Disease problems in shrimp sector in Khulna district of Bangladesh: a question of sustainability

Disease is the main restraining factor for the development of shrimp sector in Bangladesh. Both brackish water shrimp bagda (Penaeus monodon) and freshwater prawn golda, (Macrobrachium rosenbergii) farming in Bangladesh have been facing disease problem. A study on disease outbreak in both brackish water and freshwater small-scale shrimp farms (gher) in Khulna district was carried out through interviewing randomly selected 3-5% of shrimp farmers with a structured questionnaire during March to December, 2002. The study showed that 97% bagda farming ghers and 80% golda farming ghers were affected by disease. White spot disease was the severe disease for bagda, whereas, antenna rot was the main disease for freshwater prawn. Change of water and liming were carried out as control measures of disease for bagda shrimp farming, while it was only liming for golda farming. A small number of shrimp farmers (15%) used chemicals for treatment of shrimp diseases. Development of suitable farming technology to prevent disease contamination and innovation of proper treatments for diseases are required to overcome the disease problems for sustainable shrimp farming in Bangladesh

Effects of bio-slurry with chemical fertilizer on the performance of some high yielding varieties of boro rice (Oryza sativa L.)

Rice yield is greatly influenced by application of manures and fertilizer. Integrated use of organic manure and chemical fertilizer would be quite promising in providing better yield. To evaluate the effect of bio-slurry along with chemical fertilizer, a field experiment was conducted in the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, Bangladesh. The experiment was comprised of four varieties of boro (dry season irrigated) rice viz., (i) BRRI dhan28, (ii) BRRI dhan29 (iii) Binadhan-8 (iv) Binadhan-10 and four fertilizer management viz., (i) control, (ii) recommended dose of inorganic fertilizer, (iii) bio-slurry@ 5 t ha-1 + inorganic fertilizer, (iv) farmers’ practice (average 15 farmers). The experiment was laid out in a randomized complete block design with three replications. It is evident that variety and fertilizer management had significant effect on effective tillers hill-1, number of grains panicle-1 which ultimately influenced grain yield. The highest grain yield was (6.03 t ha-1) in Binadhan-8 followed by Binadhan-10 and BRRI dhan29. The lowest grain yield was found from BRRI dhan28. In respect of fertilizer management, grain yield was highest (5.90 t ha-1) in bio-slurry @ 5 t/ha + inorganic fertilizer. The lowest grain yield was found from control. The combined effect of variety and fertilizer application showed that highest grain yield (6.10 t ha-1) was found from Binadhan-8 with bio-slurry @ 5 t ha-1 + inorganic fertilizer and the lowest grain yield (4.68 t ha-1) was found from BRRI dhan28 with farmers’ practice. Thus, the variety Binadhan-8 with application of bio-slurry @ 5 t ha-1 + inorganic fertilizer was superior for obtaining highest yield

Duration of low temperature changes physiological and biochemical attributes of rice seedling

Received: June 2nd, 2022 ; Accepted: August 4th, 2022 ; Published: August 18th, 2022 ; Correspondence: [email protected] low temperature (LT) is detrimental to growth of rice seedling during boro season in Bangladesh. An experiment was conducted in growth chamber during June to October, 2021 using BRRI dhan29 as planting material. The aim of this experiment was to determine the effect of variable duration of LT on growth, physiological and biochemical traits of rice seedling and to determine the age of seedling that can tolerate cold effect. In this experiment 5, 10, 15 and 20 days old seedling (DOS) were exposed to 6 °C for 1, 2, 3 and 4 days. Seedlings were also grown under room temperature (25 °C, RT) which consider as control treatment. Seedlings were grown in plastic trays filled with mixture of soil and cowdung. The experiment was conducted following completely randomized design with 3 replications. Data on shoot length and weight, root length and weight, chlorophyll (Chl), carotenoids, malondialdehyde (MDA) and proline contain were determined after 5 days of temperature sock. The results revealed that the LT was injurious to younger rice seedling when they were exposed to LT for 1 to 2 days. The shoot and root length as well as their dry weight were reduced under low temperature. Further, the Chl and carotenoid content of younger rice seedlings degraded within 2 days of LT exposure. On the contrary, the proline and MDA content of rice seedlings increased to reduce the harmful effect of under LT. It could be concluded that the rice seedlings could tolerate the detrimental effect of LT when they attain at least 15 days

Probing the surfaces of core-shell and hollow nanoparticles by solvent relaxation NMR

Measurement of the spin-spin NMR relaxation time (or its inverse, the rate) of water molecules in aqueous nanoparticle dispersions has become a popular approach to probe of the nature and structure of the particle surface and any adsorbed species. Here, we report on the characterisation of aqueous dispersions of hollow amorphous nanoparticles, that have two liquid accessible surfaces (inner cavity surface and outer shell surface), plus the solid (silica) and core-shell (titania-silica) nanoparticle precursors from which the hollow particles have been prepared. In all cases, the observed water relaxation rates scale linearly with particle surface area, with the effect being more pronounced with increasing levels of titania present at the particle surface. Two distinct behaviours were observed for the hollow nanoparticles at very low volume fractions, which appear to merge with increasing surface area (particle concentration). Herewith, we further show the versatility of solvent NMR spectroscopy as a probe of surface character

RELEASE OF CLONE BT19 AND BT20 FOR POVERTY REDUCTION IN TEA SECTOR OF BANGLADESH

Bangladesh is a country of 140 million populations where poverty reduction is the prior challenge. With a low level of per capita income, Bangladesh needs to formulate a multi-sectorial strategy for poverty reduction. As Bangladesh is an agricultural based country poverty can be minimized by enhancing agricultural inputs to maximize our production. Tea is an important cash crop in our country. Vast population directly or indirectly depends on our tea industry. The present study was conducted to investigate yield, quality and drought performance of the two newly released variety named BT19 and BT20 by Bangladesh Tea Research Institute. The experiment was conducted at Bangladesh Tea Research Institute experimental farm where four test clones namely Sh/D/11/313, A/8/8, A/17/7, A/22/39 and a well renowned Indian clone TV1 used as a control. The experimental result revealed that amongst the four test clones A/17/7 and A/8/8 are statistically more high yielder and drought tolerant than the control. A/17/7 is more high yielding than A/8/8 but A/8/8 is more drought tolerant. So considering yield, quality and drought potentials, the test clone A/17/7 and A/8/8 have recently released as BT19 and BT20 respectively which can be used as improved planting material in our tea growing areas by small growers and small holders to increase our production, quality as well as job opportunities and national income to eradicate our poverty

Disposal Options of Bamboo Fabric-Reinforced Poly(Lactic) Acid Composites for Sustainable Packaging: Biodegradability and Recyclability

The present study was conducted to determine the recyclability and biodegradability of bamboo fabric-reinforced poly(lactic) acid (BF-PLA) composites for sustainable packaging. BF-PLA composite was recycled through the granulation, extrusion, pelletization and injection processes. Subsequently, mechanical properties (tensile, flexural and impact strength), thermal stability and the morphological appearance of recycled BF-PLA composites were determined and compared to BF-PLA composite (initial materials) and virgin PLA. It was observed that the BF-PLA composites had the adequate mechanical rigidity and thermal stability to be recycled and reused. Moreover, the biodegradability of BF-PLA composite was evaluated in controlled and real composting conditions, and the rate of biodegradability of BF-PLA composites was compared to the virgin PLA. Morphological and thermal characteristics of the biodegradable BF-PLA and virgin PLA were obtained by using environment scanning electron microscopy (ESEM) and differential scanning calorimetry (DSC), respectively. The first order decay rate was found to be 0.0278 and 0.0151 day�1 in a controlled composting condition and 0.0008 and 0.0009 day�1 in real composting conditions for virgin PLA and BF-PLA composite, respectively. Results indicate that the reinforcement of bamboo fabric in PLA matrix minimizes the degradation rate of BF-PLA composite. Thus, BF-PLA composite has the potential to be used in product packaging for providing sustainable packaging

Influence of Annealing Temperature on the Properties of ZnO Thin Films Grown by Sputtering

AbstractZinc oxide (ZnO) thin films were deposited by RF magnetron sputtering onto ITO coated soda-lime glass substrates. The effects of annealing in temperature range of 250 to 450°C on the structural and optical properties of the ZnO films have been studied. The crystalline structure, surface topology, morphology, optical properties of the films were determined using X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and UV–Visible Spectrometry, respectively. X-ray diffraction measurement showed that the annealed ZnO films were polycrystalline in nature with (002), (101) and (001) oriented crystallites of hexagonal wurtzite structure. Crystalline property and grain size of the films were found to increase after annealing. The optical band gap of ZnO films initially blue shifted (3.1–3.23eV) when annealed at 400°C and further red shifted in the range of 3.23 to 3.1eV being annealed at 250 to 450°C range. From the UV spectroscopy, the films showed transmittance over 85% in the optical bandgap spectrum. All these results indicate that post deposition annealing improves the film quality with reduced roughness and better crystalline properties that can be utilised as buffer layer in the CIGS or CdTe thin film solar cells