JWSS - Journal of Water and Soil Science

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Fecundity of Shah-Koolee in the Sefidrood river, which is one of the economic and popular fishes in northern part of Iran, was studied. From April to August 2000, 539 Shah-Koolee fishes were caught at the specific station in the Sefidrood river from the sea shore to Kisum. Seventy one samples of unspawned fishes were taken, the primary biometry was performed, specimens of the different parts of the ovary were prepared and absolute fecundity was determined through gravimetry. Maximum and minimum fecundity rates were 18860 and 2929 eggs, respectively, that related to eight- and three- years old fishes. Relative fecundity was 132±37 and 72 eggs per gram of weight. The relationship between absolute fecundity and length and weight was linear, correlation and numerical quantities of a, b and r were calculated and regression graph was drawn. Gonado Somatic Index (G.S.I.) was used to determine the natural spawning region and calssification was done on the basis of two factors, age and station. It was found that three- years old fishes with a regeneration power of 17.05 in comparison with other age groups had higher potential. This index also showed that Astaneh and Kisum stations were favorable places for natural spawning of these fishes.

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Antagonistic fungi Trichoderma harzianum (T₁, from bean fields in Ahwaz, T₂, from rice fields in Rasht), T. viride (T₃ from bean fields in Shahriar, T₄ from the collection in Plant Pest and Disease Institute, Tehran), Gliocladium virens (from bean fields in Kamal Abad, Karaj) and some fungicides (Benomyl, Carbendazim, Carboxin-Thiram, edifenphos and Zineb) were used to control sheath blight of rice incited by Rhizoctonia solani in vitro and under greenhouse conditions. The experiment was carried out in a completely randomized design with 12 treatments and four replications on Khazar rice cultivar in a soil infected by R. solani under greenhouse conditions. The results showed that the antagonistic fungi reduce sheath blight by 19.8 (T₁), 21.5 (T₂), 27.5 (T₃), 19.6 (T₄) and 18.5 (G₁) percent. The antagonistic fungi in order of efficacy were T₂>T₃>T₁>T₄>G₁. Benomyl, Carbendazim, Carboxin-thiram, Edifenphos and Zineb reduced disease by 32.5, 21.5, 12.8, 9.5 and 0 percent, respectively. Statistical analysis of data indicated that there existed no significant differences between T₁, T₃, T₄, and G₁ and Carbendazim fungicide to control disease however, the isolate T₂ was as effective as Benomyl but Zineb had no effect on sheath blight.

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Pistachio oyster shell scale is one of the important pests of pistachio in Iran whose females are reported to exist in two or three forms, each form developing on a specific part of the pistachio tree. In this study, abundance of the pest is investigated on leaves and branches for different ages, two heights and four cardinal directions of tree crown. Paralelly seasonal population fluctuations of three forms were studied on leaves, and one-and two-year-old branches separately. This insect overwintered as female mostly on one and two-year-old branches. It had two separable periods of activity, through the season. In the first period, eggs mostly hatched in April and crawlers mostly settled on leaves, fruits and newly grown twigs but rarely on older branches.These populations are male and female. In the second period, eggs mostly hatched in June, and crawlers settled mostly on leaves and one and two-year-old branches, but all individuals settled on leaves are males and those on branches are females. Population density is significantly higher on upper surface of leaves than on the lower surface. Analysis of variance showed that only significant differences existed in densities observed between trees in both generations, and also between two heights of tree crown for populations settled on wood. Two predatory species from Cybocephalidae and Coccinellidae, one ectoparasitoid from Aphelinidae and two endoparasitoids from Encyrtidae were collected as natural enemies of this pest in Isfahan.

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Numerous methods are used in the investigation of floods in catchments such as regional flood frequency analysis. Regional flood frequency analysis relies on physical, climatic and ecological characteristics of catchments and applies statistical methods to study flow records. Hosking and Wallis developed Probability Weighted Moments and presented L-moments statistics as a new tool for flood frequency analysis. In this paper, the theory of L-moments was used to study the flood frequency of central catchments of Iran. A number of 27 sites each with more than 5 years of observed data were studied. In the first step, the diagram of L-kurtosis versus L-skewness was used and proper distributions for each site were applied. In order to eliminate the heterogeneous sites, homogeneous tests based on D, H₁, H₂ and H₃ criteria were performed indicating that two sites appeared to be heterogenous. Next, using Goodness of Fit Test, the best regional distributions were determined which are GL, GEV, GN, PE3 and GPA, respectively. Finally, quantile estimates for distributions accepted at a 90% level were presented.

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Point data of weather stations are not important in and by themselves. Therefore, it is necessary to change these point data into regional information. Undesirable distribution of weather stations and their data deficiency hinder the direct determination of the regional information, unless sufficient data in the study area could be provided. Providing extra data using the geostatistical methods is practical, scientific, simple and quick, but adopting a suitable method is the basic question. The objective of the present study is to find a suitable method to estimate monthly rainfall in the central region of Iran. In this regard, the methods of kriging (ordinary kriging, log-kriging, co-kriging), weighted moving average (WMA, with the power of 1 to 5), thin plate smoothing splines (TPSS, with the power of 2 and 3 and with covariable) were used. Cross validation technique was used to compare these methods. Based on the variography analysis, the range of influence of monthly rainfall in the central region is about 450 km. The results show that TPSS, with the power of 2 and with elevation as a covariable, was the most accurate method to estimate monthly rainfall. In addition, it is preferable to use the selected interpolation method in the sub-basins with homogeneous climates instead of considering the whole region.

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Increasing application of herbicides such as atrazine raises concerns about soil and groundwater pollution. This study investigated spatial and temporal variation of atrazine concentration and its transportation in the Daneshkadeh soil series (Fine, mixed, mesic, Calcixerollic Xerochrepts) at the experimental field of Agricultural College, Shiraz University. The risk of soil and water contamination due to applying atrazine was also assessed. The PRZM-2 model was evaluated for the simulation of the atrazine concentration. The experiment had 3 plots, 209 m² each (19 by 11 m). Atrazine was applied on corn at a rate of 3.5 kg a.i./ha per plot. During the growing season, soil samples were collected from each plot 7 times through 1 m soil depth with 0.10-m increments. The observed data showed temporal reduction of atrazine concentrations in the soil profile. The maximum depth of atrazine traced was about 50 cm below the soil surface. Statistical parameters ME, RMSE, EF, and CRM were obtained to compare PRZM-2 predicted and observed soil residue concentrations. For all data, the mentioned parameters were calculated and found to be 2.78 mg/kg-soil, 12.73 mg/kg-soil, 0.49, and 0.25, respectively. The simulation results were in close agreement with the observed data. Therefore, PRZM-2 could be used for simulation of atrazine transport and groundwater pollution.

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The study of geographical extent of precipitation pattern is important because of its impact on agriculture, water resources, tourism, industry, dams, and irrigation. The principal component analysis (PCA), as an elegant mathematical tool, was applied for the regionalization of winter precipitation in central south Iran (Fars, Boushehr, and Kohgiloye and Boyerahmad Provinces). Averaging monthly rainfall data of Dey, Bahman and Esfand (20 December to 20 March) produced the time series of winter rainfall. In each individual station, correlation matrix of the normalized data was then performed for the computation of the standard PCA. Eigenvalues, eigenvectors, PC time series and the loading of the principal components were then computed. The Screet test technique was applied as a trial for addressing the problem of determining the number of PC modes that should be retained. Two of the first PCs, which account for 68.1% of total variance in the rainfall data, were kept and used for the regionalization of rainfall data. The rotation solution was then selected as a suitable tool for delineating the rainfall region associated with the retained PCs. The results indicated that for the first PC, loading became high over most part of the study area. Therefore, the time series of PC1 that accounts for about 60.4% of the variance in raw data, could be used as the regional time series of winter rainfall over most parts of the provinces studied. The second PC revealed a high loading over a small area in northern part of the regions studied (Bavanat in Fars Province). Rainfall in this station showed poor correlation with the precipitation over the neighboring station in Fars Province. It seems that the rainfall in Bavanat is mostly influenced by the Mediterranean air masses entering the area through the northern and western districts. For the other parts of the regions studied, Sudan current which encroaches the country through southwestern borders (Persian Gulf regions) make up an essential portion of winter rainfall.

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Clay minerals have considerable effects on physico-chemical properties of soils. Using different techniques, mineralogy of silicate clays and their formation were investigated in selected soils from Chaharmahal and Bakhtiari Province. The study area is about 1300 ha and its soil moisture and temperature regimes are xeric and mesic, respectively. Geomorphologically, the area consists of different landforms including pediments, outwash, hills and piedmont plain. After field and laboratory studies, five representative pedons were selected in previously determined mapping units and samples were taken for the analyses required. Clay particles from two surrounding rock formations and selected soil samples were separated and examined by electron microscopy (SEM and TEM), X-ray diffraction and infrared techniques. Illite, smectite, chlorite, palygorskite and kaolinite were present in all the soils. Considering the fact that palygorskite was not observed in nearby rock formations, this mineral is probably formed by pedogenic processes. Smectite, on the other hand, has been inherited from parent materials and also transformed from palygorskite. Other minerals had been probably inherited from parent materials. Infrared spectra confirm the X-ray diffraction and submicroscopic results.

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Soil tilth is crucial to seedling emergence, plant growth, and crop yield. Soil tilth of unstable soil is very susceptible to change. Internal forces originating from matric suction can change soil physical properties. A laboratory study was conducted on pots of a surface silty clay loam soil of Khomeinishahr series (fine-loamy, mixed, thermic Typic Haplargids, USDA), located in Research Farm of Isfahan University of Technology. Soil surface subsidence, bulk density, cone index, and tensile strength were measured after first flood irrigation. Results showed that the seedbed (0-20 cm) with a bulk density of 1.2 Mg.m^-3 will be changed to a massive soil with high values of bulk density, cone index, and tensile strength after soil wetting. Slaking, slumping and coalescence of the soil caused soil surface to subside about 1.5 cm in 20 cm soil layer. After irrigation, cone index and tensile strength increased abruptly with decreasing of moisture content. It is shown that the dominant source of strength (cone index and tensile strength) gain during drying is the effective stress due to matric suction. In the absence of external loads, physical state (tilth) of the soil returned back to the original state. Therefore, soil slaking and slumping and rearrangement of particles along with the internal forces are the factors leading to soil hardness.

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Genetic variation of 300 genotypes of durum wheat comprising CIMMYT/ICARDA and Iranian germplasm was evaluated in 1999-2000 at Researh Farm of College of Agriculture, Isfahan University of Technology located at Lavark, NaJaf-Abad. Days to heading, days to maturity, plant height, spike length, grain weight per spike, number of grain per spike, number of spikes per m², 1000-grain weight, test weight, grain yield, biological yield, and harvest index were recorded. Coefficients of correlation, step-wise regression, factor analysis and cluster analysis of characters and genotypes were conducted using the studied traits. Results indicated that considerable genetic variations exist for the traits and, in particular for grain yield, harvest index, number of spikes per unit area and number of grain per spike. Grain yield had a positive and significant correlation with days to heading, days to maturity, number of grain per spike and grain weight per spike. Factor analysis for the genotypes detected 6 factors, which explained 76.7 percent of the total variation among data. These factors basically involved potential of assimilate distribution, different aspects of plant storage, source-sink relationships, plant height and tillering potential. Cluster analysis was similar to factor analysis in grouping the characters. According to cluster analysis, the genotypes were calssified into 6 clusters with significant differences among all groups. Mean comparisons of traits in these groups showed that genotypes of groups 5 and 6 were superior in grain yield and harvest index and are beneficial to the local durum breeding objectives.

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Planting density, through its impact on the level of available environmental factors may have significant impacts on grain yield in safflower (Carthamus tinctorius L.). In order to investigate the impacts of plant density on grain yield, yield components and growth characteristics of safflower, a randomized complete block design field experiment with four replicates was conducted in spring-summer, 2000, at Lavark Research Farm (Lat. 32⁰ 32^, N and Long. 51⁰ 23^, E), College of Agriculture, Isfahan University of Technology, Isfahan, Iran. Arak-2811 and Kouseh safflower genotypes were seeded at 16.6, 22.2, 33.3 and 50 plants/m². For establishing these plant densities, plants were seeded in 12, 9, 6 and 4 cm distances, respectively, on ten 8-m-long rows spaced 50 cm apart in each plot. Plant density had no impact on plant growth stages with the exception of button formation. Genotype had significant effects on days to seedling emergence, button formation, and 50% flowering. While both number of days and accumulated growing degree-days for all growth stages decreased with an increase in plant density, Arak-2811 was earlier than Kouseh for most growth stages. Number of branches and heads per plant, number of heads per branch, number of seeds per head and harvest index showed significant decreases with increasing plant density. The decrease in the mentioned grain yield attributes was mainly negated by greater number of plants per m², leading to no significant variation in grain yield between plant densities of the two genotypes. Arak-2811 produced a significantly greater number of heads per branch and 1000-grain weight however, these differences did not lead to any greater grain yield compared to Kousehdue, mainly due to the greater number of branches in the latter. Neither of the leaf area index, leaf area duration, and crop growth rate varied significantly with plant density and between two genotypes, suggesting no difference in dry matter production capabilities of the two genotypes under environmental conditions of the present study.

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Flax (Linum usitatissimum L.), an oilseed crop, is widely adapted and grown in many regions of the world. Oil from regular flaxseed is used as an industrial drying oil because of the high level of linolenic acid (>50 %). However, the oils from new mutant genotypes of flax with a very low linolenic acid concentration (<2 %) are edible. Yellow seed colour can be used as a visual marker to distinguish edible-oil genotypes of flax from those of industrial type that are usually brown-seeded. In this study, different lines of flax with two seed colours (yellow and brown) in combination with two levels of linolenic acid (high and low) were evaluated in a randomized complete block design for agronomic traits, especially seed yield and its components. The results indicated that lines with high linolenic acid concentration had significantly higher seed yield than those with low linolenic acid. However, other characteristics including those of seed yield components were not siginficantly affected by linolenic acid concentration. Seed colour had a significant effect on number of seedling/m², basal branches, capsules per plant and seed yield per plant. Although seedling emergence was lower in yellow-seeded lines, they had more basal branches, capsules per plant and seed yield per plant. Higher seed yield per plant in yellow-seeded lines can be attributed to higher number of capsules per plant as a result of lower seedling emergence and plant density. Seed yield was not significantly different between brown and yellow-seeded lines. Thus, the effect of lower plant density in yellow-seeded lines was compensated by their higher basal branches and number of capsules per plant.

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Planting pattern through changing vegetative growth and utilization of environmental resourses affects yield components and seed yield. These effects were studied in the spring of 2000 at the Agricultural Research Station, Isfahan University of Technology, using a randomized complete block design with a split plot layout and three replications. Main plots consisted of three row distances (30 cm flat, and 45 and 60 cm on bed), and sub-plots included three planting densities (30, 40, and 50 plants m^-2). The experiment was planted on March 13 using local safflower variety of Isfahan, named Koseh. Increase in row distance and plant density enhanced most developmental stages of safflower. Leaf area index was not significantly affected by row distance but increased as planting density increased. Up to the 50% flowering stage, 30 cm row distance produced highest plant dry weight, but had the least dry weight at the end of the growing season, probably due to the strong shedding of leaves. Up to the end of flowering stage, 50 plants m^-2 treatment produced the highest plant dry weight, but ranked lower as compared to 30 plants m^-2 treatment at the physiological maturity, probably due to the shedding of leaves. Row distance had no significant effect on number of branches per plant and per square meter, number of heads per branch, number of seeds per head, 1000-seed weight and harvest index. But number of heads per plant and per square meter as well as seed yield per plant and per square meter significantly decreased as planting distance increased. Plant density had no significant effect on number of branches per plant, number of heads per square meter, number of seeds per head, 1000-seed weight and seed yield. Increase in planting density increased number of branches per square meter, but reduced number of heads per branch and per plant, seed yield per plant and harvest index. The highest seed yield (4769 kg ha^-1) was obtained with 30 cm row distance and 40 plants m^-2 treatment. On average, 397 kg ha^-1 petal was harvested, which has a large economic value. However, petal clipping, over all treatments, reduced seed yield by about 7.4%. Considering the advantages of uniform distribution of plants and adaptation of safflower to flat planting, 30 cm row distance with 40 plants m^-2 might be appropriate for planting safflower under conditions similar to this experiment.

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Dehydration of Mazafati Rutab is a method to prevent its spoilage. Dehydration is necessary for Mazafati Rutab because it contains too much moisture. If the moisture content of Mazafati Rutab is decreased properly, it need not be stored under refrigeration. The present study was carried out in an attempt to decrease the moisture content in order to increase the shelf life of Mazafati dates. Samples were dehydrated in a drying room at different drying times and 50-55 ^oC. The moisture content and quality characteristics of Mazafati dates such as acidity and sensory evaluation (texture, flavour and overall acceptability) were determined at 3-hour intervals and also drying curve of the fruit was drawn. Relative humidity in the drying room was 10-15%. During the drying process, the acidity content gradually increased due to the activity of microorganisms but organoleptic properties decreased especially affer 12 hours of drying time and at moisture levels less than 22%. Finally, drying time of 9-12 hours and acceptable moisture content of 22% were recommended. Dates with over 22% moisture levels are an easy target for microbial attack but the desirable quality of the fruit decreases at moisture levels below 22%.

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In order to compare Pseudomonas syringae pv. syringae (Pss) isolates from cereals, citrus, stone fruits and weeds by phenotypic characteristics, serological properties and pathogenicity, samples were taken during 1998-1999 in Fars Province, Karaj, Fereidan, Aligudarz and Shahrekord regions. From 350 fluorescent isolates, 47 were negative with respect to oxidase, potato soft rot and arginine dihydrolase tests but positive in hypersensitive reaction (HR) on tobacco, pelargonium, or both. In complementary biochemical tests, these isolates were identified as Pss. Based on LOPAT (levan, oxidase, potato soft rot, arginine dihydrolase and HR on tobacco leaves) tests, the isolates were divided into two groups, but based on the results of GATTa tests alone, isolates were divided into nine groups. Isolates from different hosts showed differences in lipolysis, syringomycin production, ice nucleation activity, lecithinase, pathogenicity, serology and protein profiles.

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The present experiment evaluated the effects of fat (Kilka fish oil) levels (0, 5, 10, 15 and 20%) in the diet (35% constant protein) on performance of rainbow trout. The experiment was performed in a completely randomized design, with 4 replicates, 200 grower fish with an average weight of 200±11 gr, each. They were randomly divided into 20 groups of 10 fish per group reared in separate pens. Fish were acclimated to the experimental conditions for 10 days before treatments began and then the experiment was performed over a period of 8 weeks. Measured criteria were weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), condition factor (CF) and flesh chemical composition (fat, protein, ash), and fat stored in liver. Results showed that the diet with 15 percent fat content had significantly (P<0.05) better WG and FCR than other diets, but no significant differences were observed for SGR and CF. Diets with 15 and 20 percent fat contents caused the highest fat content in meat and liver and showed significant differences (P<0.05) with the meat and liver fat content in fish fed fat-free diets. Diet with 15 percent fat content caused significantly (P<0.05) lowest protein content in meat. No significant differences were observed in the ash content of the flesh. From the results of the present study, the level of 15 percent Kilka fish oil is recommended for the rainbow trout diet.

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In this study, the effect of deficit irrigation with every–other furrow irrigation method, which is an innovated method in farm irrigation management, was examined on sorghum (Sorghum durra L.) in Bajgah and Kooshkak areas of Fars Province. The experimental design was split plot with three main plots of irrigation interval (10, 15 and 20 days), three subplots of irrigation methods (ordinary furrow, fixed and variable every–other furrow), and 4 replications. Considering the crop production cost with real and subsidized prices of water in both areas, the net benefit per unit volume of irrigation water and benefit–cost ratio were calculated. The results showed that these economic parameters for the fixed and alternative furrow irrigation methods of 10-day intervals in both areas did not differ much with those of the ordinary furrow irrigation with 10-day intervals and were even higher in Bajgah area. Furthermore, the relationship between the amount of irrigation water, water application efficiency (Ea), water price per unit volume (Cw) and the net benefit per unit volume of irrigation water (B) with different conveyance efficiencies (Ec) were determined by multiple linear regression procedure. The regression coefficients of linear fit equation between the costs and irrigation water were determined. The results indicated that with higher price of water, the farmer should increase the farm irrigation application efficiency to avoid the economic losses.

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Rice husk, an agricultural waste, is produced about 100 million tons annually in the world and 0.5 million tons in Iran. Due to growing environmental concerns about disposal of these wastes, efforts are required to apply the wastes in industry. In this research, the mechanical properties of concrete incorporating rice husk ash (RHA) in sulfate environments (such as irrigation canals) were investigated and the increase in concrete strength was compared with control samples. In order to burn the husks at a controlled temperature to obtain a highly reactive pozzolanic RHA, a furnace was designed and built. The experiments included 405 samples of cubical (707070-mm) and cylindrical (50.8101.6-mm) concrete samples (105 samples for A, B and C treatments, respectively) which were stored in different ages (7, 28, 60, 180 days) under three different conditions (solutions of magnesium, calcium and sodium sulfates). The portions of RHA as cement replacement were 20 and 30 percents for B and C treatments. The results showed that the samples of concrete containing 20 percent RHA as cement replacement had higher compressive and tensile strengths in sulfate environments at 180 days compared with those of control concretes. The concrete samples containing RHA showed sharper gradients compared to control samples of up to 180 days under sulfate conditions. The best portion of RHA in concrete was determined to be 20 percent by weight.

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An intense storm occurred on June 6, 1992 in Mashhad city and its suburb, which caused a flood in the residential areas of Najafi, Chahar-cheshmeh and Nodareh. As a consequence of the abnormally huge flood, 25 people lost their lives and many structures were destroyed. Three recording rain gages located in Mashhad city (airport, College of Agriculture, and Water Authority) and one in the suburbs (Toroq dam) recorded the temporal distribution of the storm. Twenty five other nearby rain gages in the region also recorded the event. The rainfall hyetographs and rainfall amounts were analyzed. The results of this survey showed that: a) maximum rainfall intensity over a 15-minute duration in the College of Agriculture station, one of the centers of the storm, was 112 mm/hr, b) temporal distribution of rainfall for all recording stations were nearly the same, c) these patterns were in close agreement with all historic storms, and d) a return period of 380 years was implied via comparing the maximum rainfall intensity with relevant IDF curves. As a consequence, although an intense storm had happened, it was simply an outlier.

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Studies on benefits from innovations (technical change) have mostly been performed within the framework of competitive markets. These studies indicate that if the market structure under study is not competitive, determination of technical change benefits within a competitive framework may yield distorted or biased results for different groups. Considering the noncompetitive market structure of tomato in Khorasan Province, benefits from applying biological innovation for farmers, processors and the society as a whole were estimated. The results indicate that under noncompetitive conditions in the tomato market in Khorasan Province, and as a result of the processors’ market power in buying tomato, the potential benefits of utilizing hybrid varieties have reduced for both farmers and the society by about 58 and 12.5 percent, respectively. It may naturally be concluded that farmers’ incentives to adopt hybrid varieties are attenuated because of the tomato noncompetitive market.