JWSS - Journal of Water and Soil Science

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In order to find suitable cultivar and N-topdress rates in corn planted after wheat harvest, a field experiment was conducted in Isfahan University of Technology Experiment Farm located at Shervedan, Falavarjan in 1994. The experiment design was a split plot with a randomized complete block arrangement and four replications. Main plots were four N-topdress rates (0, 90, 180, and 270 kg/ha) and the subplots were three corn hybrids (S.C.I08, S.C.301, and D.C.370). N-topdress rates had no effect on the stages of plant development (50% emergence, transition, pollination and physiological maturity). Also there were no significant effects on the number of leaves per plant, LAI, plant height and plant dry weight measured at pollination stage for different N-topdress rates. As expected, plant development stages differed among hybrids except that of time until 50% emergence. Differences in the number of leaves per plant, LAI, plant height and dry weight of plant measured at pollination stage were highly significant among hybrids. D.C. 370 had the highest values for all of these characteristics. Dry matter accumulation during growing season increased as the N-topdress rates were increased for the hybrids. Also N-topdress rates x hybrid interaction was significant for biological yield. Grain yield, number of seeds per ear, 100-seed weight and biological yield were affected by N-topdress rates and hybrid. Higher grain yield of D.C. 370 can be attributed to greater number of seeds per ear. The results of this study suggest that D.C. 370 with 90 kg/ha N-topdress rate can be used after wheat harvest in Isfahan.

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In this study, conducted in Isfahan region over a period of two years, six oilseed sunflower cultivars named Record, Venimek 8931, Chernianka, Zaria, Perdovik and Mehr hybrid were investigated in a split-split plot design. These cultivars were planted on March 29 and April 29, with and without the presence of pollinator insects. The results showed that the yield of different cultivars were significantly different (p<0.01). The planting date of March 29 caused a higher yield than that of April 29. Also the presence of pollinator insects during the bloom increased the amount of yield in all cultivars planted on both dates. Venimek and Record cultivars planted on March 29 with the presence of pollinator insects during the bloom produced the highest, i.e. an average of 3910 and 3821 kilograms of seeds per hectare and Chernianka with an average of 2944 kilograms of seeds per hectare had the lowest amount of seed. In this study, Record and Venimek cultivars in the first place and then Mehr hybrid planted on March 29 with the presence of pollinator insects during the bloom were better than the other cultivars in terms of attractiveness to honeybees, yield per hectare, seed hollowness percent, weight of 1000 seeds, germination percentage, speed of germination and the amount of oil production.

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A 46-day feeding trial was conducted with rainbow trout (Oncorhynchus mykiss) to examine the effects of partial substitution of plant protein sources with fish meal in diets. Three different sources of plant protein including soybean, sunflower and cottonseed meals were substituted by fish meal at four levels of 10, 20, 30 and 40 percentages. Each diet was assigned to triplicate groups of fish in a completely randomized design as a 3×4 factorial arrangement, with a control diet. Seven hundred and eighty fish were used in this trial. Twenty fish were randomly assigned to each of 39 pens and were acclimated in these pens to the experimental conditions two weeks before treatments began. This substitution caused no significant differences in all the criteria measured with control diet. Fish fed diets of 30 and 40 percent soybean meal substitution showed greater weight gain and better growth performance, lower FCR and higher PER values in comparison with the fish receiving other diets, although the differences were not significant. Irrespective of substitution levels, comparison of fish fed by three different sources of plant protein in their diets showed that the fish fed diet containing sunflower meal had significantly (p<0.0l) lower final mean weight and growth performance, higher FCR and lower PER than the fish receiving soybean and cottonseed meal diets. Relative liver weight of fish receiving soybean meal diets was significantly (p<0.0l) higher than those fed with cottonseed meal diets, but the difference was not significant when compared with the fish fed with the sunflower meal diets. Partial replacement of cottonseed meal resulted in a higher energy availability to fish and also better performance of fish. However, diets containing soybean meal showed not much effects on performance of rainbow trout. These results indicate that cottonseed and soybean meals can be recommended as a suitable and fish meal-sparing ingredient in diets for rainbow trout.

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Optimum rice population densities and the response of rice yield and yield components to population densities and planting pattern are important factors helping rice producers and researchers to achieve maximum productivity. For this reason, a randomized complete block design experiment was conducted during the summer of 1995 at Isfahan University of Technology Research Farm located at Lavark, Najafabad. Zayandeh-rood cultivar was transplanted with three seedlings per hill at row spacing of 15, 25 and 35 cm and hill spacing of 10, 15 and 20 cm under flooded conditions. Row spacing influenced the plant height significantly at heading and anthesis stages. Wider row spacing, enhanced days to 50% heading and anthesis and consequently grain filling duration and ripening stage coincided with unfavorable conditions at the end of the season, which decreased the percentage of maturity. Although number of tillers per unit area increased, tillers per plant decreased as row spacing was reduced. Narrow row spacing limited vegetative growth after anthesis and thereby growth rate of panicle increased. With reduction of row spacing, without any change in the percentage of full grains per panicle and grain weight, number of panicle per unit area increased but number of grains per panicle decreased. At greater row spacing, grain yield per unit area decreased although grain yield per plant and harvest index increased. Although, effects of hill spacing were similar to those of row spacing, hill spacing usually did not influence plant characters, yield components and grain yield significantly. Stepwise regression and path-coefficient analysis revealed that number of panicle per unit area is the most important yield components. It also showed that indirect effects of panicle per unit area on yield through its association with grain per panicle prevented real effects of grain per panicle on yield. Fifteen × 15 cm spacing produced maximum yield which is probably recommendable for rice production in Isfahan.

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Obtaining high seed and oil yields of sunflower requires coincidence of vegetative and reproductive stages of growth of the plant with suitable environmental conditions via selecting appropriate planting date. Since the suitable date of planting for sunflower cultivars under Isfahan environmental conditions was not determined, this experiment was conducted in 1996 at the Agricultural Research Station, Isfahan University of Technology. In this study, five dates of planting (April 27, May 12 and 27 and June 12 and 29) and three open pollinated sunflower cultivars (Record, Vnimik 8931 and Armavirec) were evaluated using a randomized complete block design with split-plot layout in three replications. Date of planting was considered as the main plot and cultivars were randomized in the sub-plots.

Number of seeds per head (SH), l000-seed weight (SW), seed oil percent (SOP) and, consequently, yields of oil (OY) and seed (SY) were significantly reduced as planting was delayed. Reduction in these traits were considered to be related to the coincidence of vegetative and reproductive growth stages with higher temperatures prevailing at later plantings. Vnimik 8931 had higher SH and SW, and thus produced higher SY. This cultivar had lower SOP than Record, but produced higher OY than Record due to its higher SY. Armavirec was ranked the least for the measured traits, except for its SH that was slightly higher than that of Record. SH was the most contributing trait to the increase in SY, and SY was the most determining trait for the increase in OY. Date of planting by cultivar interactions for SH, SY and OY were significant. Nevertheless, the highest amount of the measured traits were obtained with Vnimik 8931 at the first planting date.

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The difficulties of control of greenhouse whitefly on crops and greenhouse plants make extensive studies and investigations necessary in different areas of Iran. Morphological and biological studies were carried out on a prevailing species of greenhouse whitefly, Trialeurodes vaporariorum Westwood, in Isfahan.

In this study, six species of whiteflies T. vaporariorum on Althaea sp. and Lantana camara, Bemisia tabaci Gennadius, B. argentifolii Bellows & Perring and B. hancoki Corbett, on Lantana camara, Aleyrodes proletella L. on Brassica sp. and Aleyrodes rosae on Rosa sp. were collected. These species were described using different identification keys. Morphological characteristics and different growth stages of greenhouse whitefly including egg, 1st to 4th nymphal instars and adult were defined and figures drawn. Biological studies were conducted in 24±1°C, 65±5% RH and 16:8 (L:D) on eggplant, solanum melongena. The developmental time for egg, 1st, 2nd, 3rd and 4th nymphal instars was 7.33±0.48, 3.37±0.52, 3.25±0.45, 2.51±0.26 and 7.66±0.83 days, respectively. The total period from egg to adult lasted 24.12±0.51 days. The number of eggs laid in 24 hours varied between 1 to 10 with an average of 5.93±1.67. Life-span of the male ranged between 19 to 23 with an average of 20.88±1.54 and that of the female varied between 20 to 28 with an average of 26.44±1.17 days. Four nymphal instars were identified and three substages for the 4th nymphal instars were determined. There was a positive correlation between nymphal instars and average body length and width. Since only male offsprings were produced through parthenogenesis, the strain of greenhouse whitefly in Isfahan was found to be European.

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Plant communities of the Kolah-Ghazi National Park have been studied. The park with a wide diversity of fauna and flora species is located 36 Km south of Isfahan. 214 plant species were collected for the purposes of this study. Plant communities of the park are of an aridland vegetation type. Minimal areas of the plant communities were determined using nested plots technique. After studying the Species/Area curves, a l00-square-meter quadrat was employed to collect the cover and density data for each species. The cover data were analysed to determine plant communities using the ordination method.

Crown cover of the vegetation was found to be poor and varied from zero to a maximum of five percent in the park. The following species form the major plant communities in the park: Artemisia sieberi, Anabasis aphylla, Acantholimon spp., Cousinia piptocephala, Ebenus stellata, Pteropyrum aucheri & Scariola orientalis. The combination of these species with others forms plant communities and subcommunities. The overlapping of habitats makes mosaics which cause the formation of ecotones, thus increasing the diversity of the subcommunities in the park. Mesophytic plant communities are narrowly scattered along streams. Most of the plant communities are controlled by the adaphic factor while the biological factor has only a limited control. A Ficus spp. specimen was also collected from the mountainous region in the park which could be a new species or variety and requires further study.

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Whole corn plant was ensiled in 70 gr minisilos for 60 days to evaluate the effects of addition of two levels of Cellulomonas uda bacteria (0, 1.2×10⁵ and 2.4×10⁵ cfu per gr of fresh forage) on fermentation and chemical composition of silage. The experiment was arranged as a completely randomized design. The silos were opened after 3 and 6 days of fermentation. The criteria measured included dry matter (DM), pH, organic matter, water soluble carbohydrates, crude protein, cell wall (NDF), acid detergent fiber (ADF), hemicellulose, cellulose, and ammonia-N contents.

Both levels of bacteria significantly decreased the pH of silages after 3 days (P<0.05). The final pH of silage with the higher level of bacteria was significantly lower, indicative of a greater fermentation of cellulose in this silage. Addition of bacteria resulted in a non-significant increase in the level of final residual water soluble carbohydrates. Final silage ammonia-N concentration was less than 0.8% of dry matter in all silages and was not affected by bacterial treatment. The ADF content was decreased by 11.9% in the silage containing the lower level of bacteria and by 1.8% in the silage which contained the higher level of bacteria. The NDF content increased in the control silage and that with the lower level of bacteria but decreased by 3.6 gr Kg DM^-1 in the silage with the higher bacterial level. Hemicellulose contents increased in all silages but cellulose contents decreased by 9.38% (control), 17.37% (low bacteria) and 12.49% (high bacteria) in the control and bacteria-treated silages, respectively. The results indicated that the addition of 12×10⁵ cfu Cellulomonas uda per gr of whole fresh corn plant was effective in increasing residual water soluble carbohydrates, reducing NDF and hydrolyzing cellulose of whole corn plant.

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Astracantha adscendens is an endemic species in Iran growing on alpine and above alpine timberline habitats on the Zagross Mountain Range. These habitats are characterized by steep slopes, heavy snowfalls and long ice formation periods. The present study was carried out in Chelgerd, Bakhtiari, and Fereidan, Isfahan. Slopes, elevation above sea-level, and magnetic north azimuth were measured. The canopy cover was also measured along four radii in upward, downward, left and right directions. Regression analysis was performed for the measured values of plant and environmental factors.

The results revealed that the upward radius had a high negative correlation with slope changes while the downward radius showed no relationship with slope variations. The two left and right radii had a high and positive relationship with each other, both reducing in length as the slope steepness increased. Shrub volume decreases with increasing slope steepness. Plant shape was classified into seven groups using Sorenson similarity index and constructing the dendrogram. Snow pressure bends the stem toward the soil surface. Snow gliding pressure scratches stem and its base buds above the bent stem. Soil and debris move downward the slope as a result of snow gliding and rainfall runoff as well as wildlife and domestic animals. Snow gliding along with other natural factors have various effects on A. adscendens plant form which can be grouped under three categories: direct mechanical effect of snow, physiological effect of snow, and indirect effect of precipitation and wildlife. The environmental factors and plant physiological responses to them change the A. adscendens plant form from a funnel or ob-conical shape to a semi-funnel or semi ob-conical form.

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Soil loss due to erosion is a common problem in most parts of Iran. Reduced soil organic matter and lack of proper agricultural management have intensified the problem in recent years. Conservation tillage systems are becoming more widely used in corn production in other parts of the world because of soil losses due to wind and water erosion and energy inputs. Changes in tillage methods, however, create different environments for the germination, development and maturation of corn plants. Most corn hybrids have been selected and developed under conventional tillage systems but these hybrids mayor may not be well adapted to both systems. This study aims to evaluate the performance of five locally grown corn hybrids under zero and conventional tillage methods. The experiment was conducted for 2 years on a plot of land specified for this study. Experimental design was a split plot with randomized complete block arrangement and four replications.

Seedling and juvenile plant growth were not affected by tillage method and were similar for all hybrids. Plant dry matter was affected significantly by the cropping system and was lower in no-till method. Plant leaf area index and stem diameter reduced significantly in the no-till system. Reduction was greater in the second year of the experiment. Also grain yields were significantly different among years, tillage method and plant genotypes. Yield reduction was highest in the second year of the experiment under no-till cropping system. There was no interaction between tillage method and corn genotypes, indicating that, usually genotypes perform similarly with regard to grain yield under both tillage methods. The results suggest that corn production under no-till system in Isfahan is probably associated with yield reduction.

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Sensitivity of developmental stages of three sunflower cultivars to day length and temperature changes under field conditions were evaluated, and their development rates during various growth stages were modeled in a field experiment conducted in 1996 at the Agricultural Research Station, Isfahan University of Technology. Five dates of planting (April 27, May 12 and 27, and June 12 and 29) and three open pollinated sunflower cultivars (Record, Vnimik 8931 and Armavirec) were evaluated using a randomized complete block design with split-plot layout in three replications. Date of planting was considered to be the main plot and cultivars were randomized in sub-plots.

Number of days from planting (P) to head visible (HV) and P to first anther (FA) were significantly reduced with delay in planting as the result of increase in temperature during these periods. Number of days from P to physiological maturity (PM) was also significantly reduced with delay in P. This response, however, could not be explained by changes in temperature variables or day length. Number of days from HV to FA, in harmony with the partial stability of maximum and minimum temperatures during this period, was not affected by date of planting. Duration from FA to PM of the last planting date was significantly shorter than the other planting dates. This response was related to the persistence of the effect of high and stable maximum temperatures prevailing during HV to FA period of the last planting date. Armavirec was significantly earlier than Record and Vnimic 8931 for number of days from P to HV and from P to FA Cultivars showed significantly large differences for the FA to PM and P to PM durations. Armavirec was the earliest and Record was the latest cultivar. Based on the results obtained, it may be concluded that the cultivars under study were non-sensitive to photoperiod. Development rate (DR) of Armavirec responded linearly and DR of Record and Vnimic 8931 responded non-linearly to increases in temperature variables during P to HV and P to FA Development of Vnimic 8931 was faster than Record at high temperatures. DR of the cultivars decreased linearly during P to PM as day length increased. The relationship between DR and photoperiod could be used as a practical model for estimating P to PM duration of these sunflower cultivars.

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Muteh wildlife refuge, with an area of about 220,000 ha, is situated at 95 km north of Isfahan. In this refuge, 511 species of vascular plants belonging to 284 genera and 59 families live along with 117 species of vertebrate animals belonging to 84 genera and 37 families.

 Rare plants of the area were classified into two categories of “endangered” and “vulnerable” according to IUCN, 1996 categories. The endangered species include Astragalus chaetopodus Bunge. Astragalus eriostomus Bornm. Astragalus indistinctus Podl. and Maassoumi Cousinia phyllocephala Bornm. and Gauba Cousinia rhaphiocephala Rech. f. Cousinia straussii Hausskn. and C. Winkl. Ferula kashanica Rech. f. Onobrychis psoraleifolia Boiss. var. Psoraleifolia and var. pleiophylla Bornm. The vulnerable species include Bunium caroides (Boiss.) Hausskn. ex Bornm. Dielsiocharis kotschyi (Boiss.) O. E. Schultz Dionysia caespitosa (Duby) Boiss. Dorema ammoniacum D. Don. Dorema aucheri Boiss. Dracocephalum kotschyi Boiss. Echinophora platyloba DC. Hymenocrater bituminosus Fisch. and C. A. Mey. Pimpinella deverroides (Boiss.) Boiss. Prangos cheilanthifolia Boiss. and Thymus daenensis Celak subsp. daenensis.

 The rare animal species of the region were classified into four categories: “critically endangered”, “endangered”, “vulnerable”, and “conservation-dependent species”. The critically endangered species are Felis silvestris Schreber F. caracal Schreber Jaculus blanfordi Murray (mammals) Gypaetus barbatus Falco pelegrinoides F. cherrug and F. peregrinus (birds). The endangered species include Vulpes cana Blanford Ochotona rufescens Gray (mammals) Falco naumanni F. columbarius Chlamydotis undulata (birds) and Varanus griseus (reptilian). The vulnerable species are Gazella subgutturosa Guldensteadt Canis lupus Linnaeus Meles meles Linnaeus Hyaena hyaena Linnaeus (mammals) and Aquila chrysaetos (bird). And, finally, the conservation-dependent species include Ovis orientalis Linnaeus Capra aegagrus Elxleben Panthera pardus Linnaeus (mammals) and Ammoperdix griseogularis (bird). The results from this survey were compared with the findings from the survey of some other protected areas in Iran.

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It is believed that various types of field bean, including pinto, white and red, differ in adaptability to high temperatures and may, thus, differ in response to delay in planting. In order to evaluate this response, an experiment was conducted during 1996 at the Agricultural Research Station, Isfahan University of Technology, using a randomized complete block design with split-plot layout. Main plots consisted of four planting dates (April 28, May 13 and 28 and June 13) and sub-plots included four genotypes of common bean (red bean, c.v. Naz pinto beans, experimental lines 11816 and 16157 and a white bean, experimental line 11805).

 Number of branches per plant, number of pods per branch and per unit area, number of seeds per pod of main stem and branch, number of seeds per main stem, per branch and per unit area, 100-seed weight and seed yield significantly reduced, while harvest index significantly increased by delay in planting and consequent increases in temperature and reduction in time for growth. The lower harvest index obtained with early planting was the result of the lower efficiency of the produced vegetative growth due to the coincidence of seed filling period with high temperatures. Pinto bean line 11816 ranked the highest for number of branches per plant and harvest index among the genotypes evaluated and produced the highest seed yield (3030 kg ha^-1). Although red bean Naz ranked the highest for number of pods and seed per main stem and per unit area, it had the lowest harvest index and 100-seed weight and, consequently, produced the least seed yield (2254 kg ha^-1). The results obtained indicate that delay in planting adversely affects bean seed yield. Pinto bean line 11816 may have higher yield potential among the genotypes studied at all planting dates under conditions similar to the present experiment. No specific relationship was observed between apparent seed characteristics and plant tolerance to heat.

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Micronutrients availability including that of Zn is critical for optimum growth of plants. Zinc availability in calcareous soils of Iran is relatively low due to the presence of a large amount of CaCO₃ and high pH levels. Overapplication of phosphorus to soils may also cause P-induced Zn deficiency. The objective of this experiment was to evaluate the effect of phosphorus and zinc application on the growth and chemical composition of corn (Zea mays L.) under greenhouse conditions. Treatments consisted of a factorial combination of 5 levels of P (0, 25, 50, 100 and 200 µg P/g soil as KH₂PO₄) and 3 levels of Zn (0, 5 and 10 µg Zn/g soil as ZnSO₄. 7H₂O) in a completely randomized design with 3 replications. Plants were allowed to grow for 60 days and then cut at the soil surface.

 Results showed that P and Zn applications increased top dry weight. Applied P increased P concentration and total uptake in plants, but decreased Zn concentration and had no effect on Zn uptake. Zinc application decreased P concentration of com but increased Zn uptake and concentration. The P: Zn ratio in plants increased with P application but decreased with Zn addition. Application of P and Zn increased Fe concentration in plant but decreased Mn concentration and had no effect on Cu concentration. Prior to making any fertilizer recommendations, more research is required to precisely evaluate the response of com to P and Zn applications under field conditions.

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In order to investigate the best planting time and rice cultivars for the conditions in Khuzestan Province, seven high quality cultivars of rice namely Domsiah, Binam, Ramasanali Tarom, Sang Tarom, Hasansarai, Tarom Mahalli, Daylamani and Anboori were selected and studied in 4 planting dates starting in Mid-May, with intervals of 15 days. The experiment was conducted as a split plot design in randomized complete blocks with 3 replications for 2 years from 1995 in Shavoor Agricultural Research Station. Main plots were planting dates and subplots were allocated to cultivars.

Results of this experiment showed that significant differences existed among planting dates on grain yield only in the second year. Grain yields were different among cultivars in the two years of study. Simple and combined analyses indicated that there were significant interactive effects between planting dates and cultivars. Tiller number was different between planting date and cultivars in the first year. Interactive effect between planting date and cultivars on tiller number was not significant. Maximum grain number in spike obtained early June planting date (76 grains per spike) and lowest grain number in spike obtained early May planting date (28 grains). Among cultivars, Anboori with 152 and Daylamani with 17 grains had maximum and minimum grain numbers in spike, respectively. One-thousand grain weight was maximum in the early June planting date. Among cultivars, Binam and Daylamani had maximum and minimum grain weights, respectively. Highest fertility percentage was obtained in early June planting date compared to other planting dates. Fertility percentage of cultivars depended on temperature at growth stages before and at anthesis, which was early June for all cultivars. Among environmental factors affecting plant growth, temperature was relatively more important than other factors, particularly than the photoperiod. Even under Khuzestan conditions, there is a wide range of temperature levels for rice planting (from early March to early November) however, even this wide temperature range may not be enough to provide favourable conditions for planting all the cultivars.

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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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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.

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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.

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The objective of this research was to evaluate bromide leaching in a field under corn, wheat and alfalfa. Potassium bromide (300 kg/ha) was uniformly applied and 15 mm of water was sprinkled over the plots in the first and second years. Plots were leached 8 times during the first year and 9 times in the second year (each time with 100 mm of water). Soil samples were collected at 0-30, 30-60, 60-90 and 90-120 cm depths two days after each leaching practice. Bromide concentration in soil samples was measured using an ion selective electrode. Moisture content in each plot was measured using a neutron meter to a depth of 120 cm and after calculation of evaporation from soil surface, the net water applied was determined. CXTFIT software and Regional Stochastic Model (RSM) were used to simulate leaching under field conditions. The results showed that flow velocity and dispersivity of treatmens were not significantly different from the control in the first year, indicating that treatments had no effect on preferential flow. Control treatments were not significantly different in the first and second years. In the second year, flow velocity in wheat, corn and alfalfa treatments were 1.54, 1.86 and 2.21 times higher than flow velocity in the control, respectively. Dispersivity in alfalfa and corn treatments were 4.30 and 5.30 times higher as compared to the control. The increase in flow velocity and dispersivity is caused by an increase of preferential flow in the second year. The root channels remaining in soil at the end of the first year may also have increased preferential flow. After adding 25 cm of water, 30% of bromide leached from the top 50 cm soil in all plots in the first year and control plots in the second year but the values in the second year were 47, 67 and 70% of bromide leaching from the top 50 cm soil in wheat, corn and alfalfa plots, respectively.

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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.