IRANIAN JOURNAL OF AGRICULTURAL SCIENCES (JOURNAL OF AGRICULTURE)
Year:2006 | Volume:37 | Issue:2|Papers Count:21

Conservation tillage is said to be the best solution for control of soil erosion. A new idea for precision planting in conservation tillage is the use of punch planters which can plant through residue covers, slopes and in gravelly soils. These planters not only provide precision depth and space between plants, but also set a suitable bed necessary for good seed emergence.Furthermore, these planters eliminate thinning costs and reduce amount of seed needed per hectare. In the present research a dibble punch planter with pneumatic seed metering device was designed and fabricated. These planters punch holes at equal distances and depths in soil and then place a single seed in each hole and cover it. The laboratory and field tests were conducted to find the effects of forward speed and soil surface conditions on: multiple indexes, quality of feed index, miss index, precision, percent of holes with seed in them and planting depth means.The laboratory test was conducted in a completely randomized design with six levels of speed in eight replications. The field test was conducted in a 3×5 factorial completely randomized block design with five forward speed levels (1.7, 2.8, 4, 5.5 and 7 km/h) and three soil surface conditions: (tilled, wheat residue covered and notill) with five replications in a gravelly loam soil. According to the results of these experiments the increase of forward speeds resulted in increasing of multiple index, decreasing of quality of feed index, increase of precision, increase of miss index and decreasing the percent of holes with seed in them and somewhat reducing the planting depth means. The experiments indicated that soil surface conditions was not any effect on all parameters and this planter can plant in three soil surface conditions well. Furthermore 5.5 km/h speeds was recommended as the best forward speed at the three soil surface conditions.

Optimizing the In vitro culture condition for grapevine explants is considered as the first step to apply biotechnology in breeding and producing pathogene free plants. This research was carried out during years 2002 and 2003 on two popular Iranian grape cultivars, 'Bidaneh Sefid' and 'Shahroodi' at the Department of Horticulture, Faculty of Agriculture, Tehran University. A first experiment was conducted to evaluate the effects of explant collection date (during summer), medium kind (MS, 1.2MS,WPM) and kind of explants on number of shoots, length of shoot, leaf quality and size of callus during the estabishment stage. Explants from basal and middle parts of shoots collected early September and cultured on MS medium produced the most desirable results. In proliferation stage, the effects of BA and IBA at different concentrations in MS medium were investigated on number, length and quality of produced shoots. Eventually, IBA at 1 mgL-1 induced best results for proliferation of the two cvs. 'Bidane Sefid', and 'Shahroodi'. To determine the appropriate Auxin concentration at rooting stage, the explants were cultured in 1.2 MS medium with different IBA concentrations. Rooting was best in media without and with 0.05 mgL-1 IBA. Acclimatization step was carried out by transferring plantlets to greenhouse, using a growing medium of perlite and peat in proporation of 1:1. Plants were fertigated using a diluted nutrient of MS medium. Surviving plants were evaluated after one month, in which it was found that 85% of 'Bidaneh Sefid' and 80% of 'Shahroodi' had adapted to greenhouse conditions. Finally, on the basis of these results, a second experiment was conducted to study the meristem culture in MS medium with different BA and IBA concentrations. The best result was obtained with 0.5 mgL-1 BA in cv. 'Bidane Sefid' and 1mg.L in cv. 'Shahroodi'.

Invert syrup is widely used in confectionary industry such as biscuit production. The syrup is produced by mixes of different types of organic (e. g. citric and tartaric) and inorganic acids (e.g. HCI and H3PO4).In this study, invert syrup was produced by mixes of three different acids (chloridric, citric and tartaric). These syrups were later applied in the production of three kinds of biscuits (Tabasom, Ghand-E-Asal, and Shekarin). Finally, the effect of these syrups on the shelf life of biscuits was investigated. Four variables of moisture content (%), pH, peroxide value (meq/kg) and acidity (%) were determined. The analysis of variance (ANOVA) indicated that the kind of acid affects shelflife of products by having a substantial effect on decreasing moisture, peroxide and acidity and therefore, increasing the shelflife of the products. Results also indicated that biscuits produced by HCI mix had the better quality characteristics than the other two acids (citric and tartaric) applied.

This investigation was aimed at developing an equation for suspended sediment yield prediction in Uromia Lake basin using regional analysis. Twenty-seven subbasins were selected based on data availability, data quality of sediment concentration and flow, and spatial distribution. From among the 27 subbasins seventeen and ten were respectively used to develop the regression equation and to validate the model. Twenty-two characteristics (explanatory variables) were chosen and assessed for each subbasin. Independent combinations of explanatory variables, arranged according to their correlations, were drawn to develop regression equations. The most suitable equation was selected from among the generated equations with respect to determination coefficient, and standard error of the estimate. Variables of product of mean annual discharge and subbasin area, sum of areas facing north and west (in percent), and the areas covered with Quaternary sediments as well as lithologies susceptible to erosion (included in the equation) explain over 94 percent of variation in suspended sediment yield. The final equation bears a 25 percent mean absolute error and its efficiency coefficient is worked out to be 0.99.

A factorial experiment was conducted to investigate the response of broiler breeder hens to various levels of rapeseed meal and enzyme supplementation. Different levels of rapeseed meal (0%, 10%, 20% and 30%) at 2 enzyme levels (0 and 17 gr/ton) were fed to 47 week-old broiler breeder hens. Birds were randomly allocated to pens of 8 experimental treatments of 3 replicates. Birds were given free access to water but were restricted in diets according to broiler breeder guide recommendations. Egg production, weight, mass, as well as number of hatching eggs, hatchability of total eggs set, infertile eggs, concentration of thyroid hormones (T3 and T4) and feed intake rates were assessed as breeder characteristics. None of the rapeseed meal percentages had any significant effect on egg production, weight, egg mass as well as on hatching eggs, except the 30% of rapeseed meal (p<0.05).The effect of different levels of rapeseed meal on hatchability of total eggs set, hatchability of fertile eggs set, and infertile eggs was not significant (P>0.05). Thyroid hormone concentrations (T3 and T4) were significantly lower for 20% and 30% of rapeseed meal treatments (p<0.05). No significant reaction was observed on the part of the enzyme with the exception of positive reflection on egg weight and egg mass (P>0.05). Interaction of rapeseed meal with enzyme was not significant for any of the traits (P>0.05). Results finally indicate that we can apply up to 20% rapeseed meal in broiler breeder diets without any significant undesirable effects.

Medicinal pumpkin (Cucurbita pepo convar. pepo var. styriaca) is an annual plant belonging to the family of Cucurbitaceae. It bears a sprawling prickly stem, about 300-500 cm long.Tropical and sub-tropical regions of America are reported as origin of medicinal pumpkin. The seeds contain fatty oil, b -sitostrol and E-vitamin as active substances that are used to cure prostatic hypertrophy as well as urinary tract irritation. In this study that was carried out in College of Agriculture at Tarbiat Modarres University, the effect of five pruning treatments at different developmental stages (no pruning, 3-5 nodes, 6-8 nodes, after appearance of the first flower and after 8-10 flowers appearance) on the number and weight of fruit, some characteristics of seed fatty oil and its fatty acids were studied. The results showed that pruning at 6-8 node stage significantly effected the number of fruits, fresh and dry weight of seed in the fruit as well as in the plot. The control (no pruning) and 6-8 node stage of pruning treatment had a significant effect on the number of seeds per fruit, fresh and dry seed weight per fruit, and per plot. The greatest 1000 seed weight was obtained from control. Pruning was demonstrated to have no effect on fatty oil content but fatty acids content was affected by pruning operations.

Biological characteristics and larval feeding rate of hoverfly Scaeva albomaculata (Macqaurt) on Myzus persicae (Sulzer) were determined at laboratory conditions. The experiments were carried out in growth chamber at 25±2oC, RH 55-65% and a photoperiodism of 16:8 (L:D) h. The incubation period, larval period, pupal period and developmental time (s. albomaculata) were determined as 4.67, 11.33, 7.83 and 24.83 days, respectively. Adult longevity considerably increased (35.60 days) when fed with honey solution but in the non-feeding situation, it lasted for only 3.5 days. The results indicated that each female produced 95.50 eggs, on average, during its life time, 85.97% of which hatched to first instar larvae. There were significant differences (P<0.1) observed in daily and total feeding rate among the first, second and third instar larvae. Each larva of S. albomaculata fed on 521.10 aphids during larval period and revealed a high potential for feeding on M. persicae. The third instar larvae played an important role in feeding rate, such that 70.30% of total larval feeding was due to this instar level. Per capita daily feeding rate of the first, second and third instar larvae amounted to 8.79, 38.06 and 76.31, respectively. Because of considerable reproduction as well as feeding rate, hoverfly S. albomaculata can be employed in biological control, and in integrated management programs of different aphid species, specially M. persicae.

An experiment was conducted to determine the bioavailability of calcium in mineral oyster shell as dietary complement for laying hens. Eighty-one hens of commercial layer strain (Hy-line W-36) were allocated to 9 dietary treatments with three replicates of three hens per replicate in a completely randomized design. Treatment one as the basal diet, without any supplemental calcium, contained 0.37 % calcium. Diet 2 to 5 contained 1, 2, 3, or 4 % calcium from calcium carbonate as a standard source. Diet 6 to 9 contained 1, 2, 3, or 4 % calcium from the mineral oyster shell as the test source. All diets were isoenergetic, isonitrogenous and equal in amino acid content. Data were subjected to ANOVA procedures appropriate for completely randomized designs. Difference between individual treatments means were assessed using Duncan multiple range tests. The slope ratio assay was used to determine bioavailability of calcium in mineral oyster shell. GLM procedure of SAS was employed to obtain parameter estimates for calculation of relative bioavailability. Hens fed diets based on mineral oyster shell and calcium carbonate, exhibited very similar performances. However, hens fed 0.37% calcium did not perform as well as the others and had lower egg productions. Effect of calcium level on egg specific gravity, eggshell thickness and shell weight was significant (P<0.01). In most cases, no significant differences were observed between slopes of test and standard calcium source regression lines. In the case of egg production and egg shell thickness, slopes of test and standard lines were significantly different (P<0.05). In these cases relative bioavailabilities were 138 and 120% respectively. It is concluded that mineral oyster shell is a good calcium source comparable in bioavailability to calcium carbonate for laying hens.

The effect of six tillage systems consisting of 3 primary (moldboard, disk and chisel plows) and 2 secondary (disk harrow and field cultivator (twice)) tillage tools on corn production were studied in a factorial of two factors based on a completely randomized block design of six treatments and four replications. The experiments were conducted on Agricultural Faculty of Urmia University farms in 2002. The studied parameters were: tractor fuel energy consumption; soil penetration energy requirement, and yielded corn energy content. The results showed that the lowest and highest fuel energy consumption belonged to chisel plow+ disk harrow (962.9 Mj/ha) and disk plow (twice) field cultivator (1871.5 Mj/ha) respectively. The fuel energy consumption IN chisel plow and disk harrow treatments were found to be 30.1% and 23.3% lower than those for disk plow and field cultivator (twice) respectively. There were no significant differences observed among treatments for either corn grain or forage yields .For all treatments the calculated energy output for corn grain was between 36516.8 and 67638.3 Mj/ha, and for corn forage between 154580.1 and 212657.8 Mj/ha. For corn energy ratio (yields' energy/ consumed fuel energy) the highest were obtained from chisel + disk harrow treatment for corn grain plus forage, the lowest from moldboard plow + 2 times field cultivator treatment for corn grain, and disk plow + 2 times field cultivator for corn forage. The highest soil needed penetration energies for 5 to 40 cm depths belonged to the plots of disk plow + disk harrow, and the lowest to moldboard and chisel plow with disk harrow treatments. The results finally indicated that chisel plow + disk harrow (treatment A) with lowest fuel energy consumption, highest yielded energy and lowest needed soil penetration energy, was the most suitable tillage system.

This study was carried out in 2003to investigate the effects of different water regimes (40, 60, 80, 100 and 120 percent of water requirement) and different amounts of nitrogen (60, 120 and 180 kg/ha) as well as their interaction on quantity and quality of tomato (variety Early Urbana). The experiment was performed on the research farm of agriculture faculty of Tehran University (semi-arid area) on a clay-loam soil, using a split plot design with three replications (irrigation treatments as main plots and different amounts of nitrogen as subplots). The results obtained from statistical analysis indicated that the different treatments of irrigation and nitrogen as well as their interactions have significant effect on tomato quantity traits including total yield, marketable yield, number of fruit per plant, average fruit weight and Water Use Efficiency (WUE). The maximum marketable yield and WUE were obtained at 100% water requirement, along with 120 kg/ha nitrogen. Also, the different treatments of irrigation and nitrogen as well as their interactions exert significant effects on tomato quality characteristics including early ripening, fruit dry matter, total soluble solids, titrable acidity pH, of fruit, vitamin-C, fruit firmness and fruit N-NO3. Finally, by considering our conditions of the test place and tomato variety, it is recommended to use water requirement of 80%, along with 120 kgN/ha for optimization of crop's quantity and quality characteristics.

The present study was conducted to determine some feedstuffs nutritive values through different methods and to make a comparison between the methods. Six canulated steers (Holstein and Sistani) were taken into experiment in a completely randomized design of two observations per each replication. The amount of gas production at 0, 2, 4, 6, 8, 12, 24, 48, 72 and 96 hours and feed degradation through nylon bag method at 0 , 4 , 8 , 16 , 24 , 48 , 72 and 96 hours were measured. The feedstuffs used included: alfalfa hay, wheat straw, corn silage, concentrate and cotton seed, fed at the maintenance level. Dry matter degradabilityat 96 hours for alfalfa hay, wheat straw and corn silage were 71.52, 51.02 and 77.89, and at 48 hours for concentrate and cotton seed were 80.59, and 53.51 percent, respectively. Dry matter effective degradability for the above feedstuffs at the maintenance level was 64.40, 36.70, 66.43, 76.03 and 48.16%, respectively. Dry matter degradability for these respective feedstuffs at 24 hours was 66.93, 33.57, 68.24, 79.83 and 48.71. The amount of gas production at 96 hour of incubation for alfalfa hay, wheat straw and corn silage were 51 , 45 and 75.5 milliliters , respectively, and for concentrate and cotton seed at 48 hour of incubation were 81 and 58.5 milliliters. Correlation coefficient between dry matter degradation and gas production for these feedstuffs were 0.99, 0.99, 0.99, 0.96 and 0.99 respectively and correlation coefficient between crude protein degradation and the amount of gas production were respectively recorded as 0.97, 0.99, 0.99, 0.99 and 0.98. Due to the high correlation coefficient existing between dry matter degradation, crude protein degradation, ADF and NDF degradation, and gas production, regression equations between these parameters and gas production were assessed for an estimation of the amount of these parameters from the amount of gas production without a need for tedious digestion experiments. As an example regression equation between alfalfa dry matter degradation and its gas production was: Y = 35.724+ 0.714x. In line with 51 milliters of gas production for alfalfa at 96 hour, this equation estimated 72.14% of degradation for alfalfa dry matter during this time, which in comparison with the 71.52% from digestion experiments, there is not any significant difference observed between the two recordings.

In order to study the effect of NaCl salinity stress on the growth and ion content in five olive cultivars, an experiment was conducted in split-plot based on CRD with three replications. The main factor consisted of four levels of NaCl (0, 25, 50 and 100 mM NaCl) while subfactors were five olive cultivars (Dezfuli, Konservalia, Fishomi, Zard, Manzanila). Uniform, 1-year-old plants were planted in 20L pots containing sand-perlite mixture (1:1) and were irrigated using half-strength Coic solution. Salinity treatments were conducted for duration of five months.Results indicated that growth indices were entirely decreased during stress condition and NaCl salinity. Generally reduced plant growth occurs especially in the above ground parts of plants.The K+, Ca2+, Mg2+ cations decreased due to NaCl salinity stress, the decrease in roots being more than that in other parts of the plant. Salinity exerted no significant effect on N and P uptake. The concentration of Na+ and Cl- (DW%) in roots was higher than that in other parts of the plants (shoots and leaves) and increased by increasing salinity. Large genotypic differences were detected on Na+ transport to above ground parts (shoots and leaves). Among the five olive cultivars, Dezfuli and Conservalia exhibit a higher tolerance while Manzanila shows a lower 'tolerance to NaCl stress.

In order to evaluate the grazing capacity as well as to implement an integrated management of rangelands, it is necessary to be aware of forage quality. The most important factor influencing forage quality is the plant growth stage, which presents the most suitable time for animal grazing. In this research, samples were taken (using randomized- systematic design) from three grasses and from two forbs, namely Agropyron tauri, Dactylis glomerata, Bromus tomentellus, Ferula ovina, and Coronilla varia. Samples were collected at three phonological stages of vegetative growth, full flowering, and seed ripening from summer ranges in central Alborz (Vardavard and Gachsar). Plant samples were dried, milled, and chemically analyzed for important qualitative factors such as: DM, NDF, ADF, CP, ME, DDM, DMI, WSC, RFV.Except for DM, there were significant differences (p<0.01) observed among different species as well as among different phenological stages. Also, interaction effects of plant species and growth stages were observed to be significant for these factors. Almost in all species, the amount of CP, DDM and ME decreased with progressing growth stages, while ADF and NDF contents increased. In general, crown vetch (Coronilla varia) had the highest forage quality based on the assessed factors (RFV=257.9) and in this respect, Agropyron tauri possessed the lowest (RFV=92.1). F.ovina, D.glomerata and B.tomentellus respectively had a greater nutritive value after C.varia. Vegetative growth (first phenological stage), considering all nutritive factors (except WSC), benefited from higher values in comparison with the other stages. Considering low energy differences between first and second phenological stages and also because of higher production, and pasture availability, the second stage (flowering) was determined as the most suitable period for animal grazing (in the frame work of grazing systems).

The current study evaluated the formulation of broiler diets containing cottonseed meal (CSM) on a total amino acid versus a digestible amino acid basis with two different digestible lysine requirements. Male broiler chicks were allotted to 20 treatments with four replicates of six male chicks per replicate in a completely randomized block design in a factorial arrangement with three factors (2 levels of digestible lysine requirement x 2 amino acid formulation basis x 5 levels of cottonseed meal). The first of the twenty treatments was the com-SBM control diet based on digestible lysine requirement for maximum body weight gain. Diets I to 5 contained 0, 5, 10, 15 or 20% CSM, respectively and was formulated to contain levels of total AA equivalent to those in the first treatment. Diets 6 to 10 contained the same levels of CSM as diets I to 5 but were formulated to be equal in digestible AA content to the first treatment.Treatments II to 20 were the same as treatments I to 10 but on the basis of digestible lysine requirement for maximum feed efficiency. Control diet met an ideal amino acid ratio recommended by Illinois 2000 for all other indispensable amino acids for chicks 0 to 21-d old as determined for the levels of 1.075 and 1.179% digestible lysine. Feed and water were supplied ad libitum and uniform light was provided 24h daily. Diets were formulated based on analyzed values. Digestible amino acids were calculated using digestibility coefficients of Rhone-Poulenc (1993) and by assuming 100% digestibility of crystalline amino acids. Results indicated that Dietary inclusion of 10 to 20% CSM on a total AA and weight gain lysine requirement basis depressed chick weight gain and feed efficiency (P<0.01) in comparison to the com-SBM control diet. However when the diets were formulated according to the requirement for maximum feed efficiency, dietary inclusion of 20% CSM on a total AA basis depressed chick weight gain and feed efficiency in comparison to the com-SBM control diet (P<0.01).In both cases, formulating diets containing CSM on a digestible AA basis improved chick performance as compared to that achieved from formulation on a total AA basis (P<0.01).No significant effects of cottonseed meal level, digestible lysine requirement and amino acid formulation basis were observed on the average daily feed intake. Dietary formulation on the basis of lysine requirement for maximum feed efficiency vs the maximum weight gain had no effect on average body weight gain and feed efficiency, but numerically resulted in 1.1% improvement in feed efficiency. No significant interaction was observed between cottonseed level and amino acid formulation basis on chick performance.

Two experiments were conducted to determine the nutritive value of commercially processed cottonseed meals (CSMS) in IRAN. In exp.l, CSMS were compared for chemical composition, and then were determined for nutrients digestibility and total digestible nutrient (TDN) by in vivo technique (total fecal collection method (TFCM) and mark in method (MM)) by taking into the experiment a total of four Afshari breed sheep. In exp.2, dry matter (DM) organic matter (OM) and crude protein (CP) degradability of CSMS were assessed by in situ technique for 2, 4, 6, 12, 24, 47 and 72 h in three ruminally canulated wether sheep. In order to determine the disappearance rates in 0 h, samples were washed using cold water. Sheep were fed a total mixed ration containing 70% alfalfa and 30% barley based concentrate.DM and CP were corrected for the particles loss from bags. A completely randomized design was used to compare parameters. In exp.1, CP and cell wall (NDF) in CSMS were 25.47 to 31 and 26 to 34 percent respectively. Chemical compositions of CSMS other than NDF, were lower than tabular values of National Research Council in TFCM, the differences between means of digestible CP, digestible crude fiber and TDN being significant(P<0.05). In MM, digestible CP and TDN were significant (P<0.05). There was a high correlation observed between the two methods.Differences between means of DM and CP degradability as well as CP degradability, corrected for the particle loss from bags, were significant (P<0.05).CSMS widely varied in their ruminal availability of CP and DM. This study provides an estimation of kinetics of ruminal degradation of cottonseed meals for use in dynamic models of protein and carbohydrate digestion.

An experiment was conducted to investigate the effect of several doses of vitamin E (0, 4, 8 and 12 mg/mL of semen diluent) on the prolongation of the storage time of Fars native chicken sperm at laboratory (19-24oC) and refrigerator (4-5oC) temperatures conditions. Semen characteristics (percentage of live sperm, sperm motility and pH) were determined at 6 and 24 h after storage. Vitamin E did not significantly affect the percentage of live sperm, sperm motility, pH of diluted semen, and percent hatchability of the fertile eggs (P>0.05). Addition of vitamin E to diluents significantly (P<0.05) increased the percentage of fertile eggs obtained from diluted semen stored at 4-5oC and 19-24oC for 24 h as compared with the control group (with no addition of vitamin E). The highest percentage of fertile eggs was obtained with the dose of 8 mg/mL, for semen stored at 4-5oC for 24 h. It is concluded that for storing semen at 4-5oC for 6 h, addition of 8 mg vitamin E/mL Sexton diluent, would result in higher percentage of fertile eggs. Addition of 4 or 8 mg vitamin E/mL, would increase egg fertility when semen stored at 4- 5oC or 19-24oC for 24 h. Addition of 8 mg vitamin E/mL, increased the overall hatchability when semen was stored at 4-5oC and 19-24oC for 24 h.

Crust formation leads to development of a dense hard layer on soil surface which effectively retards seed germination and water intake. Various remedies have been proposed to overcome this difficulty. The purpose of this study was to examine the effects of polyacrylamide (PAM), pumice and straw, applied as amendments, on some characteristics of soil crust (0-10 mm) and water infiltration into soil under sprinkler and surface irrigation simulated in soil columns at laboratory. The columns were prepared by evenly packing (Db=1.4 gr/cm3) of the soil (Coars- loamy, mixed (calcareous) mesic, fluventic) in PVC tubes of 15 and 25 cm long and 15 cm diameter. Pumice at the rates of %1 and %3 and wheat straw equivalent to 2.1 and 5 tons/ha were well mixed with 0-5cm layer of soil in each column. PAM was dissolved (50 and 100 mg/lit) in tap water of EC=0.5 ds/m and SAR=2.2. Soil columns were watered either by a rainfall simulator or by continuous flooding of soil surface by application of a 2 cm head of water. Infiltration was measured during the experiment until steady state intake was realized, then the soil surface allowed to eventually dry and to crust. Bulk densities (Db) of 0-10 mm layer and penetration resistance were measured by clod and cone penetrometer, respectively. All amendments, irrespective of application rates, significantly (P<0.01) reduced Db of 0-10mm surface layer and increased its porosity. Db's averaged over amendment type and application rates were 1.36, 1.67 for sprinkling and flooding as compared to 1.82 for untreated soil, implying that amendments acted more effectively in reducing surface densification under sprinkling rather than flooding. Penetration resistance (Pr), measured 2, 4 and 6 days after irrigation behaved similar to Db. Pumice %1 resulted in lowest resistance of 3.25 kPa as compared to 4.51 kPa in untreated soil, which indicates a significant differences at %1 level.Regarding water retention behavior, only pumice %3 significantly increased moisture content at 10 kPa suctions as compared to untreated soil (0.22 versus 0.19 g/g, respectivity).

The objectives in this study were to measure urea nitrogen levels in blood serum (SUN) and milk (MUN) of lactating cows and to fine the relationship between their concentrations and pregnancy rates. Blood and milk samples were collected on the day of insemination from 80 lactating cows of a dairy farm in a period of four weeks. Cows were detected as to be either pregnant or non pregnant 45 days after insemination. Cows were also grouped by milk production (8000lit and >8000lit), lactation number (first, second and third or further) as well as interval between calving to sampling (60, 60-120 and> 120 days) and within pregnant and non- pregnants. Mean SUN and MUN concentrations in non-pregnant cows were significantly higher than in pregnant cows (p<0.05). A highly significant correlation (r=0.79) was observed between the levels of MUN and SUN. Neither the effect of milk production, lactation number and sampling day relative to calving (DIM), nor their interactions with pregnancy status were significant. Concentrations of SUN and MUN greater than the mean (15 and 13 mg/dl respectively) were associated with a decreasing (p<0.05) pregnancy rate. Serum creatinine levels did not indicate any probable renal disease. Based on this study, high levels of MUN and SUN can be detrimental to pregnancy in lactating cattle; MUN can be employed for monitoring urea nitrogen in dairy cows.

The impact of El Nino - Southern Oscillation (ENSO) phenomenon on stream flow of five rivers (Kor, Roodbal, Gare-Aghaj, Mond, and Sheshpir) in Fars province (Iran) during the period 1957-2000was investigated. The warm (El Nino), cold (LaNina),and neutral(without El Nino and La Nina) phases of ENSO were defined and time series of monthly streamflow in each phase were constructed (these time series are generally known as ENSO-streamflow composites). For every of the constructed composites the amounts of 33, 50 and 67 percentiles were determined. The ratio of these percentiles in El Nino and La Nina phases to the corresponding values during neutral periods was calculated and used as a criterion for the evaluation of the impact of warm and cold phases of ENSO on streamflow. The results indicated that, for most of the year, the occurrence of El Nino causes a considerable increase in the considered river flow. For instance, as compared to neutral period, the spring and summer discharges of Gare-Aghaj river increase by about 120%during warm ENSO phase. For the other sites the increase rate varied from about 10% to 60%. The occurrence of La Nina generally causes the increase and decrease in streamflow in winter and the rest of the year, respectively.The most considerable decrease (about 50%) was observed in Gare-Aghaj and Roodbal in spring and summer. The intensity of hydrological drought during El Nino and La Nina (except for winter) periods was found to be lower and higher than that during the neutral periods, respectively. In contrast, the probability of hydrological wet during El Nino and La Nina periods was observed to be more, and less than that during the neutral periods, respectively.

This research was conducted in Kamal-Shahr Research Station during 1381-82to evaluate the percentage of dicogamy, self-compatibility, and to select the best pollinizer for commercial varieties of hazelnut. Four trees of different varieties were selected for which some traits such as flower characteristics, type of flowering, pollination and fruit set were determined during the growing season. Pollination and fruit setting indicated that most varieties were cross pollinate, and some self pollen pollinated, and catking, so the rate of fruit set in isolated flowers is significantly different than in open pollinated ones. Fruit set in isolated flower as against open pollinated in varieties of Gerge, Gerdoii, Rasmi, Pashmineh, Fertil du cutard, Round du pimon, Negret, Paizehand Shastak-2 was 5.8 & 14.33; 12.5 & 16.5; 7 & 9.25; 7.5 & 16.75; 16.25 & 18.75; 12.5 & 16; 8 & 16.25; 5.75 & 14.33, and 5.83 & 18.33 respectively. The results of pollen compatibility showed that the abilities of Gerdooii and Gerge of varieties as pollen donor and receptor were different. It was found that variety Gerdooii is an excellent pollinizer for varities: Fertile, Rasmi, Shastak-2, Negret and Gerdooii respectively. But variety Gerge is an excellent pollinizer for varieties: Gerdooii, Fertile, Rasmi, Negret, Shastak-2 and Gerge. Finally, among studied varieties in this experiment, it was found that Fertile du cutard has the highest fruit set (13.95%) while the least fruit set was recorded for Gerge (10.29%).