نشریه علوم آب و خاک (علوم و فنون کشاورزی و منابع طبیعی)
سال ششم شماره 2 (پیاپی 20، تابستان 1381)

Agricultural insurance is one of the appropriate ways to overcome the risk in agricultural production and to increase farmers’ income security. In this study, the influence of wheat insurance, as personal-free insurance, and sugar beet insurance, as group-forcible insurance, on farmers’ risk attitudes in Fars Province were investigated as a case study. Data were collected using stratified multi-stage cluster sampling method and interviews in the years 1375-1376. The sample included wheat and sugar beet farmers in three different climates including Mediterranean, warm sub-desert and cold mountainous in Fars Province. Results of estimating risk aversion coefficients of farmers, using Safety First Rule (SFR), showed that sugar beet forcible insurance along with giving inputs, mechanization services, lookout of farms by sugar plants led to continuous insurance purchase by farmers in consecutive years. Therefore, sugar beet farmers tended to welcome insurance and the effect of insurance on their risk aversion coefficients was positive. However, discontinuity of insurance purchase by wheat farmers in consecutive years and farmers’ lack of confidence in insurace system caused the influence of insurance on wheat farmers’ risk aversion coefficient to be insignificant. Thus, sugar beet insurance type is closer than wheat insurance type to one of the main aims of agricultural insurance system, which is increasing farmers’ tendency to take risks.

This manuscript shows the findings of a research that investigated the effects of trainings on the members and the employees of the poultry cooperatives in Tehran Province on the performance of these cooperatives. To analyze the data, 2, correlation coefficient, one way-analysis of variance, and Duncan Test were used. The results of the study showed a positive and statistically significant relationship between training of members and performance of cooperatives. The more the trainings were related to type of occupation or responsibility, the larger were the effects on the cooperative performance. Cooperatives with more specialized top managers, offered more training to their members. Compared to cooperatives with more training, the members had less participation in increasing their investment.

Experiments were conducted to evaluate the effects of heat and cold treatments on the disinfestation of dry figs from Estahban. Tow types of packing bags (with or without holes), two storage conditions including one at 23oC and one cold storage condition (10oC and 2oC), 9 heat and cold treatment durations (3, 4, 5, 6, 7, 10, 15, 20 and 25 hrs) and 13 temperature treatments [23, 45, 55, 60, 65, 70, 75, 45+(-25), 50+(-25) and 60+(-25) oC] were used in these experiments. The results showed that Indian meal moth, Plodia interpunctella, which is a major pest in dry fig storage, can be satistfactorily controlled by packing figs in plastic bags with a thickness of 0.24 mm after suitable temperature treatment. Cold storage at 2oC significantly controlled all developmental stages of moths at storage. Temperature treatments at 60oC for 7hrs or more, at 65oC for 6hrs or more, and at -25oC for 15hrs or more were found to be capable of controling pest most satisfactorily without changing fruit external quality.

The effect of different media including the growth regulators on somatic embryogenesis from Mexican lime was studied. The average embryo formation after 60 days from unfertilized ovules in different media was evaluated at 0 to 33.75%. The most effective hormone to stimulate embryogenesis was GA3 at 0.01 and 0.1 mg/l concentrations. Malt extract (ME) at 300 mg/l increased embryo formation, whereas at 1000 mg/l, it inhibited embryogenesis but produced embryogenic callus. Banzyl adenine (BA) at 0.1 and 0.01 mg/l concentrations had significant effects on embryogenesis, while embryo formation was inhibited at high concentrations. Embryo development in different media was also studied. The index of mean root length to mean stem length in the MT3 medium supplemented with 0.1 mg/l of GA3 was observed to be 1.22±0.22, which was regarded a suitable medium for embryo formation, embryo development and plantlet regeneration.

Phosphorus (P) and iron (Fe) are essential nutrients for plants. Iron availability is low in calcareous soils of Iran due to the excessive amounts of CaCO3 and high pH. Overfertilization of P fertilizers may also decrease Fe availability. The objective of this study was to evaluate the effect of P and Fe on the growth and chemical composition of corn (Zea mays L.) under greenhouse conditions. Treatments consisted of a factorial arrangement of P rates (0, 40, 80, 120 and 160 mg kg-1 as KH2PO4) and Fe rates (0, 2.5, 5 and 10 mg kg-1 as Fe EDDHA) in a completely randomized design with four replications. Plants were grown for 8 weeks in a loamy soil, calssified as Chitgar series (fine-loamy, carbonatic, thermic, Typic Calcixerepts). Results showd that P application up to 80 mg kg-1 increased corn top dry matter. Corn P concentration and total uptake increased by P application but decreased by Fe application. Application of Fe up to 5 mg kg-1 increased dry matter but decreased it at higher rates. Concentration and total uptake of Fe increased by Fe application but decreased by P application. Zinc and copper concentrations decresed significantly when P was added. Manganese concentration increased at 40 mg P kg-1 but decreased at higher rates. Iron application decreased zinc and manganese concentrations but had no effect on copper.

In order to investigate the androgenic response of chickpea cultivars, two Iranian Chickpea cultivars, Pirooz and Karaj 12-60-31, were used in this study. After 7 to 10 days of cold pretreatment of flower buds, anther containing uninucleate stage of microspores were placed aseptically on MS medium supplemented with various combinations of growth regulators of 2,4-D (1,2 and 3 mg/l) and kinetin (0.1, 0.2 and 0.5 mg/l). Callus regeneration achieved using MS and modified Blayd’s media with various hormones and different sucrose concentrations. The results indicated that the callus initiation was significantly affected by 2,4-D and kinetin concentrations, and that increasing these hormones reduced callus induction. The best response obtained on media with the lowest concentration levels of 2,4-D and kinetin (1 and 0.2 mg/l, respectively). A highly significant genotypic effect and a genotype  2,4-D interaction were detected, which proved that Pirooz response was the best. Callus differentiation and organogensis occurred in MS medium supplmented with NAA, BA and 3% sucrose. Mature embryos also obtained in modified Blayd’s plus 0.5 mg/l kinetin and 10% sucrose. Cytological studies revealed the presence of haploid cells with chromosome variation in the anther derived callus. Therefore, optimizing the hormone levels of different basal media with a particular sucrose cocentration may improve haploid regeneration in chickpea. It seems a further study should be carried out to characterize calli from induction to regeneration and to determine the effect of cold pretreatment, the results of which could be used to improve anther culture response of chickpea.

The variation and path coefficient analysis of bread-making quality traits have been studied for 145 genotypes of breeding lines, cultivars and landrace varieties of wheat (Triticum aestivum L.). Bread-making quality traits of genotypes was evaluated indirectly by protein percentage, SDS and Zeleny sedimentation tests, hardness index, test weight, bread volume, grain moisture, and water absorption percentage. Hardness index, Zeleny and SDS sedimentation tests had the highest coefficient of variability (13.51%, 11.83% and 11.03%, respectively). Factor analysis for the genotypes, based on qualitative traits revealed two factors, which explain 98.23% of total variation and were named grain protein index and bread volume factors. The result of correlation analysis indicated positive and significant relationship between protein percentage, SDS sedimentation test and other bread-making quality traits. On the first and second steps of stepwise regression analysis, protein percentage was the most effective trait in explaining different qualitative trait variations. Path analysis also showed the direct and significant effects of protein percentage, Zeleny sedimentation volume, grain moisture and water absorption percentage, and bread volume on SDS sedimentation test. According to cluster analysis based on qualitative traits, the cultivars and landrace varieties, from the view poit of protein quality and quantity, had the highest potential among other groups (generally breading lines).

To estimate the relationship between honey yield and some of the morphological characters, five queen-daughters from each of 30 queen-mothers were studied. The queen-mothers were selected randomly from the apiary of Research Center of Animal Science and Natural Resources in Isfahan Province. Summer honey yield was measured from the difference of honey comb before and after honey extraction while fall honey production was calculated from area of sealed honey combs. Morphological characters were recorded using a stereodissecting microscope fitted with a calibrated micrometer reticule according to Ruttner’s procedures. The mean of honey yield for a year was estimated to be 10.05 kg. Phenotypic correlations between yearly honey production and summer and fall honey productions were estimated to be 0.49 and 0.88, respectively, while the correlation between summer and fall honey yields was low (0.019). There were significant correlations between summer honey yield with cubital-b index, tibia length and forewing width (0.28, 0.27 and 0.25, respectively). Also there were significant correlations between metatarus width with total and fall honey yields (0.22 and 0.23, respectively). Genetic correlations between metatarus length and cubital index with summer honey yield were negative (-0.75 and -0.45, respectively). It may be concluded that due to the high correlation between summer honey production and total honey yield, one could improve yearly honey production by selecting on the basis of summer yield of colonies. Among morphological traits, metatarus length, forewing width and cubital index could be used in the breeding plan in order to increase honey yield.

An experiment was conducted to determine growth and carcass characteristics of male broilers subjected to early feed restriction. Restricted birds were fed equivalent to 1/5*BW0.67 Kcal/day/bird between days 7 and 14. On days 0 to 7 and 14 to 56, all chickens received feed ad-libitum. Diets of feed-restricted birds were supplemented with 15% higher methionin and cystine recommended by NRC (1994) during refeeding in starter and grower periods. No significant differences were observed for liver, breast, heart, carcass and liver fat between early restricted birds and ad-libitum control at 56 days of age. Body weight for restricted broilers were significantly (P<0.05) lower than that of controls in 56 days. However, restricted broilers had significantly lower total-feed to gain ratio than the unrestricted control. Restricted broilers that received diets high in total sulfur amino acids in starter and grower periods had singnificantly lower abdominal fat pad than control birds.

This experiment was carried out to study the effects of Lactic Acid Bacteria (LAB) and urea on chemical composition, nutritive value and rumen fermentation characteristics of whole-crop barley. In a completely randomized design with cross over arrangement, 4 Suffolk male lambs were used. Whole-crop barley was either treated with LAB solution (35% dry matter) at the rate of 2 L/ton herbage fresh weight or urea (55% dry matter) at the rate of 40 Kg/ton dry matter herbage and ensiled for 60 days. Low dry matter silages had lower pH and higher residual water soluble carbohydrates, ammonia-N, lactic acid and ethanol and higher lactate:acetate ratios. LAB resulted in higher lactic acid content and lactate:acetate ratios. DM (P<0.001), OM (P<0.01), NDF (P<0.05), ADF (P<0.01) and total nitrogen (TN) digestibility increased with additives. Mean rumen ammonia-N concentration and pH significantly (P<0.05) increased with urea-treated silages. Rumen propionate concentration was significantly (P<0.01) higher with LAB-treated silages than with urea-treated ones. The results indicated that the addition of LAB at the rate of 2 L/ton fresh weight to whole-crop barley at 35% dry matter enhanced fermentation and nutritive value.

Pectin is used in a number of foods as a gelling agent, thickener, texturizer, emulsifier and stabilizer. Sugar-beet pulp, the residue left from sugar extraction, is a rich source of pectin. It was the purpose of this study to develop a procedure for the extraction of pectin from sugar-beet pulp and to improve the functional properties of this pectin for more potential uses. To extract pectin, pressed beet pulp was dried and powdered. Then, it was extracted under various conditions (pH 1 and 1.5, temperatures of 80oC and 90oC and extraction periods of 1, 2, 3 and 4 hr). The highest yield (22.35%) was obtained at 90oC after 4 hr at pH 1. Chemical composition of the extracted pectin and that of commercial citrus pectin were determined and compared. Also, the beet pulp pectin was used in certain foods and its functional properties were compared with those of the commercial citrus pectin. The effects of ammonium persulfate and high pH levels on the above mentioned properties were investigated. Finally, the effects of the beet pulp pectin and the commercial citrus pectin on the flavor of certain foods were evaluated. The results indicate that the extracted beet pulp pectin can be used in certain foods such as ketchup sauce as a thickener or as an agent increasing the viscosity however, it does not have the ability to form firm gels in food.

In this research, sunflower oil that was extracted and refined at Shiraz Narges Oil Company was packed in four different containers, namely, clear PET (polyethylene terephtalate), yellow PET, yellow HDPE (high density polyethylene), and metal can. Samples were kept at ambient temperature in the shelf exposed to normal light for a period of 1 year. Peroxide values were determined at 45-day intervals and TBA and anisidine values were measured at 0, 6 and 12-month periods. In order to determine the effect of artificial light, some samples in PET and HDPE containers were kept in a wooden box equiped with four (20 w) fluorescent lamps and the peroxide values of the samples were determined. Light transmittance properties of the packaging materials were measured using a spectrophotometer over a wavelength range of 350 nm to 800 nm. The data indicated that the greatest variations in peroxide, TBA and anisidine values were observed in samples in HDPE containers (significantly different at 5% level) kept under normal light and ambient temperature for a period of 1 year. It was also shown that the shelf life of sunflower oil in HDPE container was less than 6 months while for the other packaging materials it was more than one year. Samples exposed to artificial light indicated that the highest peroxide values belonged to samples in clear PET while those in yellow PET proved to have the lowest. Finally, PET container proved to be the most suitable container for sunflower oil followed by metal can. Yellow PET with the lowest transmittance percentage (350-800 nm) and peroxide value (when exposed to 20 w fluorescent lamp) could be substituted for clear PET. HDPE container proved to be unsatisfactory for sunflower oil due to high oxidation rate.

In order to study the effects of different protein feeds on honey bees (Apis mellifera L), experiments were conducted in a completely randomized block design with 15 treatments and 4 replicates. The nutritional effects of different treatments on caged bees were studied through recording half-life time (50% mortality). Pollen substitutes were soybean flour, soybean meal, bread yeast, wheat gluten, soybean flour + soybean meal, soybean flour + bread yeast, soybean flour + wheat gluten, soybean meal + wheat gluten, and wheat gluten + bread yeast. Pollen supplements were wheat gluten + pollen , soybean flour + pollen, soybean meal + pollen, bread yeast + pollen and two controls as pollen and honey. The nutritional effects of different protein sources provided by pollen substitutes and supplements were recorded on the amount of carcass protein and fatbody of honey bee workers in experimental colonies. The wheat gluten supplement and the soybean substitute showed the longest (60.58 days) and the shortest (10.53 days) half-life time of worker bees, respectively. The amount of food consumption in different treatments was not significantly different (P>0.05). The greatest DM of worker bees (dry matter of carcass) was related to soybean (34%) and the least related to yeast supplement (31.54%), which were significantly different (P<0.05). The highest carcass protein belonged to wheat gluten supplement (22.57%) and the lowest was related to yeast supplement (20.01%). The greatest carcass fat was related to soybean supplement (4.75%) and the lowest to wheat gluten supplement (3.84%). Results of the present experiments showed that soybean flour, soybean meal, wheat gluten and bread yeast can be used in pollen supplement and substitute cakes.

In 1998 and 1999, adult population density of pistachio psylla and its sex ratio were determined weekly in two orchards with yellow sticky board traps and limb jarring. Also egg and nymphal population was determined on the leaves. By studying the seasonal population fluctuaions, the efficiencies of the two methods were compared. Meanwhile, using yellow sticky boards, diurnal activity of adults was investigated. Adult pistachio psylla became active during flower and leaf bud opening. Adult capture with both methods showed a high correlation with egg and unwinged nymphal density counts, with at least five peaks (maximum six). Two peaks occurred during spring and densities were much lower in comparison with those of later generations. First adult capture was observed on yellow traps. Yellow traps were found to be a better method than the limb jarring method for the study of seasonal population from adult captures. Sex ratio was equal through out the growing season and during the warmer or cooler months of the year. However, more males were attracted to traps and more females were captured with limb jarring early in the season. Peak activites during day occurred through 9-16 p. m.

Small honeybee (Apis florea) is one of the common species in Iran. Apis florea lives in southern Iran and plays an important role in the polination of plants in this region. In a series of studies during the years 1997-1998, the genetic populations of the Iranian small honeybee and the effects of geographic and climatic conditions on the morphological variation and separation of Iranian small honeybee were investigated. For this purpose, 400 samples of worker bees from 40 colonies from 26 cities in 9 provinces were collected and twelve morphological characters were measured, using Ruttner method (1978). To determine geographical and climatological variables, average values collected by synoptic stations and other meteorological stations of Iran Meteorological Organization were used. The principal components analysis was used in the statistical analysis of the data obtained. The results show that there exist two distinct groups of small honeybee populations in Iran. Southwest of Iran hosts a class of bigger bees forming one distinct group while southeast of Iran hosts smaller bees forming the second group. Latitude has a positive correlation with size of body, wings and legs. Amount of precipitation has a nagative correlation with size of body, wings and legs. Temperature, wind speed. relative humidity, freezing days and other parameters did not show any correlations with size of body. The results from this research proved that the more northern areas with higher altitudes and more precipitation have bigger honeybees. This finding is in accordance with the Bergman law about other animals.

In this study tractive efficiency (TE) of MF285 and U650 tractors during moldboard plowing were evaluated and compared. Field experiments were conducted at the Experimental Station, College of Agriculture, Shiraz University, using a randomized complete block design with a 3*3 factorial. The soil was sandy clay loam with an average moisture content of 18% b.d. from zero to 30 cm depth. Test treatments were combinations of three tractor types or conditions (U650, MF285 liquid ballasted and MF285 with no liquid or weight ballast) and three levels of plowing depth (10-15 cm, 15-20 cm and 20-25 cm). Plowing speed was kept constant at about 4 km/h throughout the experiment. The measured or calculated parameters included: tractor drawbar pull and rolling resistance, drive wheel slip and tractor tractive efficiency. Statistical analysis of the test results showed that the primary difference between the tractor types or conditions was in their wheel slip, such that the average wheel slip of U650 was lowest (12.6%) while that of unballasted MF285 was highest (27%) and was reduced to 17.7% with liquid ballasting. Also, while growth of unballasted MF285 wheel slip with increasing plowing depth was drastically high (11% to 48%), that of U650 was quite moderate (9.7% to 16.5%). Analysis of the calculated values of TE showed that there was no significant changes in the TE of U650 with increasing plowing depth and that with an average of 73.8%, it had a desirable performance. The TE of unballasted MF285 that was over 75% at shallow plowing, dropped to 46% with increasing plowing depth, while water ballasting improved the decreasing trend of TE with plowing depth and raised its minimum value to about 63%. The overall results of this study showed that unballasted MF285 tractors had desirable TE only at shallow plowing and that for medium and deep plowing, U650 or water ballasted MF285 tractors should be used.

To increase mechanized cotton planting in areas with saline irrigation water and crust forming soil in Isfahan Province, assessment of seeders in flatland planting method with or without crust breaking is essential. An experiment was conducted at the Kabootarabad Research Station of Isfahan Research Center to compare the performance parameters of planting equipment in a clay loam soil. Four planting equipment treatments using Bazrsazan and John Deere planters and Nordsten drill along with three crust breaking methods, including rolling cultivator, rolling-type crust breaker and no crust breaking, were laid out in a factorial experiment within a randomized complete block design with three replications. Planters’ performance was evaluated by measuring the number of plants and plant spacings in each treatment, and estimation of the mean and standard deviation, multiples index, miss index, quality of feed index, precision, and hill-dropping index. Although the plant spacings, and not the seed spacings, were measured in this experiment, the indices used in this research showed the planters’ performance to be very satisfactory. The suggested hill-dropping index showed the multiple seeds dropping characteristics of the seeders to be better than those of the multiples index regardless of the crust breaking methods. In the non-crust breaking method, the multiple seeds dropping tendency of Bazrsazan planter brought about a reduction in the mean and standard deviation of plant spacings. Crost breaking caused a reduction in plant spacings for all seeders, especially for the drill whose multiple seeds dropping tendency was negligible. The results indicated that the seed metering systems in Bazrsazan and John Deere planters were volumetric rather than single seed metering devices.

In order to increase ketocarotenoid astaxanthin production by Haematococcus pluvialis, the effects of salinity, phosphate deprivation and eosin on growth and astaxanhin production were examined. The experiments were carried out in the growth chamber at 20oC under sterile conditions. The results showed that under salinity, phosphate deprivation and eosin supply, encystment was induced, and at the same time, astaxanthin formation and dry weight increased. Furthermore, by adding histidine to culture medium as a quencher of singlet oxygen, astaxanthin production significantly reduced. Therefore, it can be claimed that accumulation of astaxanthin may be related to antioxidative responses, which increased survival of algal cells under environmental stress conditions.

A number of halophytic species as Salicornia europea, Halocnemum strobilaceum, Aeluropus lagopoides, and Aeluropus littoralis were found to occupy a significant portion of the total vegetation of the surrounding area at the Zayande-Roud inlet to Gavkhoony wetland. However, their ecological demands and bioenvironmental factors by which vegetation community composition has been affected is not undestood. A compehensive knowledge of the establishment is essential for future improvements in using the above species on salanized regions. In this paper, using the ordination method. The establishment pattern of  these four species in a range of varied habitats is evaluated based on the recongition of the relative  significance of habitat soil chemical properties and vegetion crown cover to the establishment of the four species. For this purpose, 48 plants meansurements were taken along a transect, having more species variation in term of vegetation cover percentage. Furthermore, 48 soil samples were taken from the plot along the same transect in a one-year period in 1999. The soil samples were analysed for PH, EC, available Na, K, Ca and Mg as well as clay, and silt contents. The ground and field vegetation data were analysed using the Principlas Components Analysis (PCA), and Canonical Correspondence Analysis (CCA) to produce summary vectors (PCA axes) of both the soil chemistry and habitat vegetation structure datasets. The summary of ordination method quantified the degree to which soil variables and species cover were related to variability in ground vegetation composition. variation in community composition (type and percentage) was significantly related to gradient of the aforementioned soil factors. Generally, the vegatation community composition in this experiment could be considered as a key component to expand the growth and development patterns of these species to similar salinised regions.

Purple coneflower (Echinaceae purpurea (L.) Mnch) is one of the most important medicinal plants used by pharmaceutical industries in industrialized countries. The active substances of this plant are antiviral and are used as human immunostimulant. The plant of purple coneflower is not included in the Iranian flora. Therefore, the main aim of this study was to evaluate the adaptability of the plant to the conditions in the north of Tehran (Zardband region). The results from this research should contribute to large-scale production as a raw material for Iranian pharmaceutical industries. Comparison of means of the different characteristics was carried out using t-test at 5% level. Results showed that purple coneflower is adaptable to the climatic conditions in the north of Tehran and can be produced on a large scale. The suitable time for transplanting the seedling in the field was from 5 August to 5 September. Maintaining the purple coneflower until its fourth vegetative period is economical. Transplanting after this date produces woody stems and reduces both the herb yield and the quality of its active substances.