Simulation of 1D surface and 2D subsurface water flow and nitrate transport in alternate and conventional furrow fertigation   总被引：3，自引：0，他引：3  

Hamed Ebrahimian  Abdolmajid Liaghat  Masoud Parsinejad  Enrique Playán  Fariborz Abbasi  Maryam Navabian 《Irrigation Science》2013,31(3):301-316

Increasing water and fertilizer productivity stands as a relevant challenge for sustainable agriculture. Alternate furrow irrigation and surface fertigation have long been identified as water and fertilizer conserving techniques in agricultural lands. The objective of this study was to simulate water flow and fertilizer transport in the soil surface and in the soil profile for variable and fixed alternate furrow fertigation and for conventional furrow fertigation. An experimental data set was used to calibrate and validate two simulation models: a 1D surface fertigation model and the 2D subsurface water and solute transfer model HYDRUS-2D. Both models were combined to simulate the fertigation process in furrow irrigation. The surface fertigation model could successfully simulate runoff discharge and nitrate concentration for all irrigation treatments. Six soil hydraulic and solute transport parameters were inversely estimated using the Levenberg–Marquardt optimization technique. The outcome of this process calibrated HYDRUS-2D to the observed field data. HYDRUS-2D was run in validation mode, simulating water content and nitrate concentration in the soil profiles of the wet furrows, ridges and dry furrows at the upstream, middle and downstream parts of the experimental field. This model produced adequate agreement between measured and predicted soil water content and nitrate concentration. The combined model stands as a valuable tool to better design and manage fertigation in alternate and conventional furrow irrigation.  相似文献   

The possible role of stray dogs and cats in the epidemiology of some bacterial human pathogens in Egypt     

M A Siam  A M Karim  O M Hamed  A Zakaria 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1973,20(6):409-414

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Accumulation of Ions in Shoot and Seed of Quinoa (Chenopodium ‎quinoa Willd.) Under Salinity Stress     

Parisa Maleki  Hossein Ali Bahrami  Hamed Rezaei  Leila Esmaeelnejad 《Communications in Soil Science and Plant Analysis》2019,50(6):782-793

Quinoa (Chenopodium quinoa Willd.) is a high-nutrient halophyte suitable for ?cultivating in semi-arid climates and saline soils. The current study investigated the ?effect of various water salinities (EC_i) (i.e., 0.3, 10, 15, 20, and 25 dS m^?1) and different ?irrigation methods (IMs) on accumulation of calcium (Ca), magnesium (Mg), ?sodium (Na), and chloride (Cl) ions in shoot (stem+leaves) of quinoa at the end of vegetation (onset of flowering) and seed at the end of seed-filling. Therefore, 30 pots (five EC_i and two IM in three replications) were prepared with similar conditions. Considering that the salinity threshold value (STV) of quinoa varies during growth and is 8, 20 and 15 dSm^?1 at each of ?establishment, flowering, and seed-filling growth stages, the two IMs consisted of considering STV at each growth stage (T) and permanent irrigation by ?constant levels of EC_i(P). Results indicated that by increasing the EC_i from 0.3 to 25 dSm^?1 the amount of Na, Cl, and Mg in shoot increased 82.2%, 75.8%, and 8.7%, respectively, while Ca decreased 37.2%. In seeds, Na and Cl increased 43.3% and 50%, respectively, while Mg increased 8% and Ca did not change significantly. An increase in EC_i ?significantly changed ion accumulation content, especially at EC_i higher than STV, ?because it is the onset of damage due to salinity stress and particularly in? ??shoot compared to seed due to the halophytic properties of quinoa. The T ?method of irrigation was preferred due to less accumulation of Na and Cl in ?shoot and seed, and therefore less damage and loss, especially at higher ?salinities.?  相似文献   

Ecology of wood‐inhabiting fungi in northern forests of Iran     

Ehsan Bari  Hamed Aghajani  Katie M. Ohno  Roya Shahi  Mike D. C. Hale  Mohsen Bahmani 《Forest Pathology》2019,49(2)

Wood‐decay fungi are important in forest ecosystems and play an important role in nutrient and carbon recycling. The scope of this research was to identify wood‐inhabiting and wood‐decay macrofungi and determine their ecology. We sampled standing trees and dead wood of oak and hornbeam in the northern forests of Iran, specifically in Mazandaran and Golestan provinces. We assessed the influence of field slope, elevation, site direction and the height of fungal sporocarp position on the tree. The species of wood‐inhabiting and wood‐decay fungi belonged to 11 families: Polyporaceae; Stereaceae; Ganodermataceae; Physalacriaceae; Agaricaceae; Xylariaceae; Pluteaceae; Coprinaceae; Strophariaceae; Pleurotaceae; and Hydnaceae. The most common fungal species identified belonged to the Polyporaceae and Ganodermataceae and predominantly grew on trees growing on a slope of 20%, at an altitude of 700–900 m, 0–3 m from the ground a southwesterly site direction and the northern sides of both tree species. These results indicated that field slope was the most important factor in determining fungal sporocarp abundance.  相似文献   

Effects of Feeding Time on Growth,Survival, and Food Conversion Ratio of Huso huso Fingerlings     

Mohammad Sudagar  Abbas Hajibaglo  Hamed Kolangi Miandare 《Journal Of Applied Aquaculture》2013,25(1):81-87

This study was carried out to determine the effect of feeding time on growth parameters, food conversion ratio, and survival rate of Huso huso fingerlings (2.11 ± 0.03 g) over a period of five weeks. Fish in triplicate tanks were fed a commercial pelleted diet four times every 24 h on one of four schedules: at 08:00, 11:00, 14:00, and 17:00 h (day feeding); at 08:00, 12:00, 18:00, and 22:00 h (day/night feeding); at 18:00, 21:00, 24:00, and 06:00 h (night feeding); or at 08:00, 12:00, 18:00, and 22:00 h (full dark feeding). At the end of the experimental period, fish in the day-fed group had significantly (P < 0.05) better final weight, daily growth rate, specific growth rate, survival, condition factor, and food conversion ratio than day/night and night-fed groups. Performance of fish fed under full dark conditions was intermediate between day-fed and the other groups. In terms of rearing costs, daytime feeding of Huso huso is the most efficient.  相似文献   

Modeling paddy field subsurface drainage using HYDRUS-2D     

Hamed Ebrahimian  Hamideh Noory 《Paddy and Water Environment》2015,13(4):477-485

All of steady and non-steady subsurface drainage equations were developed mostly based on water flow pattern in an ordinary field conditions. However, subsurface drainage in a paddy field is quite different from subsurface drainage in an ordinary field. Thus, it is necessary to develop new equations and mathematical models to design subsurface drainage system in a paddy field. The objective of this study was to apply the HYDRUS-2D model, based on the Richard’s equation, to simulate water flow under subsurface drainage in a paddy field for various drain depths (0.5, 0.75 and 1.0 m) and spacings (7.5 and 15.0 m), surface soil textures (clay loam and silty clay loam) and crack conditions. Simulation results were compared with two well-known drainage equations. The maximum drainage rate was obtained under 7.5-m spacings and 1-m depth. With increasing drain spacings, the drainage rate decreased. Drain spacings had more effect on drainage rate and water pressure head as compared to drain depth. Drainage rates calculated by the Hooghoudt’s and Murashima and Ogino’s equations were much lower than those calculated by the Richard’s equation. The Hooghoudt’s equation, developed for ordinary fields, did not perform well for paddy fields. This study also proved the importance of cracks in subsurface drainage system of paddy fields. HYDRUS-2D stands as a robust tool for designing subsurface drainage in a paddy field.  相似文献   

A comparison of root distribution of three hardwood species grown on a hillside in the Caspian forest,Iran     

Ehsan Abdi  Baris Majnounian  Hassan Rahimi  Mahmud Zobeiri  Zahra Mashayekhi  Hamed Yosefzadeh 《Journal of Forest Research》2010,15(2):99-107

Slope is a complex environmental factor that can subject plants to a number of mechanical stresses. The anchorage of roots and improvement of slope stability mainly depend on specific properties of root systems, such as root distribution. In the present study, 24 trees (from three species) growing on gentle slopes (10–20°) were randomly chosen for root distribution analysis. The profile trenching method was used to obtain root characteristics. The findings indicated that root area ratio (RAR) decreased with depth and that maximum RAR values were observed in the upper layers; RAR values were between 0.0004% and 6.6444%. Average RAR values were not statistically different in upslope and downslope layers except in one case. The dot grid method (100 × 150 mm) usually overestimated the RAR values. The amount of roots decreased with depth following a power law. About 50% and 90% of roots were located in the first 30 and 60 cm depths, respectively. Results of analysis of covariance (ANCOVA) showed a significant effect of diameter at breast height (DBH) on total RAR but not on the total number of roots. About 70% of roots had diameter of less than 10 mm. Spearman’s correlation showed significant negative correlation between the total number of roots and the amount of N, P, and K elements, and a positive correlation between DBH and RAR. The results serve to develop understanding of the biotechnical characteristics of root systems of Caspian species.  相似文献   

Evaluation of Tunisian milk quality in dairy herds: Inter‐relationship between chemical,physical and hygienic criteria     

Ahmed Gargouri  Houda Hamed  Besma Ben Ali  Abdelfettah Elfeki  Radhouane Gdoura 《Animal Science Journal》2014,85(6):714-721

The objective of this paper was to evaluate the global milk quality in Tunisian dairy herds. Samples of milk were analyzed for chemical, physical and hygienic parameters. Milk total solids, fat content and density were consistently correlated and one of them can be used as a chemical indicator of milk quality. The somatic cell count value of 689 × 10³/mL was higher than the recommended threshold. All milk samples were positive for the major pathogen Staphylococcus aureus. These hygienic parameters were related more closely with chloride content, minerals and electrical conductivity, which allows them to be used as indicators of mammary gland infection. It was concluded that milk producers have at hand rapid and easy tools for assessing the overall quality of milk.  相似文献   

Effect of carbon nanotube on physical and mechanical properties of natural fiber/glass fiber/cement composites     

Hamed Younesi Kordkheili  Shokouh Etedali Shehni  Ghorban Niyatzade 《林业研究》2015,(1):247-251

The objective of this investigation was to introduce a cement-based composite of higher quality. For this purpose new hybrid nanocomposite from bagasse fiber,glass fiber and multi-wall carbon nanotubes(MWCNTs)were manufactured. The physical and mechanical properties of the manufactured composites were measured according to standard methods. The properties of the manufactured hybrid nanocomposites were dramatically better than traditional composites. Also all the reinforced composites with carbon nanotube, glass fiber or bagasse fiber exhibited better properties rather than neat cement.The results indicated that bagasse fiber proved suitable for substitution of glass fiber as a reinforcing agent in the cement composites. The hybrid nanocomposite containing10 % glass fiber, 10 % bagasse fiber and 1.5 % MWCNTs was selected as the best compound.  相似文献   

Phytotoxic activity of bibenzyl derivatives from the orchid Epidendrum rigidum     

Hernández-Romero Y  Acevedo L  Sánchez Mde L  Shier WT  Abbas HK  Mata R 《Journal of agricultural and food chemistry》2005,53(16):6276-6280

A whole plant chloroform-methanol extract of the orchid Epidendrum rigidum inhibited radicle growth of Amaranthus hypochondriacus seedlings (IC50 = 300 microg/mL). Bioassay-guided fractionation furnished four phytotoxins, namely, gigantol (1), batatasin III (2), 2,3-dimethoxy-9,10-dihydrophenathrene-4,7-diol (9), and 3,4,9-trimethoxyphenanthrene-2,5-diol (11), along with the known flavonoids apigenin, vitexin, and isovetin and the triterterpenoids 24,24-dimethyl-9,19-cyclolanostane-25-en-3beta-ol (14) and 24-methyl-9,19-cyclolanostane-25-en-3beta-ol (15). Stilbenoids 1, 2, 9, and 11 inhibited radicle growth of A. hypochondriacus with IC50 values of 0.65, 0.1, 0.12, and 5.9 microM, respectively. Foliar application of gigantol (1) at 1 microM to 4 week old seedlings of A. hypochondriacus reduced shoot elongation by 69% and fresh weight accumulation by 54%. Bibenzyls 1 and 2, as well as synthetic analogues 4'-hydroxy-3,3',5-trimethoxybibenzyl (3), 3,3',4',5-tetramethoxybibenzyl (4), 3,4'-dihydroxy-5-methoxybibenzyl (5), 3'-O-methylbatatasin III (6), 3,3',5-trihydroxybibenzyl (7), and 3,4',5-trihydroxybibenzyl (8), were tested for phytotoxicity in axenic cultures of the small aquatic plant Lemna pausicostata. All bibenzyls derivatives except 7 and 8 inhibited growth and increased cellular leakage with IC50 values of 89.9-180 and 89.9-166 microM, respectively. The natural and synthetic bibenzyls showed marginal cytotoxicity on animal cells. The results suggest that orchid bibenzyls may be good lead compounds for the development of novel herbicidal agents.  相似文献