نشریه علوم آب و خاک (علوم و فنون کشاورزی و منابع طبیعی)
سال دهم شماره 1 (پیاپی 35، بهار 1385)

Suitable stable channel design and optimization of river geometry can reduce cost of projects. The regime theory provides the possibility of empirical and semi-empirical investigations of stable channel design in which erosion and sediment transport are in equilibrium. The objective of this research is an investigation and a comparison of the influence of uniform and non-uniform flows on the prediction of stable channel characteristics. The following empirical and semi-empirical (extremal hypothesis) equations were selected to study the effect of uniform flow: Lacey, Chital, Kondap and Garde, and Chang. Using 24 regime channels in USA, the statistical and graphical approaches were applied to compare and to evaluate the power of prediction of the selected equations. In order to investigate the effect of non-uniform flow structure on the stable channel characteristics, 21 measured velocity profiles in Gamasiab River were applied. Using the boundary-layer theory, shear velocity was computed for each profile. Accordingly, the estimated Shields parameter using the boundary-layer approach is the most effective parameter on the regime channel prediction. Simultaneous application of the non-uniform flow effect and the boundary-layer theory not only remove the risk of spurious correlation but also improve the estimation of stable channel characteristics.

Flow structure at water intake is very complicated and three-dimensional. Due to this the application of one and two-dimensional equations can not sufficiently explain the flow structure at water intake. In this study, the simulation of flow structure at a 45 degree water intake was investigated numerically and experimentally. Here, the characteristic of separation zone and velocity distribution at 45 degree water intake were investigated using Standard k-ε and RNG k-ε models. It was found that the Standard k-ε model enables to estimate the flow and separation zone at water intake. Also, the location of separate zone at the inlet of water intake was studied using experimental and numerical approach. It was found that the separation zone at 45 degree water intake occurs at the downstream of the inlet.

Estimation of seepage is essential prior to lining of earth canals. In Iran such investigation has been achieved in some irrigation networks using empirical relationships derived in other countries. Estimation of water loss in canal is required in design, operation and management of water distribution systems. Water seepage may be determind by using empirical equations proposed by F.A.O. These equations are applicable for different soils and hydraulic parameters. However, the appropriate estimating equation should be determined for each region. Therefore, these equations should be calibrated for local usage and different canal vegetation conditions. In this investigation water losses in canals at the Rudast region of Isfahan were measured by inflow and outflow procedure. Different canals reaches were selected in soils of relatively heavy, medium and light textures. The density of vegetation population in canals were low, medium and high. The estimated seepage losses by different empirical equations were not corresponded to those of measured values. Therefore, by using the measured seepage at different soil textures and vegetation densities the empirical coefficients of six empirical equations of F.A.O. (Ingham, Davis and Wilson, Affengendon, Moritz, Molesworth and Yennidumia, Misra) were modified for the study region. The relationships between measured seepage and estimated seepage before and after modification of the empirical equations were determined by regression analysis. These equations estimated the seepage loss much smaller than the measured values. The regression parameters (selope, intercept, and coefficient of determination of regression equation) indicated that after modification, the Ingham and moritz equation with higher slopes (0.91, 1.01), lower intercepts (-0.096, -0.039) and higher coefficient of determination (0.96) estimated the closest seepage values to the measured values respectively. The misra equation was the next best equation for seepage estimation. The results of present investigation indicated that the modified Ingham and Moritz equations were the most appropriate ones for estimation of seepage losses at different soil textures and vegetation densities in the study region.

Iran with a cultivation area of 45000 ha and production of 150 ton/year is the number one saffron producer in the world. Planting of large size corms will increase flowering, but production of corms (number and size) may be affected by irrigation method or frequency. In this research which is performed in the farm of College of Agriculture, Shiraz University, the effects of method and frequency of irrigation on corm production, and the effect of produced corms on flowering were evaluated in two consecutive years. Two irrigation methods (basin and furrow) with four levels of irrigation frequencies (12, 24 and 36 days and dryland farming) were applied. In August of 2000 sample corm was taken from every plot, and the effect of applied treatment from previous growing period on corm production and the effect of produced corms on future flowering were evaluated and analyzed. Based on the results, in furrow irrigation, total number of corms and total number of corms smaller than 4 gr is significantly higher than basin irrigation. In all of the above cases, irrigation frequencies did not show a meaningful difference between themselves or in comparison with dryland farming treatment. Total weight of corms and number and weight of corms larger than 8 gr in basin irrigation were more than furrow irrigation. This is to the extent that it is considered as the main reason for the difference in the flowering of corms, and has caused the flowering of basin irrigation to be significantly higher than furrow irrigation. In basin irrigation, irrigation frequencies of 12 and 24 days had the highest amount of flowering. No significant difference was observed on average corm production between the treatments in the two irrigation methods. However, irrigation treatments in both irrigation methods showed significant differences when compared with dryland farming treatment. So, basin irrigation with irrigation frequency of 24 days is preferred over furrow irrigation due to lower water consumption and production of larger size corms which is effective in flowering.

To determine the water application efficiency in furrow irrigation more accurately, consideration of seasonal and spatial variation of infiltration properties are needed. In addition, the effectiveness of different farm management on infiltration are significant. The main objective of this research was to simulate the seasonal variation (SV) of infiltration coefficients in Kostiakov-Louise equation (KLE) in a cracking soil under two traditional farm managements. Farm studies carried out in a clay-loam soil in Karaj. The two management treatments were soil without wheat residual and soil with wheat residual by a 5 ton/ha rate. There were 22 furrows with 0.75 m width in the farm. KLE infiltration coefficients were measured using inflow-outflow and two point’s methods in six furrows. The results of this study indicated that the SV of a and k coefficients were not significant, but variation of f0 was significant which was simulated with a logarithmic model. The effectiveness of SV on cumulative infiltration (Z) was also evaluated and indicated to be significant that were simulated with a logarithmic model too. Finally, dimensionless parameter such as Z* were developed to predicate Z parameter in different irrigation time, irrigation events and different residual management. Base on the result, although residue management causes a significant difference between value of f0 and Z in two treatments, but it doesn’t effect on trend of variation during the season. It means that the trend of variation is independent of residue in soil. It is probably done because of change in some of soil physical properties such as soil bulk density and aggregate stability.

Increasing the water use efficiency through promotion of sprinkler irrigation system, in order to increase production, has been the aim of the Ministry of Agricultural-Jihad in the past decade. Considerable amount of investment and efforts have been devoted to this end. Therefore, investigation of these efforts and development of models to predict the adoption behavior of farmers are of considerable importance. A survey research was conducted in four provinces (Fars, Bushehr, Kohkiloye-va-Boyerahmad, and Chaharmahal-va-Bakhteyari). A stratified random sample of 422 farmers was interviewed including 124 and 298 adopters and non-adopters, respectively. The findings indicated that the discriminant model developed based on the multiplicity model is a better predictor of farmers’ adoption behavior than diffusion and farm structure model. Application of multiplicity model in extension of sprinkler irrigation can increase the adoption rate and as result the efficiency of extension efforts.

This research is aimed to predict erosion and sedimentation of Tang-e-Kenesht basin in Kermanshah province using MPSIAC and EPM models in GIS software. This basin has about 14348 hectare area. This region has various vegetation, geology and soil texture and land use types. The basin has divided into 9 sub-basins and its maximum and minimum elevations are 3300 and 1400 m, respectively. Needed data were collected in part through published reports, while the remainings were derived by field survey. Necessary maps in MPSIAC and EPM models were prepared in Autocad-2000 medium and were transported to Arc-Info, after some revisions to them. After constructing topologies for all polygons, we entered all layers weights in Arc-View software. Combinations of all layers were managed thereafter. Nine layers for MPSIAC model and three layers for EPM model were combined to result the final layer of erosion and sedimentation. Basin erosion was calculated as 1002.7 and 1739.2 m3/Km2 by MPSIAC and EPM models, respectively. The result for basin sediment was 521.7 and 307.8 m3/Km2, respectively. Thereafter, medium and high erosion classes were found for the two models under study, respectively. Due to not fully compatible tables for EPM model and its subjective nature, one can conclude that MPSIAC model may have better performance.

The general goal of this research was to study the effective factors on the success of the poultry-farm cooperatives in Isfahan province. Based on multi-stage cluster sampling and Chocran formulas, nine cooperatives and 173 members were selected from 15 cooperatives with 1768 members. After completion of questionnaires, the AHP method was employed for scaling. Statistical tests (factor analysis and alpha coefficient) indicated that this research has a high construction validity and reliability. The research results indicated that cooperative functions toward fulfillment of members' demands were weak. The results of the path model indicated that effective factors on the success of cooperatives (from highest to the lowest) are: knowledge of cooperative principles by the members, extra-organizational factors, education quality, managers' skills, participation in cooperative affairs, and members' education level. Also, the success of cooperatives much relies on inter-organizational factors. The amount of members' share from education, participation in cooperative's affairs, the managers' specialty and skills, and knowledge of cooperatives' principles are very weak. Research results indicated that there is a direct and statistically significant correlation between these independent variables and the success of cooperatives in Isfahan province.

The general goal of this research was to study the effective factors on the success of the poultry-farm cooperatives in Isfahan province. Based on multi-stage cluster sampling and Chocran formulas, nine cooperatives and 173 members were selected from 15 cooperatives with 1768 members. After completion of questionnaires, the AHP method was employed for scaling. Statistical tests (factor analysis and alpha coefficient) indicated that this research has a high construction validity and reliability. The research results indicated that cooperative functions toward fulfillment of members' demands were weak. The results of the path model indicated that effective factors on the success of cooperatives (from highest to the lowest) are: knowledge of cooperative principles by the members, extra-organizational factors, education quality, managers' skills, participation in cooperative affairs, and members' education level. Also, the success of cooperatives much relies on inter-organizational factors. The amount of members' share from education, participation in cooperative's affairs, the managers' specialty and skills, and knowledge of cooperatives' principles are very weak. Research results indicated that there is a direct and statistically significant correlation between these independent variables and the success of cooperatives in Isfahan province.

Paleosols include soils formed under climatic condition different from the present. Although such soils are widespread in central Iran region, adequate investigations of them are yet to be carried out. Micromorphology is one of the most important tools in plaeoclimatological studies. This investigation was carried out to study microscopic features of two paleosols from Isfahan province to reconstruct the paleoclimatic condition during the Quaternary. The results of this study indicate that strong clay coatings are presented in Sepahanshahr paleosol, indicating moisture regime in the past. This paleosol is polygenetic due to calcite and gypsum accumulation during drier periods compared to clay illuviation condition. Micromorphological features in Segzi paleosol indicate that this area has experienced a swampy environment during the younger Dryas. The overall results from this study indicate that climatic oscillation evidences during Quaternary have been preserved in paleosols from Isfahan region.

Heavy metals have deleterious the effects on nodulation and N2 fixation of Rhizobium- Legume symbiosis, due to their inhibitory effects on the growth and activity of both symbionts. This research has been undertaken to evaluate the effect of Cd tolerance of native rhizobial strains on diminution of the Cd detrimental effects on Sinorhizobium meliloti-alfalfa symbiosis. For this purpose, a greenhouse experiment was conducted based on Randomized Complete Block Design. The treatments in this experiment included: plants inoculation with 6 bacterial strains (sensitive, partially tolerant and tolerant to Cd), 5 levels of Cadmium (0, 2, 5, 10, 20 mg/kg soil) and non-inoculated control. In different levels of Cd, the effects of bacterial inoculation on root nodule number and total amount of nitrogen in plant shoot were compared. The results indicated that soil pollution by Cd even at 2 mg/kg had significant effect on symbiotic properties of rhizobial strains, and according to Cd tolerance of various strains, the mentioned effect was different. Decreasing effect of Cd concentration on root nodules and nitrogen concentration in plants that were inoculated with sensitive strains in comparison with plants inoculated with tolerant strains was 68.31% and 40.8%, respectively. In this research, R95m was introduced as the best strain because of its ability for nodulation and nitrogen fixation.

Drought stress is one of the most important environmental stresses in reduce of growth and plants production. Determination of resistance mechanisms to environmental stress in plant improvement is very important. In order to , experiment with osmotic potentials of PEG (zero (control), -4, -8 & -12 bar) and alfalfa genotypes was done. The selected alfalfa genotypes namely, Yazdi(tolerant), Nikshahri(moderate) and Ranger(sensitive) were grown in hydroponic culture. After 4 weeks, they were harvested in order to determination of proline accumulation and Ca+2, K+ and Na+ concentration. The data showed with increasing of drought stress, proline accumulation were increased, but its rate was different among genotypes and organelles. Concentrations of K+, Na+ and Ca2+ increased with increasing of osmotic stress and there was significant different between genotypes. The K+/Na+ ratio in the shoots and roots of plant was decreased, when drought stress increased. Morphological and biochemical data showed Yazdi genotype was more tolerant to drought stress in compare with studied genotypes.

To determine the genetic structure, general and specific combining ability of some important agronomic characters, eight rice cultivars including 5 lines and 3 testers were crossed in Rice Research Institute of Iran (RRII), at Rasht, in 2000. Parental lines and F1 were planted in a Randomized Complete Block Design with three replications in the year 2001. Eleven important agronomic traits including yield and its components were recorded. Analysis of variances based on line×tester method showed that the mean squares for all traits were significant at 1% level. General combining ability (GCA) was positive and significant for grain yield in Khazar and Salary. Kanto and Salari have showed a negative and significant GCA for fertile tillers, as one of the most important yield components. Lines 213, 229 and Domsiah had negative and significant GCA for days to 50% of flowering. The lines with positive GCA can inherit those characters to progenies positively. While the lines with negative GCA can negatively transfer those characters to progenies. Estimation of components of genetic variance indicated that the number of fill grain per panicle and days to 50% of flowering were controlled by additive gene effects. It indicated that these traits can be transferred into progenies. For traits such as grain yield, fertile tillers and length of flag dominant gene effects was predominant.

A major source of photoassimilates deposited into the seeds is the closest photosynthetic source to the latter sinks. While the contribution made to grain yield by floral parts and the adjacent photosynthetic surfaces has been determined for a number of crop plants, such information lacks regarding safflower. Thus the present study was aimed at estimating the contribution of photosynthesis of safflower head and the two adjacent leaves to the grain yield of this oil seed crop. A 4-replicate RCBD field experiment was conducted at Lavark Research Farm, Isfahan U. of Tech., using four genotypes (Nebraska10, Kouseh, Arak2811 and K12) and three levels of shading (heads only, heads and the two adjacent leaves and control) on safflower heads following pollination, using khaki paper bags. Genotypes differed in terms of days to heading and maturity, height, number of heads per plant, number of seeds per head, 1000-seed weight, seed weight per head and grain yield per plant. Shading on safflower head and the two adjacent leaves led to a significant decrease in number of seeds per head, 1000-seed weight, seed weight per head, grain yield per plant and harvest index. There was not a significant difference between the two levels of shading treatment. It could be concluded that, with the environmental conditions experienced during spring 2003 at Isfahan, the photosynthetic products of safflower head and the two adjacent leaves may contribute to grain yield per plant by as much as 37 percent.

A chick bioassay with chemically defined amino acid (AA) diets was conducted to compare four different AA profiles: the NRC 1994, Feedstuff 2002, Rhone Poulenc Animal Nutrition 1993(RPAN) and Illinois Ideal Chick Protein (IICP) AA profiles. This battery study involved male and female chicks during 7 to 21 days of age. Indispensable AA were rationed to lysine according to requirement ratios presented in the four profiles. Digestible lysine set at 1.07 and 0.98 % of diet for male and female respectively. This experiment was carried out in a completely randomized block design using 2 5 factorial arrangement with for replicate per each diets were kept isonitrogenous (2.6 % N ) by varying levels of L-glutamic acid. All diets were checked to have at least 0.3 % proline and 0.6 % glycine. Diets for all profiles contained 3200 kcal ME/kg and a positive control diet were used according to NRC 1994 recommendations. Chicks fed a common corn-soybean meal diet for 160 h and were raised in the floor pen. Then chicks weighted individually and allocated to battery pens so that most uniformity between pens occurs. Four battery pens of five chicks were fed one of four different profiles or positive control diet in both male & female. Weight gain and feed efficiency measured for each pen at day 21. Results indicate an improved weight gain and feed efficiency in male rather than female (p<0.5). Chicks fed positive control diet weighted more (p<0.5). Between semi purified diets chicks fed diets formulated with NRC AA ideal ratios had significantly (P<0.5) better weight gain and gain: feed in both sexes relative to IICP and RPAN, but not to Feedstuff. RPAN had worst weight gain and feed: gain in females. Results of this experiment indicated that new ideal ratio of theronine (relative to lysine) in IICP for starter period may be under-estimated.

The Drying process is one of the most important factors which are effective on the milling quality of rice and its economic value. In order to investigate the effect of dryer parameters on milling quality of rice and their relationships, one of the usual rice varieties (Binam) of Gilan province with an average milling quality and the initial moisture content of 20.5% was selected. Drying process was performed on the basis of a complete randomized design with 20 treatments and 3 factors including temprature (at five levels of 30, 40, 50, 60 and 70 °C) , air velocity (at two levels of 0.5 and 2 m/s) and final moisture content of paddy (at two levels of 10.5% and 14% on wet basis equal to 11.7% and 16.3% on dry basis respectively). Results of the experiments indicated that increase of temprature or air velocity reduces drying time but increases drying rate constant (K). It also revealed that decrease of final moisture content of paddy increases drying time significantly, but doesn’t have any significant effect on drying rate constant (K). Correlation test indicated that milling loss (breakage) has a negative relation to drying time and a positive relation to drying rate constant(K), however, bending strength has a positive relation to drying time and a negative relation to constant of K. Regression of qualitative properties of paddy including: milling loss (breakage) and the bending strength over drying time and constant of K revealed that drying time is a better criterion for predicting the mentioned qualitative properties.

For production of fabricated potato chips, two potato- cultivars namely, Agria and Marfona, were obtained from Daran region of Isfahan Province and stored in cool storage at a proper and constant conditions ( T = 9°C and RH=85% ) . Specific gravity, dry matter and reducing sugars were determined at the time. Potato granule was prepared from both the cultivars by the Add-back procedure. To prepare a sheetable dough, potato granule, corn flour, emulsifier, shortening, water, starch, salt and wheat flour were used. After formulation of a non- adhesive dough, it was sheeted to thickness of mm and formed into slices of 3 cm diameter. These slices were processed by baking, vacuum drying, deep frying and combination of pre-drying and deep frying methods. To select the sample with the best texture a multiple comparison taste panel was held .The best method was baking at 125 for 30 minutes. To improve flavor and acceptability of selected chips, different seasonings (garlic powder, pepper, thyme, lactic acid, onion powder, salt, sugar) were used in chips formula and were compared by multiple comparison and triangle tests. Panelists selected treatments containing salt, pepper and garlic powder as the best formulatins.

Dasht Yari plain is nearly 580,000 hectares which is under engraving gully erosion and unfortunately the gully development rate is increased in the recent decades. Satellite images may provide quick, extensive, and valuable information for the interpretation of morphometric characterstics of gully erosion expansion due to having attributes such as time series, relatively low cost, large coverage, and finally being capable of digital analysis. Therefore, this research was initiated to use these possible capabilities to find a quick and cost effective method to determine the morphometric characteristics of gullies with use of the Landsat ETM+ digital data of Dasht Yari plain in Chabahar county in southeast of Iran. The Landsat 7 data of 2001 and the field data collected from 25 selected gullies from the same area were used as control in this study. After geometric and haze corrections with use of spectral enhancement methods such as linear enhancement and color composites, the images were made ready for visual interpretation and selection field sites for the subsequent field sampling. On the selected 25 gullies, the field data collection including width, length, and height of gullies at 25%, 50%, and 75% cross sections was performed. At the end of the image processing, with use of image interpretation techniques such filtering, fusion and principal component analysis (PCA), morphometric characteristics of the gullies was computed and compared with the field data. Mean comparison and F and t-student tests were used to verify any statistical differences between two set of the data. The results showed that the data set were different at 1 and 5 percent levels. From the image processing methods, the PCA method had the smallest difference with the field collected data. Therefore, we may conclude that PCA method may be used for monitoring the gully expansion in the Dashat Yari plain and similar plains in the southeast of Iran.

Present study investigates macrobenthic invertebrates and their community structure in Chafrood river to classify and assess the study sites regarding the environmental anthropogenic factors. Along a 9 km distance, 8 study sites were selected, and macrobenthic were monthly sampled using a surber sampler (1600cm2, 250 μ mesh net) with 3 replicate at each station. Collected samples organisms were fixed with 4% formalin and laboratory process including sorting, identification and enumeration of the animals were preceded. During the study 73 benthic taxa were identified which were dominated with aquatic insects larvae especially orders Diptera and Ephemeroptera. The maximum and minimum total abundance was 2335 ind.m-2 in station #2 and 1639 ind.m-2 in station #4 respectively. Benthic animals' frequency data were summarized to community structure metrics including total richness, EPT richness and ratio of EPT frequency to Chironomidae family. A Shannon- Winner diversity index and Hilsenhoff family level biotic index was also determined for each studied station. Result of cluster analysis for stations, based on the community structure metrics and diversity index, was in accordance with the station classification using biotic index and both classify the affected stations at the same group.

Saline soils and halophytic vegetations are common features and part of the habitat pattern in deserts and steppes. The saline area is developing in arid lands. Investigation effects of halophytes on soil characteristics and adaptive mechanisms of the various halophyte types is essential for controlling saline environments. Juncus gerardi is a perennial grass-like halophyte and Halocnemum strobilaceum is a succulent halophyte shrub. The distribution of these species is mound like in the field. The soil samples of the mounds for investigating the effect of these species on plant root environment were compared with near regions in Korsiah saline area in Darab. Also the consentration some ions of live and dead organs and tissues of these species were studied for recognition of their adapive types. The results show that Juncus gerardi decrease salinity in 0-30 cm of topsoil, therefore the Ec decreased 37%. But salinity increased significantly in 30-60 cm depth. The identification of ions in plant tissues showed that the concentration of ions is low in dry matter. This is 0.33% of dry matter for Sodium. This is a way to rescue from dry conditions by selective absorption of ions. The comparison of root environment of Halocnemum strobilaceum with near regions showed a significant decrease in salinity in 0-30 cm and 30-60 cm depth decreased 27% and 40% respectively. The identification of ions concentrations in plant tissues reflect the high amounts of ions, therefore the plant tissues composed of 8.18% of Sodium. The comparision of ion concentrations in different live and dead tissues of plants a Significant increase of the amounts of ion in the dead tissues in comparison with the live tissues. Therefore this species excrete much quality of salts in their dead tissues and organs and so combat this problem.

Range suitability and its grazing capability are the most important criteria in rangeland analysis and monitoring. Determination and monitoring of factors affecting on range suitability and diagnosis of them are important .All range ecosystem components affect range suitability. Which among them physical and vegetational factors, forage production, water resources and sensitivity to erosion were considered. The objective of this research was to determine range suitability of Lar, Dasht bakan, Ardestan, Siahrood rangelands to design a model for sheep grazing. This study was carried out in four regions, two of them (Siahrood and Lar) located in Alborz mountain chain, Ardestan in center of Iran and Dashtbakan in Zagros mountain chain. According to the results among physical factors, slope remoteness of watering points and sensitivity to erosion had more effect on grazing capability than vegetation factors. In Siahrood watershed aboundancy of poisonous plants, high slope, transient watering points and non resistant formations were limiting factors. High slope, sensitivity of soils and stones to erosion, kind of exploitation in Lar watershed affected range suitability. In Ardestan watershed, low range productivity, presence of invader plants, erosion, remoteness of watering points are major limitation of range suitability. In Dasht Bakan factors including slope, elevation, dispersion of water resources and transient water resources were limited grazing capability. In land evaluation each land utilization type has certain land use requirement and each land unit has certain land qualities. Utilization of rangeland based on grazing capacity, range readiness and recreation of degraded rangeland can improve suitability of rangelands in the studied areas.