Journal of Water and Soil Science
Year:2002 | Volume:6 | Issue:3|Papers Count:25

For the study of field wind erosion and the design and evaluation of wind erosion control techniques, detailed observations of soil partivle transport and vertical destribution of eroded soil partiles are needed. The objectives of this study were: 1) To describe one device for soil transport partivle measurement, Le the BSNE sediment catcher, and 2) To swath height in esteem Isfahan. The BSNE sediment catcher is a wind erosion sampler that traps eroded material at seven heights of 0.24, 0.60, 1.08,2.00,3.00, and 4.00 m above the soil surface. Each trap consists of a steel container with an inlet and outet, mounted on a wind vane that rotates about a central pole. Before using the sampler in the field, it was tested and calibrated in the wind tunnel. The results showed that the average trapping efficiency with speeds ranging from 5.2 to 7.2 m sec-1 for 4 different 0.44 to 0. 68. However the trapping efficiency depended on wind speed, particle size distridetion, particle density and type of sediment. The sampler had the lowest efficiency for particles < 44µm.A BSNE sediment catcher was installed in Babaii Air Base. After a sampling perion, the sediment in each trap was collected and weighed. The trapped materials were a mixture of salutation and suspension. Vertical distribueroded sediment that the amount of soil colleted decreased with increased height and the percent age of fine particles(<63µm) increased with height. The amount of trapped materials for each cm2 frontal intake with increased height were 12.00,3.42, 1.44, 1.56,0.75,0.21, and 0.39 g cm-2,respecitively, for the one sampling period.

Fertility, developmental time and adult longevity of walnut aphid, Chromaphis juglandicola (Kalt.) and its parasitoid wasp, Trioxys pallidus (Hal.) were studied under controlled conditions with a constant temperature of 26±2°C, relative humidity of 60±5%, and 16:8 (L:D) photoperiod. Populations of walnut aphid and parasitoid wasp were reared on walnut seedling in a growth chamber. The mean developmental period, daily fertility rate, and progeny sex ratio were combined to construct demographic life tables. From these tables, intrinsic natural rate of increase (rm),net reproductive rate (Ro)and mean generation time (Tc) were calculated. The net reproductive rate (female offsprings per female per generation) and intrinsic rate of natural increase values were 34.69 and 0.278 in walnut aphid and 53.85 and 0.385 in parasitoid, respectively. The mean generation time was 12.75 days in walnut aphid and 10.35 days in parasitoid. Values of rw (weekly multiplication of the females) indicates that T.pallidus is able to multiply 14.81 times per week, whereas the population of walnut aphid multiplies by only 7.001 times in the same period. The population of parasitoids doubled within 1.8 days while the aphid took 2.49 days. Mean pre-imaginal period was 9.14±0.34 days for male and 9.16±0.12 days for female parasitoids on a mixture of different nymphal stages of host. In walnut aphid it was 9.30±0.10days. The pre-imaginal periods of parasitoid decreases as the aphid host ages. Longevity of adult male and female was 6.17±0.22 and 6.87±0.23 days, respectively, and 12.24±0.94 days for walnut aphid.

Side channel spillways have a common usage in conveyance and distribution networks, high dams, water and wastewater treatment plants, and surface drainage networks. A side channel carries spatially varied flow with increasing discharge and their water surface profiles is a main feature in the design process. Usually, the bottom width of the channel is flared in the flow direction and an end sill is also installed at the downstream end to provide a control section and to generate an even water surface profile. In this study, the impact of installing an end sill on the flow characteristics in a non-prismatic side channel is presented. Six distinct longitudinal profiles were clearly observed in each run and the difference between the mid points of the maximum and the minimum profiles of each run was used to evaluate the sill effects on the water surface profile and the energy dissipation. The results indicated that the maximum and the minimum differences are, respectively, equal to critical depth and half of it generated at the channel downstream end. Also, based on an envelope of the data, a method was proposed to determine the maximum potential impact of an end sill that might have on the flow depth, which could also be considered as a guideline in the design process.

Of the many hydraulic structures developed by man, the weir is perhaps the olsest. Weirs are used for the measuremsnt of discharge and regulation of water flow. The most common types of weirs are broad- crested, sharp- crested, circular crested and cylindrical and ogee crest weirs. Advantage of the circular- crested and cylindrical weir compared to the other weirs include simplicity of design, stable overflow pattern, larger coefficient of discharge and the associated lower costs. In the present study, potential flow around a circular cylinder are adapted to determine the velocity distribution at the crest section and to develop a model for coefficient of discharge Cd for circular- crested weirs. These results were evaluated using present test data for three types of weir models, namely, cylindrical, semicylindrical and semicylindrical with different heights and also Dressier theory. The results of the study showed that the experimental velocity profile agree very well with the theoretical profiles for the range of the study. Also, the prediction of the velocity distribution over the weir crest crest using Dressier theory is alays less than the proposed model and measured data. The predicted values of coefficient of discharge Cd based on the proposed model agree well with Cd determined from discharge measurements. For the cylindrical model, the coefficient of discharge can be predicted from 7% and for the semicylidrical with different heights within ± 5%.

In quantitative land suitability evaluation, economical aspects land evaluation such as impact of environmental physical factors on agricultural crops production and the omount of yield per surface unit are considered. The purpose of this research was to study of quantitive land duitaility of northern Baraan area located in east of Isfahan city. The study was carried out in contnuation of the previously accomplished qualitative lamd suitability evaluation of the area. The achieves economical studies include economical data collection, matching inputs and outputs and gross margins analysis. Radiation- thermal production potential of the crops was calculated bsed on plant physiology and temperature (FAO model). It is 10. 45, 10. 11, 13.64 and 11.93 ton/ha wheat, barley, maize and rice, respectively. Radiation- thermal thermal production potential, observed and marginal yields and the results of the qualitative land evaluation were used to do quantities land evolution and to determine the corresponding suitability classes. The predicted yield in different land units varies between 1.64 and 9.17 ton/ha for wheat, 1. 81 and 9 ton/ ha for barley, 2. 06 and 9. 42 ton/ ha for maize and 2.35 and 7.14 ton/ha for rice. Presence of significant correlation between the observed and the predicted yield indicates validity of the used evaluation methods. The results of quantitative land evaluation shows that most of the land units and slightly to moderately suitable for wheat, barley, maize and rice. A few land units are not suitable for these crops. The best land utilization type in each land unit can be selected through a combined consideration of quantitative land evaluation results, benefit ability of each land unit and impact of the land use on the soil. Rice cultvation is not recommended in the studied area, because of its adverse effect on soil physical properties and soil drainage.

 To study grain quality trality traits and their relationships with high molecular weight (HMW) and low molecular weight gluten in (LMW), subunits, 104 durum wheat genotypes were used. Six grain quality characteristics comprising wet and dry gluten content, test weight, grain horsiness, protein content and SDS sedimentation volume were studied. HMW and LMW glutenin subunits were evaluated SDS-polyacrylamid gel electrophoreses (SDS- PAGE) in 33 genotypes. Statistical analysis including correlation coefficients, factor analysis, cluster analysis of genotypes based on qualitative traits, analysis of variance in qualitative traits based on based on HMW, LMW, and combination of subunits as well as all of subunits, and canonical correlation analysis between gluts in subunits and qualitative traits were used. Factor analysis of the genotypes detected 2 factors, which explained 65 percent of the total variation among the data. These were named quantitative protein and qualitative protein. Based on cluster analysis, the genotypes were classified into gour clusters. The genotypes in groups 2 and 4 were beneficial in terms of protein quantitative and qualitatiy. In evaluating glutrnin subunits, 7 HMW subunits and 2 LMW subunits were detected. Subunit null of Glu- AI was observed. Subunits 7+8, 6+8, 13+16 and 20 at Glu- BI were observed; however, neither of them had significant differences in qualitative traits, but 6+8 and 7+8 had a higher SDS sedimentation rate than 20. LMW-1 and LMW-2 had significant differences in protein content and SDS sedimentation; LMW-1 had higher protein contet where as LMW-2 had higher SDS sedimentation. Combibation of subunit LMW-1 / HMW 7+8 had the highest protein content and LMW-2 / HMW 7+8 has the highest SDS sedimentation. Results of canonical correlation showed that presence of<MW-2 and HMW 7+8, and absence of LMW-1 and HMW 20 in durum wheats caused an increase in SDS sedimentation and a reduction in protein content and gluten content.

Edible-oil flax (Linum usitatissimum L.) can be an alternate oil-seed crop in Isfahan region. Seeding date is very important in obtaining higher grain yields and a successful flax production. The present study was conducted at the research farm, Isfahan University of Technology in the year 2000 to determine the effect of seeding date and genotype gn yield, yield components and maturity of edible-oil flax. In this study, a RCBD with three replications, in which the treatments were organized as a split-plot experiment, was used. Seeding dates (Oct. 17, Nov. 16, March 15, April 13, May 14, June 13, July 15) and genotypes (four breeding lines of edible-oil flax) were considered as the main and the sub factor, respectively. The number of capsules per plant, seeds per capsule,100-seed weight and seed yield were highest for all genotypes in the first seeding date. Average seed yield in the first seeding date was almost twice, triple and eight times as much as the second, third and the last three seeding dates, respectively. In the second seeding date there was no emergence because of low temperature. The genotype and seeding date interaction on seed yield and maturity was significant. In general, delayed seeding was accompanied by reduction of emergence, number of days to maturity, yield and yield components in all genotypes, with the exception that the last seeding date led to increased number of days to maturity and seeds per capsule. Based on regression analysis, seed weight, number of seeds per capsule and number of seedlings/m2 were the most important components that contributed in seed yield variation, respectively. But, most of the variations in seed yield per plant was affected by number of copsules per plant and number of seeds per capsule, and in that order.

During 1998-99, a field experiment was conducted to investigate the effects of residual Processed Municipal Waste Leach ate (PMWL) on growth and yield of wheat (variety Roshan). The treatments consisted of residual amounts of 0, 150, 300 and 600 t/ha of PMWL and a residual N, P, K, and Zn fertilizer treatment in a randomized block design with 3 replications. In 1998, rice seedlings were transferred to 3x4 m plots. After harvesting the rice, wheat was seeded in the same plots without any new treatment. Processed municipal\vast leach ate and fertilizers were applied during the rice growth. Residual effects of PMWL increased the amounts of available macro- (N, P and K) and micronutrients (Fe, Cu, Zn and Mn) in soil which, in turn, promoted the grain and straw yield of wheat compared to the control. Straw and grain yield increased tromp 1.67 and 3.50 t/ha in control to 3.93 and 12.80 t/ha in 600 t/ha of PMWL, respectively. The residual effects of PMWL had no significant effect on heavy metals concentrations in plant. The effects of residual PMWL in the soil were proportional to the amount of leach ate applied. However, more investigations are recommended to fully understand heavy metals effects on soil, plant, and environment.

Alternate bearing is a key factor in limiting citrus production. Chemical controls have proved to be the most effective solution to this problem. Two different experiments were conducted to study the effects of different growth regulators (GA3,NAA, Ethephon) and urea on alternate bearing control in Kin now mandarin (Citrus reticulate). In the first experiment, GA3 at concentrations of 0, 25, 50, 75 and 100 mgl-1 were applied 3 times during late autumn and early winter 1993 on off trees. Flowers reduced as a result of GA3 application in the following spring but increased in the second spring. Best results obtained with 50 and 75 mgl-1. In the 2nd experiment thinning agents: NAA (0, 100,200 and 300 mgl-1), ethephon (0,100,200,300 mgl-1) and urea (0, 4, 8 and 12%) were sprayed to the trees on on-year, when the fruit lets were about 0.75-1 cm in diameter. The results indicated that urea had no effect; however, both NAA and ethephon were effective on thinning of fruits and control of fruiting. Ethephon at 200 and 300 mgl-1, and NAA at 400 mgl-1 gave the best results.

Prediction of watershed responses and simulation of runoff rate and volume are required for design of most water resources projects. For this purpose, different hydrolofic methods and event based or continuous hydrologic mathematical models are applied. In this research, a continuous hydrologic model, Stanford Watershed Model- IV (SWM- IV) is used for simulation of annual and monthly volumes and mean daily runoff flow produced in Roodzard representative basin with 896 km2 area located in southwest part of Iran. The accuracy of the simulation outputs were checked using the sensitivity analysis over reasonable of input sata related to Roodzard watershed. Calibration and verification of the standford model were performed using the data of 1976- 1977 and of four consecutive years (1978- 1981), respectively. The output of the SWM- IV model showed that the values of annual and monthly runoff, groundwater, and monthly interflow can be simulated in closed agreement and acceptable precision corresponding to observed data. The model is also to combine the hydrologic components of the basin to determine the dominant flow of the study watershed. Actual evepo-transpiration and annual runoff coefficient are the other parameters that have been estimated successfully by the model. However, the range of coefficient of determination (R2) for the observed and predicted daily flow values was0.44 to 0.81 for the available data. Therefore, application of the model is recommended for predicting of the hydrologic responses of various sizes of watersheds size in Iran.

This research was conducted in Kooshkak Farm Research Station of Shiraz University in 1997 and 1998 in order to determine crop coefficient and water requirements of rice, using lysimeter. The variety used was Champa-Kamfiroozi which is an early mature variety and is grown by most farmers in the area. Results showed that potential evapo-transpiration varied from 3.76 to 9.34 mm/day. Penman FAO method was used in calculating reference evapo-transpiration. Crop coefficient was 0.97 in the initial growth stage, 1.25 in the mid-season growth stage, and 1.09 at the time of harvest. Total crop evapo-transpiration rates in 1996 and 1997 were 560 and 757 mm, respectively. Average deep percolation rates in the growing season was 3.4 and 3.5 mm/day in 1996 and 1997, respectively. Finally the total water requirements of rice in 1996 and 1997 were 1983 and 2361 mm, respectively.

The presence of large amounts of calcium in the equilibrium system of calcareous soils of arid and semi-arid regions affects the chemical reactions of soluble and exchangeable phases. Exchange phenomenon is one of these chemical reactions in which calcium plays an important role. K-Ca equilibria are important equilibria in calcareous soils and may be an answer to many problems in soil chemistry and fertility, specifically on the availability of potassium. Little work of this nature has been done in Iran. In this work, a variety of calcareous soil samples from northern Khorasan were examined. First, regression equation between potassium adsorption ratio (KAR) and exchangeable potassium ratio (EKR) in 26 soil samples was found to be EKR=0.02+2.48KAR, R2=0.77.Gapon exchange selectivity coefficient (KG) was estimated as 2.48 for the soils. Furthermore, in 14 calcium saturated soil samples, different concentrations of K were added until equilibrium was reached and EKR and KAR relations were determined for each soil with a regression coefficient higher than 0.91.KG ranged between 1.21 to 3.34. For the potassium range used in the soils studied, KG was constant and almost matched theKG obtained from EKR and KAR relation of the first step. Based on this equation, the effect of soluble K on exchange K in the presence of Ca and Mg as dominant cations in calcareous soils may be evaluated.

The main objective of the present study is to investigate the production and marketing of fresh figs in Garmsar Region. Semnan Province has the largest area under fresh figs in Iran. About 84 percent of this area is in Garmsar region, hence, it was selected as the study area. Data were collected by random sampling method through interviews with a sample of 70 fresh fig producers in Garmsar region in summer 1999. The production functions of fresh figs were estimated using tran slog form for the study region. Technical efficiencies for fresh fig producers were estimated using translog stochastic frontier production function. Results of the current study revealed that farmers are not using some of the inputs optimally. Study of technical efficiencies. The average of retail, wholesale and marketing margins of one kilogram of fresh figs were estimated to be 900,550 and 1450 Rials, respectively. Also, marketing efficiency was calculated as 151%.

The general characteristics of salt-affected soils and soil structure degradation process are partially known, but the effects of saline and sodic conditions on mechanical properties of soils are not well recognized. In this study, the effects of electrical conductivity (EC) and sodium adsorption ratio (SAR) on tensile strength of soils with different organic carbon contents were assessed under laboratory conditions. The soil samples were collected from Dasht-E-Naz, at Sari region in the North of Iran. The samples had the same clay mineral (Illitic) and the main difference between them was the organic carbon content, subjected to different cropping. systems. The tensile strength was determined on soil samples which had been treated by solutions having defined EC (0.5 and 4 dS/m) and SAR (0,5, 15). The tensile strength was positively related to organic carbon content, but negatively to SAR. With increasing SAR, tensile strength decreased, and at a given SAR, the treatments with higher EC showed higher tensile strength. The analysis of variance showed significant differences (at 0.01) between soil samples (four levels), soil sampling depth (two levels), EC (two levels), and SAR (three levels) for all variables under investigation. For soil factor, the order of averages were: Virgin soil> Permanent pasture (Festuca) > Intensive cropping> Permanent pasture (Agropyron).

 Evaluation of uric acid contents of poultry excreta was examined for use in the estimation of apparent protein digestibility. Uric acid was determined either by high-performance liquid chromatography or by spectrophotometric method. A high-pressure liquid chromatographic assay was used with absorbance measured at 285 nm. The method used a reverse-phase system with a C18-bonded column (250*4.6 mm, i.d.). The mobile phase was distilled deionized water. Injection volume was 20µI with a flow rate of 1 ml/min. Correlation (r) between the two methods for uric acid content of excreta from birds fed diets with different methionine levels was 0.976. The uric acid values were then used to determine apparent protein digestibility. The apparent protein digestibility values, when corrected for uric acid nitrogen, were comparable with those calculated from amino acid analysis.

Effect of supplemental phytase on phosphorus and protein utilization and perfonnance of broiler chickens fed on eight different wheat varieties were evaluated. The phytate contents of wheat varieties were detennined. In a completely randomized design with a 8x3 factorial arrangement, 384 day-old commercial male broiler chicks (Hubbard×Peterson) were divided into 96 groups, four chicks per group. Each of the 24 experimental diets (eight varieties) and three levels of phytase (zero, 500 and 1000 FTU/Kg) were given to four replicates for a period of 21 days. At 21 days of age, chickens of each replicate were weighed and killed by cervical dislocation. lleal contents were collected and analyzed for P, N, phytate and chromic oxide. Left tibia of two birds in each replicate were removed, pooled and stored at -20°C for bone ash detennination. There was a significant (P<0.03) difference in phytate contents between different wheat varieties. Effect of wheat varieties on body weight, feed conversion ratio and bone ash was significant (P<0.05). Added phytase improved body weight, feed consumption, feed conversion ratio and bone ash significantly (P<0.05). Phytase added at 500 FTU/Kg, improved protein digestibility significantly (P<0.01), but increasing the supplement to 1000 FTU/Kg had no further effect. Difference between enzyme levels (500 and 1000 FTU/Kg) was not significant regarding body weight, feed. consumption, feed conversion ratio and bone ash. Overall addition of phytase to the diets containing wheat caused an improvement in performance, protein digestibility, and phytase phosphorus utilization in broiler chickens, and can, therefore, be used in diets to reduce feed cost and environmental problems.

Due to the need for new fumigants to control insects that attack food commodities,the toxicity of acetone was determined on some species of stored pest insects in Urmia University in the year 2000. In empty space tests, the LC50 values of acetone for Oryzaephilus surinamen sis (L.), Callosobruchus maculates (F.), Tribolium confusum (Duv.) and Sitophilus granaries (L.) were 15.40, 15.51, 17.55 and 18.26 µl/liter,respectively.The experiments of acetone penetration to wheat mass revealed that the application of acetone in headspace led to the penetration of acetone vapours into the wheat mass and killing the S.granarius and T.confusum had been concealed in interkernel space.The comparison of LC50 values of empty space tests with LC50values of penetration experiments revealed that the increase in penetration toxicity was 8.63 fold for S. granarius. A similar trend was observed for T. confusum adults. In hidden infestation tests, the application of acetone to the headspace resulted in destroying the developmental stages of s. granarius concealed in wheat and achieved 75% mortality at a dose of 160 µl/liter during seven weeks. Acetone showed no deleterious effects on the germination and vigor of wheat seeds.