EM38 for volumetric soil water content estimation in the root-zone of deep vertosol soils     

M.B. Hossain  P.V. Lockwood  P. Frazier 《Computers and Electronics in Agriculture》2010,74(1):100-109

Electromagnetic induction sensors, such as EM38, are used widely for monitoring and mapping soil attributes via the apparent electrical conductivity (EC_a) of the soil. The sensor response is the depth-integrated combination of the depth-response function of the EM38 and ‘local’ electrical conductivity (EC_az) at depth. In deep, Vertosol soils, assuming the instrument depth-response function is not perturbed by the soil and where volumetric moisture content at depth (θ_v(z)) dominates EC_az, EM38 should be capable of predicting average moisture content without recourse to mathematically complicated, and unstable profile inversion processes. Firstly a multi-height EM38 experiment was conducted over deep Vertosol soils to confirm the veracity of the EM38 depth-response function and test the concomitant hypothesis of the EM38 response being an integrated (i.e. additive) combination of depth-response function and θ_v(z). Secondly, depth profiles of moisture content were used to calibrate the EM38 to infer average θ_v(z) within the ‘root-zone’ of crop plants—here taken to be surface—0.8 m and surface—1.2 m. EM38 calibration was performed using soil samples acquired from both extracted cores and excavated pits. Mathematical summation of measured θ_v(z) from sectioned cores and the known depth-response function of the EM38 was found to explain 99% and 97% of the variance in measured EC_a for horizontal and vertical dipole configurations at multiple sensor heights above the ground. Average θ_v from surface to 0.8 m () and surface to 1.2 m () explained only 37% and 46% of the variance in on-ground EC_a for vertical dipole configuration measurements compared to 55% and 56% of the variance for horizontal dipole configuration. In a separate validation experiment, the shape of the vertical moisture profile proved highly influential in determining the ability of the calibration equations to infer underlying average moisture content, especially where the depth profile shapes differed between sensor calibration and subsequent field validation (for example following rainfall or irrigation).  相似文献   

Performance of mono‐sex tilapia (Oreochromis niloticus) in rice field with different ditch size          下载免费PDF全文

Md. Akhtar Hossain  Md. Anisur Rahman Mridha  Abul Kalam Md. Azad Shah  Md. Nahiduzzaman  Md. Sharif Uddin 《Aquaculture Research》2015,46(8):1891-1901

The effects of ditch size on growth and production of mono‐sex tilapia, Oreochromis niloticus in rain fed concurrent rice–fish system were technically and economically evaluated for a period of 4 months. Three different ditch sizes were tried: 5%, 10% and 15% of the total cultivable rice field. The fish fingerlings stocking density (5000 ha^?1) and management practices were similar in all plots. The water temperature, dissolve oxygen, pH, Secchi disc visibility, ortho‐phosphate, ammonia nitrogen and alkalinity were found to be in the range of 31.5–31.9°C, 5.10–5.27 mg L^?1, 7.56–7.62, 34.81–35.41 cm, 0.88–0.96 mg L^?1, 0.014–0.021 mg L^?1 and 66.23–69.76 mg L^?1, respectively, and all the values were found suitable for tilapia fish farming. Sediment organic matter, available nitrogen and phosphorous were increased significantly (P < 0.05) in all plots after cultivating the fish. Larger ditch size (15% of the total land area) resulted in significantly (P < 0.05) higher specific growth rate, survival and fish production compared with the smaller (5%) and medium (10%) ditch sizes. However, significantly (P < 0.05) higher net income and benefit–cost ratio were obtained in medium ditch size with the values of 2.6% and 3.6% higher than the smaller and larger ditch sizes respectively. It is concluded that rice–fish farming in a rain fed ecosystem of Bangladesh with medium ditch size and stocking density of 5000 ha^?1 mono‐sex tilapia can achieve better economic return.  相似文献   

A survey on the faunal diversity of Savar Upazila, Dhaka, Bangladesh     

Hossain E  Chowdhury MM  Iqubal KF 《Pakistan journal of biological sciences: PJBS》2008,11(3):373-379

A survey was conducted during January to December 2006 to assess the status of faunal diversity of Savar Upazila, Dhaka, Bangladesh. A total of 30 species of birds, 24 species of winter birds, 7 species of reptiles, 3 species of amphibians, 15 species of mammalians and 32 species of fishes were recorded. Relative abundance of those species were determined. Of the birds, House Sparrow (Passer domesticus) was abundant while Blyth's Kingfisher (Alcedo hercules), Rock Eagle Owl (Bubo bengalensis), Hooded Pitta (Pitta sordida), Black-headed Oriole (Oriolus xanthornus), White-winged Duck (Cairina seululala) and Duck (Anser indicus) were rare. The relative abundance of winter bird could not be assessed because of their migratory habit. Striped keelback (Amphiesma stolata) and Common Smooth Water Snake (Enhydris enhydris) were very common while Black pond turtle (Geoclyms hamiltonii) and Pond tortoise (Melanochelys trijuga) were recorded as endangered. Common Toad (Bufo melanostictus) were abundant but Bull Frog (Rana tigrina) was rare. Asiatic Wild Dog (Cuon alpinus) and House Mouse (Mus musculus) were abundant while Common Otter, Large Indian Civet, Irrawaddy River Dolphin, Indian Hare were rare. Carpu, Silver carp, Tilapia, Nilotica were abundant while, Freshwater Garfish, One stripe spinyeel and Grey Featherback were rare. Landfilling, deforestation, poaching, industrial effluents and current jal were identified as major threats to the faunal diversity of Savar area.  相似文献   

Identification of bacterial agents causing mortality in postlarvae of giant freshwater prawn (Macrobrachium rosenbergii) in south‐west coastal districts of Bangladesh          下载免费PDF全文

Farzana E Hossain  Abu Mohammed Ramim  M Shafiqur Rahman  Ali Muhammad Omar Faruque  M Niamul Naser  Muhammad Manjurul Karim 《Aquaculture Research》2017,48(7):3545-3555

Following an incidence of freshwater prawn Macrobrachium rosenbergii postlarvae (PL) mortality in hatcheries in summer 2012, samples from dead PL, rearing water and prawn feed from two south‐west coastal districts of Bangladesh were collected to isolate, identify and characterize the agents causing PL mortality. Antibiogram profile of sixteen randomly selected bacteria, isolated from dead PL, that grew on TCBS, to 20 different antibiotics belonging to 12 major groups revealed that the drug resistance pattern varied from moderate (56% to the drugs: ciprofloxacin, cefotaxime, nitrofurantoin, kanamycin) to complete (to penicillin, ceftazidime and oxacillin) level. To identify the isolates, amplified rDNA restriction analysis (ARDRA) classified them in to four groups, and RAPD (randomly amplified polymorphic DNA) typing yielded nine different types of isolates within these four ARDRA groups. The 16S rDNA gene sequences identified that the groups were genotypically diverse belonging to the bacterial species: Enterobacter cloacae, Klebsiella pneumoniae, Exiguobacterium profundum and Enterococcus casseliflavus, respectively, that all demonstrated their killing potential to PLs in a simulated environment. The study therefore identified four different bacterial pathogens, one of which, Exiguobacterium profundum is reported for the first here in Bangladesh, that demand special consideration for disease management strategy.  相似文献   

Response of berried prawn (Macrobrachium rosenbergii) to commercial probiotics          下载免费PDF全文

Devkusum Barua  Jewel Das  Istiaq Ahmad Chowdhury  Md Sohrab Hossain  Hiranmoy Bhattacharjee  M Zahedur Rahman Chowdhury  Nani Gopal Das  S M Sharifuzzaman 《Aquaculture Research》2017,48(12):6016-6020

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Evaluation of Meat and Bone Meal as Replacement for Protein Concentrate in the Practical Diet for Sutchi Catfish,Pangasius hypophthalmus (Sauvage 1878), Reared under Pond Condition     

M. Abdul Kader  Mahbuba Bulbul  Saichiro Yokoyama  Manabu Ishikawa  Shunsuke Koshio  M. Sakhawat Hossain  Gias Uddin Ahmed  M. Arshad Hossain 《Journal of the World Aquaculture Society》2011,42(3):287-296

An 80‐d feeding trial was conducted to evaluate meat and bone meal (MBM) as replacement of protein concentrate (PC) in practical diets for sutchi catfish, Pangasius hypophthalmus. Triplicate groups of juvenile sutchi catfish (initial weight 4.80 g) were stocked at the rate of 20,000 fish/ha in 12 earthen ponds (30 m² each). Four isocaloric diets (4.12 kcal/g) were formulated by replacing 0 (Diet 1, control), 33 (Diet 2), 67 (Diet 3), and 100% (Diet 4) PC protein with MBM. The growth parameters [final weight, % weight gain, and specific growth rate (SGR)] of fish fed Diets 1, 2, and 3 were not significantly different (P > 0.05) from each other but were significantly (P < 0.05) higher than those in Diet 4. The protein content in fish fed Diet 4 was significantly (P < 0.05) lower than the others. The total production of fish in different treatments ranged between 1917 and 2648 kg/ha/80 d. A simple economic analysis determined that the highest net profit (Tk. 52,965/ha) was obtained with Diet 2 and the lowest (Tk. 27,127/ha) with Diet 4 having 100% PC protein replacement. From the results of the study it is concluded that MBM can substitute up to 67% PC protein in catfish diet without hampering the growth and feed utilization.  相似文献   

Dietary supplementation of β‐glucan improves growth performance,the innate immune response and stress resistance of red sea bream,Pagrus major          下载免费PDF全文

M.A.O. Dawood  S. Koshio  M. Ishikawa  S. Yokoyama  M.F. El Basuini  M.S. Hossain  T.H. Nhu  A.S. Moss  S. Dossou  H. Wei 《Aquaculture Nutrition》2017,23(1):148-159

A 56‐day feeding trial was conducted to evaluate the effects of supplemented diets with β‐glucan (BG) at four levels [0 (D1), 250 (D2), 500 (D3) and 1000 (D4) mg BG kg^?1] on red sea bream, Pagrus major. The obtained results revealed a significant increase (P < 0.05) in final body weight, weight gain, specific growth rate, feed intake, body protein content, lysozyme activity and tolerance against low‐salinity stress test in all BG‐supplemented groups when compared with BG‐free group. Furthermore, D4 group resulted in a significant increase in feed efficiency ratio, protein gain, protein and lipid digestibilities, serum bactericidal activity and peroxidase content when compared with D1 group (P < 0.05). Haematocrit and plasma protein content in D3 group were significantly higher than those in D1 group (P < 0.05). Interestingly, BG supplementation decreased glutamic oxaloacetic transaminase (GOT) in D2 group and reactive oxygen metabolites in D2, D3 and D4 groups when compared with D1 group. Following low‐salinity stress test, significantly higher amounts of secreted mucus were observed in fish fed D2 and D4 diets than those from fish fed D1 diet (P < 0.05). In conclusion, the supplementation of BG improves growth, stress resistance and immune response of P. major.  相似文献   

Nucleoside by‐product dietary supplementation influences blood chemistry,immune response,oxidative stress resistance and intestinal morphology of juvenile amberjack,Seriola dumerili          下载免费PDF全文

M.S. Hossain  S. Koshio  M. Ishikawa  S. Yokoyama  N.M. SONY  T. Fujieda 《Aquaculture Nutrition》2017,23(6):1390-1400

We explored the influence of nucleoside by‐products (NBP) on blood chemistry, immune response, oxidative stress and intestinal morphology of Seriola dumerili. Four experimental diets were formulated where diets 1–3 are semipurified and supplemented with liquid NBP at concentration of 0 (D1, negative control), 30 (D2) and 90 (D3) g/kg. Diet 4 (D4) is a fishmeal‐based positive control diet. Each diet was randomly allocated to triplicate groups of fish for 50 days. The results revealed a significant influence of NBP supplementations on total cholesterol, blood urea nitrogen and triglyceride level. Lysozyme activity (LA), total serum protein (TSP) and peroxidase activity (PA) also increased with NBP supplementation as compared to the negative control. TSP, PA and LA were numerically higher in diet groups D2 and D4, respectively. Anterior enterocyte height (hE) was higher in diet group D4, while NBP‐supplemented groups showed intermediate values with D1 group and negative control group showed significantly lowest value. Supplementation of NBP also increased anterior fold height (hF) and microvillus height and posterior hF, hE and microvillus height compared with D1. Finally, we concluded that NBP can be used as a cheaper nucleotide/nucleoside source for amberjack. Supplementation of more than 30 g/kg in diets improved blood chemistry, non‐specific immunity, oxidative stress resistance and intestinal morphology of amberjack.  相似文献   

Vibrogen‐2 vaccine trial in lumpfish (Cyclopterus lumpus) against Vibrio anguillarum     

Setu Chakraborty  Trung Cao  Ahmed Hossain  Hajarooba Gnanagobal  Ignacio Vasquez  Danny Boyce  Javier Santander 《Journal of fish diseases》2019,42(7):1057-1064

Lumpfish (Cyclopterus lumpus), a native fish of the North Atlantic Ocean, is utilized as cleaner fish to biocontrol sea lice infestations in Atlantic salmon aquaculture. However, bacterial infections are affecting cleaner fish performance. Vibrio anguillarum, the aetiological agent of vibriosis, is one of the most frequent bacterial infections in lumpfish, and effective vaccine programmes against this pathogen have been identified as a high priority for lumpfish. Vibrogen‐2 is a commercial polyvalent bath vaccine that contains formalin‐inactivated cultures of V. anguillarum serotypes O1 and O2, and Vibrio ordalii. In this study, we evaluated Vibrogen‐2 efficacy in lumpfish against a local isolated V. anguillarum strain. Two groups of 125 lumpfish were bath‐immunized, bath‐boost‐immunized at four weeks post‐primary immunization, and intraperitoneally (i.p.) boost‐immunized at eight weeks post‐primary immunization. The control groups were i.p. mock‐immunized with PBS. Twenty‐seven weeks post‐primary immunization, the fish were i.p. challenged with 10 or 100 times the V. anguillarum J360 LD₅₀ dose. After the challenge, survival was monitored daily, and samples of tissues were collected at ten days post‐challenge. Commercial vaccine Vibrogen‐2 reduced V. anguillarum tissue colonization and delayed mortality but did not confer immune protection to C. lumpus against the V. anguillarum i.p. challenge.  相似文献   

Tropical hilsa shad (Tenualosa ilisha): Biology,fishery and management     

M. Shahadat Hossain  S. M. Sharifuzzaman  Muhammad Abdur Rouf  Robert S. Pomeroy  Md Delwer Hossain  Sayedur R. Chowdhury  Sheikh AftabUddin 《Fish and Fisheries》2019,20(1):44-65

Tropical hilsa shad, which is an anadromous fish migrating from the sea to spawn in freshwater river, constitutes an important fishery in some Asian and Middle East countries, particularly in Bangladesh. But, historical information on hilsa biology and ecology has confronted the scientists and policymakers with research and management challenges. We have reviewed both the old and recent findings on hilsa fishery to document the status of knowledge and potential gaps, necessary to comprehend for formulating a more effective fishery management plan. Thus, there has been a decline in hilsa catches in the riverine system associated with shift in fish migration routes, indiscriminate harvesting of brood and juvenile fish, and degradation of habitat. Specifically, the riverine hilsa catches peaked in the 1960s, declining thereafter, and became relatively abundant in marine waters since 1990s. Biological data indicated that hilsa goes through multiple reproductive cycles; therefore, a comprehensive understanding of reproductive biology, recruitment by various cohorts, stock abundance and habitats across the life cycle are necessary to accurately impose fishery regulatory measures, such as fishing ban in spawning season in Bangladesh. Moreover, domestication initiative is important for artificial seed production and mariculture development of hilsa that can not only offer economic return to small‐scale farmers but also reduce the growing pressure on capture fishery. Importantly, the arrangement of co‐management is found ideal as fishermen, scientists and managers can work jointly to improve the regulatory processes and to sustain the hilsa fishery over time.  相似文献