JWSS - Journal of Water and Soil Science

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Iron (Fe) availability is low in calcareous soils of Iran due to high pH levels and presence of excessive amounts of CaCO₃. Overfertilization by phosphorus (P) fertilizers may also decrease Fe availability. The objective of this study was to evaluate the effects of P, Fe and their interactions on the growth and chemical composition of soybean [Glycine max (L.) Merrill] under greenhouse conditions. Treatments consisted of a factorial arrangement of P rates (0, 40, 80, 120 and 160 mg kg^-1 as KH₂PO₄) and Fe rates (0, 2.5, 5 and 10 mg kg^-1 as FeEDDHA) in a completely randomized design with four replications. Plants were grown for 8 weeks in a loamy soil, classified as Chitgar series (fine-loamy, carbonatic, thermic, Typic Calcixerepts). Results showed that P application up to 80 and Fe at 2.5 mg kg^-1 increased shoot dry matter. Phosphorus concentration, total uptake and P:Fe ratio in soybean increased by P application but decreased by Fe application. Application of Fe up to 2.5 mg kg^-1 increased dry matter but decreased it at higher rates. Concentration and total uptake of Fe increased by Fe application but decreased by P application. Interaction of P and Fe had no effect on shoot dry matter. Zinc (Zn) and copper (Cu) concentrations decreased significantly when P was added and manganese (Mn) concentration increased up to 40 mg P kg^-1 but decreased at higher rates. Iron application had no effect on soybean Zn and Cu concentrations but decreased Mn concentration at all rates. Prior to any fertilizer recommendations, it is necessary to study the effects of P, Fe and their interactions on soybean under field conditions.

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In a completely randomized design (CRD) experiment with 6 treatments and 4 replicates per treatment, the effect of energy and protein dilution during 6-12 days of age was tested in broilers. Rice hull was used for dilution of energy and protein at levels of 0.05 (control), 10, 15, 20, 25 and 30 percent. The metabolizable energy and crude protein content of the experimental diets were 3089, 2780, 2626, 2472, 2317 and 2163 KCal/kg and 21.45, 19.29, 18.23, 17.16, 16.10 and 15.02 percent, respectively. The results indicated that diet dilution at early age (6-12 days) increased feed consumption but energy and protein intake and weight gain were reduced. No significant differences in body weight were observed due to compensatory growth among treatments. After feed restriction, feed intake was lower for the birds receiving diluted diets as compared to control. Meanwhile feed efficiency somewhat improved among the birds fed with diluted diets, but the differences were not significant. Diet dilution had no significant effect on carcass and abdominal fat percentage at the slaughter age (45 days). Diet dilution with rice hull at 20 and 25 percent decreased feed consumption and improved feed efficiency and, therefore, its use can reduce feed cost.

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The effect of adding two urea levels (0.5 and 0.75% on fresh basis) to whole-crop barley (WCB) on chemical compositon and digestibility in Ghezel rams was studied. The effect of including these silages in the ration of fattening Ghezel and Mehraban rams was also investigated. Urea supplementation of WCB silage resulted in an increase in pH, total nitrogen level, and ammonia-nitrogen concentrations (P<0.05). Apparent digestibility coefficients of dry matter, organic matter, acid detergent fiber, and neutral detergent fiber of WCB silage were not affected by urea treatment (P>0.05), but apparent digestibility coefficient of total nitrogen was higher for 0.5% urea-WCB silage. Apparent digestibility coefficients of total nitrogen and nitrogen balance were higher for 0.5% urea-WCB silage than for 0.75% urea-WCB silage, but the differences were not significant. Ruminal fluid pH at 2.5 h, and ammonia-nitrogen concentration at 4 h post-feeding were higher for 0.75% urea-WCB silage than for 0.5% urea-WCB silage (P<0.05). BUN levels (<20 mg per dl) in sheep fed with a mixture of alfalfa hay and silages were not affected by the treatment. The potential and effective degradabilities of dry matter and crude protein were higher for 0.75% urea-WCB silage. Feed performance and carcass characteristics were not significantly different amongst diets. The results showed that urea supplementation at 0.75% fresh basis, at the time of ensiling, may have a beneficial effect on feeding value of WCB silage.

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A total of forty-three isolates of Ascochyta rabiei obtained from infected seeds and plants of chickpea from different areas of Kermanshah, Lorestan, Hamadan, Kordestan, and East and West Azarbaijan provinces were studied during the period 1996-1999. A rapid and simple method was developed for pathogenicity test in CDA (chickpea seed meal dextrose agar) medium. CDA medium was inoculated with different isolates and incubated at 21±1 ^oC for 9 days. The disease severity was scored as 0-100% at 24-hour intervals up to five days. Virulence forms were designated according to spectrum of disease reactions of each isolate. Thirteen isolates (IK04, IK08, IK10, IK13, IK14, IK17, IK19, IK21, IL01, IL10, IO00, IE04, IE06) were distinguished as highly virulent (HV) and 7 isolates (IK03, IK06, IK15, IE01, IE08, IL04, IL06) as weakly virulent (WV). Polygalacturonase activity of these isolates from 6 days old inoculated PZ (pectin zymogram) medium were assayed. Comparison of the results of pathogenicity test and PG activity of 43 isolates demonstrated that HV isolates show predominant enzyme activity while the WV isolates show enzyme activity.

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The biology of predatory fly, Leucopis glyphinivora Tanas. was studied under greenhouse conditions. Adult longevity was 8 days and the average fecundity was 35.7 eggs. Incubation period, the 1st, 2nd, 3rd larval instars and puparium duration averaged 2.7, 2.16, 3.48, 5.7 and 8.45 days, respectively. Each generation lasted about one month. The predator efficiency was studied by applying the egg together with the adults of A. fabae at ratios of 1:1, 1:2, 1:4, 1:8 and 1:16 on broad bean. First larval instar was exclusively feeding on small nymphs (1st and 2nd nymphal instars) of aphid. Predator:prey ratios of 1:4, 1:8 and 1:16 decreased the number of prey to 97.9%, 98.8% and 61%, respectively, but ratios of 1:1 and 1:2 were unsuccessful in decreasing the number of preys due to predatory larvae leaving the host plant for searching small nymphs of aphid. As a result, the predatory larvae were efficient merely in a particular range of aphid density and age structure.

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To determine the effects of spawning frequency and density of incubating eggs on the survival rates of eggs and larvae in rainbow trout, five different groups of broodstocks with varying spawning frequencies were stripped. After fertilization, the percentage of survival at different stages of development, from eying, hatching to free swimming fry stages and also growth rates of larvae were determined. Moreover, the effects of incubating egg density (4000, 7000, 10000 per tray) on the different developmental stages of egg through free swimming larvae for each group of broodstock was studied. The study was carried out in a completely randomized design as a 5*5*3 factorial arrangement with three replicates. The results indicated that survival and growth rates are significantly correlated with spawning frequency (P<0.05) so that, survival and growth rates from fertilization to free swimming fry in broodstocks at their third and fourth spawning period were significantly different from the results obtained for broods in the first, second and fifth or higher spawning periods (P<0.05). Although the holding densities had no significant effects on the growth rate of larvae from different broodstocks, the survival rates from fertilization to free swimming stage was affected by incubating density so that the significantly lower value was recorded for density of 4000 per tray (P<0.05). In general, the results indicate that eggs obtained from broodstocks at their third and fourth spawning years have a better performance than those obtained from younger and older spawners. Also, the low holding density of eggs could decrease the performance of the fertilized eggs during incubating period.

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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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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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In this study, two data ranges of uniform flow (bulk parameters) and non-uniform flow (local parameters) are employed to investigate resistance to flow and the factors affecting it using velocity distribution of boundary layer theory. The results indicate that the cross-section form factor or adjustment roughness coefficient of logarithmic law can not improve the prediction of flow resistance. On the other hand, it is possible to ameliorate the prediction of resistance to flow by application of the Froude number and the Shields parameter along with the integration constant of the logarithmic velocity distribution. Also, there is no improvement in flow resistance prediction by taking into account power equations. On the other hand, the application of boundary-layer characteristics such as displacement thickness and momentum thickness in velocity profile can remove the risk of spurious correlation. Based on the measured velocity profiles for non-uniform flow in Gamasiab river, a new flow resistance equation is suggested in which the following bulk parameters are considered: flow depth, maximal velocity at the water surface, and friction slope.

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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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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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Thirty genotypes of pistachio cultivars and related species were evaluated for genetic diversity using three polymorphic isozymes, i.e. Esterase, Peroxidase and Malate dehydrogenase. Young leaves of pistachio were crushed with extraction buffer containing: 20% sucrose, 0.01 M dithiothretiol, 2% polyethylene glycol, and 8% polyvenyl polypyrollidone. Samples were analyzed using isoelectric focussing on polyacrylamide gels containing 2% (W/V) ampholyte. All the three isozymes revealed high degrees of polymorphism in pistachio cultivars and related species. Maximum polymorphism was observed for Est. enzyme. A total of 19 bands in Est. and 28 bands in MDH were observed in a wide range of pH gradient however, in Per. there were 11 bands all of which located in a narrow range of pH gradient. Cluster analysis based on the three system enzymes revealed that all the 30 pistachio genotypes were in 8 main classes and 20 subclasses and the extent of genetic similarity reduced from cultivated varieties to species, which were finally classified in 3 groups. Sarakhs variety, a wild type of P. vera, was classified in a group between cultivated varieties and species.

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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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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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A ruminal in situ experiment using three fistulated ewes was conducted to determine dry matter (DM) and crude protein (CP) degradation of steam–flaked broomcorn (SFBr), ground broomcorn (GBr) and ground barley (GB). Grain samples were suspended in the rumen of sheep for 0, 2, 4, 8, 16, 24 and 48 h. Nylon bags were washed with tap water after removal. Effective degradability of DM at outflow rates of k = 0.05 and k = 0.08 h^-1 was significantly higher for SFBr than for GBr (59 and 53% vs. 43 and 35%). SFBr has considerably higher soluble DM than GBr and GB. Insoluble DM of SFBr was lower than that of GBr and GB. Solubility of CP in broomcorn grain was significantly decreased by steam–flaking, but degradation rate of insoluble CP was not altered. Results from this study showed that SFBr supplies the major source of availabe nutrients for rumen microorganisms compared with GBr. In other words, using the most efficient processing method for ruminants will be necessary.

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In order to investigate the effects of mineral compounds as complementary nutrients for silkworm, Bombyx mori, an experiment was performed in CRD with five treatments including: 1%, 5% and10% concentrations of multi-mineral mixtures (nitrogen, phosphorus and potassium) with normal and distilled water treatments as controls. The larvae were fed by mulberry leaves from Shien Ichenoise variety up to the fourth instar. From the beginning of the fourth instar, the supplementary leaves were used once a day. The supplementation of the leaves was done by spraying the solution on them. The amount of total protein and uric acid in haemolymph of a 6-day 5^th instar larva was measured. The value of total protein compared to controls had significantly increased in all mineral treatments. The larvae's weight on the third day of the fifth instar had significant difference from controls, but the weight of silk gland did not show such a difference. However, uric acid of insect's blood demonstrated little differences but it showed no statistical significant differences from that in controlled insects. Despite this, the weight of cocoon, cocoon shell and pupa also had significant differences compared to controls, where this enhancement was higher in females than in males. Due to increase of the number of eggs, statistically there was a significant difference between the 10% treatment and others. The compounds had decreased the hatching percentage.

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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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Soil erodibility in arid regions, particularly in less developed soils, greatly depends on parent material. The objectives of this study included comparison of the potential of runoff and sediment production in soils with different parent materials and identification of the highly sensitive parent materials in Golabad watershed, 60 km northeast of Isfahan, with about 160 mm of annual precipitation and various geological formations, as one of the highly erodible watersheds in Iran. Soils formed on twelve different parent materials were selected. Rainfall simulator was run for 80 minutes on three replicates of each soil. To have an idea about the rate of runoff and sediment generation with time, runoff loaded with sediment was collected every 10 minutes using plastic containers. After measuring the volume of each runoff sample, it was dried and the amount of sediment was measured. The mechanical parameters of the applied rain were: intensity about 40 mm/hr, rain drop average diameter: 6.56 mm plot size: 1 m² and kinetic energy of 13.7-17.2 J/m².mm. Based on the rainfall simulation experiments, soils formed on green andesite and slightly dissected alluvium derived from both sedimentary and igneous rocks created the highest amount of runoff. They also created runoff much more rapidly as compared to other soils. In contrast, soils developed on granodiorite and moderately undulating alluvium produced the least volume of runoff. Furthermore, maximum quantity of sediment was produced from the soils occurring on green andesite and shale. The least sediment yield was observed in soils developed on granodirite and moderately undulating alluvium. Soils formed on shale created the highest sediment concentration and no significant differences were observed among other soils. Based on the results obtained, soils were ranked according to sensitivity to erosion. It is concluded that soil parent materials have a high influence on the production of runoff and sediment yield in Golabad watershed.