kinetics of Zn sorption by ten calcareous soils of Iran were measured and fitted to several equations (zero-, first-, second-, third-order, parabolic diffusion, simple Elovich, and exponential equations). Two initial concentrations of zinc i.e. 20 and 80 mg Zn l-1 were used and observations were carried out for 100 hours. The time required to reach the near equilibrium state was about 24 hours, by which time most of the Zn in solution had been sorbed. Zero-order, first-, second-, and third-order equations did not adequately describe zinc sorption kinetics. Both simple Elovich and exponential equations did adequately describe the data. Regression analysis indicated that the total CaCO3, active CaCO3, clay content, and specific surface area were closely related to the coefficients of these two equations. The magnitude coefficients of the equations were positively related to these soil properties. Thus, Zn sorption kinetics can be predicted from data collected during routine soil evaluation.

Gypsiferous soils occur in xeric, ustic, and aridic moisture regimes. Environmental conditions affect the mode of gypsum formation. Gypsiferous soils in Fars Province, southern Iran, are found in piedmont plains, flood plains, and alluvial plains. The objective of this work was to investigate the micromorphology of gypsum crystals formed under different soil moisture regimes. The results indicate that lenticular crystals of gypsum have been frequently found in more developed soils, whereas under aridic soil moisture regime such form is rare and they are frequently found in the subsurface horizons. Columnar, prismatic, and blade forms of gypsum are found in areas with aridic moisture regime, where soils are highly leached. Formation of gypsum pendant under gravels is dominant in piedmont plains with limited moisture in the profile. Complex gypsum crystals were found in low rainfall regions. It seems that surface runoff, as well as hydrological system of the region, transfers gypsum from geological sediments in higher elevations to coarse-textured soils of flood plains. In landscapes with xeric and xeric-aridic soil moisture regimes, lenticular, euhedral and subhedral crystals of gypsum were abundant. The results of this study indicate that, in addition to soil moisture, texture and landscape position play a significant role in the formation of pedogenic gypsum. Well crystallized gypsum was observed in soils with silt loam, sandy loam, and loamy texture. Observation of gypsic horizons suggests that the accumulation of gypsum took place under per descendum process in the soils studied.

This research was conducted under greenhouse conditions to evaluate the optimum combination of irrigation and fertilizer levels to attain the best yield and quality of tomato crop. The experiment was conducted by using a split-plot design with three replicates. Irrigation levels were applied to the main plots and fertilizer levels to the sub-plots. For each experimental unit, the irrigation levels were W1=8mm/day, W2=7mm/day, W3=6mm/day, and W4=5mm/day. Fertilizers treatments varied during the growing season. For the period after transplanting till flowering, the treatments consisted of weekly applications of F1= (N1, P1, K1, respectively, 9.8, 6.13, 7.35 g /plot), F2= (N2, P1, K1, respectively,14.7, 6.13, 7.35g/plot), F3= (N2, P2, K1, respectively,14.7, 9.19, 7.35 g/plot), and F4=(N2, P2, K2, respectively, 14.7, 9.19, 11.0 g/plot). Fertilizer levels were increased as the plants developed during the growing season. Plant height and the number of flowers per tomato plant were measured during the growing season and at harvesting time. Random samples of tomato leaves and fruits were taken from each experimental plot to determine the percentage of dry matter, total nitrogen, phosphorus, and potassium contents of fruits and leaves. Total yield during harvesting period and average fruit weight were also measured. Results indicated that irrigation and fertilizer levels had significant effects on the number of flowers per plant and W1F2 combination was significantly the most effective treatment compared to the other treatments. Plant height was not affected significantly by any treatment. The total yield significantly increased in W3F1 treatment. Average fruit weight was significantly higher in W2F3 as compared to the other treatments. The percentage of dry matter was significantly affected by the treatment W3F3 in both leaves and fruits. Total leaf contests of nitrogen, phosphorus, and potassium significantly increased in W2F4 treatment. Total nitrogen content in tomato fruits did not show any significant difference among different treatments, whereas fruit phosphorus and potassium contents significantly increased in W2F3 and W4F4 treatments.