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91.
Md. Abu Hanif Ranjan Mitra Roy Md. Shafiqul Bari Polash Chandra Ray Md. Shoaibur Rahman Md. Faruq Hasan 《Small-Scale Forestry》2018,17(4):505-522
Agroforestry is one of the most sustainable land management systems practiced around the world due to the socioeconomic benefits that it brings to farmers. In Bangladesh, farmers practice agroforestry, applying indigenous knowledge. The present study was designed to identify the present status, management practices and its role in improving the livelihoods of farmers in northern Bangladesh. Data for the study were collected through quantitative and qualitative methods. A total of 29 tree and 38 agricultural crop species were planted by the102 farmers interviewed. Mangifera indica (relative prevalence 49%) is the most predominant species, followed by Eucalyptus camaldulensis (relative prevalence 35.4%). Farmers of northern Bangladesh plant trees in cropland for fruits (90%), fuel wood (87%) and timber production (79%). Fruit trees were planted with wider spacing while forest and fuel wood species were planted with narrower spacing. Farmer’s livelihoods improved enormously by practicing agroforestry as they have more access to food, fodder and fuel wood which is reflected by greater access to livelihood capitals (except social capital). However, farmers have experienced increased incidences of pests and diseases to the annual crops and trees. Agroforestry practices increases species diversity, ensure economic return and sustain farmer’s livelihoods. 相似文献
92.
93.
Eva van Gorsel Nicolas Delpierre Ray Leuning Andy Black J. William Munger Steven Wofsy Marc Aubinet Christian Feigenwinter Jason Beringer Damien Bonal Baozhang Chen Jiquan Chen Robert Clement Kenneth J. Davis Ankur R. Desai Danilo Dragoni Sophia Etzold Thomas Grünwald Lianhong Gu Bernhard Heinesch Lucy R. Hutyra Wilma W.P. Jans Werner Kutsch B.E. Law Monique Y. Leclerc Ivan Mammarella Leonardo Montagnani Asko Noormets Corinna Rebmann Sonia Wharton 《Agricultural and Forest Meteorology》2009,149(11):1919
Micrometeorological measurements of nighttime ecosystem respiration can be systematically biased when stable atmospheric conditions lead to drainage flows associated with decoupling of air flow above and within plant canopies. The associated horizontal and vertical advective fluxes cannot be measured using instrumentation on the single towers typically used at micrometeorological sites. A common approach to minimize bias is to use a threshold in friction velocity, u*, to exclude periods when advection is assumed to be important, but this is problematic in situations when in-canopy flows are decoupled from the flow above. Using data from 25 flux stations in a wide variety of forest ecosystems globally, we examine the generality of a novel approach to estimating nocturnal respiration developed by van Gorsel et al. (van Gorsel, E., Leuning, R., Cleugh, H.A., Keith, H., Suni, T., 2007. Nocturnal carbon efflux: reconciliation of eddy covariance and chamber measurements using an alternative to the u*-threshold filtering technique. Tellus 59B, 397–403, Tellus, 59B, 307-403). The approach is based on the assumption that advection is small relative to the vertical turbulent flux (FC) and change in storage (FS) of CO2 in the few hours after sundown. The sum of FC and FS reach a maximum during this period which is used to derive a temperature response function for ecosystem respiration. Measured hourly soil temperatures are then used with this function to estimate respiration RRmax. The new approach yielded excellent agreement with (1) independent measurements using respiration chambers, (2) with estimates using ecosystem light-response curves of Fc + Fs extrapolated to zero light, RLRC, and (3) with a detailed process-based forest ecosystem model, Rcast. At most sites respiration rates estimated using the u*-filter, Rust, were smaller than RRmax and RLRC. Agreement of our approach with independent measurements indicates that RRmax provides an excellent estimate of nighttime ecosystem respiration. 相似文献
94.
Lopez-Benavides MG Williamson JH Lacy-Hulbert SJ Cursons RT 《Veterinary microbiology》2009,134(1-2):186-191
Heifers managed under pastoral conditions are at risk from Streptococcus uberis mastitis infections at calving. A total of 397 heifers from six farms around New Zealand were enrolled in a study to identify and enumerate S. uberis on teat-ends of heifers in the peri-partum period, and to understand the effect of teat-spraying in the pre-calving period on the prevalence and incidence of S. uberis mastitis post-calving. Heifers were randomly assigned to Control or Sprayed groups. Sprayed heifers were teat-sprayed once, three times a week (Monday, Wednesday and Friday) with a commercial iodine-based teat sanitizer, starting at 3 weeks prior to calving and ending at day of calving. Across three farms, all glands of cows in both groups were sampled at calving to determine S. uberis intra-mammary infection (IMI) prevalence. For all farms, clinical mastitis (CM) cases detected during the week after calving were sampled and submitted for bacteriological analysis. Swabbing of teat-ends of 54 heifers from one farm showed that heifers had a pre-existing S. uberis contamination averaging 610 colony-forming units per swab (cfu/swab), at 3 weeks prior to calving. At calving, teat-end contamination was 560 cfu/swab for Sprayed heifers and 1775 cfu/swab for Control heifers. Two weeks after calving, teat-end contamination was similar between both groups, at 30 cfu/swab. The prevalence of S. uberis IMI was significantly lower in the Sprayed (3.5% glands) vs. the Control (7.4%) heifers in the first week after calving. There was a trend for Sprayed heifers (3.6% heifers) to have a lower incidence of S. uberis CM compared with Control heifers (7.4% heifers). It is concluded that teat-spraying in the dry period is a management option that could contribute to controlling heifer S. uberis mastitis in the transition period. 相似文献
95.
Tessa Mazor C. Roland Pitcher Wayne Rochester Michel J. Kaiser Jan G. Hiddink Simon Jennings Ricardo Amoroso Robert A. McConnaughey Adriaan D. Rijnsdorp Ana M. Parma Petri Suuronen Jeremy Collie Marija Sciberras Lara Atkinson Deon Durholtz Jim R Ellis Stefan G. Bolam Michaela Schratzberger Elena Couce Jacqueline Eggleton Clement Garcia Paulus Kainge Sarah Paulus Johannes N. Kathena Mayya Gogina P. Daniël van Denderen Aimee A. Keller Beth H. Horness Ray Hilborn 《Fish and Fisheries》2021,22(1):72-86
Bottom trawl fishing is a controversial activity. It yields about a quarter of the world's wild seafood, but also has impacts on the marine environment. Recent advances have quantified and improved understanding of large‐scale impacts of trawling on the seabed. However, such information needs to be coupled with distributions of benthic invertebrates (benthos) to assess whether these populations are being sustained under current trawling regimes. This study collated data from 13 diverse regions of the globe spanning four continents. Within each region, we combined trawl intensity distributions and predicted abundance distributions of benthos groups with impact and recovery parameters for taxonomic classes in a risk assessment model to estimate benthos status. The exposure of 220 predicted benthos‐group distributions to trawling intensity (as swept area ratio) ranged between 0% and 210% (mean = 37%) of abundance. However, benthos status, an indicator of the depleted abundance under chronic trawling pressure as a proportion of untrawled state, ranged between 0.86 and 1 (mean = 0.99), with 78% of benthos groups > 0.95. Mean benthos status was lowest in regions of Europe and Africa, and for taxonomic classes Bivalvia and Gastropoda. Our results demonstrate that while spatial overlap studies can help infer general patterns of potential risk, actual risks cannot be evaluated without using an assessment model that incorporates trawl impact and recovery metrics. These quantitative outputs are essential for sustainability assessments, and together with reference points and thresholds, can help managers ensure use of the marine environment is sustainable under the ecosystem approach to management. 相似文献
96.
Catfish hatcheries use copper sulphate pentahydrate (CuSO4·5H2O) as an economical control for saprolegniasis on eggs. This study determines hatch rate of channel catfish, Ictalurus punctatus (Rafinesque 1818), eggs in hatching troughs containing 23.8 °C flow‐through well water when treated with 100 mg L?1 CuSO4·5H2O (10 times the proposed therapeutic dose). Eggs were treated daily until the embryos reached the eyed stage. Fry survival in the control and 100 mg L?1 CuSO4·5H2O treatments was significantly different (15% and 71% respectively). This study demonstrates that there is a considerable margin of safety in using CuSO4·5H2O as a catfish egg treatment to control saprolegniasis. 相似文献
97.
Ershad MistriSoumen Routh Dipa Ray Saswata SahooManjusri Misra 《Industrial Crops and Products》2011,34(1):900-906
Castor oil was converted to maleated castor oil (MACO) without any catalyst. MACO was characterized with FTIR, NMR, molecular weight and viscosity measurement. Tung oil (20 wt%) was added to MACO as reactive diluent. Non-woven jute felts were used as reinforcing material. The MACO was polymerized and crosslinked in situ during composite fabrication. The curing behavior of MACO with free radical catalyst was investigated by differential scanning calorimetry (DSC). The MACO/jute composites were tested for their flexural properties, impact strength and dynamic mechanical properties and compared with similar unsaturated polyester resin/jute composites. The flexural moduli of both the composites were nearly similar. The impact strength of MACO/jute composites was 42% higher than that of UPE/jute composites. The damping property of the MACO/jute composites was higher than that of UPE/jute composites over a wide range of temperature. 相似文献
98.
T. Phukan K. Kabyashree N. Singh G. Jha R. V. Sonti S. Genin S. Kumar Ray 《Plant pathology》2017,66(5):835-841
Ralstonia solanacearum is a phytopathogenic bacterium that colonizes the xylem vessels of host plants leading to a lethal wilt disease. Although several studies have investigated the virulence of R. solanacearum on adult host plants, infection studies of this pathogen on the seedling stages of hosts are less common. In a preliminary observation, inoculation of R. solanacearum F1C1 on 6‐ to 7‐day‐old tomato seedlings by a simple leaf‐clip strategy resulted in a lethal pathogenic condition in seedlings that eventually killed these seedlings within a week post‐inoculation. This prompted testing of the effect of this inoculation technique in seedlings from different cultivars of tomato and similar results were obtained. Colonization and spread of the bacteria throughout the infected seedlings was demonstrated using gus‐tagged R. solanacearum F1C1. The same method of inoculating tomato seedlings was used with R. solanacearum GMI1000 and independent mutants of R. solanacearum GMI1000, deficient in the virulence genes hrpB, hrpG, phcA and gspD. Wildtype R. solanacearum GMI1000 was found to be virulent on tomato seedlings, whereas the mutants were found to be non‐virulent. This leaf‐clip technique, for inoculation of tomato seedlings, has the potential to be a valuable approach, saving time, space, labour and costs. 相似文献
99.
Cultivars with submergence tolerant quantitative trait locus (SUB1) greatly enhance submergence tolerance at vegetative stage. Whether such cultivar is better off or not at reproductive stage submergence is not known. Due to uncertainties in rainfall pattern and delayed monsoon, flooding at later stages corresponding to reproductive stage is very much common now. Therefore, the main goal of the present investigation is to work out the effect of submergence at reproductive stage on yield and yield attributes in three rice cultivars namely Swarna, Swarna-Sub1, and Baliadhan (a traditional rice cultivar showed similar reaction to SUB1). The present study envisages that submergence at reproductive stage greatly decreased the grain yield even though there was no mortality of plants. Yield reduction was greater at flowering stage followed by booting and panicle initiation stage. Swarna-Sub1 performed significantly better compared to Swarna when submergence was given at panicle initiation stage. Swarna-Sub1 and Baliadhan both maintained greater quantities of carbohydrate and total dehydrogenase activity yet the yield reduction was greater in Swarna-Sub1 compared to Baliadhan due to greater chalf formation in the former. The cultivar with SUB1 is quite better off at reproductive stage submergence. Baliadhan is superior to Swarna-Sub1. 相似文献
100.
Colin F Quinn John L Freeman Ray JB Reynolds Jennifer J Cappa Sirine C Fakra Matthew A Marcus Stormy D Lindblom Erin K Quinn Lindsay E Bennett Elizabeth AH Pilon-Smits 《BMC ecology》2010,10(1):19