نشریه علوم آب و خاک (علوم و فنون کشاورزی و منابع طبیعی)
سال نهم شماره 4 (پیاپی 34، زمستان 1384)

The vertical pipe intake is an economical structure relative to the other alternatives. VPI usually installed near the water surface and prevents from the coarse sediment entrance to the system. The strong vortex in VPI entrance is a major problem which may reduce the system efficiency. Recognizing the vortex affected parameters, helping engineers to design anti vortex structures. In this study an experimental model is built to study the effect of tangential velocity, flow direction at approach channel outlet on the discharge coefficient of vertical pipe intake. By dimensional analysis it is indicated that the vortex in VPI could be defined by the dimensionless numbers (Reynolds, Weber, Froude, Circulation and Submergence). The relationship between the Froude, Circulation and Submergence numbers are presented. By using this relation one can determine the Submergence number and then calculate the discharge coefficient of vertical pipe intake.

In this study the impact of climate change on temperature, rainfall and river flows of the Zayandeh Rud basin under two climate change scenarios for two periods (2010-2039 and 2070-2099) are investigated. For the evaluation of future climate change impact on stream flow to Chadegan reservoir, the global circulation model (GCM) outputs of the HadCM3 model (monthly temperature and precipitation) with two scenarios, A2 and B2, are obtained and downscaled to the local level for the selected time periods. The results indicate that the annual average of precipitation decreases and temperature increases for both periods that are more pronounced for the period 2079-2099. Such that 10% to 16% decrease in precipitation and 3.2 to 4.6ºC increases in temperature can be anticipated for scenarios A2 and B2, respectively. To predict future stream flow changes due to climate change, artificial neural networks (ANNs) have been applied and trained by the several input models and architectures for rainfall-runoff simulation. The results indicate that the maximum of 5.8% decrease in the annual flows. Comparison of the two scenarios indicates the more critical situation in scenario A2 for the basin.

Of the applications of remote sensing and satellite images in natural resources is distinguishing and detection of changes in land surface. The image classification using Maximum Likelihood (MLC) is one the prevalent method which is used in a study of the application of TM and ETM+ satellite images to detect sediment deposition on an implemented floodwater spreading scheme. In order to implement the research, field sampling and checking were done using transect networking method by selection of 30 sample points in floodwater spreading area as well as another 30 control points in the study area. The results of the study are shown that detection of sediment deposition using MLC method by application of LANDSAT TM and ETM+ can lead to increase the precision of change detection up to 82 percent. Furthermore, the results also show that the trend and changes due to sediment deposition on water spreading area can be precisely detected. Considering the present and potential applicability of the applied method in distinguishing changes due to sediment deposition on land surface which is absorbed on 450 hectares of water spreading area in this research study, it can be pointed out that the use of this method in larger area could be tend to increase the precision of change detection and to decrease the required time.

The Effect of various NaCl levels on the shoot content of trace elements, in the seedlings of five citrus species namely: Bakraei (Citrus reteculata X C. limetta), Volkamer lemon(C. volkameriana), Sour orange(C. aurantium), Sweet lime (C. limetta) and Mexican lime(C. aurantifolia), were studied in a glasshouse, by a randomized complete block design with factorial arrangement and four replications. One-year old seedlings of each species were grown in the pots, containing native soil (pH=8.2) and irrigated with water supplemented with 0(control), 20, 40 and 60 mM NaCl. At the end of experiment, the amount of Fe, Zn, Mn, Cu, Cl and B in shoots were determined. The amount of trace elements varied among the species even in the control plants (no salt). Salinity had different effects on the shoot content of trace elements. Salinity reduced Fe content in the shoot of all species except in Bakraii and sweet lime and increased the amount of Zn in the shoot of all species except in Bakraii. The Mn content was reduced in the all species but increased in sour orange. Salinity reduced the amount of Cu in the shoot of volkamerina but had no effect in the other species. The amount of Cl increased in the shoot of all species with salinity. Boron content in the shoot of all species except in sour orange, increased with low salinity level but decreased with increased salinity levels. However in sour orange, salinity in the all levels decreased the amount of B in the shoot of seedlings.

Chenges in the soil characteristics is rather continuously. A method that takes this continuity into account would present a realistic pattern of soil distribution either in taxonomic or geographical space. The fuzzy set theory provides such an approach. In this study, the robustness of fuzzy clustering in soil pattern recognition was evaluated in a subcatchment of western Iran. The clustering carried out on the basis of minimization of an objective function in assigning membership values to each pedon in each fuzzy class. Fuzziness exponent values from 1.15 to 1.5 were used. The following validation of the resulted clusters (classes), optimal number of classes in whole, morphological and particle-size subsets were determined 8, 4, and 5 respectively. Plots of membership values across the landscape indicated class overlap and considerable contiguity. Considering low differentiation of these young soils and the high similarity among their properties, the method indicated a high capacity in recognizing different soil types over the study area. Furthermore, there was relationships between the soil fuzzy classes and landform. Thus, the method is capable in continuous classification, which could be so important in construction of continuous soil maps at low aggregation levels, e. g., pedon.

The soil potassium status and effect of soil physical and chemical properties on it were investigated using 109 surface soils (0-30cm) from four regions in Guilan province. Neutral molar ammonium acetate extractable K (K-NH4OAc), boiling molar nitric acid extractable K (K-HNO3) and water soluble K were determined. Results showed that CEC and clay were normally frequency distributed while distribution frequency of other variables such as silt organic carbon and pH were not normal and have significant skew and kurtosis. In addition sand, K-NH4OAc and K-HNO3 has logarithmic normal distribution. Water-soluble potassium was affected by sand, pH, O.C and K-NH4OAc (R2a=0.73**). Ammonium extractable potassium was affected by soluble potassium, non-exchangeable potassium and CEC (R2a=0.72**). Boiling nitric acid was affected by exchangeable potassium and silt (R2a=0.55**). Geographic distribution of K-NH4OAc data shows amount of it in central parts of Guilan, particularly Sepidrood river watershed is more than other regions. Fomanat region soils have the less clay, CEC, K-NH4OAc and K-HNO3. According this study about 68.8 percent of Guilan soils was classified in the range of medium to very low potassium status.

Manganese toxicity occurs in many agricultural and natural ecosystems under the various soil conditions such as the nature of substrate, acidity, flooding or vicinity to the mining areas. The objective of this work was to study the effects of excess Mn in the growth medium on three important crop species, namely rice (Oryza sativa L. cv. T. Hashemi), maize (Zea mays L. cv. SC.704) and sunflower (Helianthus annuus L. Mehr). Plants were cultured in the hydroponic medium under controlled environmental conditions and treated with 0 (control), 25 50, 75 and 100 µM Mn for 12 days. Dry mass production, the effect of supplemental Mg and Ca on the toxicity expression, root respiration and K+ leakage from shoot and root tissues were studied under the Mn treatments. In order to study the effect of light intensity on the expression of toxicity symptoms, plants were cultured under the different light conditions, thereafter their growth and metal uptake and transport were studied. Sunflower plants treated with the 50 µM Mn and higher, showed dark-brown spots associated with the trichomes on the leaves and petioles. Maize plants developed interveinal chlorosis and any visual leaf symptoms was observed in rice. In all of the studied species, a great portion of the absorbed Mn was translocated into shoot, the highest transport was observed in sunflower and the lowest in maize. No significant correlation was observed between the expression of Mn toxicity and the accumulation rate of Mn. Growing under the low light intensity, in addition to the lowering biomass production, increased or decreased the toxicity effect depending on species. Mn-toxicity-induced root respiration was not associated with the differential response of species to Mn toxicity. In contrast the change of K+ leakage from shoot and root tissues was well correlated with the toxicity response of tested plants.

In order to evaluate the effects of plant densities (10, 13, 20 and 40 plant/m2 ) on the yield and yield components of two cultivars (Partow, Gohar) and a line (VC-1973A) of mungbean [Vigna radiata (L.) Wilczek] a field experiment was conducted at the Seed and Plant Improvement Institute (SPII) of Karaj in Summer 1998. This research carried out in a factorial experiment based on Randomized Complete Block Design (RCBD) with 4 replications. The results indicated that VC-1973A line had the highest grain yield. This line has superiority to other cultivars, due to the early and uniformity of seed maturity and easy mechanized harvest. Plant density has a significant effect (p<0.01) on the grain yield, in such a way that the densities of 20 and 10 plant/m2 outyielded the highest (2221 kg/ha) and lowest (1650 kg/ha) grain yield respectively. Among the yield components, only the number of pods per plant indicated a significant difference due to the plant density. Correlation coefficient between attributes indicated that the plant height and height of first pod internode had a positive correlation with the plant density, while the correlation of the plant density with harvest index (HI), branch number and pod number per plant was negative. More over it seems that the pod number per plant is the most important components of mungbean’s yield, because it has a high (r = 0.88) and significant (p<0.01) correlation with the grain yield.

The Genetic basis of grain yield and related characteristics were studied by a generation mean analysis in five crosses of winter wheat (Triticum aestivum L.). “Roshan”, “Mahdavi”, “Inia”, “Atila” and “Goscoyin” cultivars along with their F1, F2, BC1 and BC2 populations were evaluated by a split-plot design with crosses as the whole plot in a randomized complete block design with two replications and generations were applied as the subplots. Analysis of variance revealed significant differences among generations for studied characteristics including the grain yield per plant, the number of spikelet per plant, the number of spikelet per spike and grain weight per spike. For the majority of traits and crosses, F/DH1/2 was less than one, indicating that the sign and magnitude of gene actions were different. Estimates of broadsense and narrow sense heritabilities were low for the grain yield per plant compared with other traits, rating from 28.5% to 58.6% and 24% to 48,5% for the five crosses, respectively. Genetic components of generation means were calculated by fitting different models and choosing the best model indicated that the impact of additive, dominance and epistasis genetic components in controlling the traits depend on the cross and the trait under study.

This study was conducted to evaluate the effects of four levels of irrigation (irrigation of plants after I1 = 40, I2 =60, I3 = 80 , and I4 = 100mm of evaporation from class A pan) and four plant densities(D1 = 30, D2 = 40, D3 = 50 and D4 = 60 plants/m2) on the seed yield and seed quality in three soybean cultivars(V1=Hobit, V2=Williams and V3=Hill) in a split factorial design, based on the completely randomized blocks, with three replication for two years(2001 and 2002). The Irrigation treatments were assigned to the main plots, and the plant densities and cultivars to the sub plots. Results indicated that soybean seed yield was influenced by the different irrigation and plant density levels in the both years. Irrigation levels I2 produced the highest and I4 the lowest seed yield. It was also revealed that the plant density D3 produced the highest and D1 the lowest seed yields. Among the cultivars under investigation, V2 produced the highest and V3 the lowest seed yield . Seed oil and its protein contents both were affected significantly by the irrigation levels, plant densities and cultivars in both years. The plants receiving I1 treatment had the highest and those having I4, the lowest percentages of seed oil. Changes in the plant densities also affected seed oil and protein content. The plant density of D1 caused the seeds to have the highest oil and lowest protein percentages. However, D4 decreased oil and increased protein percentages. The highest water use efficiency was obtained from I3 and that of the lowest value from I1. The results also indicated that D4 had the highest and D1 the lowest water use efficiencies. Therefore, it could be concluded that the water use efficiency can be increased by increasing the plant density per unit area. The highest efficiency for biological and grain yield belonged to V2 and V1 respectively where as the lowest efficiency for those two mentioned characters belonged to V1 and V3, respectively. However, the treatment I2V2D2 is recommended for higer the seed yield production per unit area.

To obtain a suitable explant and efficient culture medium for plant regeneration in spinach, two cultivars of Melody and Karaj local seedlings were chosen. A hypocotyl and cotyledon segments as well as shoot tip explants were dissected from seedlings. The explants were then cultured on MS medium supplemented with IAA, GA3, NAA, and BAP and their response to this media was studied. A completely randomized design with different replicates was used to conduct the experiments. Callus was formed at the base of the hypocotyl explants on the medium containing 15 mg.l-1 IAA, and 3.4 mg.l-1 GA3. Calli capable of regeneration was obtained after subculturing on the medium containing 2 mg.l-1 IAA, and 3.4 mg.l-1 GA3 at the rate of 38 percent. The vitrified plantlets were abnormally glassy, and translucent which might have high water content. It was a physiological disorder which was overcome when an improved agar medium raising to 9 gl-1 was used. Callus has been obtained only from the hypocotyl explants, while regeneration has been obtained from shoot tip cultured on the medium containing 0.02 mgl-1 BAP at the rate of 80 percent.

Under irrigation and in double-cropping system, a large amount of plant residue remains after harvest that along with the limited time for residue decomposition and complete seedbed preparation, necessitates reduced tillage and special residue management. In the present study, the effects of various seedbed preparation methods on vegetative growth, yield components and seed and oil yields of sunflower (Euroflor hybrid) were studied in a barley-sunflower cropping system during 2001 at the Agricultural Research Station, Isfahan University of Technology. Three residue management treatments (standing, partly removed and burned) along with five tillage systems (moldboard + disk chisel + disk disk moldboard and furrower as the minimum tillage) were laid out in a split-block design with three replications. Burning residue treatment significantly increased plant dry weight at various developmental stages and also head diameter. Number of seeds per head, 1000 seed weight, harvest index, and oil yield were non-significantly higher in the burned residue treatment. Seed yield was significantly higher in the burned and partly removed residue treatments. Moldboard + disk and chisel + disk treatments significantly produced higher plant dry weight at various developmental stages, head diameter and seed yield. Number of seeds per head, 1000 seed weight, harvest index, and oil yield were non-significantly higher in these treatments. Minimum tillage ranked the lowest for these traits. The results of this experiment indicate that chisel + disk treatment with the partly removed residues might be an appropriate seedbed preparation method in a barley-sunflower double planting under conditions similar to this experiment.

An experiment was conducted with the male Ross broiler chicks from 1 to 42 days of age to test the effects of different dietary protein and lysine levels on performance, carcass characteristics, and N excretion. Treatment diets consisted of three levels of supplemental lysine in starter and grower period (0, 0.15, and 0.30 %) and the two levels of protein (20.84, 17.84 in starter, and 18.12, 16.12% in grower period) with 2900 Kcal ME/kg diet. The results indicated that the Reducing dietary protein decreased significantly the weight gain in starter, grower, and total period up to 6, 4.6, and 5.6%respectively (P<0.05). It also decreased the feed consumption in starter period (P<0.05). Decreasing dietary protein had no significant effect on gain to feed ratio and breast meat yield, but increased abdominal fat percentage significantly (P<0.05). Increasing dietary lysine increased the feed consumption in starter and weight gain, gain to feed ratio in grower and total period of the experiment (P<0.05). Increasing lysine in diet caused a significant increase in breast meat and tight yield, and percentage. Adding supplemental lysine reduced the N excretion in starter period significantly (P<0.059). N excretion reduced significantly by decreasing dietary protein (P <0.05). Dietary treatments had not significant effect on mortality percentage. The results of the present experiment indicated that with providing limiting amino acids and adding supplemental lysine to diet, the crude protein could be reduced up to 3 and 2 percent in starter and grower periods respectively. Reducing the crude protein had not adverse effect on the feed efficiency.

In the current experiment seven catheterized broiler breeder hens were used at 60 weeks of age. Retention of 14CO2 in the body of the hens following continuous infusion of NaH14CO3 during each of tow-30-hr continuous infusion studies was determined. Oxidation rate plateau was established within two hours in each experiment. Recovery of 14CO2 at the steady state in the first and second study were 91.09 and 87.55 percent respectively and were not significantly different. Mean breath 14CO2 recovery was 89.32 percent and hence retention was 10.68 percent. Recovery of 14CO2 in breath was not significantly affected by laying of egg or photoperiod. Recovery of 14CO2 during the fed state was significantly lower than the fasted state. The results of this experiment indicated that, using of uncorrected data for the retained isotope into body, lead to 10.68 percent AA requirements underestimation in broiler breeder hens by indicator amino acid oxidation technique.

In a completely randomized design with 3×5 factorial arrangement, the metabolizable energy and nutrients digestibility of three varieties of sorghum grains (low, medium and high tannin) with and without supplemental phytase were determined and was compared with corn and wheat. Three varieties of sorghum were selected from the 36 varieties according to their tannin content and were grown togther with corn and wheat under the same environmental conditions. Supplemental phytase was added at three levels (0.0, 500 and 1000 FTU/kg) to each grain. The metabolizable energy (ME) and nutrients digestibilities were determined by the mature male Leghorn with the method of Sibbald. The results indicated that different grains had different ME, apparent and true digestibilities regarding dry matter, nitrogen and phosphorus. Medium tannin sorghum had the highest apparent and true metabolizable (AME and TME) energy, whereas the high tannin sorghum showed the lowest AME and TME. The apparent and true dry matter digestibilities of corn was more than the other grains (P<0.001). Medium tannin sorghum had the highest apparent and true nitrogen digestibilies than the other two varieties (P<0.001). Difference between tested grains regarding apparent and true phosphorus digestibilities were not significant. All measured criteria were the lowest for the high tannin sorghum. Adding 500 FTU/Kg phytase caused an improvement (P<0.001) in AME, apparent and true dry matter digestibilities and true nitrogen digestibility. Although added phytase improved apparent and true phosphorus digestibilities and true nitrogen digestibility, but the differences were not significant. The differences between 500 and 1000 units phytase was not significant and the results indicated that 500 FTU/Kg phytase was sufficient to improve the nutritional value of grains under study.

Improvement of feed efficiency in dairy farming economically has a great importance. In this study, the genetic parameters of net energy efficiency and its relationships with milk yield, 3.2% fat corrected milk, body weight, gross income and income over feed costs were investigated, by the 2589 monthly records collected from the 723 lactating cows in the 3 herds. The different requirements of energy were estimated, by the National Research Council (NRC) models. A general linear model was employed for determining significant factors affecting each trait. The genetic parameters were estimated by a multivariate analysis with the derivative free approach of restricted maximum likelihood algorithm. The animal models contained the fixed effects of herd-year-season, parity number and stage of lactation, the regression coefficients of each trait on the dietary levels of rumen undegradable protein and metabolizable energy, and the random effects of animal additive genetic, permanent environment and residuals. The heritability of milk yield, 3.2 percent fat corrected milk, body weight, net energy efficiency, gross income and income over feed cost, were estimates 0.31, 0.32, 0.30, 0.34, 0.24 and 0.29 respectively. The results of this study indicated that the direct selection for net energy efficiency might genetically improve the feed efficiency. It also seems that the selection for fat corrected milk may be effective for the indirect improvement of feed efficiency and economic performance of dairy cows.

Production and consumption of whole tomato and/or its products(tomato paste, tomato juice, ketchup, etc) is incearsed all over the world. Annual production of tomato in Iran is about 3.4 million tons (MT), part of that is processed in the tomato paste factorise, which are mostly located in khorasan province. Since tomato variety has a determinant effect on the physico-chemical and organo leptical properties/quality of tomato and its products, an investigation was performed to evaluate the impact of variety and storage time of four tomato varieties, Cal.j.n.3, Early Urbana Y, Early Urbana 111and Peto early C.H which were selected according to a national project and were monitored according to their brix, pH, Acidity, Sugar and Salt contents, total and non soluble solids. Results indicated that Early Urbana 111 and Peto early C.H contained the highest amounts of soluble solids along with the highest pH. Also it was evidenced that these varieties were the most stable varieties as the least compositional changes was seen in them.

The Two cultivars of kiwi fruit, Hayward and Abbot, with the desirable quality were harvested on time from Valiabad, a region in Tonekabon (Mazanddaran Provicnce). Fruits were graded and packed in the wooden boxes, cartons and low density polyethylene (LDPE) films, the fruits were cold stored in a proper and constant conditions (T= ±0.5 & RH=90-95%) for a period of 6 months. Samples were taken in completely randomised design from each package for intervals of 30±3 days and during storage (6 months). Chemical characteristics such as the total soluble solids(TSS), titratable acidity as citric acid, dry matter, vitamin C and the Physical characteristics such as yield point (Y.P.), yield point strength (Y.P.S.), penetration force (P.F.) and penetration stress (P.S.) were measured. Statistical analysis was performed with the factorial experiment in an unequal completely randomized design and the means compaired by Duncan multiple range test. The results indicated that, cv, Abbot has shorter shelf life, 4 months, compared to Hayward with 6 months storage period. Hayward contained more dry matter than Abbot throughout the storage period. Total soluble solids of cultivars increased and titrable acidity as citric acid decreased during storage. Vitamin C of Abbot was more than Hayward throughout the storage. Total factors in relation to texture and physical properties decreased by time such texture Hayward cv.after six month storage and in Abbot after four month storage was softer. As the final conclusion, wooden bins packaging for longer storage and plastic packaging for monotonous rippening of kiwifruit was the best in compared with other packaging.

Greenhouse whitefly, Trialeurodes vaporariorum West., is one of the most important pests of field crops and ornamental plants in greenhouses which usually controlled by chemical insecticide and/or by biologic control factors. In this study the effect of singular and integrated use of Confidor and predator, Chrysoperla carnea (Steph.) against different nymphal instars of the pest on tomato plant was investigated. This experiment was carried out in 7 treatments, each in 3 replicates. Treatments included predator alone, the use of insecticide alone, and 4 integrated treatments of both the predator and insecticide. The predator was released at 5, 10, 15 and 20 day intervals after insecticide application. The control (water), insecticide spray and release of the predator were repeated each 10 days. In integrated treatments, insecticide was applied only once at the beginning of the experiment. The results showed that there was a significant difference between treatments. Pest control was not achieved with one or two attempts of release of predator or spray of insecticide. Pest elimination was only observed after third spray in insecticide treatment and 3 releases of predator beginning 20 days after spray in integrated treatment. These two treatments were shown to be of equal effectiveness in pest control. Also pest population was controlled after 5 releases which began 5 days after insecticide application. The use of the alone predator was statistically found to be less effective than treatment with the insecticide alone. Generally, integrated treatment is a promising alternative approach to pest control in longterm. It has clear advantages over chemical control in terms of pest resistance, environmental and general pest control issues. .

Fecundity and sex ratio are the important factors in the quality control of parasitoid, Trichogramma. In this research, the effect of the host egg deprivation on these factors in Trichogramma brassicae Bezdenko was evaluated. The experiment was conducted with four treatments, each in five replications in a completely randomized design. Twenty mated females (24 h old) were transferred into the glass tubes (1.5×10 cm) separately and were fed by honey 20% daily. In one treatment, parasitoids were provided with the 150 host eggs (Sitotroga cerealella) in first day, but in other treatments the 150 host eggs were offered after 2, 4 and 6 days. In order to obtain fecundity, black eggs were counted after 3 or 4 days. After emergence, adult parasitoids were recognized as male and female by their antennae and sex ratio was obtained. Results indicated that as parasitoids, Trichogramma sp., were deprived from the host eggs longer, more decrease was observed in fecundity and female ratio. Therefore, parasitoid quality was decreased by the host egg deprivation.