Year:2006 | Volume:12 | Issue:2|Papers Count:26

The purpose of this research is analysis of the mathematical structure of production and cost function for wheat. Methodology of this research is based on duality theory, where the theory indicates behavior production and the cost function similarities. In this study, for parameters estimation such as: elasticity of production, production coefficient and return to scale ,trans-log cost function is chosen, that is a robust framework to analysis the production relations instead of production function. In this approach, we can avoid some of the restrictions such as: homogeneous production function and nonlinearity of inputs. For estimation of the input demands and increasing efficiency of model, a system of equations and seemingly unrelated regressions is used instead of single equation estimation. Data for research is obtained summarizing by information about hundred wheat producers in the area of arasbaran. Where the coefficient of determination model is ninety percent showing goodness of fit. The results of the fitting model indicates chemistry fertilizer-seed and machinery-labors are complementary. The complementary between labor and machinery, may lead us to mechanization policy and increasing of employment, this could be done by banking loan. Results also show that the quantity of morishima elasticity of substitution and elasticity factor ratio, labor-fertilizer and seed -machinery services greater than one. Thus, there exists a robust substitution relationship between them. Hypothesis of production homothetic, return to scale, unit elasticity of substitution, and Cobb-Douglas function are rejected by likelihood ratio test (LR).

Increasing demand due ever-increasing growth of population has revealed the role of agricultural research in development of this section, through establishing and cultivating new technologies, in other to convince policy makers to allocate credits is necessary matter. In this study, the researches on presentation of Mahdavi variety and its cultivation in farmers' level for plantation, become economical evaluation in Isfahan Province. On this basis, in the first by using of attributive research method, the essential information including of cultivation and research costs allocated to wheat is got from Isfahan Province natural resources and agriculture researches center. Also, farmers' income and costing information was cumulated by survey research from the research society including of Mahdavi farmers in Isfahan and khomeinishahr city, through completion 105 questionnaires with personal method. In order to suitable sample choice, used from the multi stratified cluster sampling method. Research results indicated that the benefit cost ratio of researches in introduction and reconciliation of mentioned variety in operating years was more than one, and therefore in point of economical, agriculture researches in this connection have a companied necessary economical explanation. As, instead of one Rial investment in researches during operation and introduction years, the benefit to the rate of 8.1 Rials, has been created.

Alfalfa seed pests, such as alfalfa seed wasp, Brochophagus roddi (Hym.Eurytomidae) and alfalfa seed weevil, Tychius aureolus (Col.Curculionidae), cause high reduction in alfalfa seed production, but no sampling program for population estimate and management of them has been developed. During two years (2001& 2002), the spatial distribution of immature stages of these insects was determined using the crowding indices (ID,Cx, X*, Id & 1/k), Taylor's power law and Iwao's regression technique. All indices indicated an aggregated distribution of two insects in lucerne seed fields. Compared with Iwao's regression, Taylor's power law provided a better description between variance and mean density.The coefficient of Taylor's power law for alfalfa seed wasp and alfalfa seed weevil were (a= 0.5, b= 1.02 ± 0.06, r2 = 0.95) and (a= 0.275, b= 1.06±0.05 r2= 0.82) respectively and these for Iwao's regression were (a =0.08, b = 2.95±0.06 r2= 0.5) and (a =0.09, b =1.07±0.14 r2= 0.29) respectively.

In this study, the fecundity, development period, emergency percent, longevity, sex ratio, hind tibia length and brachypterous or apterous adults wasps of Trichogramma brassicae Bezd. In it's rearing on eggs of Sitotroga cerealella Oliv. Were evaluated in 24±1oC, 65±5% RH and 14:10 (L: D) for five generations. The mean amount of investigated characteristics for adult wasps was obtained: fecundity: 34.55 eggs per female, development period: 11.61 days, emergency: 93.52%, longevity: 3.04 days, female's ratio: 64.56%, hind tibia length: 160.48 microns and brachypterouses or apterous: 6.02%.The efficacy of T. brassicae increase until 3th generation and then decrease in following genereation. The results indicated the suitability of S. cerealella as a host for rearing of T. brassicae.

In order to investigate and determine the anastomosis groups of Rhizoctonia solani in potato, the infected plants were collected mainly from Sarab, Ajabshir, Tabriz, Bostanabad and Bonab in 1999 and 2000. Then 62 isolates of Rhizoctonia were isolated and purified. Study on their morphology, pathogenicity and anastomosis were indicated that about 85.4% of isolates belonged to AG-3 group, 6.4% to AG-4, and 3.2% to AG-5 of Rhizoctonia solani, and also two binucleate Rhizoctonia sp. were obtained from the potatos. One isolate did not belong to any of the anastomos with any of the tester cultures. The most important agent of the infection potato Rhizoctonia solani AG-3 was being studied in the areas.

To examine and evaluate the variation and process of deterioration of accessions of Medicago sativa seeds, which saved in Natural Resources Gene Bank, this experiment were carried out using 22 accessions. All of the accessions were examined in a complete randomized design with three replications under two different conditions, germinator and glasshouse. The recorded traits of the germinator test included, germination percentage (G.P.), speed of germination and vigor. The recorded traits of the test in glasshouses included G.P., speed of germination, plant height, number of tillers and root length in 40 days after planting. Significant differences were found among accessions for most of the traits. Variation among accessions was significant in one or both of the environments. The results of correlation coefficient study showed that speed of germination, could be a very good indicator of seed vigor. Negative correlation was found between reduction of G.P., speed of germination and seed vigor in germinator condition and G.P., speed of germination, plant height and root length in glasshouse condition. Therefore, seed deterioration not only reduces G.P, but also decreases the speed of germination and seed vigor. In all of the Medic ago sativa accessions, G.P. of stored samples of each year was different from other years, therefore reduction of G.P., was highly affected by origin of accessions. It was not possible to differentiate between the effect of maintaining condition and origin of seed. It is suggested that, for better Gene bank management, accessions, have to be considered as regeneration units of collected seeds.

Evaporation from the soil surface especially in arid and semi-aried regions has an important role in hydrological cycle of life. In these regions, the major part of water which enters the soil, returns to atmosphere via evaporation from the soil surface. Accumulation of salts also occurs in soil profile in regions with high water table because of evaporation from the soil surface. So evaporation from the soil surface not only loses water, but also it is the major cause of soil salinization. The main difficulty in accurate estimation of evaporation in field condition is the lack of simple functions with the least input data, so that most of the times the avaible function are experimental without any physical base. The main goal of this study is to calculate evaporation from the bare soil surface with numerical solution of Richards’ equation with initial and boundary condition of nonsteady and one dimensional evaporation in regions with low water table. It is not possible to use physical model in regions with deep water table because making similarity between lower boundary condition is difficult. Using Water Balance Model in various regions and existing condition and trends of changes, determined its parameters. These parameters determined the final evaporation in Karaj, Torbat Heidarieh and Mashhad respectively: 174, 116, 297 mm in 20, 44, 62 days in June 2003, August and September 2002, July and August 2002. LEACHM Computer Model which is called unlimited depth by lower boundary and free drainage by the above computer model was used in this study with initial and boundary conditions of evaporation. Numerical solution of Richards’ nonsteady and one dimensional equation was the base of LEACHM Computer Model. The amount of final evaporation in the above regions was calculated by the input parameters of the above computer model in filed and laboratory. The amount of final evaporation in above region was respectively: 170, 111, and 290 mm for the distinguished periods. The difference of the obtained results of water balance model with LEACHM Computer Model was less than 5 percent in these regions. This amount of difference is not so important in field experiments, and there is a good crossespondance between the results.

Physical properties of watersheds are not uniform throughout the watershed. Distributed rainfall runoff models have been developed to account for spatial distribution of watershed characteristics on flood hydrographs. On the other hand, due to advances in geographical information systems (GIS), the possibility of using distributed rainfall-runoff models has become more feasible. This research studies the effect of grid cell size on flood hydrograph in Kan watershed with an area of 206 Km2 located North West of Tehran. A distributed hydrological model on the basis of SCS infiltration and Clark flow routing using Visual Basic programming language is developed. Landsat TM Color composites bands 1, 4, and 7 are used for lithology recognition by hard classify method in IDRISI software. For determining infiltration in each classified lithology, infiltration measurements by rainfall simulator are conducted in each lithology zone. The result of this research shows that with increasing cell size from 30 meter to 960 meter, maximum flood discharge decreases. The rate of decrease depends on the spatial variation of rainfall and physical properties of land in the basin. By decreasing spatial variation of rainfall and infiltration in the watershed, the variation of maximum flood discharge will decrease. The results of this research show that by increasing time step from 10 minutes to 30 minutes, the computer run time will decrease by more than 50%, while maximum flood discharge will decrease by about 0.5%.

Flood is among phenomena which bring about considerable damage each year. This has been attracted greatly by hydrologists. Regional analysis procedure has numerous applications in determining floods discharge by applying geomorphologic parameters and multivariable models. The data on peak discharge in 11 hydrometric stations in a period of 30 years were collected in this study. Next, peak discharge for return period of 2 to 1000 years was calculated by utilizing homogeneity, statistical efficiency tests and statistical suitable distributions. After that, by the help of the software SPSS, peak discharge and 14 characteristics including area, perimeter, length and slope of main stream, slope of basin, length and width of equivalent rectangle, basin length, compactness coefficient, the sum of stream length, the mean height of the basin, precipitation mean in basins. Then, models for each one of the return periods were represented. In such models, the characteristics of the basin with the most effect on peak discharge were applied. Next stage involved grouping the sub basins into three homogenous regions by cluster analysis and correlation equations were presented to increase the accuracy for each of these groups. Using such models, peak discharge in the ungauged sub basin can be obtained.

In order to investigate the effect of drought stress on grain yield and chlorophyll, in Rapeseed cultivars a field experiment was conducted as split-plot arrenged in a Randomized Complete Block Design(CRBD) with four replication of karaj in 2002/03. There were two factors, Irrigation at two levels as main factors (80 percent of evaportation, as control, and drought stress from started stem elongation stage) and cultivars in 10 levels: Sarigol, Goliath, Heros, Comet, Amica, Sw 5001, Crackerjack,Eagle, Wildcat, Sw hotshot, as sub factor. Results showed that no significant difference on grain yield beetween cultivars, irrigation levels, and interaction effects. The maximum number of seed in the main branches pod (25.75), chlorophyll ratio (2.29 a/b) and chlorophyll percent (%69.33) belonged to Amica (p<0.05). Maximum total chlorophyll, chlorophyll b (1.37 mg/g.fw) and Chlorophyll a (1.56 mg/g.fw) belonged to Swhotshot (p<0.05). Interaction effect of irrigation levels and cultivars showed that on Irrigation condition, maximum percent of chlorophyll a (72.23%) and chlorophyll ratio (2.73 a/b), belonged to Heros.Swhotshot had maximum chollorophyll content and chollorophyll b in drought stress. Also Heros had maximum chlorophyll a (1.63 mg/g.fw) and grain yield (3830 kg/ha), in the same condition relationship to other cultivars, that maybe had a better adaptation to the drought stress.

In order to investigate the effect of different times and levels of nitrogen fertilizer application on yield, yield component, and dry matter remobilization efficiency of two winter wheat cultivars, a field experiment was conducted by using split factorial in the basis of randomized complete block design, in three replications, during 2001-2002 in the Shiraz region. Main plots were assigned two levels of cultivars (Falat and Yavaros) and sub plots including rates and times of nitrogen application. The results showed that there were significant difference between cultivars in number of fertile ear, number of grain per ear, 1000-grain weight, grain yield, and harvest index, as, durum wheat was superior in number of grain per ear, 1000-grain weight , and harvest index and Falat cultivar in number of fertile ear, and grain yield.The effect of nitrogen application rate was different on above traits. By increasing of nitrogen application all above traits were increased. The best method of nitrogen partitioning obtained in T2 and T3 application times. There were significant differences between cultivars in dry matter remobilization efficiency. And this factor increased by increasing in rate and time of nitrogen application. In general, it seems that 180 kg N ha-1 with two or three partitioning of it will increase grain yield. Also, dry matter remobilization efficiency has been affected under genetic characteristics and environment. Higher production of dry matter at anthesis stage would be resulted to higher dry matter remobilization. Nitrogen stress also increased Dry matter remobilization efficiency.

Kernel yield in corn is defined by the number of kernels per area and individual weight of each kernel. The objective of this study was to determine the kernel potential of current corn hybrid for assimilate avaibility. This experiment was conducted in experimental farm of Islamic Azad University, Fasa branch in summer 2003. A factorial experiment based on randomized complete block design with 4 replications was used. The first factor was including hybrids of KSC 604, KSC 647 and KSC 704 and the second factor had in two levels of assimilate source increasing with cutting of half of the cob and control. The cobs were cut in width two weeks after silk emergence. Consequently, assimilate sources for the remained cob doubled. The results showed that dry matter weight of hybrid KSC 704 kernel was more than hybrid KSC 604. This is due to being longer Effective Filling Period (EFP) of KSC 704. Kernel filling rate had not significant difference among hybrids. EFP of hybrid KSC 704 with cutting of cob was longer from control in hybrids KSC 604 and KSC 704, but source increasing did not influence the kernel weight. Consequently, kernel is limited in assimilate avaibility and will influence in field management.

An experiment was conducted to evaluate the effects of plant density and planting pattern on yield and qualitative characteristics of peanut (Arachis hypogaea L.) in Bandar Kyashahr Guilan province Investigating Field in 2002. A randomized complete block design was used to incorporate factorial combinations of four plant density (3, 5.3, 8.3 and 14.8 plants per m2) and two special arrangements (square and rectangular arrangement) with three replications. The results of the experiment showed that the planting pattern have effected on above ground yield, pod yield, kernel yield, percentage of seed oil production, and oil yield, but. Influences Square planting pattern was higher than to the rectangular planting pattern. Planting pattern did not effect the seed protein production. The 8.3-plants/m2 densities had higher above ground yield, pod and kernel yield, oil yield than the others. The peanut planting densities did not effect on the oil and protein production of peanut seed.

Onion (Alium cepa L.) is one of the most important vegetable crops related to Alliaceae family. Onion seed is important for producing of yield with high quantity and quality, and seeds with higher 1000 seeds weight and germinability power have importance role for producers. Effects of sowing date, plant density and onion size on seed yield of Azarshahr Red onion variety was studied using a factorial experiment based on a randomized complete blocks design with four replications at Islamic Azad University of Tabriz. Onions were planted at four sowing dates ( 5, 20 Mar. and 7, 23 Oct.), four onion sizes ( 3.5-4.5, 4.5-5.5, 5.5-6.5 and larger than 6.5 centimeter) and three densities (14.3, 11.4 and 9.5 plants/m2). Analysis of variance indicated that seed yield, stem lodging percentage, umbrella diameter and seed yield of per plant by sowing dates, by onion size and all traits exception to remaining plants percentage by plant density were influenced. Interaction of sowing date by onion size on seed yield and stem height at 5% probability level, and on stem lodging percentage and seed yield of per plant at 1% probability level, interaction of sowing date by plant density on seed yield and seed yield of per plant at 5% probability level and on stem lodging percentage and umbrella diameter at 1% probability level, and also the interaction of sowing date by onion size by plant density on seed yield, umbrella diameter and seed yield of per plant and thus interaction of sowing date by plant density on traits of seed yield, umbrella diameter and seed yield of per plant were significant in 99% probability level were significant. There are significant correlation between seed yield and remaining plants percentage, umbrella diameter, seed yield of per plant and stem height. The results showed that sowing date of 20Mar., onions with larger than 6.5 centimeter diameter and density of 143000 plants/ha is the best treatment combination in Tabriz area.

This study was conducted to determine the affects of different combination of medium over Lignum anther culture to induction and plant regeneration. Anthers were placed inside culture medium of MS that containing five different combination of regulator. Medium with 1 mg L BAP and 2 mg L 2,4-D producted significantly higher amount of callus and significant increase in regeneration the same culture medium in addition 1 mg L NAA and 2 mg L BAP was seen . Between five tested levels of Thyamin Hydrocloride medium with 8.0 mg L H.T. had maximum regeneration. Maltose concentration had significant influence on callus percent production from anther. Between five levels of Maltos used culture medium cotaining 6 until 9 percent of Maltos had maximum regeneration. Sucrose concentration had significant affect on number of callus that product radicle and regeration percentage and also Sucrose had effected on frequency of microspores that transformed to mature plant and frequency of spontaneous double chromosomes in microspores that were transformed to mature plant.

This study was carried out in Rice Research Institute of mazandaran in 2002-2003 to find out the interaction effects of irrigation and nitrogen on some morphological and physiological Characteristic of rice plant (Oryza sativa L.). A split-plot factoriel design with 3 replication was carried out. Three methods irrigation (flooded, periodicity and saturation irrigation) perform as main plot and different amounts of urea apply as secondary plot. This study performs on rice NEDA variety. Amounts of nitrogen apply in 100,200 and 300 kg/ha form. Increase of amounts of nitrogen lead to increase of growth parameters such like heigh, tiller number, leaf area, total dry weight and amount of chlorophyll but decrease of starch. Effects of different methods of irrigation were significantly on parameters of above. Comparison of means showed that statistically significant is between irrigation methods of flooded and periodicity to saturation method whereas significant increase of growth parameters and amount of chlorophyll demonstrated in flooded and periodicity treatment in comparison to saturated treatment. Also interaction effects of irrigation and nitrogen were significant on parameters of above whereas saturated treatment lead to decrease of nitrogen uptake and growth parameters.

In order to determine the most important yield components of rapeseed cultivars (Brassica napus L.) a field experiment was conducted in 2000 at experimental field of Karaj Research Institute for Seed and Plant Improvement. In this experiment 25 Rapeseed cultivars were compared in a randomized complete block design with four replications. The differences between cultivars was significant (p< 0.05) for seed yield, oil seed percent and therefore higher seed yield was 4.26 t/h for ARC-2 cv. and either the higher oil yield was 1.94 by that cultivars and there was significant differences between cultivars (p< 0.05).SLM-046 and Ryder were the greatest among all 25 cultivars for oilseed contents with 41.30 and 46.21 respectively.

A field experiment was carried out in investigation on effects of different irrigation regimes on quality of mulberry plant in 2000-2001(irrigation at T1= 0% or control, T2=60%, T3=80%, T4=100%, T5=120% and T6=140% on the basis of the moisture deficit by evaporation from class A pan). Quality variables of mulberry leaf recorded at end of irrigation period with random sampling (simultaneous with silkworm rearing period). Then obtained leaves were analyzed chemically and then obtained data also statistically were analyzed too. Obtained results showed that %K, % moisture, % N and % protein were significant different statistically. However % P was not significant at these periods. Furthermore irrigated mulberry leaf quality was better than control group. However N, protein and P percentage were not showed significant different between various irrigation regimes.

In this study, possibility of the use of four kinds of chemicals namely a monoammonium phosphate and diammonium phosphate, ammonium sulphate and mixture of Monoammonium phosphate and borax (70:30) as fire retardants with 12% concentration for Iranian beech wood(Fagus oriental is Lipsky) was surveyed. Wood samples were prepared according to JISA-1322 standard. To make wood samples fire retardaning, they were impregnated with dipping and Lowry methods. Impregnated samples with diammonium phosphate by Lowry method have the best fire resistance properties. These samples have 143%less in weight loss, 77.96%less in fire point, 67.93%less in duration flow after removing the burner and 54.83% less in percent of carbonization in compared with control samples. Wood samples impregnated by diammonium phosphate have highest compression strength parallel to grain; hardness and samples impregnated by ammonium sulphate have the least total shrinkage.

In this research, applications of statistical quality control process in Sima choob Company have been investigated. Sima Choob produces various wood products per order only. Statistical quality control process includes all control investigations and diagrams. In this research, work in progress and the finished products were studied, using standard MIL-STD tables, current statistical techniques and control diagrams (X, R, C, and U) of qualitative and quantitative characteristics of their raw materials. The results obtained from statistical quality control process showed that during the research time and in the raw material section, the quality of twin wheels lot, 40Cm rail, Tran's rod, laminated particleboard, and medium density fiberboard was not compatible with the acceptable standards of the company. This leads to return of the raw material as well as imposing more control on the suppliers of such products. On the other hand, work in progress lot and finished products were compatible with the company's standards. Since data lots were located in the control limits of assembling, painting and other sections indicated that the whole process had been under control during the research time. In general, it can be concluded that using statistical quality control process for the raw materials, work in progress, and the finished products would enhance the quality and the useful life of the products.