Journal Of Science And Technology Of Agriculture And Natural Resources

Online ISSN: 1028-7655
Publications
Article
In this investigation, the effect of seed source on the germination and survival of Acer velutinum Boiss. was assessed. Seeds were collected from 11 seed sources ( located at 20 to 2200 meter a.s.l in Mazandaran forests) and planted in a mountain nursery (Orimelk located at 1550 meter a.s.l) as completely randomized block design with three replications. The results show that the effect of seed source on germination and survival was statistically significant (p<0.01). Germination and survival rates were lower for the Pasands, Ashak and Deis sources, and the maximum seed germination was related to Lamzer site. Effect of seed sources on survival of seedling was significant too. The maximum and minimum survival was related to Lajim and Ashak, respectively. Regarding plan table seedling, the effect of seed source was significant. The maximum efficiency of seedlings has been found in Lajim, Lamzer, Parke Noor and Sangdeh sites, while the minimum range of efficiency was related to Ashak and Pasand2.
 
Article
It is important to investigate the genetic diversity and evaluate symbiotic effectiveness of the indigenous rhizobial population. It helps understand the responses of indigenous isolates to different rhizobial inoculants. In spite of the importance of bacterial diversity, there are a few scientific reports about it in Iranian soils. Genetic diversity of 150 isolates of Sinorhizobium isolated from Hamadan soils was studied by using PCR / RFLP 16S-23S rDNA technique. The results showed that all isolates clustered in three different groups. Group (I) formed 122 isolates and they were quite similar to Sinorhizobium meliloti from viewpoint of genetic characteristics. Twenty five isolates were clustered in Group (II) and they belonged to Sinorhizobium medicae. Group (III) had two isolates and they were new species and quite different from the other groups. Shannon diversity index was different within eleven different land units (Medium gradient mountains, Level lands, Plateau, Foot slopes, Depressions and Composite land) and there was a correlation between Shannon index and some soil properties. Difference in Similarity index showed that Sinorhizobium groups in each land unit were different.
 
Article
The masculinization effects of 17α-methyltestosterone were investigated on the two developmental stages of guppy (Poecilia reticulate), namely, newly born fry and gravid females. The first group was treated with two doses of androgen, (30 and 60 mg/kg food), each for a period of 15 and 30 days and the second group (gravid females) was treated with the food doses of 400, 450 & 500 mg/kg in a 10 day duration prior to parturition. After three months, the first group masculinization ratio of 62.14% was attained only in 60 mg/kg at three-day long treatment and other treatments had no significant effect on masculinization. In this group all the treated fish developed male secondary sexual characteristics after 3 or 4 weeks. However, the above-mentioned characteristics disappeared gradually when hormone therapy was stopped. In the second group, all the treatments were significantly different from control group. 450 and 500 mg/kg treatments had the highest masculinization percentage (90.82 and 97.07, respectively) but the differences were not significant. Also there were 9.18% females in 450 mg/kg treatment and 2.93% intersex in 500 mg/kg treatment. But the so-called group mortality was higher and fecundity lower than those in the control group. Finally, it should be noted that hormonal treatment had not any significant effect on masculinization of newly born fry and with the regard to the effect of 450 mg/kg treatment on masculinization and mortality percentage, it can be introduced as the best treatment.
 
Article
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.
 
Article
In order to study the effect of spur dike position in the bend on the process of scoring, some tests were done in a laboratory flume of Plax glass material with 180 deg bend and R/B=4/7. In this research, by setting an spur dike in the laboratory flume with positions of 30,60,90,120,150and 160 degrees, discharge rates of 20 ,24 and 28 Lit/s , and fixed depth of 13 cm, the process of scoring around spur dike in pure water was investigated. For flume bed, gravels of uniformly granulated sizes were used. The results showed that the maximum scoring in the length of river bend is obtained with increasing the rate and angle of position up to the angle of 60 deg, and then from position of 60 deg the rate of scoring decreases up to the position of 120 deg, and finally the increase in the position up to 160 deg results in the maximum scoring.
 
Article
Evaluation of genetic improvement of grain yield and other traits in cultivars released in different years is useful to determine plant breeding impact on grain yield improvement, to define future selection criteria and to identify the desirable environment and traits for further assessment. This study was conducted to evaluate the genetic improvement for grain yield and other traits of twelve oat (Avena sativa L.) cultivars released in Canada during 1921- 1997, at Research Farm, College of Agriculture, Isfahan University of Technology, during 2001-3 in a randomized complete block design with three replications. The regression of mean grain yield on released year of the cultivars showed that the rate of increase in grain yield during a 76-year period is 32.63 kg h-1 year-1 or 0.63% per year. Breeding programmes have inereased harvest index, grain number per panicle and fertile tillers /m2. The effort of breeders in this period was to decrease plant height and days to heading. The other traits had small changes and showed no specific trends. In general the results of this study showed continous improvement of grain yield in this period. Genetic improvement of grain yield in evaluated cultivars closely correlated with harvest index. Therefore, most variation in grain yield of oats was due to variation in harvest index. Although much of the improvement in grain yield described here could be attributed to the increased harvest index, the scope for further improvement in this character may be limited. Further yield improvement of oats might be achieved by combining high biological yield with high harvest index.
 
Article
In order to study changes in morphophysiological traits of wheat cultivars released from 1940 to 2000 in Iran and to determine the association of these traits with grain yield, an RCBD experiment was conducted with 15 wheat cultivars released during past 60 years in Arsanjan (Fars province) in 2006 and 2007. Results indicated that grain yield increased significantly during these 60 years (r=0.912, P<0.01). HI and BY increased significantly with increasing grain yield. The changes in photosynthesis rate were not significant during this period, but transpiration rate and stomotal conductance in recent cultivars increased significantly. Chlorophyll index also increased in new cultivars. Among yield components, grain number per ear increased significantly, but increase in ear number was not significant. Plant height decreased significantly in new cultivars. The results showed that during wheat breeding in Iran, increasing HI, grain number per ear, transpiration rate, stomatal conductance and decreasing plant height had the highest role in wheat yield increase. The role of BY and ear number per area were lower in grain yield increase. It seems that present HI values are near the highest possible value, but the opportunity for increasing grain yield by mean of HI is still possible.
 
Article
To investigate land use changes, Qale Shahrokh basin (15098.1 ha area) was selected. Satellite images of Landsat sensors (MSS, TM and ETM+) were used. After improvement and different enhancement analysis of images such as FCC, PCA, the study area was checked using GPS and topographic maps (1:50000) and other information. Land use units were determined using classified random sampling method. Maps accuracy was assessed after performing different classifications. Final land use maps of 1354, 1369, 1381 years were produced using a hybrid method with fine accuracy. Trend of land use changes was investigated during the study periods. Results showed that during the first period (1354), most area of land use was rangeland with sparse vegetation cover (%41.6) and least area was irrigated farming (1.5%). Also, during the second period (1354-1369) most area of land use was rangeland with sparse vegetation cover (%43.4) and least area was irrigated farming (4.1%). During the third period (1369-1381), the maximum area of land use was dry farming (%35.6) and minimum of area was irrigated farming (7%). Maximum land use change was related to rangeland with medium vegetation cover. They were changed into dry farming and rangeland with sparse vegetation cover during 1354 to 1369. During 1369 to 1381, maximum land use changes occurred on poor rangeland with sparse vegetation cover and rangeland with medium vegetation cover was changed into irrigated and dry farming.
 
Article
Monitoring Land Use and Land Cover Changes have a significant role in environmental programming and management. Satellite data is an essential tool for detecting and analyzing environmental changes. Many change detection techniques have been developed which have advantages or disadvantages. Change Vector Analysis (CVA) technique is one such a method. This method is based on radiometric changes between two dates of satellite imagery. Main advantage of this method is that it provides direction and magnitude image of change. The aim of this study was to describe change vector analysis technique and it applies to detect land cover change in Isfahan area during an 11-year period. The data used for this study were two images Landsat: TM 05 June 1987 and 03 June 1998. Correction radiometric was not carried out because of the similar sensor and acquisition time of the remote sensing data. After geometric correction, the study area was selected from Landsat images. Change vector technique was applied to analyze magnitude and direction of change. The change map showed Kappa and overall accuracy coefficient of 63.19% and 74.4%, respectively. The results showed that the changed land cover was 3340 ha during this period. Overall, the results show that 1325 hectares (especially agricultural lands) have been converted into urban areas, agricultural areas were increased up to1385 hectares, and 435 hectares of agricultural areas were converted to other land use over the period of study. This study showed that CVA is a robust approach for detecting and characterizing radiometric change in multi-spectral remote sensing data sets.
 
Article
An intense storm occurred on June 6, 1992 in Mashhad city and its suburb, which caused a flood in the residential areas of Najafi, Chahar-cheshmeh and Nodareh. As a consequence of the abnormally huge flood, 25 people lost their lives and many structures were destroyed. Three recording rain gages located in Mashhad city (airport, College of Agriculture, and Water Authority) and one in the suburbs (Toroq dam) recorded the temporal distribution of the storm. Twenty five other nearby rain gages in the region also recorded the event. The rainfall hyetographs and rainfall amounts were analyzed. The results of this survey showed that: a) maximum rainfall intensity over a 15-minute duration in the College of Agriculture station, one of the centers of the storm, was 112 mm/hr, b) temporal distribution of rainfall for all recording stations were nearly the same, c) these patterns were in close agreement with all historic storms, and d) a return period of 380 years was implied via comparing the maximum rainfall intensity with relevant IDF curves. As a consequence, although an intense storm had happened, it was simply an outlier.
 
Article
Application of meteorological indicators has extensive use in drought monitoring. However, hydrological indicators can also play an effective role in this task. In this research, one of the rare approaches in drought monitoring with hydrological indicators namely Chang method has been applied and assessed for the Tehran basin using daily time step. The results have been compared with the unique meteorological drought index, EDI (effective drought index) and show the capabilities of the hydrological method and its more sensivity to water resources deficit. For instance, application of these procedures for the 1998 to 2000 drought spell in Tehran province revealed that Change method declares 31.1 % of times in very severe drought whereas it is 3.7 in EDI. Because of applying different indicators (e.g. reservoir and ground storage), a combination of both procedures is an ideal approach for drought monitoring in which the water inputs to the system as well as storage and consumptions are considered. The applied methodology makes it Possible to distinguish droughts due to rainfall deficit from the ones, which are resulted from water resources miss management.
 
Article
Navel oranges and Clementine mandarin are classified as early cultivars and when fruits are left on the trees, fruit firmness and juice content will decrease. Plant growth regulators have been used to improve fruit quality. Gibberellic acid (GA3) and 2,4-D isopropyl ester sprays were used to increase juice content ,peel firmness and delay senescence in Navel oranges and Clementine mandarin. Factorial experiments were arranged in a complete randomized block design with three replications and each block consisted of three trees. Chemicals were sprayed on the branches (north and south of each tree) with 10 liter sprayer to the point of run-off during fall of 2004 and 2005 ,in a commercial orchard in Jahrom in the south east of Fars province, Iran . In both years of study, GA3 at 100,150 and 200 mgl-l and isopropyl ester 2,4-D at 8,12 and 24 mgl-1 were sprayed on September 30 (diameter of Navel 64 mm and diameter of Clementine 46 mm), October 14 (diameter of Navel 69 mm and diameter of Clementine 48 mm ) and November 7 (diameter of Navel 70 mm and diameter of Clementine 50 mm) and fruits of Navel oranges and Clementine mandarin were harvested 45 and 35 days after last the spray treatment, respectively . The results of experiment revealed that Navel oranges responded better with second application (Oct.14, diameter 69 mm ) and Clementine mandarin with the first application (Sept.30, diameter 46 mm ). Juice content and fruit firmness at harvest increased. GA3 increased juice content even better than 2,4-D isopropyl ester but delayed senescence, 2,4-D was more effective in increasing fruit sizing in both cultivars. GA3 at 150 and 200 mgl-1 and 2,4-D at 24 mgl-1 when compared with the untreated resulted in highest juice content of fruits.
 
Article
Probable Maximum Precipitation (PMP) is the maximum possible amount of precipitation which could occur in a gauging station, a region, or in a watershed. Probable maximum precipitation is usually estimated by two general methods: the first is synoptic method in which short period (hourly) meteorological parameters such as dew point, wind speed and air pressure are used. The second is statistical method which is based on the statistical analysis of the 24-h maximum precipitations. In this study, the amount of 24-h PMP was estimated by Hershfield, Bethlahmy and modified Bethlahmy methods using date obtained from meteorological and Ministry of Energy over 15 or more years. The results showed that there exist large differences between statistical and synoptic methods; however, there are rather smaller differences between Bethlahmy and synoptic methods. For modified Bethlahmy method, the results were multiplied by a coefficient of relative humidity. Then the calibrated 24-h PMP values were estimated for all meteorological stations of Iran and a contour map of 24-h PMP for the country was developed. Results showed that a minimum value of 24-h PMP (110 mm) occurred in the central part of country and a maximum amount (260 mm) was found in both south and north parts of Iran.
 
Article
Differential lock is a means of improving tractor performance. This system causes the revolution of the axles to become equal. It, improves traction, decreases abrasion of drive tires, improves fuel consumption, and increases tractor work rate. Despite advantages of the system, differential lock has not been optimized in Iran. Thus, a semi-automatic differential lock system for MF-285 tractor was designed and developed. First of all, the different parts of the system were designed, selected, assembled. Under critical conditions, the designed system should disengage the differential lock. Critical conditions for engaging this system are: using of independent brake pedals, high forward speed, and turning the steering wheel. For sensing and measuring the critical conditions, proper sensors were selected. Output signals of these sensors were sent to a micro controller to decide the continuous engaging or disengaging. Finally, a MF-285 tractor was equipped with the designed system. The tractor performance in primary tillage was evaluated using a mounted moldboard plow with a width of 110 cm and a working depth of 25 cm. These tests showed that unbalanced weight distribution on wheels and unequal traction capacity under drive wheels cause the slip of one wheel to be 6 percent higher thananother. This system improves the unequal slip problem and decreases fuel consumption by 0.5 L/ha.
 
Article
A total of 179,460 monthly test-day milk records (thrice a day milking) obtained from 17,946 Iranian Holstein heifers distributed in 287 herds and calved from 1986 to 2001 were used to predict breeding value of animals. Monthly test-day milk production was analysed by applying a covariance function in which the effects of herd-year-season of production (HYSOP), age at test day (covariate), additive genetic and permanent environmental effects were included. Orthogonal legendre polynomials up to order 5 (quartic) were also implemented in the covariance model to take account of the genetic and environmental aspects of milk production variation over the course of the lactation. In the present research, breeding values of individual animals based upon 305-day and monthly test-day milk yields were compared. The results indicated that ranking of ten top sires, dams as well as progenies changed as the genetic evaluation of animals switched from the traditional (based on 305-day milk yield) to the new method that was based on the covariance function. Regression analysis of average breeding value of progenies on the first year of their calving showed that the amount of genetic trend obtained from the covariance function for 305-day milk yield was greater than that of the 305-day model (11.607 vs. 3.860 Kg/year) over the period of 16 years of calving. The phenotypic trend for lactation milk yield was 92.97 Kg per year which was statistically significant. This finding indicates that a large proportion of annual increase of milk production of Holstein heifers in Iran has been due to environmental rather than genetic improvement.
 
Article
Sorghum grain is an important cereal to be cultivated in tropical and sub-tropical areas. The extension of its cultivation and application in animal and poultry diets may reduce the need for imported corn. In order to determine the nutritive value of sorghum, 36 sorghum grain (SG) varieties and one type of corn were grown at the same location. The grains were analyzed for their nutrient composition. Results from of proximate analyses showed that the ash, crude protein (CP), phosphorous (P) and acid detergent fiber (ADF) contents of SG were 1.72±0.54, 11.6±1.18, 0.34±0.03 and 8.35±3.93, respectively. The ether extract (EE) of SG was lower than Iranian and imported corns. Iranian corn had higher amounts of CP (10.7%), EE (5.9%) and CF (3.3%) than the imported one (7.8, 4.2 and 2.25). Tannin contents of low and high SG varieties were 0.021% and 0.998%, respectively. The apparent and true metabolizable energies (AME and TME) of SG were decreased due to increasing the tannin contents. The values of TMEn (3853, 3771 and 3213 Kcal/kg) showed significant differences (p 0.05) between MTS (3458 Kcal/kg) and the two corn grains (3406 Kcal/kg).
 
Article
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.
 
Article
In order to study the effect of NaCl priming on some agronomical and physiological traits of corn (single cross 704), an experiment was conducted at Agricultural Research Station of Bahonar University of Kerman in 2005. The experimental design was completely randomized designs with 3 replications. Treatments were a combination of all different levels of two factors including salinity levels (1, 4, 8, 12, 16 dS/m) and salinity solution for NaCl priming (1, 4, 8, 12, 16 dS/m). Results showed that salinity and NaCl priming had significant effects on total emergence, mean time to emergence, root and stem length, number of leaf, relative water content, ion leakage and K+/Na+. Mean comparison showed that increasing salinity decreased all plant characteristics (with the exception of mean time to emergence and ion leakage) by %49.5, %33.49, %23.97, %18.64, %14.05 and %40.20, respectively. However, increasing salinity led to 1.2 and 1.3 increase in mean time to emergence and ion leakage of leaves, respectively. Mean comparison also showed that NaCl priming decreased negative effects of salt stress, and all mentioned traits under NaCl priming increased as compared with control. The results showed that NaCl priming is a useful method for increasing salt tolerance in corn plant.
 
Article
To evaluate the effect of plant density and detopping on grain yield, protein content biological yield harvest index, growth indices, number of cob in each plant, No. of row per ear, No. of grain in each row, thousand seed weight of corn (Zea mays L. ar. SC 704), an experiment was conducted at the experimental statues of Research Center of Uremia Agricultural College in 2004. The Treatment design was split plot in randomized complete block design with four replications. The main plots included plant density at three levels (53000, 66000, and 88000 Plants/ha) and the subplets comprised three levels: (1) no detopping (control); (2) removing canopy only; and (3) removing canopy and three leaves above the node. Analysis of Variance of data showed that both detopping treatment and plant density influenced the number of kernel per ear ,1000 grain weight, ear weight, total dry weight of biomass, seed yield and harvest index. Canopy detopping led to a marked increase in photo assimilateion import grains. The highest plant density evaluated, 88000 plants per hectare with detopping of three above leaves had the highest number of cobs per square meter. In plant density of 53000 plants per hectare and canopy detopping treatment, the number of grain per ear was greater than other densities. The efficiency of harvest index increased under corn detopping compared with control, and this increase with an increase in photosynthesis contributed to grain yield. It was concluded that major increase in grain yield under high plants density and tassel detopping was due to improvement of physiological indices.
 
Article
The increasing cultivation of corn in Ahwaz and the direct relation between the increase of the summer corn yield and its perfect irrigation in sowing period all together have made the research regarding this crop necessary. Deciding over the suitable irrigation scheduling of corn (hybrid SC.704) in summer by utilization of class A evaporation pan is the focal point of this research. Accordingly, a project was conducted in the form of stadistical perfect accidendal block in four repetitions and four treatments in 1383 on Ahwaz Azad university research land situated in Choneibeh. The irrigation treatment had four levels of T1,T2,T3 and T4 in class A evaporation pan containing of four levels of 50,75,100 and 150 mm, carried out in split plot. The suitable irrigation period was chosen according to the best treatment performance and its components, and the total amount of water in the taking period defines the depth of irrigation. The soil texture is clay lomy silty and the internal soil is silty clay. According to the amount of the accumulated evaporation from class A evaporation pan and taking the plant coefficient (Kc) into consideration, the amount of needed evapotrans piration was calculated and the amount of needed water for plot was measured by water counter. Then a comparison between the means by the use of Donken multi domains test was made and in this way the superior treatment was selected. Accordingly, the most suitable time for irrigation of summer corn in Ahwaz was after 50 mm of accumulated evaporation from class A evaporation pan which equals ten irrigation in the growing period. So in order to acquire 12 tons of seed yield in each hectare, at least 9600 m^3 of water for every hectar is needed. However, given the equal amount of water, with 3 times decrease in irrigation in treatment T2 in comparison with T1, a performance near 11 tons and with five times decrease in irrigation and ten tons in treatment T3 a performance near 10 tons can be attained.
 
Article
In order to investigate the effects of moisture stress, nitrogen fertilizer, manure and integrated nitrogen and manure fertilizer on yield, yield components and water use efficiency of SC 704 corn (late maturing, non-prolific and dent). In 2005, a field study was conducted in agricultural experiment station of the college of agriculture, Tarbiat Modares University. The type of design was randomized complete block with factorial arrangement and three replications. For the study, four levels of nitrogen fertilizer (0, 92, 184 and 276 kg N ha-1), integrated fertilizer (46 kg N ha-1 + 2/5 ton ha-1 FYM, 92 kg N ha-1 + 5 ton ha-1 FYM and 138 kg N ha-1 +7/5 ton ha-1 FYM ) and organic Farm Yard Manure (5, 10 and 15 ton ha-1 FYM ) along with three levels of irrigation (optimum irrigation (control), water stress 75% optimum irrigation and water stress 50% optimum irrigation) were used as treatments. The results showed maximum seed yield was produced with 92 kg N ha-1 + 5 ton ha-1 FYM and average of seed yield was 7976 kg ha-1. Maximum corn seed yield resulted when optimum irrigation water was applied and average seed yield was 7041 kg ha-1. When water stress was imposed in 50% and 75% of optimum irrigation, seed yield was decreased by 33 and 12%, respectively. The best seed yield was obtained with interaction of 5 ton ha-1 FYM and optimum irrigation. Also, maximum water use efficiency was obtained in using 50% of optimum irrigation. Maximum water use efficiency was obtained with interaction of 92 kg N ha-1 + 5 ton ha-1 FYM and imposition of water stress in 50% optimum irrigation. Results showed that adequate nitrogen fertilizer slightly increased corn seed yield under stress, and integrated (nitrogen and manure) fertilizer increased corn seed yield under stress. But seed yield greatly increased with optimum irrigation. Integrated fertilizer application increased seed yield even with severe moisture stress. Application of integrated chemical fertilizers and manure produced better seed yield and also decreased the amount of chemical fertilizers and improved soil physical and chemical characteristics.
 
Article
Forest future depends on forest stands regeneration. Soil is one of the principal capitals in the forest area. It is important to minimize damages to the forest ecosystem during logging operation. In forestry and forest management, it is significant to know the effect of forest logging damages on regeneration, sapling and soil compaction. This study was carried out in Asalem Beech forest area, in the north of Iran. The forest was harvested by selective cutting method. A systematic and randomized sampling method was used for data collection. Analysis of variance (ANOVA) techniques and binomial distribution were used for data analysis. The results showed 14.5 ± 0.99 percent of regeneration and saplings of forest stands were destroyed and damaged by logging operations with 20 m3/ha intensity per year. 9.12 ± 0.83 percent of saplings were totally destroyed and 5.3 ± 0.63 percent were damaged. These damages were caused due to felling, accumulating, skidding and landing. Soil bulk density in range of 0-10 cm depth, logging and skid trails areas were increased 17.54 and 35.61 percent, respectively. To reduce logging damages and soil compaction in forestry, and manage the forest, we need a suitable organization of timber extraction operation, careful designing and standard construction of skid trails on the basis of logging maps before felling the trees down.
 
Article
To study the effects of planting date and density on yield and its components in chickpea (Cicer arietinum L.) genotypes under dryland conditions of Khorram-Abad, an experiment was conducted during 2005-2006 growing season at the Agricultural Research Station of Lorestan Weather Department. Three sowing dates (March 6, March 21, and April 5) and two chickpea genotypes (Greet and Flip 93-93) with four plant densities (18, 24, 30 and 36 plants m-2 ) were evaluated using a randomized complete block design with split-factorial design in three replications. Dates of planting were considered as the main plots, genotypes and plant densities were randomly distributed in sub-plots with factorial arrangement. The result showed that delay in planting from March 6 to April 5 significantly reduced number of pods per plant, number of grains per pod, 100-grain weight, grain yield and dry matter. Increasing plant density led to a significant decrease in number of pods per plant, number of grains per pod and 100-grain weight. However, grain yield and dry matter increased firstly with increasing plant density and then decreased. Planting date and density had no significant effect on harvest index, while genotype of Greet produced a larger number of pods per plant, grain yield as well as final dry matter. Also Flip93-93 produced a bigger number of grains per pod, greater grain weight and harvest index. The maximum grain yield was obtained with genotype of Greet at the first planting date in 30 plants m-2 density. It could be concluded that due to thermal and drought stress occurring in late spring,, early planting of Greet genotype at 24-30 plants/m2 may lead to a suitable increase in grain yield.
 
Article
A population of offspring from a cross between ‘Golden Smoothee’ × ‘Shafi Abadi’ apple which was developed by two methods of controlled pollination (with and without covering after controlled pollination) was used to investigate the inheritance of microsatellite alleles and the necessity of covering in controlled pollination of apple. DNA was extracted from 60 seedlings (30 from each method) as well as corresponding parents and the probable source of unwanted pollen. Four microsatellite loci (CH03d12, CH03d07, CH04a12 and CH03c07) which were polymorphic among parents were selected and their florescent primers were prepared. DNA amplification was carried out using different colored florescent primers, and alleles size were determined using ABI377 automatic gene sequencer and Gene Scan Software version 2.0 according to internal standards. Results showed that all seedlings shared one allele at each locus with each parent indicating their hybrid and true to type nature. There were no differences between two methods of controlled pollination in terms of unwanted pollination and there were no off type seedling originating from unwanted pollen source. Allele distribution among the progenies showed their co-dominant mode of inheritance, and no significant difference with Mendelian co-dominant ratio (1:1:1:1) was observed using chi square (x2) test. These results showed that there was no need for covering after controlled pollination of apple at least for less sensitive cases such as cultivar breeding which takes lots of time and cost for controlled pollination of many flowers in a limited time span. Results also showed the importance and potential of microsatellite loci in detecting parent-offspring relationship prior to inheritance study of characters and alleles, bulk segregation analysis, gene and linkage map and historical reconstruction of fruit tree pedigree.
 
Article
After construction of a dam across a river, sediments settle behind the dam. It is important for dam designers to estimate the rate and distribution of sediments in the reservoir. In this study, the accuracy of area-increment and area-reduction empirical methods to predict the sediment distribution of Dez, Dorudzan and Shahid Abbaspour reservoirs is evaluated. The last measurement of sediment in these reservoirs was in 2003 (Dez), 2005 (Dorudzan) and 2005 (Shahid Abbaspour). The comparison between actual sediment distribution and predicted sediment distribution by using area-increment and area-reduction methods showed the maximum error at the depth of sediment behind the dam. At higher elevations, the error decreased and reached zero when the elevation was maximum. For Dorudzan reservoir, which has the least sediment volume (31 Mm3), the area-reduction method is less accurate, as compared to the area-increment method (81% vs. 37.5%). For Dez and Shahid Abbaspour reservoirs, where their sediment volume is high (608 and 737 Mm3, respectively), the error of the two methods is relatively equal (in Dez, 29% for both methods, and in Shahid Abbaspour, 22% for area-reduction and 25% for area-increment methods). After long-time sedimentation, the shape factor decreased and reservoir type of all three reservoirs changed to 2.
 
Article
A pot experiment was designed to investigate the effects of full, above and below ground interactions of wheat with wild oat on leaf characteristics and root to shoot ratio. This experiment was conducted as a factorial based on randomized complete design with four replications. The treatments included four interference levels (above ground, below ground, above and below ground and check wheat and wild oat) and four wild oat densities (2, 4, 6 and 8 plants/pot).The effects of full and root interference on wheat and wild oat traits was greater than shoot interference. For both species, full and below ground interaction significantly decreased the number of leaves, flag leaf area and chlorophyll content of flag leaf compared to above ground interaction and control. All traits of wild oat were reduced by above ground interaction compared to control. Number of leaves of wheat and wild oat showed greatest susceptibility to interaction treatments. There was no significant different between full and root interference. When wild oat density increased, the number of leaves, flag leaf area and chlorophyll content of flag leaf of wheat decreased. With strongest competition followed by enhanced wild oat density, root to shoot ratio in wheat and wild oat increased, which indicates more susceptibility of shoot than root to interference mean competition. This ratio for wild oat was more than wheat, thus, it is concluded that wild oat has higher rooting ability compared to wheat.
 
Article
Similar to plants, soil salinity may reduce microbial growth and activities in different ways. The aim of this study was to determine the effects of different levels of salinity on some microbial indices in the presence and absence of plant's living roots. In this study, five levels of salinity using NaCl, CaCl2, MgCl2 and KCl; and three soil media (soil with no plant, soil cultivated with wheat and clover) replicated three times consisted our factorial experiment arranged in a completely randomized design. Results show that salinity caused a significant reduction in accumulated microbial respiration, microbial biomass carbon, substrate-induced respiration, and carbon availability index in uncultivated soil and in the soils planted with clover and wheat. Results also show that salinity caused a significant increase in metabolic quotient (qCO2) in uncultivated soil, and soils planted with clover and wheat. Microbial activity of cultivated soils at high salinity levels was almost similar to that of the uncultivated soils. We observed a small difference in soil microbial activity among the three media at high salinity levels, indicating the role of indirect effects of salinity might be less important with increasing salinity levels. We also found out that at low salinity levels, the available carbon was not a limiting factor for soil microflora, while at high salinity levels the activity of soil microbes might be carbon-limited. The lower values of qCO2 in cultivated soils compared with the uncultivated soil support the positive influence of root and its exudates on soil microbial activity in saline soils. The existence of plants in saline environments may help in alleviating the detrimental influence of low to medium salinity on most soil microbial activities, likely via the added root exudates and root turnover.
 
Article
In this research the effect of Super Absorbent Polymer (SAP) on the crop growth, wilting point, sunflower survival, water holding capacity, and irrigation interval was investigated. The experiment was conducted with different concentrations of absorbent hydrogel (Igeta): 0% (control treatment), 0.05%, 0.1%, 0.2%, and 0.3% (w/w). The soil textures were sand, loam, and clay. The experiment was a completely randomized design with three replications. The results of this research are: 1- Adding of Igeta to the soil changed solid, liquid, and gas phases. Application of 0.05%, 0.1%, 0.2%, and 0.3% (w/w) of Igeta increased the volume of clay, loam and sand soils between 10-40% , 5-32% and 9-37%, respectively. 2- With application of Igeta, absorption of nutrients (N, P, and K) was increased. Maximum absorption nutrients occurred at the level of 0.05%, 0.1%, and 0.3% with confidence level of 90% for clay, loam, and sandy soils, respectively. 3- Igeta increased water holding capacity and irrigation intervals. Increasing in irrigation interval was between 30-130% in clay, 60-120% in loam, and 150-300% in sandy soils. Water saving in clay, loam, and sandy soils was 30%, 40%, and 70%, respectively. 4- at the level of 0.3% Igeta, starting time of temporary wilting point was delayed from 4 to 10 days (150%) in clay and loam soils, and from 4 to 12 days (200%) in sandy soil. The starting time of permanent wilting point was delayed from 8 to 12 days (50%) in clay, 7 to 12 days (71.4%) in loam, and 9 to 14 (55.5%) days in sandy soils. Therefore, application of Igeta delayed starting time of permanent wilting point between 50-71% and temporary wilting point between 150-200%.
 
Article
In the present study, the effects of sodium metabisulphite concentration (2, 4, 6, 8, 10%), dipping time (2.5, 5.0, 7.5, 10 min.) mixing of the solution including: continuous mixing , once per 2.5 minutes , once per 5.0 minutes and without mixing (I, II, III, IV) and pH of the solution (4.62, 3.62, 3.42) on the absorption of sulphure dioxide by halved Riogrande variety tomatoes prepared for sun drying were investigated. The experiment design was completely randomized plots with the order of 5, 4, 4 and 3 treatments, each with four replications. The results showed that increasing the solution concentrations, dipping time, mixing and decreasing pH increased the rate of SO2 absorptions. The increment of SO2 in tomato under the effect of the above mentioned factors have been shown in different tables and figures. The mathematical models of relationship among the rate of absorption of SO2 , the concentration of sodium metabisulfite solution, dipping time, also the effect of metabisulfite solution pH were developed. Significant differences were found in these increments in all the treatments (α= 0.01).
 
Article
Among the biodiversity of soil microorganisms, bacteria have the basic role in soil functions. In order to determine the diversity and abundance of soil bacteria in arid regions, and also to study the effect of agricultural practices on them, a study was conducted in winter wheat fields on Shirvan, Mashhad and Gonabad. In each region, high and low input fields of winter wheat and a natural system for comparison were selected. Use of agricultural inputs was criteria for selection of low and high input fields in each region. Soil sampling was done on fields and natural systems and organic matter content, abundance and diversity of soil bacteria were measured in soil samples. Species richness and abundance of soil bacteria was affected by region and so that natural system of Gonabad has the minimum of species richness among the studied systems and the differences of other systems was not significant. Abundance of soil bacteria in 1 g dry soil was maximum in Gonabad and minimum in Shirvan. Abundance of soil bacteria was affected by organic matter and in low and high input systems of Gonabad and low input system of Mashhad was greater than other systems. Overall, 19 species of bacteria that belonged to 4 genus were detected. Results showed that species richness and abundance of soil bacteria in studied systems were relatively low and agricultural practices have not significant impact on these organisms, so that species richness and abundance of soil bacteria were improved in agricultural systems of Mashhad and Gonabad. Pattern of bacterial diversity showed that regional and agricultural stresses were affected on bacterial function so that in high level of stresses, species richness decreased and function of soil bacteria was restricted to decomposition of organic matter. Therefore, organic matter of soil must be increased and agricultural stresses must be decreased to improve of soil bacterial functions.
 
Article
Bridge abutments are usually located in the floodplain zone of rivers where velocity and shear stress are not uniformly distributed. The influence of channel geometry and lateral momentum transfer in compound flow field on the scouring phenomenon has not been fully investigated and understood yet. The impact of lateral momentum transfer on the local scour at abutments terminating in the floodplain of a compound channel is presented in this paper. It is shown that, by accounting for lateral momentum transfer at small floodplain/main channel depth ratios (λa/H
 
Article
Correlation between components of Q/I and wheat (Triticum aestivum L.) growth indices was studied in a greenhouse experiment during 2003-04 growing season. Eighty soil samples (0 – 30 cm depth) were collected randomly in farms around the Abyak region, Ghazvin province. Twenty-one samples were then selected based on soil texture and NH4OAC-K. The research included treatments of 21 soils and two potassium (K) levels (0, 100 mg/kg) and was conducted in a factorial manner in a randomized complete block design with three replications for studying correlations between Q/I and treatments. Effect of potassium application on the wheat growth was found to be significant at 5% level. The effect of soil properties on wheat growth was also found to be significant at 1% level. However, the interaction of K and soil was not significant. There were no significant differences among the different equilibrium time intervals. The soil potassium buffering capacity (PBCK) values were strongly correlated with CEC (r =0.996**), clay content (r = 0.921**) and moisture saturation percentage (r = 0.811**). Final equation derived from stepwise regression for prediction of PBCK was as follows: PBCK = 7.419 CEC –19.743 R2adj = 0.782** The equilibrium potassium activity ratios (ARke) were strongly correlated with soluble potassium (r =0.846**), NH4OAC-K (r =0.730**), SP (r = 0/794*), OC (r = -0.477ns) and clay content (r=-0.602*). Similarly, readily exchangeable potassium (ΔK0) was strongly correlated with ammonium acetate extractable potassium (r = 0.871**), soluble potassium (r = 0.778**), saturation percentage (r = 0.551*), organic carbon percentage (r=-0.045ns) and clay content (r=-0.206ns). There was no significant correlation between ΔK0 and ARKe with potassium uptake values by wheat. In contrast, there was a strong correlation between PBCK values and potassium uptake by wheat (r = 0.729**), and relative wheat yield (r = 0.735**). There was no significant correlation between Q/I parameters when KCl and K2SO4 were used, and the soil physicochemical properties. However, Q/I parameters obtained from KCl showed a higher correlation with wheat plant's growth indices.
 
Article
Safflower having oil with high unsaturated fatty acids is a very valuable plant. However the sensitivity of safflower to some pests as safflower fly (Acanthiophilus helianthi), particularly in drought stress conditions has limited its production. In order to evaluate the effect of drought stress on population density and damage of important safflower pests, especially safflower fly, an experiment was conducted in the field using 5 irrigation treatments including 50, 70, 90, 110 and 130 mm evaporation from class A pan in a randomized complete block design with three replications. The local safflower variety used in this study was Isfahan land variety, Kooseh. In each irrigation regime, the half of one plot was locally sprayed by Chlorpyrifos in 2ml per liter of water to be compared with non-sprayed part. During 8 weeks of sampling, population of aphids, Uroleucon carthami, leafhopper, Empoasca decipiens and safflower fly, A. helianthi and also percentage of damaged heads by safflower fly were measured. The results showed that in non-sprayed conditions, the highest safflower fly (2.38 flies per net) and aphid population (165.57 aphids per plant) was observed at 130 mm evaporation regime. Drought stress also decreased (30.23 %) safflower seed yield. Severe drought stress together with non-spaying may increase safflower pests population particularly safflower fly and reduce seed yield. However low level of drought stress (70 mm evaporation from class A pan) may decrease relative number of insects and save irrigation water. Drought stress also decrease the population of leafhopper. In this study, 70 mm evaporation regime was the optimum irrigation treatment regarding lower aphid and fly damage (15.86% damaged heads in non-sprayed condition) and higher safflower seed yield (1687.5 kg/ha in sprayed condition).
 
Article
The commercial potato is an autotetraploid species. Certain allotetraploid species such as S. acaule despite theire identical ploidy level are not crossable with commercial potato due to their different endosperm balance numbers. The aim of this experiment was to investigate the possibility of germplasm transferring from allotetraploid species to cultivated potato by the use of diploid species and 2n gametes. For this purpose, one clone of S. phureja was crossed with S.acaule. The resulting F1 seeds were planted the next year. For evaluation of male fertility and unreduced gametes, the pollen samples of F1 hybrids stained with acetocarmin glycerol were assessed. For chromosome counting the tips of stolons were fixed and after staining with aceto – iron- hematoxilin were squashed. For future crossing some hybrids were grafted on tomato stocks. Cytologycal observation revealed that hybrids were triplod. Male fertility of hybrids as expected for odd ploidy was low, but approximately all of them had a few large stainable pollen (putative 2n). crossing of the hybrids as male parent with S. tuberosum was not successful, but reciprocal cross was successful and 72 seeds were obtained from 380 pollination . considering EBN, it is exected that the resulting seeds originate from fertilization of unreduced gametes of triploid and n gamates of S. tuberosum to be pentaploid or near pentaploid. The applications of these hybrid in potato breeding via ploidy manipulation have been discussed.
 
Article
The influence of Nitrogen (N) rates on mineral nutrient uptake in stem and seeds, proline and carbohydrate in flag leaves of Wheat (Triticum aestivum L . Var Chamran) under saline conditions was studied in a field experiment in 2003 and 2004. The experiment was conducted using a split plot design with three replications. The treatments comprised five levels of salinity: 1.5, 5, 10, 15 and 20 ds/m in main plot and three nitrogen levels: 50 , 100 and 150 kg N/ha in sub plot. Salinity treatments were applied in a clay–loam soil by water with NaCl and CaCl2 (5:1 by wt ). The results showed, the nutrient uptake was influenced by both salinity and N treatments. With the Exception of magnesium in seed, salinity increased nitrogen, calcium and magnesium concentrations in seed and stem in both years. By increasing salinity levels, the concentration of potassium in stem and seed decreased and Sodium concentration increased. In the stem the concentration of Sodium in the 20 ds/m was about 17 and 22 times more in the first and second year, respectively. In these experiments, by increasing salinity and nitrogen treatments, proline concentration in flag leaves increased in the two stages (flowering and milky stages) in both years. Salinity had similar effect on carbohydrate accumulation in both stages, but nitrogen treatment had two different effects on carohydrate concentration. In flowering stage, by increasing nitrogen application, carohydrate concentration increased but in milky stage decreased.
 
Article
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.
 
Article
In order to study the effects of salt stress and leaf feeding by ascorbic acid on antioxidant enzyme activity, proline accumulation and lipid peroxidation on leaves and roots of Brassica napus L. cvs. Okapi, an experiment was conducted as a factorial in a completely random design with three replications. Plants were exposed to salt stresses by NaCl solution (200 mM) and foliar were treated by ascorbic acid solution (25mM). Catalase, Superoxide dismutase and peroxidase activity were assayed in shoot and root. Also, malondialdehyde content and proline and chlorophyll in leaves were determined. The results showed that the activity of all antioxidant enzymes (except for SOD in roots) were increased significantly in plants under salt stress, and ascorbic acid application, as a antioxidant decreased their activity in leaves, but in roots it was not effective. Total protein content in leaves and roots decreased significantly under salinity condition. Ascorbic acid treatment increased total protein content under salt stress in both roots and shoots. Measurement of malondialdehyde content in leaves and roots showed that lipid peroxidation was increased by active oxygen species due to salt stress, and ascorbic acid reduced lipid peroxidation only in leaves. Chlorophyll content was also decreased by salinity compared to control. According to the result of present study, ascorbic acid application decreases deleterious effect of salinity.
 
Article
Understanding the nitrogen remobilization by plant, in order to obtain cultivars with higher quality, has specific importance in plant physiology. In this experiment, a bread and a durum wheat cultivar, were treated with different rates and times of nitrogen application, by using split factorial on the basis of randomized complete block design with three replications at Shiraz region during 2001-2002. Main plots consisted of two levels of cultivars ( Falat and Yavaros) and sub plots included nitrogen (40, 80 and 160 (kg ha-1) and times of nitrogen application (T1= all N fertilizer at planting , T2= 1/2 at planting + 1/2 during stem elongation and T3= 1/3 at planting + 1/3 during stem elongation + 1/3 at heading stage). The results showed that there was a significant difference between cultivars in flag leaf nitrogen content at maturity stage, N remobilization and its efficiency from flag leaf to grains and also grain protein percentage. Durum wheat was more efficient in nitrogen remobilization and therefore, had a higher grain protein percentage. Increase in rates and times of nitrogen application had significant effect on most of the measured traits. There were significant interactions between cultivars, rates and times of N application, indicating that durum wheat was more efficient in N remobilization from flag leaf to the grain. It appeared that N remobilization efficiency was the important factor affecting the grain protein percentage. Also increases in yield are associated with corresponding decreases in wheat protein.
 
Article
Soil fertility measures such as cation exchange capacity (CEC) may be used in upgrading soil maps and improving their quality. Direct measurement of CEC is costly and laborious. Indirect estimation of CEC via pedotransfer functions, therefore, may be appropriate and effective. Several delineations of two consociation map units consisting of two soil families, Shahrak series and Chaharmahal series, located in Shahrekord plain were identified. Soil samples were taken from two depths of 0-20 and 30-50 cm and were analyzed for several physico-chemical properties. Clay and organic matter percentages as well as moisture content at -1500 kPa correlated best with CEC. Pedotransfer functions were successfully developed using regression and artificial neural networks. In this research, it seemed that one hidden layer with one node was sufficient for all neural networks models. The best regression model consisting of organic matter and clay variables showed R2=0.81 and RMSE=7.2 while best corresponding neural network with a learning coefficient of 0.3 and an epoch of 40 had R2=0.88 and RMSE=0.34. Data partitioning according to soil series and soil depths increased the accuracy and precision of the functions. Compared to regression, artificial neural network technique gave pedotransfer functions with greater R2 and smaller RMSE.
 
Article
Drought is a natural feature of the climate condition, and its recurrence is inevitable. The main purpose of this research is to evaluate the effects of climatic factors on prediction of drought in different areas of Yazd based on artificial neural networks technique. In most of the meteorological stations located in Yazd area, precipitation is the only measured factor while generally in synoptic meteorological stations in addition to precipitation some other variables including maximum and mean temperature, relative humidity, wind speed, dominant wind direction and the amount of evaporation are also available. In this research it was tried to evaluate the role of the type and number of meteorological factor (as inputs of ANN model) on accuracy of ANN based drought prediction. Research area is a part of Yazd province containing only one synoptic and 13 non-synoptic meteorological stations. Three-year moving average of monthly precipitation was the main input of the models in all stations. The type of ANN used in this study was time lag recurrent network (TLRN), a dynamic architecture which was selected by evaluation of different types of ANN in this research. What was predicted is the three-year moving average of monthly precipitation of the next year, which is the main factor to evaluate drought condition one year before it occurs. For the Yazd synoptic meteorological station, several combinations of input variables was evaluated and tested to find the most relevant type of input variables for prediction of drought. However, for other 13 stations precipitation data was the only variable to use in ANN models for this purpose. Results in all stations were satisfactory, even where only one input (precipitation) was used to the models, although the level prediction accuracy was different from station to station. Result taken from this research, indicates high flexibility of ANN to cope with poor data condition where it is difficult to get acceptable results by most of the methods.
 
Article
Erosion features map is one of the basic maps in erosion and sediment studies considered important in watershed management programs. For preparing soil erosion features map (1:250000 scale), a study was conducted in Jajroud sub-basin of Tehran, Iran. Working unit maps were prepared from integrating: A) plant cover, geology and slope B) land-use, geology and slope; C) land-use, rocks sensitivity to erosion and slope and D) land-use, rocks sensitivity to erosion and land units. Working unit maps obtained from integrating layers were compared with three other maps consisting of working units maps according to E) land units F) rocks sensitivity to erosion units and G) image photomorphic units. Erosion features intensities in 314 control points were controlled and erosion features ground truth map was prepared by Thiessen method and using satellite imagery. Erosion features map was crossed with different working unit maps. Results showed that D map was better than A, B and C maps with regard to economic considerations. Accuracy was 53.0 and 42.9% for methods of land unit and rock sensitivity which resulted in the maps not suitable for differentiating soil erosion features. Root Mean Squared Error of working units showed that the error of land unit and rock sensitivity methods was more than image interpretation and integrated layers methods. The highest coefficient of variation was related to land unit and rock sensitivity to erosion methods and was the least for image interpretation and integrated layers methods. The greatest precision, therefore, was related to image interpretation and integrated layers methods. In general, working unit map of image interpretation was the best method for preparing soil erosion features map.
 
Article
The use of suitable empirical models for estimation of soil erosion and sediment yield is essential because of nonexistence or shortage of associated data in many watersheds. In the present study, the applicability of the USLE and its different versions Viz. MUSLE-S, AOF, MUSLT, MUSLE-E, USLE-M and AUSLE in estimation of storm-wise sediment yield from standard plots installed in dry farming, ploughed and rangeland treatments was evaluated. To conduct the study, the entire input data were collected from plots installed in three replicates in each treatment in Khosbijan Natural Resources Research Station in Arak Township. The models’ estimates were then compared with the observed sediment data for 12 storm events. Contrary to high correlation among different models’ estimates, the models used in estimation of measured sediment data were found inapplicable. However, significant relationship (r=94.4%) and non-significant relationship with correlation coefficients less than 50% were found between MUSLE-E, and MUSLE-S and MUSLE-E estimates and measured data in rangeland, dry farming and ploughed treatments, respectively.
 
Article
In order to predict Caucasian maple (Acer velutinum Boiss. ) seedling growth based on nursery Orimel, Eighty six one year old seedlings located at 1550 meters above sea level in Sari, north of Iran were randomly selected. Collar diameter, height, leaf area, photosynthesis area and leaf area/leaf weight ratio were determined. Then multivariate regression models between leaf characteristics and growth characteristic were drawn. The results indicated that number of leaves and photosynthesis area can estimate the height growth of a seedling. Also, mentioned characteristics of leaf can estimate the biomass of stem as a well as growth characteristics. According to the correlation between growth characteristics and leaf characteristics, it would be concluded that the photosynthesis area of leaf can be suitable for early selection of seedling for reforestation. Also, this result shows the importance of increasing the establishment and growth of maple seedlings in plantation areas.
 
Article
Potassium is one of nutritional element that has an important effect on the quantity and quality of rice plant. Knowledge about the K critical level and plant response to different application rate of K, can effectively help with the proper use of this element. Therefore, in this study potassium (K) critical level for rice (Khazar variety) and prediction equation for grain yield were determined in 21 rice fields of Guilan provience during 2001-2002. After land preparation, 6 experimental plots (4×5m) were constructed in each selected field. Nitrogen and phosphorus were applied before transplanting, based on soil test from urea and triple superphosphate, respectively. Potassium was applied in different rates including 0, 100, 200, 300, 400, and 500 kg ha-1 of K2O as muriate potassium. Khazar variety was transplanted in a space of 25×25cm, just after fertilizing of plots. Plots were harvested in 5 m2 at the end of maturity stage from the first node above the ground, and grain and straw were measured separately. Statistic analysis was done on grain weight based on 14% moisture. The results showed, that effect of different K fertilizer application in 5% and the effect of soil type in 1% were statistically significant on the grain yield. The mean increase of grain yield in responsive fields to K application was 982 kg ha-1. The results also showed that the responses of rice fields with available K less than 100 mg kg-1, 100-160, and more than 160 mg kg-1 to KCl application were high, moderate and low, respectively. Potassium critical level based on 90% relative yield was determined as 110 mg kg-1 of soil . In final relative yield, prediction equation, available potassium, potassium content of irrigation water, and rate of KCl fertilizer application entered positively in the equation, while available phosphorus showed negative effect on relative yield.
 
Article
This experiment was conducted to evaluate the effects of adding acetic acid to drinking water on the performance and ileal microorganisms of broiler chickens. In a completely randomized design with 5 treatments and 5 replicates, 300 day-old commercial mail broiler chicks (ROSS) were divided into 25 groups, 12 chicks per group. Each of the five levels of acetic acid added to drinking water (0.0, 0.1, 0.2, 0.3, and 0.4%) were given to five replicates for a period of 21 days. All groups were fed a practical corn-soybean based diet. During the experiment, chickens were not fed any antibiotics or coccidiostats. The diet formulation for all groups was the same. At 14 and 28 days of age, one chicken of each replicate was weighed and killed by cervical dislocation. Ileal contents were collected and used for microbial evaluation. At 49 days of age, one bird from each pen was killed to weigh gastrointestinal tract, liver, pancreas and abdominal fat. The number of total aerobes and colliforms per gram of ileal contents were enumerated on the appropriate bacteriological media. There was no significant difference in feed intake, weight gain, feed to gain ratio, live body weight, gastrointestinal tract, abdominal fat, liver and pancreas weights (p>0.05). Also, the differences among treatments for total aerobe and coliform counts were not significant (p>0.05). Under the conditions of this study, addition of acetic acid as an organic acid into drinking water at the levels used could not affect the performance and ileal microbial counts of chickens.
 
Article
Alternate bearing is a key factor in limiting citrus production. Chemical controls have proved to be the most effective solution to this problem. Two different experiments were conducted to study the effects of different growth regulators (GA3, NAA, Ethephon) and urea on alternate bearing control in Kinnow mandarin (Citrus reticulata). In the first experiment, GA3 at concentrations of 0, 25, 50, 75 and 100 mgl-1 were applied 3 times during late autumn and early winter 1993 on off trees. Flowers reduced as a result of GA3 application in the following spring but increased in the second spring. Best results obtained with 50 and 75 mgl-1. In the 2nd experiment thinning agents: NAA (0, 100, 200 and 300 mgl-1), ethephon (0, 100, 200, 300 mgl-1) and urea (0, 4, 8 and 12%) were sprayed to the trees on on-year, when the fruitlets were about 0.75-1 cm in diameter. The results indicated that urea had no effect; however, both NAA and ethephon were effective on thinning of fruits and control of fruiting. Ethephon at 200 and 300 mgl-1, and NAA at 400 mgl-1 gave the best results.
 
Article
Due to the need for new fumigants to control insects that attack food commodities, the toxicity of acetone was determined on some species of stored pest insects in Urmia University in the year 2000. In empty space tests, the LC50 values of acetone for Oryzaephilus surinamensis (L.), Callosobruchus maculatus (F.), Tribolium confusum (Duv.) and Sitophilus granarius (L.) were 15.40, 15.51, 17.55 and 18.26 μl/liter, respectively. The experiments of acetone penetration to wheat mass revealed that the application of acetone in headspace led to the penetration of acetone vapours into the wheat mass and killing the S. granarius and T. confusum had been concealed in interkernel space. The comparison of LC50 values of empty space tests with LC50 values of penetration experiments revealed that the increase in penetration toxicity was 8.63 fold for S. granarius. A similar trend was observed for T. confusum adults. In hidden infestation tests, the application of acetone to the headspace resulted in destroying the developmental stages of S. granarius concealed in wheat and achieved 75% mortality at a dose of 160 μl/liter during seven weeks. Acetone showed no deleterious effects on the germination and vigor of wheat seeds.
 
Article
Germination of strawberry seeds from self- and cross pollination of 4 commercial cultivars were evaluated under mist and in vitro cultures. The study was conducted in McGill University in Quebec, Canada, during 1994 and 1995. Self-pollination of Chambly and Redcoat cvs., and cross pollination of Oka × Chambly as well as Redcoat × Veestar and their reciprocals were used. At maturity, fruits were harvested and their seeds were separated. A sample of each seed lot was grown in greenhouse under mist condition and in vitro using MS medium. In the latter, both intact and cut seeds were used. Germination index (containing germination velocity and rate) was used as a criterion for germination evaluation. The results showed that there was no sign of germination in intact seeds 40 days after cultivation on MS medium; however, cut seeds containing plantlets started germination 2 days after cultivation and obtained 90 percent of the germination after one week of culturing on the medium. Germination of seeds under mist condition began 15 days after sowing and showed a minimum of 55 to 87 percent in different genotypes till the end of the experiment period (60 days). Germination index (GI) under this condition ranged from 15.4 to 26.1. GI comparison of seeds under in vitro and mist conditions indicates a lower germination rate in different genotypes under mist condition. This study also showed that the rate of germination in strawberry seeds could range from 0 to 100 percent depending on genotype and type of treatment used. The best treatment for a synchronized and rapid germination was found to be using cut seeds containing the plantlets on MS medium.
 
Article
Carotenoids are one of the most important and widely distributed pigments in nature and have essential biological functions in organisms. They also impart distinctive and attractive coloration to the breeding animals. Over the past two decades, application of microbial carotenoids has attracted the attention of researchers due to their natural and economic advantages. However, carotenoid producing yeasts with lactose assimilating capacity have rarely been studied and there are few references on the use of lactose as a carbon substrate, such as whey, for the biosynthesis of yeast carotenoids. In this study, a red carotenoid-producing yeast, Rhodotorula acheniorum, was isolated from the sap of birch trees at Masseh Chal in the Taleghan village. The yeast thus isolated was identified through microscopic, macroscopic and biochemical tests. The yeast has both the abilities of lactose assimilation and carotenoid production. The optimal conditions of culture were determined and maximum biomass and carotenoid production were 9.9 g/lit, 290 µg/g, respectively. Chemical analyses of extracted carotenoids have shown that the major portion of the yeast consists of β-carotene, torulene and torularhodin. With regard to the fact that whey is one of the by-products of cheese industries and that its proper disposal has long been a major problem, the most desirable way of handling this waste is to utilize it as a substrate in the production of useful products such as carotenoids.
 
Article
Achillea wilhelmsii Koch. is an aromatic plants belonging to Asteraceae family that has relatively wide distribution in different parts of Iran. In this study, we compared essential oil contents and constituents in two wild populations under two different ecological conditions (Fars and Khorasan Provinces, South West and North East of Iran respectively). The blooming herbs were collected and the essential oils of the samples were extracted after drying by “Clevenger apparatus”. Essential oil constituents were determined by GC and GC-MS. Our results showed that “Khorasan” population of Achillea wilhelmsii contains more essential oils than “Fars” population (0.65 and 0.2 % v/w respectively). Thirty components of “Khorasan” population that were 96.94% of total components were determined successfully and the main components were camphore(19.06%), cembrene(10%), 1,8-cieole(8.78%), alpha pinene(8.06%) and linalool (7.47%). Thirty-two components (91.98%) of “Fars” wild population were determined and the main components were isopentyl-isovalerate(9.46%), alpha pinene(8.75%), 1,8-cineole(8.70%), eudesmol(10-epi-gama)(5.56%), spathulenol(4.94%). Cembrene(10%), Germacrene B( 5.68 %) and Sabinene(4.34%) were detected in Mashhad population but not in Shiraz population. 10-epi Gamma Eudesmole(5.65%), Benzaldehyde dimethyl acetal(4.47%) and Ionone (4.29%) were detected in Shiraz population but not in Mashhad population. In conclusion, there are differences between these two populations as far as essential oils content and constituents are concerned.
 
Top-cited authors
Afyuni Majid
  • Isfahan University of Technology
A. Arzani
  • Isfahan University of Technology
Ahmad Ghanbari
  • University of Zabol
Abolfazl Tavassoli
  • Payame Noor University
Mahdi Babaeian
  • University of Bojnord