JWSS - Journal of Water and Soil Science

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During recent years, worldwide concern has been focused on the potential for contamination of surface waters and ground waters by agrochemicals in runoff and soil water from irrigated fields. Given this perspective, it is very important to correctly evaluate the levels of different agrochemicals in water, both from human toxicological and environmental viewpoints and to develop management strategies for reducing agrochemical loads to acceptable levels in the environment. The main objective of this study was to assess the qualitative changes of tailwater due to the use of agrochemicals and thereby to determine contamination loads. Four farms (A, B, C and D) were chosen in the Foumanat region in the F₂ unit in 1996. The areas of these fields ranged from 0.22 to 0.6 ha having a number of unequal successive basins with variable inflow and outflow rates.

 A quantitative analysis showed that the tailwater ratio in farms A, B, C and D ranged from 2 to 64% during the irrigation season. The outflow water was classified as C₃S₁. The changes in qualitative factors were not significant and did not follow any certain pattern during the irrigation season. The changes in SAR, EC, Cu, Zn, B, P, K and DO in the inflow and outflow waters were also insignificant. After fertilizer application, the increase in nitrogen concentration in the outflow was significant. The average pollution loads in the inflow and outflow were about 1618 and 1476 kg/day/ha, respectively. The remaining load in the rice fields was about 142 kg/day/ha, which was meaningful at 1% level. The fifth farm (E) located in Lahidjan was sprayed with diazinon. Water samples were analyzed each day for diazinon residues for 10 days after application. Sample analysis showed that the concentration of the insecticide was 93.08 mg/l immediately after application and gradually reduced to 0.98 mg/l ten days after spraying.

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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.

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Iron (Fe) availability is low in calcareous soils of Iran due to high pH levels and presence of excessive amounts of CaCO₃. Overfertilization by phosphorus (P) fertilizers may also decrease Fe availability. The objective of this study was to evaluate the effects of P, Fe and their interactions on the growth and chemical composition of soybean [Glycine max (L.) Merrill] 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 FeEDDHA) in a completely randomized design with four replications. Plants were grown for 8 weeks in a loamy soil, classified as Chitgar series (fine-loamy, carbonatic, thermic, Typic Calcixerepts). Results showed that P application up to 80 and Fe at 2.5 mg kg^-1 increased shoot dry matter. Phosphorus concentration, total uptake and P:Fe ratio in soybean increased by P application but decreased by Fe application. Application of Fe up to 2.5 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. Interaction of P and Fe had no effect on shoot dry matter. Zinc (Zn) and copper (Cu) concentrations decreased significantly when P was added and manganese (Mn) concentration increased up to 40 mg P kg^-1 but decreased at higher rates. Iron application had no effect on soybean Zn and Cu concentrations but decreased Mn concentration at all rates. Prior to any fertilizer recommendations, it is necessary to study the effects of P, Fe and their interactions on soybean under field conditions.

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In a pot experiment, the growth (Dry matter) responses of 18 rapeseed varieties to three levels of NaCl salinity induced by 1.2, 6, and 12 dS.m^-1 were investigated using a factorial experiment with a randomized complete block design in 3 replications. The results indicated that salinity reduced total dry matter, Na concentration, K/Na ratio, ion selectivity of K versus Na, and leaf water potential while it increased K concentration. However, the leaf water potential of the plants had the highest and a significantly negative correlation with total dry matter accumulation. Therefore, it seemed that leaf water content of the plants could explain the tolerance or sensitivity responses to salinity. The rapeseed varieties were accordingly ranked into different groups. The varieties viz, Alice, Fonax, DP.94.8 and Licord were classified as saline tolerant group, and varieties such as Okapi, Akamar and Eurol as saline sensitive group. The remaining eight rapeseed varieties were moderately tolerant. Moreover, the response of rapeseed varieties viz. Consul, VDH8003-98 and Orient were different such that the above explanation could not be applied to them. Therefore, halophytic strategies for these three varieties might be worth further investigation.

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In order to find the high-yielding and adaptable cultivars in different environments, eight cotton genotypes including two early maturity hybrids were studied and compared with the Varamin cultivar as control in a randomized complete block design with four replications in six regions in 1997 and 1998. Using Barttlet test, some of the environments were eliminated from statistical analysis. Therefore, combined analysis of variance and other statistical calculations were carried out based on environment (Year×Location) on the assumption that environment was randomized and cultivars remained constant during the entire study. In combined analysis of variance, genotypic effect (in yield) was significant at 1% probability level. Combined analysis of variance also showed significant differences for the main effect of environment and genotype×environment intreaction at 1% probability level. To select the best genotype with a high and stable yield, parametric statistics of stability including type 1 stability (S²_i,CV_i), type II stability (b_i,σ_i², w²_i), type III stability (Sd²_i) as well as non-parametric statistics such as mean of genotypic rank (R), standard deviation of rank (SDR), and simultaneous selection of parametric and nonparametric statistics for yield and stability (Ys_i) were calculated. Overall, considering the important agronomic and technological characteristics of genotypes such as yield, earliness, span length, fiber strength, percentage of uniformity, and micronariae index, the hybrid Coker×Bulgar was selected as high-yielding and stable cultivar to be substituted for Varamin cultivar across the planting area.

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The biological parameters of cabbage aphid, Brevicoryne brassicae (L.) was studied in the laboratory conditions under the three constant temperatures (20, 25 and 30 ºC), RH 60±5% and a photoperiod of 16:8 (L:D) using 40 first instar nymphs. Among nymphs, 40%, 55% and 10% of them completed their nymphal period in 20, 25 and 30 ºC, respectively and developed to adult stage. In 30 ºC, the most biological acitivities of aphid were disrupted and the most individuals (nymphs and adults) were killed. Most developmental periods, longevity and the amount of reproduction in 20 ºC were significantly greater than other temperatures. In temperatures 20, 25 and 30 ºC the last individual of a cohort died in age of 33, 29 and 16 days, respectively. The life expectancy of cabbage aphid in the first day of experiment was 13.93, 10.50 and 7.19, respectively according to the mentioned temperatures. There was a little difference between net reproduction rates in temperatures 20 and 25 ºC (16.74 and 15.92, respectively). Net reproduction rate was reduced extremely in temperature 30 ºC (1.75). The intrinsic rate of the increase in the temperatures 20, 25 and 30 ºC were 0.187, 0.226 and 0.042, respectively. The results indicated that 25 ºC was the optimal temperature for biological activities of B. brassicae and its highest population growth was observed at this temperature.

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Consumption of foods with low glycemic index (G.I.) by diabetic patients helps maintain their blood sugar at acceptable levels. Ordinary jam has a high G.I. The purpose of the present investigation was to prepare a dietetic jam using nutritive and non-nutritive sweeteners. The investigation was carried out in four steps. First, glycyrrhizin was extracted from licorice extract powder, its ammonium form was prepared, and its purity was assay by HPLC. Secondly, based on a completely randomized design various types of jam were prepared using different combinations of sorbitol, fructose and ammonium glycyrrhizin. Thirdly, the prepared jams and their reference controls were evaluated for color, flavor, texture and overall acceptability by a selected taste-panel and were also subjected to physical analysis using Hunter Lab colorimeter and Bostwick consistometer. Two jam preparations were finally selected on the basis of their overall acceptability. Finally, glycemic indices of the selected jams were determined using NIDDM volunteers. The results showed that ammonium-glycyrrhizin enhances the overall acceptability of the selected product (P<0.05). As G.I. values for the selected jams were low (23.5 and 23.9), their consumption by diabetic patients and their production on a commercial scale are recommended.

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The first Iranian hybrid monogerm cultivar of sugarbeet was developed in 2000 after an 8-year period of R&D activity. The cultivar is not only a high yielding variety but enjoys a good resistance to bolting and Sercospora. The study sought to estimate the rate of return to the public investment made to develop this variety, using the economic surplus approach. The results revealed that the investment has got an internal rate of return of 117 percent and that it has produced an exchange saving of $28.7 million. This finding indicates that the investment has been highly productive and that the field suffers underinvestment.

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This research was carried out to determine the optimum conditions for acidic extraction of gelatine from cattle bones. The effects of different treatments such as pH (1.8 to 2.6), temperature (60 to 80°C) and time (40 to 120minutes) on yield of extraction, gel strength, viscosity and absorption (420 nm) was measured. Coefficients of central composite rotatable design (CCRD) and regression surface response.... (RSREG) were used. The coefficients for yield, gel strength, viscosity and absorption were 0.990, 0.991, 0.998, 0.928, respectively. According to variance analysis of the data, there were significant differences between the effects of three variables (pH, temperature and time) on yield of extraction and viscosity, but no significant difference was observed between the effects of temperature and pH on gel strength and absorption, respectively. Comparisons of the averages of functional characteristics of acidic and commercial gelatin showed that viscosity and strength of acidic gelatin were higher than those of commercial one. The optimum conditions were found to be: pH=1.88, temp. 80°C and 118 min., to reach the highest yield and pH=1.88, temp. 60°C and 48 min. to get maximum strength, and pH=2.56, temp. 69°C and 118 min. to obtain the maximum viscosity and finally, pH=2.6, temp. 62°C and 48 min. for minimum absorption. Also, the results revealed that there were significant differences between trace elements content (Fe, Ca and Pb) of commercial and acidic gelatins. Although, acidic gelatin contained higher amount of the elements, but these amounts were still less than maximum values which are allowed to exist in gelatin. Amino acid compositions of both gelatins were almost identical.

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  Citrus stubborn disease is caused by the helical mollicute Spiroplasma citri. The pathogen is naturally transmitted by sap feeding leafhopper vectors. In the present study attempts were made to detect S. citri in presumptive vectors. Leafhoppers were collected from various wild and cultivated plants in citrus growing areas in Jirfot. Fifteen leafhopper species were identified and 12 species were analyzed for the possibility of carrying S. citri with an antiserum prepared against a citrus strain of S. citri by indirect ELISA. S. citri was detected in leafhopper species by ELISA in Austroagallia sinuata, Psammotettix alienus, Circulifer haematoceps, Orosius albicinctus and Psamotettix striatus. However, S. citri was isolated only from the last three leafhopper species in LD10 medium. These leafhoppers were primarily captured from sesame fields. Therefore, these potential vectors and sesame farms may play a key role in the epidemiology of S. citri in the surveyed area.

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  Effect of change from the conventional (flooding) to subsurface irrigation system was studied on mature pistachio trees (Cultivar Ohadi) in Kerman pistachio research station for four years. This experiment was carried out in a randomized complete block design including 7 treatments and 3 replications. The experiment also used two irrigation intervals (7&14 days) and three water rates according to pan coefficient (20%, 40%& 60% evaporation from surface of class A pan) for subsurface irrigation system with 6 treatments the conventional (flooding) irrigation system was tested as control. The pipes of subsurface irrigation system were installed at 90cm distance from trees trunk at each side of trees, and 50cm from soil surface. Mean of pressure and discharge in the pipes was 0.8 to 1 atmosphere and 5.4 Lh^-1m^-1, respectively. Different factors of quantity and quality pistachio yield, current vegetative growth, water use efficiency and soil electrical conductivity were measured. The results showed that change of conventional (flooding) to subsurface irrigation system is possible and the best treatment can have water rate of 7174 m³ha^-1y^-1 with 14 days irrigation interval. In comparison with other treatments, this treatment has better quantity and quality pistachio yield. Water use efficiency (WUE) of this treatment was 164g dry yield per cubic meter. Nevertheless, application of water rate of 4783 m³ha^-1y^-1 can result in the deficiency of irrigation water. At this water rate, WUE was 177g dry yield per cubic meter. However, it was found that the application of lower water rate (<4783 m³ha^-1y^-1) produced severe effects on the treated pistachio trees, e.g. decreasing the growth rate, yield and increasing the early splitting in pistachio fruits. Finally, it is concluded that 14-day interval irrigation is the preferred treatment for pistachio trees. Also, soil salinity showed considerable change in subsurface irrigation treatments after irrigation system was changed, especially in the first year.

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This paper analyzed the effect of transaction costs on supply response of rice producers in Iran. Some of these producers participate in market as sellers or buyers and others remain self-sufficient. Farmers have different responses based on fixed and proportional transaction costs. The data used in this research consisted of information about 260 rice producers in Mazandaran province in 2004. The results indicated that lowering transactions costs would increase output by both increasing market participation and increasing production for market participants. Given that transaction costs affect market participation, aggregate supply will respond to changes in the transaction cost structure through its effect on market participation. It is recommended that policies reducing transaction costs be applied as a complementary policy to price policies to affect supply response.

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Common kilka were chilled during 1, 2, 3, 4 and 5 days to determine the influence of such storage times of fish over the quality of the final canned product. For this propose, common factors for determination of fish quality (moisture, total lipid, free fatty acid, peroxide, thiobarbituric acid and fatty acid profile) were selected and compared with the formation of fluorescence compounds in fish tissue and filling media of canned kilka. In this work common indices showed higher oxidative and hydrolytic rancidity of canned samples compared to raw material but the trend of deterioration with the increase of chilled storage time was not well shown. However, filling media fluorescence compounds was significantly increased with the increase of chilled storage time and the decrease of fish primary quality (P< 0.05). According to the present results, fluorescence detection of interaction compounds can provide a good technique to assess quality differences in the final product as its relates to the quality of the raw material used.

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Modeling plant response to salinity and nitrogen deficiency is very important for estimating optimum yield in arid and semi-arid regions. For this purpose, the models of Leibig-Sprengel (LS) and Mitscherlich-Baule (MB) originally proposed to explain plant response to nutrients only were modified to evaluate plant yield response to combined nitrogen and salinity stress conditions. Afterwards, in order to model canola (Brassica napus L.) response to combined salinity and nitrogen stress, an experiment was designed with different nitrogen and salinity levels. The water salinity treatments consisted of non-saline water, 3, 6, 9 and 12 dS m-1. The nitrogen treatments were 0, 75, 150 and 300 mg kg soil-1 added as ammonium nitrate. The results indicated that both modified models can satisfactorily predict canola yield. However, the modified MB model (R2=0.94) provided better estimation than the modified LS model (R2=0.87). The calculated statistics including Maximum Error, Root Mean Square Error, Modeling Efficiency, Coefficient of Determination and Coefficient of Residual Mass for the modified models indicated that the estimated relative grain yield for soil nitrogen, salinity and each rate of soil nitrogen in salinity levels by modified MB model compared with those by modified LS model is closer to the measured relative yield. Therefore, the use of modified MB model for estimating canola relative grain yield in salinity and nitrogen stresses is recommended. Using modified LS model showed that the salinity threshold value changes with the applied nitrogen. In this case, by application of each 75 mgN kg-1 soil, the salinity threshold value decreased 4 dS m-1 in saline conditions. Application of nitrogen decreased chloride concentration in grains under saline conditions. Nitrogen uptake also augmented with increasing canola transpiration, because nitrogen was carried over from soil to the uptake sites mainly by mass flow.

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Magnetic susceptibility (χ) measurements are widely used for the evaluation of soil profile development. Fourteen soil profiles were studied in a relatively wide range of climatic conditions in Fars Province. Citrate-bicarbonate-dithionite (CBD) extraction and micro CT-Scan images were used to evaluate the source of magnetic susceptibility. The results showed that soil samples lost 23 to 91 percent of their magnetic susceptibility after CBD extraction (χCBD), reflecting differences in the source (pedogenic or lithogenic) of magnetic susceptibility. Greater values of the decrease were noticed mostly in well developed soil profiles as well as in soil surface. 22 to 89% of the decrease was observed in frequency dependence of magnetic susceptibility (χfd) after CBD extraction. A significant positive correlation (P<0.01) was obtained between χCBD and χfd in the soil studied. Micro CT-Scan images with a spatial resolution of 33 µm showed lithogenic magnetic Fe oxide (magnetite) grains.

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Seventy- two 26-weakk-old white leghorn layers (w-36) were fed commercial diets containing 0, 2 and 4 fish oil and the diets were iso-caloric and iso-nitrogenous. Hens were randomly assigned to 3 treatment diets, with 3 replicates and 8 layers in each. The experiment was conducted over a period of 12 weeks in order to study the effects of feeding fish oil on fatty acid composition of egg yolks. The yolk of eggs was extracted and cholesterol content was determined in each period. Statistical analysis of results was performed using the general linear procedure (GLM) of the SAS and means were compared using Duncan’s multiple range test. As a result, saturated fatty acid (myristic, palemitic and stearic acid), ω-7 (palemitoleat) and ω -9 (oleat) and arashidonat in egg yolk was not significantly (P>0.05) different among treatments, but the linoleat and ω -6 fatty acid were decreased in all FO treatments (P<0.05). The linolenic acid did not vary in treatments but the other ω -3 fatty acids (eicosapentaenoate and docosahexaenoate) were increased in FO treatments and there was a statistically significant difference between treatments (P<0.05). The ω -6/ ω -3 ratio was decreased from 18 in control to 3.8 and 2.31 at 2 and 4% treatments, respectively(P<0.05).

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Forest roads must be constructed according to technical standards and guidelines which have been published by the scientific and operational organizations. Recently, hydraulic excavators have been used beside the bulldozer for excavating the forest roads. Thus, it is necessary that their ability in construct of standard cross sections be compared. This study was conducted in Lattalar forest which is located south of Sari city (Mazandaran Province). 60 cross section samples were randomly selected for each machine in slope classes of 30-40, 40-50, 50-60 and 60-70%. Then, cross sections were taken by niveau and clinometer. The results in different slope classes showed that the hydraulic excavator and bulldozer had no significant effect on cut and fill slopes length and gradient. Roadbed width in bulldozer construction area was more than the hydraulic excavator at probability level of 1%. Also, there was a significant difference between the hydraulic excavator and bulldozer earthworking width in slope classes of 30-40 and 40-50% at probability level of 5 and 1%, respectively, whereas this difference was not significant in other slope classes. Finally, the average standard cross sections for hydraulic excavator and bulldozer were 89.96 and 84.81%, respectively.

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In this study, two kinds of packages namely tinplate (TP) can and flexible pouch were used for black cherry in syrup. Samples were taken in the same condition in these two packages. Other variables were temperature (4 levels) 4, 23, 35 and 40°C and time (4 levels) 0, 30, 60 and 90 days after preparation of the samples. Samples were digested according to the approved method of AOAC (AOAC, 1990). The total concentrations of Iron, Tin and lead, were determined by atomic absorption spectrophotometer. The mean concentration of Iron, Tin and Lead was 4/858 ppm, 38/459 ppb, 38/459ppb in TP cans and 3/161 ppm, 387/978ppb, 33/993 ppb in flexible pouches. Statistical analysis showed that at %5 probability level, the mean value of Iron content of the product packed in TP cans were significantly higher than the control the same was true about both lead and Tin content. However, this trend was not proved in flexible pouches. Furthermore, temperature had a significant effect on the metal content of the samples.

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This study was conducted to determine the effect of 3 extractants on K release from biotite, phlogopite and muscovite. The minerals were grouped to <60 and 60-100 µm size classes. Particles CEC were saturated with calcium. Sequential extraction up to 30 times was carried out using 0.01M HCl, 1M NH4OAc and 0.05M BaCl2 solutions and cumulative concentration of K was calculated for each extractant. There was a difference among the 3 extractants in cumulative K release values from the three minerals. The highest values of cumulative K release were obtained by 0.01M HCl and 1M NH4OAc for less than 60 and 60-100 µm particle sizes, respectively. The amount of K release from muscovite was even higher when 1M NH4OAc and 0.05M BaCl2 solutions were used as extractants. This might indicate that muscovite cannot be considered as an ineffective source of available K in soils. Furthermore, particle size had a great impact on nonexchangeable K release from micaceous minerals. Coarser particles released higher quantity of K as compared to that of finer particles. Therefore, particle size distribution of different micaceous minerals in soils may be a factor that causes a difference in the amount of K release from soils.

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Uprooting trees and pit – mound micro topographies are due to creation of heterogeneity condition in soil ecosystem. Pay attention to mountainous condition of hyrcanian forests in Iran and presence of trees with high diameters (old trees), therefore, it is imagined that many of trees are prone to uprooting. Thus, the aim of this research is studying variability some of soil physico - chemical characters in uprooted trees location and pit – mound position. For this purpose, twenty hectare areas of Tarbiat Modares University Experimental Forest Station studied that is located in Mazandaran province, northern Iran. Numbers of thirty four uprooted trees were found. Five microsites were distinguished including mound top, mound wall, pit bottom, pit wall and closed canopy. Soil samples were taken at 0 - 15, 15 - 30 and 30 - 45cm depths from all microsites using core soil sampler (81cm2 cross section). Soil acidity, water content, organic matter, total nitrogen and carbon to nitrogen ratio measured in the laboratory. A statistical result is indicating that the most water content, organic matter and nitrogen devoted in pit bottom. Mound top and wall included maximum of acidity. The most value of carbon to nitrogen ratio found in mound wall, as well. Soil acidity showed no significantly differences among different depths. The results of this research can be considered in forest soils survey and forest management.