Zeolite influences on nitrate leaching,nitrogen-use efficiency,yield and yield components of canola in sandy soil     

Majid Aghaalikhani  Majid Gholamhoseini  Aria Dolatabadian  Aydin Khodaei-Joghan  Kamal Sadat Asilan 《Archives of Agronomy and Soil Science》2013,59(10):1149-1169

With regard to the low cation-exchange capacity and large saturated hydraulic conductivity of sandy soils, a field experiment was carried out in 2006–2007 to determine the impact of zeolite on nitrogen leaching and canola production. Four nitrogen (N) rates (0, 90, 180, and 270 kg ha^–1) and three zeolite amounts (3, 6 and 9 t ha^?1) were included as treatments. The results demonstrated that the highest growth parameters and seed yield were attained with 270 kg N ha^?1 and 9 t zeolite ha^?1. However, the highest and the lowest seed protein percentage and oil content were obtained with 270 kg N ha^?1 accompanied by 9 t zeolite ha^?1, respectively. Nitrate concentration in drained water was affected by nitrogen and zeolite. The lowest and highest leached nitrate values were found in control without N and zeolite (N₀Z₀) and in treatments with the highest N supply without zeolite (N₂₇₀Z₀), respectively. In general, nitrogen-use efficiency decreased with an increase in N supply. Application of 9 t zeolite ha^?1 showed higher nitrogen use efficiency than other zeolite amounts. Also, application of more N fertilizer in soil reduced nitrogen uptake efficiency. In total, application of 270 kg N ha^?1 and 9 t zeolite ha^?1 could be suggested as superior treatment.  相似文献   

Allometric equations for urban ash trees (Fraxinus spp.) in Oakville,Southern Ontario,Canada     

Paula J. Peper  Claudia P. Alzate  John W. McNeil  Jalil Hashemi 《Urban Forestry & Urban Greening》2014,13(1):175-183

Tree growth equations are an important and common tool used to effectively assess the yield and determine management practices in forest plantations. Increasingly, they are being developed for urban forests, providing tools to assist urban forest managers with species selection, placement, and estimation of management costs and ecosystem services. This study describes the development of allometric equations for Fraxinus americana and F. pennsylvanica growing in Oakville, Canada. With data collected from 103 ash trees, five allometric models were tested to develop equations estimating diameter-at-breast-height (dbh), tree height, crown width and crown height, using age and dbh as explanatory variables. Mean annual growth rates are presented to demonstrate species growth performance and were not significantly different over the first 40 years of growth for the two species. Of all the tested random coefficient models for both species, the cubic with weight 1/x provided the best fit for estimating dbh from age. The best models for other parameters were the loglog for crown height from dbh, the quadratic for crown diameter from dbh, and the linear for tree height from dbh for F. americana. Model types showed more consistency for F. pennsylvanica with linear providing the best fit for crown diameter, crown height and tree height from dbh. The number of model types suggests the difficulty of fitting any single model to the vast array of conditions affecting plant growth in urban areas where management practices and environment can significantly influence tree size and growth. These models may be used to estimate the growth of ash tree populations in Oakville and communities with similar climate, soil, planting, and management environments.  相似文献   

Effect of performed operations management on the amount of sediment production in natural forests     

Seyed Armin Hashemi  Alireza Eslami  Sahar Tabibian 《中国林学(英文版)》2013,15(3):214-221

The present study on the sediment production in natural forests was carried out on an 13,284 ha area,ocated in Guilan Province, in the north of Iran. This area is under intensive management. We first analyzed the physi- sal factors of the area. Then, the amount of road construction, afforestation and harvested wood volume, as well as the harvesting method in the region were determined for the years between 1993 and 2010. The results show that the aver- age annual amount of sediment production in the entire region, over this 18-year period, has increased annually at a rate of 3.54 t.km-2 （R2 = 0.56） at a confidence level of 95%. Operations management and management methods used in ：his forest area has affected the amount of sediment production. Clear cutting and extensive harvesting methods in the region caused an increase in the amount of sediment production, as indicated by a coefficient of determination of 0.71, mplying that forest management may be considered effective and in harmony with the environment.  相似文献   

A scanner based neural network technique for color matching of dyed cotton with reactive dye     

Elham Sadat Yazdi Almodarresi  Javad Mokhtari  Seyed Mohammad Taghi Almodarresi  Mahdi Nouri  Ali Shams Nateri 《Fibers and Polymers》2013,14(7):1196-1202

Conventional theory for color matching is Kubelka-Munk, but it fails in some situations. New intelligent procedures such as neural networks could learn the behavior of a complex system and produce accurate prediction. This paper investigates the ability of MLP (multiple layer perceptron) neural network for color matching of cotton fabric. Three reactive dyes, namely Levafix Red CA, Levafix Yellow CA and Levafix Blue CA were used for experiments. The dyed samples were scanned and L * a * b * histogram were extracted. Different neural networks were trained and tested using L * a * b * histogram of fabric’s images and also L * a * b * values (D65, 10°) of fabrics. The results were encouraging. For neural networks including the L * a * b * histogram in input vector, colorants and their concentration were predicted with a mean square error (MSE) less than 10^?5 and an average value of color difference (CMC (1:2)) less than 1.5 for approximately 80 % of testing data.  相似文献   

Identification and characterization of fungi associated with internal wood lesions and decline disease of willow and poplar trees in Iran          下载免费PDF全文

H. Hashemi  H. Mohammadi 《Forest Pathology》2016,46(4):341-352

During the study of fungal trunk pathogens associated with urban trees decline in Shiraz (Iran), a serious decline of willow and poplar trees was observed. Therefore, an investigation was conducted on these trees in some areas of this city during spring and summer 2012 and 2013, to determine the main fungal trunk pathogens associated with these ornamental plants. Plant materials were collected from trees exhibiting disease symptoms such as yellowing, shoot canker, shoot dieback, defoliation and internal wood necrosis and decayed wood. Fungal isolations were made from discoloured or decayed wood tissue onto 2% malt extract agar (MEA) amended with streptomycin sulphate. Nine species, Fomes fomentarius, Diplodia seriata, Lasiodiplodia theobromae, Dothiorella sarmentorum, Neoscytalidium hyalinum, Diatrype whitmanensis, Phaeoacremonium rubrigenum, P. aleophilum and P. parasiticum, were identified based on morphology and DNA sequence comparisons. Pathogenicity tests were performed on detached shoots of willow and poplar trees under greenhouse conditions. Lasiodiplodia theobromae caused the longest lesions on willow. On poplar shoots, the longest lesions were caused by P. parasiticum. Diplodia seriata produced the smallest lesions on both woody hosts. First reports from willow wood include P. parasiticum, P. rubrigenum, D. whitmanensis, L. theobromae, D. seriata and N. hyalinum, while new reports from poplar wood include P. parasiticum and Do. sarmentorum. Based on our knowledge, this is also the first report of D. whitmanensis in Iran.  相似文献   

The Potential of Green Manure Mixtures to Provide Nutrients to a Subsequent Lettuce Crop     

Omid Reza Zandvakili  Elnaz Ebrahimi  Masoud Hashemi  Parisa Akbari 《Communications in Soil Science and Plant Analysis》2017,48(19):2246-2255

The objectives of this greenhouse experiment were to quantify the benefits of green manure (GM) diversity and to assess effect of GM on a succeeding lettuce crop. Species included barley (B), field pea (P), sunn hemp (S), and buckwheat (U). Treatments included single plantings of B and P and mixtures of B and P (BP), B, P, and S (BPS), and B, P, S, and U (BPSU). The pea GM had the highest shoot concentration of potassium, calcium, magnesium, manganese, zinc, and iron. Roots had higher concentrations of nutrients than shoots. Accumulation of nutrients in legumes was higher than in barley. The CO₂ flux from the soil suggests that the most intensive mineralization period occurred within two weeks after incorporation of GMs. The mixtures and single planting of P mixtures had a significant benefit over single planting of B regarding fresh and dry weight of the lettuce.  相似文献   

Wicking phenomenon in polyacrylonitrile nanofiber yarn     

Mahbube Sadat Musavi Jad  Seyed Abdolkarim Hosseini Ravandi  Hossein Tavanai  Razieh Hashemi Sanatgar 《Fibers and Polymers》2011,12(6):801-807

The aim of this paper is to investigate vertical wicking in polyacrylonitrile (PAN) electrospinning nanofiber yarn using image analysis. Colored liquid rising phenomenon into the yarn and the distance of liquid rise were determined as a function of time. The kinetics of capillary rise follows the Lucas-Washburn equation. The results show that capillary rise rate coefficient is being reduced with increasing yarn twist, due to the reduction of continuity and size of capillaries. Increasing heat treatment stretch from 0 % (draw ratio=1) to 50 % (draw ratio=1.5) increases the capillary rise rate coefficient, due to the more homogeneity of capillary spaces in the yarn structure and increasing heat treatment stretch from 50 to 100 % (draw ratio=2) reduces capillary rise rate coefficient, because of the low capillary length. The present study indicates that an appropriate choice in production parameters of nanofiber yarn is all important in obtaining the desired properties of capillary rise.  相似文献   

Silage fermentation profile,chemical composition and economic evaluation of millet and soya bean grown in monocultures and as intercrops          下载免费PDF全文

E. Jahanzad  A. Sadeghpour  M. Hashemi  R. Keshavarz Afshar  M. B. Hosseini  A. V. Barker 《Grass and Forage Science》2016,71(4):584-594

In recent years, dairy farmers in semi‐arid regions have shifted from maize (Zea mays L.) as their primary source of feed to drought‐tolerant crops, such as millet (Pennisetum glaucum L.), due to lack of water for irrigation. However, millet alone may not provide feed of sufficient quality and crude protein content for dairy cows. A field experiment was conducted in 2 years to evaluate (i) whether intercropping millet with a relatively drought‐tolerant soya bean cultivar (Glycine max Merr, cv. Williams) could improve silage quality with minimum yield penalty, and (ii) if the application of molasses could further enhance the nutritive value of silage of millet–soya bean intercrops. There were three intercropping ratios (60% millet with 40% soya bean, 50% millet with 50% soya bean, 40% millet with 60% soya bean) and monocultures of millet and soya bean. Mixed forages were treated with three levels of molasses: M₀ (without molasses), M₁, and M₂ (2·5 and 5% fresh matter respectively). Inclusion of soya bean in millet crops resulted in decreased silage yield compared with millet alone. The highest yield was obtained from the ratio of 60% millet with 40% soya bean. Molasses‐treated silage had higher lactic acid, lower pH, and lower acid detergent fibre (ADF) and neutral detergent fibre (NDF). Silage produced from millet–soya bean intercrops exhibited enhanced fermentation, indicated by lower pH (3·64) and higher lactic acid (16·63 g kg^?1 DM) than silage from monocultures. Intercropping ratios had lower water‐soluble carbohydrate, ADF and NDF than millet monoculture. Overall, an intercropping ratio of 60% millet with 40% soya bean was advantageous over other ratios in terms of higher yield, nutritive value and economic value.  相似文献   

Comparison of the minor coat protein gene sequences of aphid-transmissible and -nontransmissible isolates of <Emphasis Type="Italic">Citrus tristeza virus</Emphasis>     

Ali Barzegar  Heshmat Rahimian  Haleh Hashemi Sohi 《Journal of General Plant Pathology》2010,76(2):143-151

The nucleotide sequences for the minor coat protein (CPm) gene and its deduced amino acid sequences for two aphid-transmissible and two nontransmissible isolates of Citrus tristeza virus (CTV) from symptomless orchard trees of Miyagawa satsuma [Citrus unshiu (Macf.) Marc.] on trifoliate orange [Poncirus trifoliate (L.) Raf.] and declining Washington navel [C. sinensis (L.) Osb.] trees on sour orange (C. aurantium L.) rootstocks were analyzed and compared with those of highly transmissible CTV strains available in GenBank. The isolates produced severe symptoms on indicator plants and their aphid transmissibility was assayed through acquisition by A. gossypii of CTV and subsequent inoculation feeding on young Mexican lime seedlings. The CPm gene nucleotides and coded amino acid sequences were very similar among the nontransmissible isolates and among the transmissible. Five of 73 nucleotide substitutions that existed between CPm gene nucleotide sequence of nontransmissible and transmissible isolates caused changes in the deduced amino acid sequences of the nontransmissible isolates. Two nucleotide substitutions yielded new amino acids with similar properties. However, the three remaining mutations led to substitution of new amino acids with a different charge and polarity at positions 14, 238 and 239. The last two mutations occurred at the C-terminal region of the CPm, which is implicated in the formation of a salt bridge that helps to maintain the protein’s tertiary structure. Amino acid substitutions can affect aphid transmission efficiency by altering the conformation of the proteins or masking motifs involved in the interaction between CPm and aphid stylets.  相似文献   

Responses of Soya bean Yield and Yield Component Distribution across the Main Axis under Source–Sink Manipulation     

X. B. Liu  S. J. Herbert  A. M. Hashemi  G. V. Litchfield  Q. Y. Zhang  A. R. Barzegar 《Journal of Agronomy and Crop Science》2006,192(2):140-146

Extensive studies have been conducted regarding the source–sink alterations on soya bean [Glycine max (L.) Merr.] yield, but limited information is available for the seed yield and distribution of yield components across main nodes under whole‐plant light‐enriched conditions. A 2‐year research was conducted at the University of Massachusetts Agronomy Farm under ambient and light‐enriched conditions for two old and two new cultivars planted with a normal density. A randomized block design was used in each year. Light enrichment was initiated at the onset of flowering by installing a 90‐cm tall wire mesh fencing (mesh hole size 4–5 cm) adjacent to the centre row and sloping away at a 45° angle and was left in place for the remainder of the growing season. Five source–sink manipulations were initiated following the establishment of light enrichment. The yield sensitivity of the two old cultivars to the changes in source strength and light‐enriched conditions during reproductive period was much greater than that of the two new cultivars. The increased yield by light enrichment in various manipulations of source–sink treatments was, in part, due to increased branch contribution. Most pods were produced at the nodes in the middle sections of the plants and appeared in higher node position in new cultivars compared with the old cultivars. Seed number per pod and seed size was quite uniform across all node positions. Seed size of both the old and the new cultivars was responsive to changes in the source–sink ratio and changes in the environment during the growth of the soya bean plant. The results suggested that soya bean plants showed several mechanisms to control or realize their excess reproductive potential in a constantly changing environment.  相似文献