JWSS - Journal of Water and Soil Science

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Effect of different times and levels of nitrogen fertilizer application on growth and grain yield of spring wheat cultivar “Ghods” was studied during 1993-1994 growing season at Karkadj, Agricultural Experiment Station, College of Agriculture, University of Tabriz, using a split plot design with three replications. Main plots were assigned to five levels of N fertilizers (0, 40, 80, 120 and 160 kg/ha) and subplots to five times of applications [all of N fertilizer at planting (T^₀) 1/2 at planting + 1/2 during tillering stage (T₁), 1/2 at planting + 1/2 during heading stage (T₂), 1/3 at planting + 1/3 during tillering and 1/3 at heading stages (T₃) and 1/4 at planting + 1/4 at tillering + 1/4 at stem elongation and 1/4 at heading (T₄)]. Results showed that different levels of N applications affected grain yield and biological yield significantly, while the effect of split application and also N levels × times of application interaction on these two traits were non-significant. Growth stages of wheat were not significantly affected by different N Levels and times of application. Dry matter accumulation, leaf area index, and crop growth rate, in response to growing degree days during growing season, increased when higher levels of N fertilizer were applied. Leaf area index and crop growth rate initially increased up to anthesis and then decreased. Crop growth rate decreased to zero level at soft dough stage and then became negative. Variations in relative growth rate and net assimilation rate, in relation to growing degree days, decreased when different levels of N fertilizer were applied at early part of growing season it was maximum while at later growth stages decreased and finally became negative, Times of N application and level × time interaction during growing season did not affect the growth indices significantly.

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In order to study the genetic variation among local varieties of onion in Iran, an experiment was conducted in the Research Center, Faculty of Agriculture, Tabriz University. Sixteen populations were evaluated for agronomic characteristics and also total seed proteins via SDS-PAGE. Cluster analysis and principal component analysis were used to group the onion populations under study.

 Analysis of variance showed significant differences among varieties for leaf color, leaf length, texture tightness, onion yield per plant, and number of edible layers. No significant differences were observed for the number of twin onions, bulb diameter, and onion dry weight. Hamadan (98-148), Arak (98-95, 98-96, 98-97, 98-103), and Zanjan (98-223) populations acquired the highest onion yield per plant. The significant differences between populations for the majority of characteristics proved the existence of genetic variation in the Iranian onion germplasm. The results from cluster analysis for agronomic characteristics were the same as those from the cluster analysis for the onion yield per plant. The 16 populations were divided into 4 groups. Cluster analysis for the electrophoresis banding pattern resulted in two groups, which was not similar to the dendrogram of agronomic traits. Using principal component analysis, the first principal components determined 97.57% of the total variation. Onion yield per plant was the most important trait in the first principal component and onion dry weight was the second trait in the rank.

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In order to compare the effect of drip and furrow irrigation methods with different quantities of water (50%, 75%, and 100% of the amount of water evaporated from class A pan evaporation during irrigation intervals) on yield and quality of tomato, an experiment was conducted on a silty loam soil in Mashhad Agricultural Research Station. The experimental design was a factorial trial with completely randomized blocks and. four replications.

The results showed that the highest yield (51 t/ha) was obtained from the treatment of drip irrigation with 100% water application. This amount was 4.5 tons higher than the yield from furrow irrigation treatment. Deficit irrigation by 25 and 50 percent decreased total yield by 34.7% and 67.95% in the drip irrigation method and by 27.57% and 64.29% in the furrow irrigation, respectively. Water use efficiency in drip irrigation was two times higher than that in the furrow treatment. Quality and chemical composition of the fruits were not significantly different in the two irrigation methods. Increasing the water deficit, however, increased the amount of soluble solids of the fruits.

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A field study was conducted at the College of Agriculture, Ferdowsi University of Mashhad, to investigate the effect of irrigation with treated municipal wastewater on the yield and quality of lettuce and some soil characteristics. Five irrigation treatments were applied to a clay loam soil, classified as fine loamy mixed mesic Calcixerollic Xerochrepts, in a randomized block design with 5 replications. The treatments consisted of T1 (Irrigation with treated wastewater over all growing season), T2 (Alternate irrigation with treated wastewater and well water), T3 (Irrigation with well water and application of cattle manure), T4 (Irrigation with well water plus fertilizer N and P), and T5 (Irrigation with well water only as control). Chemical analysis of well water proved to be a suitable source for agriculture.

The results showed that the yield was higher in T1, T2, T3 and T4 as compared to the control treatment. Maximum fresh and dry yields were obtained from T3 & T1 and T1 & T3, respectively. Plant tissue analysis showed an increase in macronutrients (N, P, K) and heavy metal concentrations in shoots and roots of lettuce in the first four treatments as compared to the control. In T1, iron concentration was maximum while that of cadmium was minimum. Furthermore, microbial contamination was considerably higher in T1 and T2. Soil analysis indicated that in plots treated with wastewater, electrical conductivity, total nitrogen, available phosphorus, soluble boron and heavy metal concentration increased. However, their values were all below international standards. More experiments seem to be necessary in this regard.

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In this study, susceptibility of the first three larval stages of Spodoptera exigua to Bacillus thuringiensis was investigated. To determine the LC₅₀ values for each larval instar, 6 different logarithmic concentrations of Bacillus thuringiensis were used. A control was also included in each of the bioassays. The value of LC₅₀ for 1st instar larvae, that had been treated one to four hours after hatching, was 311.617 ppm. For the 2^nd and third instars, the larvae values of LC₅₀ were 1356.95 and 2708.27 ppm, respectively. It was clear that larval susceptibility to Bacillus thuringiensis decreased with age. In order to enhance the Bacillus thuringiensis efficiency to control Spodoptera exigua under field conditions, Bacillus thuringiensis should be applied at egg hatch peaks.

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The reaction of forty two barely landraces, mostly from Azarbijan Province and a susceptible cultivar, Zarjo, was studied under greenhouse conditions in the presence of four highly virulent isolates of Pyrenophora graminea, i.e. Marand 3, Ajabshir 2, Khasseban-Tireh, and Bostanabad. The experimental design was a split-plot based on randomized complete blocks with three replications. Landraces were considered as sub-plots and the isolates as whole plots. The seeds were inoculated by the sandwich method and responses of the landraces were evaluated by the method of Mathur and Bhatnagar. The resistance of landrace #1 to the isolates of Marand 3 and Ajabshir 2 and that of landrace # 27 to the isolate of Ajabshir 2 was observed. These landraces could be used as a source of vertical resistance in barley. Landraces 6, 8, 11, 12, 13, 15, 17, 25, 27, 28, 29, 31, 33, 34, 36, 37 and 41 were classified within the range of partial resistance to partial susceptibility, which may be utilized as the sources of horizontal resistance.

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The fire blight with the bacterial causal agent, Erwinia amylovora (Burrill) winslow etal. is one of the most important diseases of the pome fruits that causes the economical losses to quince, pear and apple productions, respectively, in some parts of country. To determine the infection severity of the 43 raturally infected pear cultivars in collection of karaj horticulture research division and also for studing the reaction of these cultivars against disease, the evaluation was performed by the USDA standard system for these cultivars in collection. In this study, although the most of cultivars had been infected on the natural conditions, but disease severity was significantly different between them. By the USDA system, pear cultivars were divided in the 2 classes. Percentage of pear cultivars in very susceptible and moderately susceptible classes were 81.4 and 18.6 respectively. Also for dividing the pear cultivars, beside of USDA method, SPSS software and the cluster analysis were also by the UPGMA method and cultivars were divided into 3 clusters, but it seems that the classification of cluster analysis did not conform with USDA system. Correlation of I.V.S in the artificial tests and the disease severity by natural infection was very significant (r= -0.83).

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Conventional soil survey methods for soils within the watersheds in Iran require a significant budget with many soil surveyors and much time. Additionally, no accurate and reliable information exists on the spatial variability of superface soil parameters in order to predict the soil loss by different models (RUSLE, PISAC, EUPOSEM, MORGAN). Also information on planning and management activities is lacking. These limitations call for methods of estimating soil properties using minimum sampling derived from important terrain parameters. This study was performed to develop soil-landscape models in three geological units (E2Sc, Ku, Plc), in a part of Mehr- watershed, Sabzevar. Six soil variables selected for this study were topsoil clay, gravel, sand, organic matter content, field capacity and bulk density measured at 316 sites on a regular 100m grid. Topographic attributes were calculated by a digital elevation model with 100m spacing. Finally, multiple linear regression analyses relating soil to topographic attributes were performed and then models were validated by additional sample points (78 of 316). The developed regression models showed significant relationships between surface soil properties and topographic attributes such as elevation, slope, aspect, wetness index, stream power index and sediment transport index. The mean errors and root mean square errors in the validation of the models were low and acceptable. The regression equations could explain only 26 to 72 % of the variability measured in the soil attributes in the watershed scale with 100m spacing.

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Overgrazing is the most important agent which causes accelerated soil erosion and land degradation in arid and semi-arid zones of Iran. Appropriate planning and land use in these areas based on land suitability evaluation provide a suitable base for conserving the land and controling desertification. Land evaluation identifies possible alternatives in land use which will more effectively meet national or local needs and assists in assessing the consequences of these alternatives. Extensive grazing refers to the land utilization type in which animals feed in natural pastures. This study was performed to evaluate physical potential of the given watershed for grazing by sheep and goats, and assess the limiting factors for the land utilization type in Mehr watershed, Sabzevar, Khorasan province. Land qualities which were evaluated include accessibility to animals, soil erodibility, moisture availability, rooting conditions, salinity and alkalinity, and drinking water availability for animals. Above mentioned land qualities were assessed by appropriate land characteristics. The requirement of grazing land utilization type was defined in terms of rated land characteristics. Matching of requirements of LUT with the land qualities of each pixel of DEM (prepared in 200×200m by GIS software) resulted in a rating for every land characteristics. Some characteristics such as slope, aspect, and distance to drinking water for animals were calculated directly by GIS. Land index for every pixel was calculated by square root method. Finally, qualitative and physical land suitability classes were determined based on land indices and classified to polygons which would be suitable in grazing management. The results were interpreted under two different scenarios. In the first scenario, drinking water for animals was supplied by permanent sources and in the second one, the supplying of water was developed to temporary rivers besides the permanent sources. With the analysis of spatial modeling it was possible to assess the land suitability with higher accuracy. Overall results showed that the given area was not highly suitable for grazing at all. The most limiting factors included moisture availability for plant growth, slope, rock fragment and outcrops and distance to drinking water. Also during the late winter, spring and early summer, when the seasonal rivers were supplying the drinking water, the limitation of given area was decreased.

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During years 2000 and 2001, biology and population changes of two- spotted spider mite (T. urticae) was studied on five bean cultivars of two species at 25±1ºC temp., 45±4% RH and 15: 9 (L:D) photoperiod, using leaf disks made from 2-, 6- leaf and flowering stages of the plants. The mite mass rearing was carried out on tomato plants under the same environmental conditions and the effects of feeding on 4 cultivars of phaseolus vulgaris namely Chiti Var. Zanjan, Picher, Sunray, Contender and Vigna unguiculata, Var. Kameran as host plants. Biological features as fertility, percentage of egg hatch, duration of embryonic and larval development, percentage were also Studied of lraval mortality, duration of nymphal stages, developmental period from lava to pre- oviposition stages, oviposition period, adult mite longevity, number of progenies, their percentage mortalities, and sex ratios were determined. The results indicated that the two cultivars Chiti Var: Zanjan, Contender, and species Vigna unguiculatat Var. Kameran at 2- leaf stage appeared to be suitable hosts causing higher egg production and hatches, lower embryonic and larval developmental time and lower rate of larval mortality, lower nymphal developmental period, lower duration from larval stage to preoviposition, extended oviposition period and higher adult longevity. In contrast, the cultivars, Sunray and Picker were shown to be unsuitable hosts. Regarding 6- leaf stage, the cultivar Contender and Vigna unguiculatat, were considered as suitable hosts in relation to embryonic developmental time, number of larvae, duration of larval stage, and rate of mortalities, nymphal developmental time and duration from larval stage to pre- oviposition, extended oviposition stage, sex ratio and adult longevity. But the cultivars Chiti, Picker and Sunray appeared to be unsuitable hosts. In relation to the number of eggs and percentage of egg hatch, number of larvae and nymphs, nymphal mortality rates and sex ratio, the cultivars, Picker and Sunray were considered as suitable hosts at their flowering stage but Vigna unguiculatat and Contender were identified as unsuitable ones.

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Rape seed (Brassica napus L.) containing more than 40 per cent oil is one of the best oilseeds for cultivation in Iran. Sclerotinia stem rot is one of the important diseases of the rape seed, the causal agent being Sclerotinia sclerotiorum. The aim of our study was to assess the effect of the disease on the quantity and quality of the extracted oil and remaining foodstuff in a field experiment. In this research three cultivars including Okapi, SLM046 and Talayeh were examined under field conditions using a factorial design (cultivars and inoculations were two factors under study). The cultivars were inoculated with SK₄ isolate of S. sclerotiorum. The inoculation was done on the plant stems at 30 cm height above the soil using Lewartosca method during mid flowering stage. One thousand- seed weight and glucosinolate, erucic and oleic fatty acids contents of the seeds were determind after the harvest. The results indicated that the infected plants in comparision with the controls had a lower 1000- seed weight and oleic acid content and a higher glucosinolates and erucic acid contents. There were significant differences among the genotypes in respect to all the studied traits except 1000- seed weight. Inverse correlation was observed between 1000- seed weight and erucic acid content or oil glucosinolates contents. It was concluded that the disease can reduce quantity and quality of seed oil and other nutrient contents.

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  Parsi Zira, Bunium persicum (Boiss.) B. Fedtsch., which is called Mountainous or Black Zira, is one of the most important medicinal plants with high economic importance. Generally, there is a little information about in vitro culture of Bunium persicum. Fragmented embryo was used as an explant in Bunium persicum regeneration. In this method, a great callus induction and regeneration only on the same medium without any subculture occurred because of being young and having better interaction with medium, leading to reduction of tissue culture time, infection and chemical consumption. In this research, B5 media containing different concentrations of plant growth regulators, NAA and 2,4-D only or together with Kin, were used. The experiment was conducted using completely randomized design with 30 treatments and 10 replications per treatment. The highest callus number was obtained from the treatment containing 0.1 mg/l 2,4-D and 2 mg/l Kin or 1 mg/l NAA and 2 mg/l Kin. Regeneration occurred in some treatments without Kinetin, showing that Kinetin is not essential for Bunium persicum regeneration. The treatment containing 0.1 mg/l NAA and 4 mg/l Kin was the best one for regeneration. The best treatment for somatic embryogenesis was 2 mg/l 2,4-D.

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  Great sturgeon is one of the most economically important species. However, in recent years overfishing, illegal fishing, etc., have resulted in severe declines in the stocks of this species. For conservation, stock of this species, determination of gonadal situation and its gonadal growth exchanges is very important. This paper is a histological approach to gonadal staging in 74 Huso huso in the 4 – and - 5 - year old classes. The fishes were reared in brackish water concert tanks under controlled conditions. A small section of the gonads of each fish was removed by biopsy. The gonadal tissue was fixed in buoin solution. They were dehydrated in different diluted solutions of alcohol and chloroform until they were clear. Then they were embedded in paraffin and sectioned at 7 µm and stained by hematoxylin and eosin method. Of the four-year old fish, %56 and %44 were males and females, respectively. %6 of males were at stage I %11 stage I-II %61 stage II %13 stage II-III %11 stage III-IV and %8 were at stage IV-V. %3 of the females were at unknown stage %3 stage I %11 stage I-II %60 stage II %14 stage II-III and 9% stage III. Of the 5 year old fish, %12.5 of males were at stage II % 25 stages II-III %50 stages III and %12.5 were at stage IV. %62.5 of females were at stage II and %37.5 were at stage II-III. Results of this study Compared with those obtained from fishes of the same age class studied in natural habitats as well as the results obtained for the farmed sturgeons from freshwater medium indicate that there is no similarly in the stage of gonadal development in different conditions. Longest stage in tow sexes was stage II that is longer in females, and passing of stage II in males is faster. Males showed more sexual maturity than females. Gonadic growth in culture medium is faster than wild condition, and it is faster in brackish water than fresh water. So, we can state that brackish water is a suitable medium for gonadic growth of Great sturgeon.

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A considerable portion of threshing losses and waste of rice takes place in threshing stage. One of the effective factors in threshing losses and waste of threshing units, threshers and harvesting machines, is the drum speed. In this research, effects of three factors including drum speed (five levels), crop moisture content (two levels) and rice common varieties (four varieties) on threshing losses and waste were studied. The thresher T25 was used for the investigation. It has wire loop type tooth. Dependent factors included unthreshed grains percentage (threshing losses) and damaged grains percentage. The obtained data was analyzed by split–split plot test based on Complete Randomized Blocks Design. The mean values were compared using Duncan’s Multiple Range Test. The tests results revealed that significant effect of variety type and drum linear speed on threshing losses (P<0.01). Furthermore, the effects of variety type, moisture content and drum speed on damaged grains were also significant. The optimum drum speed was 14 m/s. The most and the least of threshing losses belong to Hashemy and Binam varieties, respectively. Among the tested varieties, Binam variety showed the highest percentage of the damaged grains. In general, decreasing the crop moisture resulted in increasing the mean damaged grain.

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Safflower (Carthamus tinctoius L.) is an Iranian native crop that is adapted to different environmental conditions of this country. Sixteen safflower varieties/lines were spring-planted in 6 research stations including Sararood (Kermanshah), Maragheh, Ghamlo (Kordestan), Khodabandeh (Zanjan), Shirvan (North Khorasan)and Khohdasht (Lorestan) with and without drought stress conditions each in a RCBD with 3 replications. Some drought resistante indices including Mean of Productivity (MP), Geometric Mean of Productivity (GMP), Tolerance (TOL), Stress Tolerance Index (STI), Stress Susceptibility Index (SSI) for seed yield and genotypes Cell Membrane Stability (CMS) were calculated. Results showed that STI was the most appropriate index to identify drough resistant genotypes. Estimation of STI from mean of all stations revealed that Gila, CW-4440 and PI-537598 with high STI showed high seed yield in both stress and non-stress conditions. Caculation of STI standard deviation for these genotypes showed that Gila had less STI stability over the locations than other two genotypes so, CW-4440 and PI-537598 are more stable in drought stress resistance. Analysis of variance for cell membrane stability (CMS) of genotypes showed the significant differences in 1% level of probability between genotypes. S-541 had the highest and Kino-76 had the lowest CMS. There were significant and strong correlations between STI, MP and GMP with CMS namely, genotypes with more stable membrane having more drought resistance in field condition. So, cell membrance stability can be a useful and fast method to screen germplasm and identify drought resistant genotypes. Cluster analysis based on STI,MP,GMP, CMS and seed yield in both stress and non-stress conditions divided genotypes into 3 groupes. Results of clustering also identified S-541, Gila, CW-4440 and PI-537598 as 4 superior genotypes and confirmed the results of other methods.

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Eight multiparous Holstein dairy cows with 634±44 BW, 57±6 DIM, and 46.7±3.1 kg daily milk yield were assigned to a duplicated 4×4 Latin square design for 21-day periods (adaptation, 14d sample collection, 7d). The treatment diets were: 1) no pistachio by-product (control), 2) 5% of pistachio by-product, 3) 10% pistachio by-product and 4) 15% pistachio by-product. Corn silage in control diet was replaced with pistachio by-product. The blood metabolites (2h after feeding), DMI, daily milk yield and milk compositions were not affected by the treatment diets. The economically corrected milk (ECM) and fat corrected milk (FCM) were decreased linearly by increasing pistachio by-product in the diet (P<0.1). By increasing the by-product level in the diet, digestibility of DM, OM, NDF and ADF were decreased linearly (P<0.05). Daily rumination and chewing activity alone or per DMI, NDFI or ADFI were linearly decreased when the by-product level increased in the diet (P<0.1). The results showed that the pistachio by-product does not seem to be suitable for complete replacing of the roughages in the diet and it can be used as a part of forage in the diet up to 10% of DMI.

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This study was set up in the research station of Rice Research Institute of Iran (RRII) to determine the response of three hetrotic Indica × Indica rice hybrids (Bahar1, IR75221H and IR69688H) to anther culture on four induction media (N6, modified N6, chu and modified chu). To evaluate hybrids, the percentage of calluses which had been made from anthers in early uni- to mid- uninucleate stage and the number of regenerated plantlets of calluses in those media were determined. The results indicated that genotype, composition of callus induction medium and their interactions significantly affected callus percentage, total plant regeneration and production of green and albino plants. IR75221H hybrid was considerably superior for callus induction (1/64%) and Bahar1 hybrid was the most desirable for producing of green plants (3/43%) and total regeneration (12/24%). IR75221H hybrid produced higher albino plant (10/66%) and IR69688H hybrid produced lower albino plant (6/45%). The best medium culture in the case of callus induction was modified N6 (2%) and total regeneration (21/82%) produced green plant (5/6%), and albino plant (16/22%) was modified Chu among all media culture. However, genotypes showed different results in each media culture, and responses to hybrid of anther culture was low, but by changing the media culture we increased the response of culture.

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In order to estimate the loss of rice caused by white tip nematode, (Aphelenchoides besseyi), to Alikazemi cv., two series of experiments were conducted in greenhouse and microplot conditions at Rice Research Institute, Rasht (Guilan province) during 2005-2006. The microplots sizes were 0.5×2 meter. Rice seedlings were inoculated by plastic tube method with 0, 100, 300, 500, 700 and 900 nematodes per plant. The experiments were arranged in greenhouse and microplot conditions as a completely randomized design and completely randomized block design with four replications, respectively. The factors under investigation consisted of symptoms (number of plants and Leaves infected), yield and population density of nematodes. The variance analysis of data showed significant differences among treatments in all parameters. The minimum infestation level leading to symptoms and yield loss in microplot condition (500 nematodes) was greater than greenhouse (300 nematodes). Regression analysis of data revealed that the yield reduction was mainly explained by population of nematodes in greenhouse and microplot (R2= 92.56, R2 = 91.55). Also, there was a positive correlation at 5% level of probability between disease incidence and nematode population (R2= 84.42, R2 = 75.27). The resulting equations from regression can be used to estimate crop loss from population of nematodes.

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Canola (Brassica napus L.) as one of the oilseed crops has recently received lots of attention due to its suitable oil quality and high oil percentage. To evaluate the effect of water deficit stress on canola genotypes with regard to yield, drought tolerance quantitative indices and identify drought tolerant genotypes, an experiment was conducted in research farm of seed and plant improvement Institute (Karaj) using completely randomized block design with four replications, and 25 genotypes under two stress and non stress conditions. Genotypes were evaluated regarding drought tolerance. Drought tolerance quantitative indices include MP, GMP, STI, SSI and TOL. Result of variance analysis showed significant differences among genotypes as regards all indices and seed yield of genotypes in both conditions at 1% probability level. MP, GMP and STI indices were selected as the best indices for selection of tolerant genotypes in regard to analysis of correlation between seed yield in two stress and non stress conditions and drought tolerance indices. Results indicated that Genotype Vectra was the best genotype, because of its proper mean yield in both stress and non stress conditions. Multivariate biplot figure display showed that MP, GMP and STI indices had high correlation coefficient with each other, and tolerant genotypes were located near tolerance indices. Also results of three dimensional scatter plot and cluster analysis indicated that genotypes Modena, Jura, Eshydromel, Vectra, Dante, Zarfam, Esbetty and Olano were tolerant to drought stress, and genotypes Olpop, GKHelena, RG4504 and Olphi were sensitive genotypes.

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The objective of this research was to predict head rice yield (HRY) in fluidized bed dryer using artificial neural network approaches. Several parameters considered here as input variables for artificial neural network affect operation of fluidized bed dryers. These variables include: air relative humidity, air temperature, inlet air velocity, bed depth, initial moisture content, final moisture content and inlet air temperature. In aggregate, 274 drying experiments were conducted for creating training and testing patterns by a laboratory dryer. Samples were collected from dryer, and then dehulling and polishing operations were done using laboratory apparatus. HRY was measured at several different depths , average of which was considered as HRY for each experiment. Three networks and two training algorithms were used for training presented patterns. Results showed that the cascade forward back propagation algorithm with topology of 7- 13-7-1 and Levenberg-Marquardt training algorithm and activation function of Sigmoid Tangent predicted HRY with determination coefficient of 95.48% and mean absolute error 0.019 in different conditions of fluidized bed paddy drying method. Results showed that the input air temperature and final moisture content has the most significant effect on HRY.