Journal of Agricultural Sciences and Natural Resources
Year:2006 | Volume:13 | Issue:4|Papers Count:19

Gorgan Plain with an area more than 5000 km2 is located in the southeast of Caspian Sea. Since groundwater is the major source of water for domestic, industrial and agricultural uses in the area, it is necessary to ensure groundwater quality by protecting them against pollution sources. In this study, hydro geochemical data from 96 irrigation wells were used to evaluate water quality and to determine processes that control water chemistry. The samples were classified into five groups (I, II, III, IV and V) according to their geochemical characteristics using cluster analysis. The results indicate that the groundwater quality and geochemical characteristics of clustered samples are consistent with the geology and hydrography of the area. Samples collected from the area close to the recharge points which had been covered with gravels and sands were clustered into group I. The amounts of parameters such as pH and TDS as well as the concentration of HCO3 and SO4 in area which had been covered by silty soils were higher as distance from the recharge points increased (groups II and III). The highest concentrations of chlorine and sulfate belong to the northern parts of the study area (groups IV and V), which is mainly covered by fine grain sediments of clay. Spatial distribution of the statistical groups showed that the samples from each group are in close proximity to one another suggesting the same processes and/or flow paths. Overall, the results showed that groundwater clustering based on water chemistry could be applied to the contamination susceptibility assessment for ground waters in different areas.

Acid and saline seeps are an increasing problem in the most part of the world and Australia as well. They are areas of bare soil or reduced crop production. Seasonal surface sampling through topo-sequence of the study area and analytical results of XRD, SEM and VNIR indicate that morphological and mineralogical changes within a natural acid saline seep affected landscape revealed that seasonal differences in surface mineralogy. These dynamic and seasonally influenced changes to surface and near surface mineralogy of an acid saline seep affected landform during the wet months, due to water logging, the sulfidization process dominates, while during the drier months, oxidative weathering of pyrite and iron hydrolysis results in precipitation of iron oxyhydroxides at and near the surface with the generation of acidity. During the dry season, the surface mineralogy of the natural seepage zone is dominated by salts (halite), sulfates (gypsum and barite) and importantly, iron oxyhydroxides gel precipitates and crusts (ferrihydrite, goethite, schwertmannite). The study found the iron oxyhydroxide minerals present in the surface crusts and precipitates reflect acid conditions, as opposed to halite and gypsum that reflect only saline conditions. The visible near infra-red (VNIR) reflectance spectra of the surface minerals from unaffected, salt crusted and acid seep areas, showed spectral differences expressed in the VNIR region due to absorption bands of iron oxides and hydroxides. This difference in the surface mineralogy during summer months can be readily identified via multi-spectral and hyper-spectral remote sensing methods mainly during summer, and therefore regionally mapping for identification of surface mineralogy due to spatial and temporal distribution of acid seeps, which has caused degradation of agricultural lands is suggested.

A Mollisols catena formed on calcareous parent material in semiarid region of western Iran was studied in order to investigate the effects of the depth of groundwater and landscape position on the organic carbon content (OC) of mollic epipedons, genesis of subsurface horizons and variations of clay minerals. According to landscape position, soils were grouped in three categories. Soils formed on the upper section of the alluvial valley bottom i.e. Typic Calcixerolls with the deepest water table, had lower OC and thinner mollic epipedon comparing to other soils. The soils were not saturated and showed no evidence of redoximorphic features. Presence of secondary carbonate and calcic horizons were mainly related to the dissolution of the carbonate in the upper soil horizons and its downward leaching and precipitation in the lower horizons. Speckled and striated b-fabric of the near surface soil horizons are the evidences of carbonate depletion from surface layers. Soils of the mid-valley section i.e. Vertic Haploxerolls, with water table depth (1-2 m) have periodic saturation. Thickness of the mollic epipedons and OC were lower than the soils of the lower valley bottom. Soils of the lower valley bottom or low lands classified as Fluvaquentic Endoaquolls had thick dark mollic epipedons and the highest OC comparing to other soils. In the well-drained soils, illite was dominant. In contrast, in poorly drained soils of the lower valley bottom, smectite was the dominant clay mineral.

Early planting of cotton in spring increases growing season duration, lint quality and extends cotton cultivation to cool regions and also play major role in control of pest especially at the end of the season. Improvement of seed germination and seedling growth at low temperature of spring is therefore one of the most important of breeder's objectives in Iran and other places in the world. This study was carried out using 23 genotypes of cotton including eight parents with 15 F1 crosses that made among them as North Carolina Design // at experimental field of Iranian Cotton Research Institute (Hashem Abad, Gorgan), and seed technology laboratory (Gorgan University of Agricultural Sciences) in 2004 and 2005. To evaluate potential of seed germination and seed ling growth at low temperature in laboratory we use cool test (18°c in dark incubator) and in field, seeds were planted much earlier than the traditionally date of planting by local cotton farmers. Results showed sufficient genetic variation for seed germination and seedling growth at low temperature among the studied genotypes. Due to considerable difference between F1 crosses and parents, they can be used in hybrid seed program and also for selection superior genotypes to improve seed germination and seedling growth factors. Estimates of broad-sense heritability indicated that genetic factors had critical role in control of evaluated traits, however, environmental factors had neglectable effects. The estimates of narrow-sense heritability indicated that breeders could use selection methods to improve rate of germination in field and seedling height of cotton in low temperature. On the basis of correlation coefficient among the studied traits it could be concluded that selection for improvement of seed germination and seedling growth at low temperature via other corresponding traits is possible from different process based on genetic basis of material, because correlation coefficient among the traits was varied for parents and F1 crosses.

This study was carried out to evaluate agronomic traits of selected safflower genotype in two moisture regimes at the research farm of Isfahan University of Technology. Different genotypes including selected lines from local populations of safflower along with two exotic cultivars were evaluated in two adjacent experiments using a randomized complete block design with three replications. In one of the experiments, the irrigation was conducted based upon the depletion of 50% and in the other one based upon the depletion of 85% of soil moisture content. The results showed that there were significant differences among the genotypes for all of the traits including number of days to initiate of flowering, 50% flowering, and maturity and also for plant height, number of heads per plant, number of seeds per head, 100- seed weight, seed yield per plant and seed yield per plot in both irrigation regimes (P<0.01). The stress conditions due to irrigation based on the depletion of 85% of soil moisture content had significant effect on all the traits and it caused a reduction of 29.4%, 20.6% and 3% in seed yield per plant, seed yield per plot and days to maturity, respectively. Based on the average of genotypes, seed yield per plant was 30.71 and 21.69 g, seed yield per plot was 3452 and 2742 kg/ha and days to maturity was 123.7 and 120 days in the first and second irrigation regime, respectively. The interaction between genotypes and irrigation regimes was significant for all traits, expect for the number of days to flowering, 50% flowering, number of seeds per head and seed yield per plant. The significant interaction effects indicated that the amounts of stress effect on genotypes were different. Average seed yield for the genotypes ranged between 2004 to 4174 kg/ha and 1438 to 3458 kg/ha in the first and second irrigation regime, respectively. The existing genetic variation for seed yield in both irrigation regimes indicates that selection for improvement of seed yield can be effective and it is possible to produce high yielding cultivars for growing in moisture stress conditions. The seed yield of dominant growing cultivar in Isfahan province (Koseh) was 3525 and 2394 kg/ha in the first and second irrigation regime, respectively; however, the genotypes of E2428, S3110 and A1 had high seed yield in both irrigation regimes, thus they can be grown in both environmental conditions.

The response of second third instars as well as adult Pulvinria aurantii Cock. to mineral oil and the determination of LC50 & LC90 was tested, using bioassay technique under laboratory conditions of 25±4°C,75±5 R.H. and 12h. of L.D. In this research, six different concentrations of mineral oil were chosen and sprayed on fourteen Two-year old sweet orange (Thomson Navel on Citrus aurantium (rootstock)) trees. From each tree, ten leaves and each leaf five crawlers on average were tested. Probit analysis has been done using P/PROBAN LSTATS computer programmed after preliminary calculations. Based on the laboratory results and our calculations, the rate of mineral oil concentration which caused the death of 50% and 90% of second, third instars was 0.593 & 1.013 liter in one hundred liters of water, respectively. Considering the rate of LC90 to control the instars and adult female of Pulvinaria aurantii Cock. As well as their fiducially limit, the most suitable mineraloil concentration range for instars seems to be between 0.919% to 1.222% and for adult female between 1.887% to 3.183%, respectively.

To evaluate the plant origin materials against B.tabaci, during 2002 and 2003 the following treatments (Neemarin, Neemak, Neemak Super, Neem plus, Exotic Neem Azal TS, Iranian Neem Azal TS, Amitraz and control 1, 2.5, 0.5, 2.5, 1.2, 1.2 and 2 lit/ha respectively) were tested. During 2003, Azadirachtin 1.5 lit/ha was also added to the treatments. The experiments were conducted under a Completely Randomized Block Design with four replications. Observations on pest population (nymphs) were done 3, 5, 7, 10 & 15 days after spraying. The results showed that, there was a highly significant difference between treatments in reducing the pest populatin, also there was a significant differences among different dates of observations due to each treatment. Neemarin in both years showed best result in 10 days after spraying, Neemak and Neemak Super after 7 days , whereas Neem plus and Exotic Neem Azal TS in 2002, after 5 days and in 2003, 10 days after spraying. Iranian Neem Azal TS & Amitraz in 2002, after 7 days & in 2003, after 10 days. Finally Azadirachtin in 2003, showed best result in 7 days after spraying with 94.55% reduction in pest population. During 2002, the highest percentage of pest reduction was observed due to Iranian Neem Azal TS in 7 days after spraying (89.07%) and lowest result due to Neemarin in 15 days after spraying (56.89). Whereas during2003 the highest percentage (96.7%) of reduction was observed due to Neemarin in 10 days after spraying, and the lowest reduction (18.15%) due to Neemakin 3 days after spraying. The results showed that some plant origin material can be replaced with insecticides for the control of this pest.

Iran is one of the main producers of barberry. Barberry is widely grown in south khorasan. The main objective of this study was to investigate technical efficiency and marketing of barberry. Data set were obtained by random sampling through barberry producers and interviewing with wholesalers, retailers in 1381 (2002). In order to estimate technical efficiency of the producer's stochastic frontier production function was applied. Marketing, retail and wholesale margins and marketing efficiency were calculated. Marketing path also was drawn. The results of this study revealed that it is possible to increase technical efficiency by decreasing differences between high-efficiency producers and low-ones. The marketing, retail and wholesale margins of one kilogram of barberry were calculated as 4000, 1000 and 3000 Rials, respectively. Marketing efficiency was obtained as 32% indicating unefficiency in barberry marketing.

User's partnership in revisory and reviver of pasture and watershed management is a necessary matter caused an important part of project success. Today, people participation role in revision, revival and natural resources management is touchable, a new event of county forests, and pastures organization. In 2004, this study is done with purpose of evaluating social-economical projects of pasture and water shed management in kchik reagent sphere. To obtain effective factors on lake of participation of users preliminary studies are done on questionnaires including questions in social, economical, natural, by method simple accidental sampling is followed in number of 108 users. Examination results showed the participation of 87.7%, from this 39% of projects have not informed, 35% of them have lake of capital and more than a quarter is also lack of necessary notice of advantages of project execution. In relation to participation in future designs of users, it is suggested presence of financial aids and also agricultural tools (equipments).

Identification of hazard flooding areas is very important for sound management of flood control in urban basin. In this research, the stability of five bridges were investigated which are mainly located in residential and overpopulated areas of Gorgan city. First, for bridge cross sections, the maximum flood discharges with different return periods are calculated by using residual sum of squares and Creager methods at Gorgan Hydrometric Station. Then, by field surveying and the Manning's method, the maximum discharge of water passing the bridges was calculated. In this research, it became clear that the down stream bridges do not have the power of water passing with high return period.

In contrary to different benefits that a river may have for urban, industrial and agricultural sectors existed on neighboring areas, it may be supposed as a serious threat to the vicinity areas as well as structures constructed on it. The construction of unsuitable and ill-designed structures such as bridges, flood walls, groins and dikes may have significant effects on flood occurrence and exaggeration. The effects may be imposed through changing the cross sections, flow velocity, storage area, flow level and surface area. In the present study, the effects of groins and drops on inundation depth and extension have been investigated in a 7 Km reach of Kan River, Tehran. The hydraulic analyses were made for floods with 5 to 700 years return periods using HEC-RAS computer software package in two situations of structures presence and absence. The results of the study revealed that the trend of changes occurred in flood depth and the type of hydraulic structures and channel geometric conditions affects area as well. The results also showed that the drops were more effective on flood main characteristics than groins. The non-significant effects of groins on flood area and significant role of drops on inundation depth was found to be as another finding of the present research.

In order to induced meiotic gynogenesis in rainbow trout (Oncorhynchus mykiss), spermatozoa genome was destroyed by DV irradiation (10050 mw/m2) and after fertilization with intact ovum, diploidy was returned by thermal shock (28±0.5°c) in 15 minutes. Thermal shocks were applied in 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 minutes after fertilization. DV irradiation was supplied from a germicidal lamp (15 w) with maximum intensity at 254 nm. Before irradiation, sperm was diluted with two kinds of solution and then irradiation, was done at 10 minutes on magnet stirrer. Albinisms were used as a phenotypic marker for monitoring of gynogenetic rainbow trout offspring. Furthermore, determination of diploidy was confirmed by preparation of chromosome slides from larval stages of fishes. Results show that, best gynogenetic yield was achieved in treatment which using shock on 35 and 50 minutes after fertilization.

Callus production potential and callus growth rate in the stem explants of five to 6-year-old Tehran pine (Pinus eldarica M.) was investigated in three different culture media MMS, WPM1 and WPM2. The results, accompanied with analysis of variance in completely randomized design, showed a significant difference between three above mentioned culture media, regarding the production potential of the callus in the confidence level of %0.01 Moreover, the comparison of the means of the data by the use of the new Duncan multiple range test in the 0.01 level indicated no significant difference between MMS and WPM2 culture media but a significant difference between both media and WPM1. From the quality point of view, it appeared more appropriate callus in MMS culture medium in comparison to WPM2. In addition to, the essential hormone conditions for callus production and growth in different treatments of MMS basal medium was studied precisely and the results, analyzed with the above mentioned statistical analysis, indicated that 2,4-D is an essential component for stimulation of callus production and is more effective than NAA for callus production. The increase in this hormone concentration up to 7.5 mg lir-1 caused increase in callus production but the growth rate of the callus in subsequent subcultures was higher in lower concentrations of this hormone. Furthermore, appropriate callus production and optimum growth rate was observed in concentrations of 0.5-7.5 mg.lir-1 kinetin as a stimulator of growth with 2, 4-D.

High level of contamination in heavy metals created naturally or through human activity brings about environmental pollution. Application of proper plants to metal contaminated soil has been the target of attention during recent decades. Since the natural presence of heavy and radioactive elements around Ramsar was reported, five herbaceous species: Calamintha officinalis, Epimedium pinnatun, Parietaria judaica, Digitalis nervosa and Brachypodium sylvaticum were tested to measure the absorption capabitity of eight elements: Fe, A1, Zn, Ni, Cu, Pb, Cr, Co. Plant and soil samples were collected from Ramsar in the spring and summer, 2002. Results showed absorption of eight heavy elements: Fe, A1, Zn, Ni, Cu, Pb, Cr and Co by five herbaceous species. Amount of iron and aluminum in both plant species and soil was greater than that of other elements. Plant Species such as D.nervosa and Pjudaica showing wide endomycorrhizal intracellular development were major absorbents of heavy metals. Further, absorption of most elements was found more frequently in summer than spring and studied plants shared a great potential to absorb lead. Generally, results indicate the presence of a variety of endomycorrhizal fungal spores in soil.

An expert system prototype was developed to simulate the process of quality determination made by the plant managers in a pistachio processing plant. The primary task was determination of pistachio quality from random samples taken from truckloads of nuts delivered to the plant. Based on the knowledge and experience of the plant managers, a hierarchical decision making strategy was proposed to mimic the action taken by the experts to determine the quality of the nuts. From numerous interview sessions, observations, and practical work in the processing plant, a knowledge base using crisp set rules was designed. The results indicate that the expert system decisions and those of the domain experts agreed in 86% of the cases and in the remaining 14% of the cases, the differences were not likely to cause major impact on the decision outcome.

One of the most important products of tomato is tomato paste and characteristics improvement is noticeable. In this research, the effect of whole and break tomato preheating on consistency and other properties of tomato paste has been studied. The results showed that heating the whole tomato at 85°C resulted in better preserving of pectin, color quality, and improving the consistency. Furthermore, in conventional heating process, increasing the temperature up to 100°C led to keep more quantity of pectin and improving the consistency; however, the color quality decreased significantly.

Iran is one of the main producers of barberry. Barberry is widely grown in south khorasan. The main objective of this study was to investigate technical efficiency and marketing of barberry. Data set were obtained by random sampling through barberry producers and interviewing with wholesalers, retailers in 1381 (2002). In order to estimate technical efficiency of the producer's stochastic frontier production function was applied. Marketing, retail and wholesale margins and marketing efficiency were calculated. Marketing path also was drawn. The results of this study revealed that it is possible to increase technical efficiency by decreasing differences between high-efficiency producers and low-ones. The marketing, retail and wholesale margins of one kilogram of barberry were calculated as 4000, 1000 and 3000 Rials, respectively. Marketing efficiency was obtained as 32% indicating unefficiency in barberry marketing.

Current paper seeks to investigate the relationship between agricultural productivity and rural-urban migration in Iran for period 1971-2004. Main hypothesis of this study suggest that increase of agricultural value added as a result of suitable and appropriate investment in this sector cause to grow of rural per capita income and so decrease the rural - urban migration. Results of this study confirm this hypothesis that there is a positive relationship between income gap and rural-urban migration and emphasize on the policy of reduction of migration by investing in rural sector.