Journal of Agricultural Sciences and Natural Resources
Year:2006 | Volume:13 | Issue:2|Papers Count:24

In order to study the effects of irrigation regimes and mother-bullb size on qualitative and quantitative traits of onion seed (Allium cepa L. CV. Texas Early Grano), an experiment was conducted at Kabootar Abad Research Station of Isfahan during two growing seasons (2000-2001 and 2001-2002). The experiment design was split-plot with a randomized complete block arrangement and four replications. Main factor included three irrigation regimes based on evaporation from class A pan (I1=after 50±3mm, I2=after 70±3 mm and I3=after 90±3mm) and sub factor included two motherbulb sizes (3-6 and 6.5-8.5 cm). The results showed that seed yield, capsules/umbel and seeds/capsule in I3 were significantly lower than I1 and I2 irrigation regimes and there was no significant difference between I1 and I 2 in seed yield and yield components (umbels/m2, capsules/umbel, seeds/capsule and 1000-seed weight). Seed yield, umbels/m2 and capsules/umbel increased significantly as mother-bullb size increased. Among yield components, umbels/m2, capsules/umbel and seeds/capsule had the most contribution to seed yield and these yield components explained about 96% of seed yield variations in this experiment. Percent and rate of seed germination in I3 was significantly lower than I1 and I2 irrigation regimes (P<0.05) but mother-bulb size didn't have significant effects on seed quality traits. Generally, irrigation after 90±3 mm evaporation from class A pan decreased yield and seed germination. Also, irrigation after 70±3 mm evaporation from class A and mother-bulb size of 6.5- 8.5 cm might be the most suitable criteria for irrigation and onion seed production in areas with similar conditions to this experiment.

The objective of this study was to examine the effects of irrigation frequency and irrigation water quantity on yield and fiber quality of two cotton cultivars. This research carried out in split plots design with three replications and silty clay loam soils at Hashemabad Cotton Research Station of Gorgan in 2000 and 2001 years. Irrigation frequencies of 13 and 26 days were main plots, irrigation water quantities of 50% and 100% of water requirement were subplots and cultivars of Sahel and Siokra were considered as sub-sub plots. The results showed during two years there was significant difference between yield, lint percentage, fiber length, uniformity and elongation but without significant difference between strength and micron airy. Irrigation frequency showed insignificant effect on fiber strength but significantly affected the yield, lint percentage, fiber length, uniformity, elongation and micronairy. So that irrigation frequency of 13 days showed higher fiber length, uniformity, strength and elongation, but lower micronairy and lint percentage than irrigation frequency of 26 days. The irrigation water quantity significantly affected fiber length but with no significant effect on yield and other quality properties. Higher lint percentage, uniformity, strength and elongation but lower micron airy was observed in 50% water requirement compared to 100% water requirement. Higher elongation but lower yield and micron airy were observed with Sahel cultivar than Siokra. These differences were significant, but there was no significant difference for other quality properties. Considering yield, water use and cotton fiber quality, it can be concluded that the superior treatment was irrigation frequency of 13 days with 50% water requirement and Siokra cultivars.

In recent years, the arid area of Zeydabad as a pistachio production pole has faced intense reduction of water level and rapid increase of water salinity and their related impacts on the agricultural development due to over extraction and misuse of the groundwater. The main objective of this research was to study the effects of water level reduction on the salinity of groundwater. The variation trend of water table drawdown and groundwater salinity was first determined according to the data of 29 piezometric and observation wells during a ten year period (1993 - 2003). 18 water samples were then obtained along east-west transects (3 samples from each transect) and water salinity was measured in the laboratory. Correlation coefficient was calculated between water table reduction and water salinity parameters along each transect. In addition, statistical difference of water table height and water salinity of piezometric and observation wells were studied by Chi-square test during the data period. The results showed that the water table reduction had a significant effect on the water salinity along transects A, B, C and D, but not along E and F. Over extraction of the groundwater was mainly responsible for the salinity of groundwater in the four first transects. Artificial recharge of the waste water of Sirjan city caused non significant variation of the groundwater salinity in E and F transects.

This investigation was carried out to determine the minimum irrigation period for Acacia tortillas and the use of its results in a forestation programs in Hormozgan province. This study was carried out in Sarkhoon research station that was located in east north of Bandar-abbas in 1994. This species is important as forage for livestock, rural traditional fuel wood supply, bee keeping, soil conservation, prevention of erosion, wildlife survival and ecosystem balances. In this investigation propagation was done in September and their planting in land were done in January. This plan was treatment with different irrigation period during the project (from January 1994 to January 1995). The amount of water used in each irrigation time was 20 litters. This experiment designed in randomized block. Our treatments in this experiment were 10, 20, 30, 40 and 50 days interval irrigation and check was irrigared only one time. After 5 years according to the survival of plants, the statistic analysis was done. The maximum surviving of plant in this experiment was related to 10 day interval irrigation. As this experiment was approved that more than 80% of plants were survived in check with one time irrigation. We suggested that it can be developed by only one time irrigation.

Seed emergence and early growth of seedlings of 5 citrus species were investigated. A complete randomized design with factorial arrangement was used with 10 replications in each treatment. In each replication ten healthy seeds of each Bakraei (Citrus reteculata X C. limetta), Volkamer lemon (c. volkameriana), Sour orange (c. aurantium), Sweet lime (c. limetta) and Mexican lime (c. aurantifolia) species were cultured in 2L pots, containing sterilized quartz sand, after surface sterilization with chlorox, and placed in the greenhouse. The post were irrigated with 1/10 Hogland nutrient solution supplemented with 0 (control), 20, 40 and Mm NaCl (salinity stress treatments) for 70 days. Appearance of shoot in the surface of pot was index of seed emergence. Number of emerged were counted daily. At the end of experiment, shoot length, crown diameter and shoot, root whole plant fresh and dry weights were measured. Using the seed emergence data, no. of days to reach the 50% seed emergence, final seed emergence and percentage of healthy seedlings at the end of experiment, were calculated. Results showed that all the species varied significantly in regard to all the measured indices. Salinity stress affected these indices and the responses were different in regard to species and the salinity levels. Low salinity level (20 mm) had little effects on properties of seed emergence, but high salinity level (60 mm) had high effects. General concluded that, in seed emergence stage, Bakraei was the most tolerant followed by Mexican lime, Sour orange, Sweet lime and Volkamer lemon.

This study has been conducted to survey the effects of seed testa and period of stratification on the germination percentage of Aeer velutinum. The experiment was achieved in a factorial design in a frame of completely randomized design (CRB) with two factors of period of chilling and seed testa. In each experiment, 100 seeds were applied. Treatments were included of two types of seeds, seeds including testa and seeds without testa. These seeds were under three periods of moist chilling; 0 days as control, (without moist chilling), 10 and 20 days. The mean of germinated seeds (%) in different treatments used as the variable of the experiment. Data were analyzed using SPSS and Excel software program. The best germination was obtained after application of 20 days of consecutive stratification for the seeds without testa. This result showed a mean of 59.66 (%) germination for the recent treatment.

Stubble mulches on the rainfed farms will increase the shear strength of topsoil against overland flow. The evaluation of flow resistance of crop residues in the arid and semi arid rainfed farms in south of Iran is very important due to its soil texture and rainfall regime. Especially in the spring and summer that there are some floods and no vegetation cover on the ground. An open hydraulic flume with 15m length, O.3m width and 0.5m depth was used to simulate concentrated overland flow on the native rangeland around Lamerd City. Four treatments including rainfed farm mulches, poor pasture (vegetation density less than 20%), moderate (vegetation density between 20 and 40%) and good pasture (vegetation density higher than 40%) were examined. For each treatment, four to five discharges from low to high were used and hydraulic parameters and sediment were measured directly. Results of this study show that the critical shear stresses for erosion initiation were 22.1, 20.54, 38.61 and 39.68 dyne/cm2 for rain fed farm mulches, poor, moderate and good ranges respectively and the threshold of sheet erosion of crops residuals is higher than poor pasture and less than moderate. On the other hand, calculated soil erodibility factors are 0.37, 0.56, 0.51 and 0.32gr./m2-sec, respectively that show flow resistance of rainfed farm mulches is between moderate and good pastures. Finally the critical flow rates were 1.5, 0.75, 2.2 and 2.54 lit/sec for rain fed rain mulches, poor, moderate and good ranges, respectively. It implies that rain fed farm mulches can decrease flood damages.

In order to study the effects of row spacing and seed rate on phenology stages, vegetative characters and incidence of Sclerotinia stem rot on two genotypes of canola, an experiment was conducted at agricultural research station of Gonbad during 2002-2004. The experiment was a factorial split plot in a RCBD with 4 replications. Two varieties (Option 500 and S-3) and 3 seed rate (4, 6 and 8 kg/ha) were arranged in a factorial form in main plots and 3 row spacing (12, 24 and 36 cm) were subplots. The result of combined analysis showed that the Sclerotinia stem rot in first year was more than that of second year of experiment because of higher growth period duration, plant height, and lodging and lower stem diameter in first year of experiment. The disease in first and second year of experiment was 15.9 and 1.4 percent, respectively. The percentage of disease in Option 500variety (10%) was more resistant than that of S-3 variety (7.3%) because of higher stem diameter, lower plant height and too lodging in S-3 variety. The percentage of disease increased with increase of seed rate and row spacing because of increase in plant height, lodging and decrease in stem diameter.The percentage of disease in 4, 6 and 8 kg seed/ha was 5.5, 9.2 and 11.2 percent, respectively. Also the percentage of disease in 12, 24 and 36 cm row spacing was 5.7, 8.5 and 11.7 percent, respectively.

Future climate change may have major influences on growth, yield and water use of crops. The objective of this study was the evaluation of the effects of climate change on growth, yield and water use of chickpea under rainfed and irrigated conditions of Maragheh (north-west of Iran). Simulating future climate for a doubled CO2 concentration by using GISS and GFDL models showed that, during chickpea growing season, mean temperature increases by 3.5-4.5°C and solar radiation and rainfall changes by -2 to 4% and -15 to 4%, respectively. Simulations with a computer model for chickpea (CICER) showed that under doubled CO2 conditions, growing period decreases by 10 to 13% due to warming, grain yield changes by 28 to 45% under rainfed conditions and by -1 to 15%under irrigated conditions, water use reduces by about 15%, but water use efficiency increases by 39-42% and 13- 22% under rainfed and irrigated conditions, respectively.

To evaluate genetic diversity of lentil land rates, screening quantitive indices of drought resistance, and identifying drought resistant, 51 lentil land rates were tested in an augmented design under two irrigated and rainfed conditions in the research station of Dr.Nakhjavani, Kahriz of Urmia. Basedon the potential (Yp) and stress (Ys) yield, quantitive criteria of drought resistance as: mean productivity (MP), tolerance index(TOL), geometric mean productivity (GMP), harmonic mean (HM), stress susceptibility index(SSI) and stress tolerance index (STI) were calculated. Significant difference was found among the lines for all the calculated indices, potential and stress yield, indicating the existence of genetic variation, possibility of selection for drought resistance as well as hybridization for the genetic and breeding studies. The highest stress yield, GMP and STI were related to WAZ-79- 1501. Correlation analysis between indices, potential and stress yield indicated that the most suitable criteria for screening lentil lines under two irrigated and rainfed conditions were STI, GMP and SSI. Cluster analysis showed the farthest genetic distance between drought resistant lines numberWAZ-79- 1501 and WAZ-79-1507 and drought susceptible lentil land rates WAZ-79-1515, WAZ-79-1545, WAZ-79-1536, WAZ-79-1542, WAZ-79-1532, WAZ-79-1538, WAZ-79-1550, WAZ-79-1521, WAZ-79-15, WAZ-79-1522, WAZ-79-1541, WAZ-79-1551, WAZ-79-1513, WAZ-79-1549, WAZ- 79-1519, WAZ-79-1544, WAZ-79-1540 and WAZ-79-1534.

To study the effect of 5 commonly grown crops in Golestan province in rotation with wheat, a randomized complete block design experiment, with 4 replications, was used. Seeds of corn, sesame, sunflower, soybean and cotton were planted in a field that was previously under wheat cultivation. At the end of their growing season, samples were taken from their rhizosphere and their mycorrhizal fungi population, species richness and percentage of mycorrhizal roots were compared with those of wheat. The results showed that wheat rotation with corn or sesame or sunflower was more effective than with soybean or cotton and can conserve population and diversity of these useful fungi.

In order to study the nitrogen remobilization of rice genotypes under different nitrogen fertilizer levels, a field experiment was carried out in the rice research institute (Rasht/Iran) during 1999-2000. A split-plot design based on randomized complete blocks with four replicates was used. Three nitrogen levels, includes of 0, 150 and 300 kg/ha as the main plots and three rice genotypes includes of 424,506 and 507 as the sub plots were applied. The results showed that nitrogen remobilization had significant differences among different levels of nitrogen. Moreover the interaction between nitrogen treatment and genotype had significant effects on nitrogen remobilization. Different part of shoot of rice genotypes showed different responses related to remobilization of nitrogen, and contribution of grain nitrogen from leaves was more contributed than other parts. There were negative correlations between grain yield and nitrogen remobilization. While there were positive and significant correlations between grain yield and harvest index and days number to 50% an thesis. Also correlation coefficient between nitrogen remobilization and biomass were negative and significant. Moreover, correlation coefficients between nitrogen remobilization and day's number to maturity were positive and significant.

Bean (Phaseolus vulgaris L.) can be supplied part of nitrogen by biological nitrogen fixation. The object of this study is evaluating efficient strains in comparison with N fertilizer in randomized complete block design with four replicates and 13 treatments used in this experiment in Khomein Bean Station. Treatments included ten different Rhizobium strains, two levels of nitrogen fertilizer (200 and 400 kg urea ha-1) and control (without inoculation and fertilizer). The results showed that treatments were significantly effective on dry matter, N concentration, N uptake, number and weight of nodules in the first stage sampling (50% flowering). The maximum dry matter and N concentration were obtained with bacterial treatment No 8 and weight of nodules with bacterial treatment No 1. But maximum N uptake was obtained from fertilizer treatment No 11 (3.765 m-2).Results at the end of the season showed that treatments were significantly effective only on yield but not significant on dry matter, N concentration and N uptake. The maximum yield and dry matter were obtained from bacterial treatments No 6 and 4, but maximum N concentration (3.432%) and uptake (6.314 grm-2) resulted from fertilizer treatment No 12 (400 kg urea ha-1). There was no significant difference between treatments. Therefore based on the information of this research and other useful aspects, effective rhizoidal strains can be successfully used for bean cultivation.

There is a paucity of information reading dates and densities on growth of lateral branches and main stem and hence their proportion in yield chickpea variety of Hashem. An experiment was carried out at Agricultural Research Station of Gorgan, Iran. The experiment was a split plot arranged in a Randomized Complete block design with four replications. Three planting dates (5th December, 20th January and 5thMarch) and four planting densities (16, 32, 48 and 65 plants per square meters) were main and subplots, respectively. Plant height, nodes in main stem and lateral branches and pods number on main stem and lateral branches and 100 seed weight were measured. Seed yield was also measured. Planting data had no effect on pods per main stem and secondary branches, proportion of main stem for yield per plant but had a significant effect in pods primary branches, seeds per pods, 100 seed weight and yield. With an increase in plant density, the fertile pods decreased on main stem, and primary and secondary branches. Increase in plant density increased contribution of main stem for yield per plant form 14.5 to 25 percent, and it had no effect in primary branches proportion, but decreased the contribution of secondary branches for yield per plant form 40 to 25 percent. Contribution of main stem, primary and secondary branches for yield per plant were 21, 45 and 31 percent, respectively.

The general goal of this research was to study the factors effecting on the success of the poultry farm cooperatives in Golestan and Mazandaran provinces. Based on multi-stage cluster sampling and Chocran formulas, 11 cooperatives and 101 members were selected from 21 cooperatives with 1395 members. After completion of questionnaires, the AHP scaling method was employed. Statistical tests (factor analysis and alpha coefficient) showed that this research was high in construction validity and reliability. The research results showed that cooperative functions toward fulfillment of members' demands were weak. Results of the path model showed that effective factors on the success of cooperatives (from highest to the lowest) are: knowledge of cooperative principles by the members, performance of cooperatives union, rate of benefit other organization from cooperatives participation in cooperative affairs, extra-organizational factors, the rate of member sharing instruction, managers' skills. 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 were very weak. Research results indicated that there is a direct and statistically significant correlation between these independent variables and the success of cooperatives in Golestan and Mazandaran provinces.

Employment in the rural areas is one of the key policies in the higher education programmers in agriculture. It is believed those who are willing to study agriculture at the universities will apply to study agriculture with a better motivation if they have a positive attitude on the employment. So that they will have not only a positive attitude to work in the rural areas but also will have a better efficiency after employment in the agriculture section. Therefore, the study was conducted using questioners filed by 806 students. The results showed that the majority of the students are interested to work in the rural areas. The rank of the attitude was 2.86 out of 5 in compare to the other variations. The attitude of the employment in the rural areas had a significant relation with other variations such as sex, field of study, entrance year to the university, the place of living, background to live in the village and happiness from the field of the study. The majority of the students believed farness from the family and low income are main factors to prevent them to work in the villages. The study was suggested that allocation a proportion of the study places at the faculties of agriculture to the villagers and making a balance between the number of the girls and boys at the faculties will facilitate the employment in the villages. The support of the banking systems from the graduates of agriculture through the paying loan to work and live in the villages will be also a plus.

Recently, natural resource economists have studied ecosystem value of natural resources and its role on human welfare is ensured. These studies have made a considerable progress in valuation of environmental and ecological services and ecosystems can offer. Determination of existence value of north forests of Iran, adjacent to Caspian Sea, and measure of individual's willingness to pay (WTP) based on contingent valuation (CV) and dichotomous choice (DC) are subjects of this research. Logit model was used for measuring of individuals WTP. Estimation parameters of the model are based on method of maximum likelihood (ML). The Results showed that 65.8% individuals have willing to pay for existence of north forests of Iran. The mean of WTP for existence value of these forests is RLs 15153 household/month or annual value of RLs181836 for a household. The existence annual value was estimated 1.2 million RLS/ha for north forests of Iran.

The ability of artemia nauplii to act as carrier of the oxolinic acid in 3 concentrations 5, 10, 20% w/w fatty acids was studied. The enrichment was applied for prevention of Persian sturgeon (Acipenser persicus) larvae that was challenged on Aeromonas hydrophilic. The concentration of oxolinicacid in artemia nauplii increased with increasing of drug in enrichment medium and it was significant.The highest survival of the fish larvae (100%) attained from series of non challenged, but therewas no observation significant different among series of enriched and unenriched by drug and challenged and non challenged on Aeromonas hydrophila. In this study, the results showed that the use of unenriched Artemia urmiana with oxolinic acid in initial stages of growth of Acipenser persicus larvaewas cause to increase of resistance to Aeromonas hydrophila infection.

In this investigation, human chorionic gonadotropin (HCG) was used to induce spawning in captive adult goldfish Carassius auratus gibelio with weight 146.75+3.5gr and length 21.63+0.56 cm at ambient temperature 16-18°C. The best HCG injected, was calculated 1500 IU/kg for males and females with 53% FECUNDITY FOR FEMALES. Males response to HCG injection was favorable and 2 males were able for 4 females eggs fertilization. The eggs after 5.5 days with 84.5% were hatched in 17°C and not significantly (p<5%) correlated between HCG treatments were observed. When goldfish larvae were fed phytoplankton (mainly Chlorella), zooplankton (paramecium, rotifers and Daphnia) and Culex larvae, after 37 days rearing period were reached in 500 mg weight and 250 mm length. Specific growth rate (SGR) and Condition factor (CF) were calculated 0.149 and 3.2 that indicated favorable larval rearing.

The samples of Sunflower stalks were collected from Behshar and Neka. The average fiber length, cell wall diameter and thickness measured were 0.9581lm, 23.605 and 5.927µm respectively. The components of chemical and depithed stalk including: cellulose, lignin, ash and extractives content using Alchol-Aceton and NaOH 1% were measured as 39.93, 22.24, 12.49,4.92,36.10% and 47.37, 21.20, 7.50, 3.61, 34.00%, respectively. The following optimum conditions were selected regarding of pulp yield 43.80% and kappa number 82.55: with cooked chemical substances: 20% Na2o applied, on the basis of dry sunflower stalk, pulping temperature: 170°C and residence time at maximum temperature: l80min. Pulp refining carried out with PFI revolutions 150 and 500 RPM up to freeness 372 and 328ml CSF, respectively. Statistical analysis showed that physical and mechanical, properties of hand sheets with basis weight 127gr/m2 NSSC pulp made from Sunflower stalk with freeness 328ml CSF are better than mixed hardwood NSSC pulp (except burst index) and NSSC pulp of Sunflower stalk with freeness 372ml CSF. Furthermore, no significant difference was observed between mixed hardwood NSSC pulp and NSSC pulp of Sunflower stalk with freeness 372ml CSF.

The effect of Caucasian Elm (Zelkova carpinifolia), Oak (Quercus castanifolia), Mulberry (Morus alba), Ash (Fraxinus excelsior) as woody plants, Rose (Rosa damascene) and Fumitory (Fumaria sp) as non woody plants extractives on durability of Beech (Fagus orientalis), Maple (Acer insgin), Alder (Alnus subcordata), and Lime (Tilia sp) were studied. First wood species having extractives were cut to small pieces and then were chipped and milled by using Tappi (T20403-76) standard. Acetone and Methanol solvents were used to extract soluble materials from wood durable species. Extractives percentages were measured and wood specimens of perishable species measuring 0.5x1x5 cm were prepared. The fungus (Trametes versicolor) was selected and taken from the forest (Darabkola in Mazandaran state). Extractives were injected into non-durable wood species by negative atmospheric pressure for 15 min, and then treated wood specimens were oven dried at 50°C. Treated and untreated wood blocks again oven dried, cooled, sterilized, and exposed to the fungus. Milled wood (with and without extractives) as control specimens were poured into Pyrex tube glasses, oven dried, cooled, weighed, sterilized and also exposed to the fungal attacks. At the end of experiment, mycelium was removed from surfaces of exposed wood samples and wood blocks were oven dried, cooled, and weighed. Results showed that weight losses of wood species except Lime significantly decreased. Other results indicated that Alder and Lime absorbed solvents more than Beech and Maple. However, Mulberry extractive significantly was inserted to wood samples less than other wood extractives.

In regarding to the vast areas of saline habitats and the shortage of forage in Golestan province, this research was conducted on the effects of protection on vegetation and soil surface. The area was protected from grazing for 15 years. Two key area were selected within and outside the excluded area and three transects of 100m were selected on each key area and 10 random plots of 4-m2 were sampled systematically. Production, canopy coverage and density of different species were measured using quadrates. To assess the soil characteristics, two profiles were dug along each transect, which one of them was under story and the other was outside of canopy coverage of shrubs. Production was measured by double sampling. Statistical results indicated that canopy cover in protected areas was significantly higher than unprotected areas. Shrub and perennial forbs have the highest plant composition in unprotected and protected areas respectively. The density of dominant shrub (Halocnemum strobilaceum) was significantly decreased inside the excluded area. Production was significantly increased in protected area. Shrub and annual grasses have the highest production in unprotected and protected areas respectively. Protection was significantly reduced the electric conductivity but increased soil nitrogen. PH and organic matter did not changed by protection.