A comparative study on the effect of commercial fish feeds on the growth of Thai pangas, Pangasius hypophthalmus

A 70 day long experiment was carried out to evaluate three commercial pangas feeds available in Bangladesh viz. Quality Feeds Ltd. (QF), Aftab Bohumukhi Farm Ltd. (ABF) and Saudi-Bangla Fish Feed Ltd. (SBFF) (designated as treatment_T1 T2 and T3) on the growth of Pangas, Pangasius hypophthalmus. Each treatment had two replicates using six experimental ponds of each 80m2 size. The stocking density was 250 fish/80m2. At the beginning, the fish were fed twice daily at 15% of their body weight which was gradually reduced to 10 and 6%, respectively for the rest of the period. The ranges of water quality parameters observed were: temperature 29.0°C- ~5.1 °C, pH 6.85 - 8.52, DO 1.71 - 7.65 mg/1 and transparency or Secchi depth 14.5 - 30.0 em. The mean weight gain of fish was significantly (~<0.05) higher in T3 followed by T2 and T. The specific growth rate (SGR) ranged. between 4.09 and 5.06, feed conversion ratio (FCR) values between 1.54 and 1.61 with treatment T1 showing the lowest FCR. Protein efficiency ratio (PER) values ranged between 2.03 and 2.11. The survival of fish varied between 90.4 and 91.6%. The significantly (P<0.05) highest production of fish (kg/ha/70 days) and profit (Tk/ha/70 days) was observe in T3 (SBFF) followed by T2 (ABF) and T1 (QF), respectively. The result of the study showed that on the basis of nutritive value and growth performance of pangas, feed from Saudi-Bangla Fish Feed Ltd. is the best

Non-puddling practice for rice-based cropping system increases carbon sequestration in soil

In Indo-Gangetic Plains, intensive rice-based cropping systems with conventional crop establishment practices has been followed for many years. Contradictory results are reported about the effect of rice monoculture or rice-upland crop rotations on soil properties. While CA practices may sequester C into the soil organic C pool and improve soil health, in most cases, the practice of CA in rice-upland rotations is only partial; conservation tillage and residues retention are followed for upland crops only but not for rice. So, whatever benefits may accrue from CA practices followed for upland crops are lost by several wet tillage operations followed by puddling. In the EGP, rice-upland crop growers are now adopting CA increasingly, namely non-puddling of rice, in the intensive triple cropping systems (Alam et al. 2016; Haque et al. 2016). The incorporation of minimum tillage and retention of more residues in these systems of the EGP will change the dynamics of C in soil but nature of these changes has not been explored yet. The study was, therefore, conducted to determine the C cycling in soils of rice-upland triple cropping systems under CA practices

Influence of various composted organic amendments and their rates of application on nitrogen mineralization and soil productivity using chinese cabbage (Brassica rapa L. var. Chinensis) as an indicator crop

There is a diversity of locally available nitrogen (N)-rich organic materials in Samoa. However, none of them was evaluated for their N supplying capacity after composting in Samoan Inceptisols for vegetable cultivation. Thus, N-releasing capacity of five composted organic amendments (OAs) namely macuna, gliricidia, erythrina, lawn grass and giant taro, and their two application rates (10 and 20 t ha−1) were assessed through a laboratory incubation and a crop response study using Chinese cabbage as a test crop. Among the OAs, composted mucuna was characterized by a higher total N (2.91%), organic C (63.6%) and NO3−N content (341 mg N kg−1). A significant difference in N mineralization was observed among the OAs as well as application rates. The highest N mineralization was recorded in composted mucuna followed by gliricidia, erythrina, lawn grass, and giant taro. A crop response study also showed a similar trend. Mucuna treatment had the highest biomass yield and N uptake followed by gliricidia, erythrina, lawn grass, and giant taro. Leguminous composted OAs @ 20 t ha−1 performed substantially better in all the plant growth and yield parameters, and N uptake compared to 10 t ha−1 that was not the case for non-leguminous OAs. Thus, non-leguminous OAs should be applied at 10 t ha−1. All the composted leguminous OAs showed promising results while mucuna was the best in both the application rates. Therefore, mucuna can be promoted to supply N for crop cultivation in Samoa, other Pacific Islands and tropical countries where N fertilizer is costly and not easily available

A practical biogas based energy neutral home system for rural communities of Bangladesh

Growing demand of energy consumption, subsequent increase in energy generation costs, and increased greenhouse gas(GHG) emissions, as well as global warming from the conventional energy sources, encourages interest worldwide to bring a higher percentage of renewable energy sources such as biogas into the energy mix to build a climate friendly environment for the future. Moreover, due to high investment and maintenance costs, governments are not providing enough support for grid extension and delivering electricity to remote locations or rural areas, in particular, in under-developing countries like Bangladesh. Therefore, this paper presents an Energy Neutral Home System (ENHS) that can meet all its energy requirements from low-cost, locally available, nonpolluting biogas generated from animal waste, in particular, chicken and cow manure. The proposed ENHS has been developed for rural community, typically an area of 200 families, and will not only provide cooking gas and sustainable and affordable power supply to the community with low emissions, but will also facilitate high quality fertilizer for agricultural purposes. In-depth analysis clearly demonstrates that the proposed ENHS not only offers electricity and cooking gas to the community with the lowest costs, but also reduces the energy crisis and GHG emissions and can play an active role in developing socio-economic infrastructure of rural communities in Bangladesh in many ways

Screening of promising biofortified short duration lentil cultivars for conservation agriculture in North-west Bangladesh

In Bangladesh, lentil (Lens culinaris Medikus subsp.culinaris) production was 0.26 million tons from 0.20 million hectares (average yield 1.3 t ha-1) which is 29 % of the total national pulse production (AIS, 2016). Globally, it is cultivated as a rainfed crop on 3.85 million hectares (m ha) with a yield of only 1.1 t ha-1 (Erskine et al., 2011). In rice based cropping patterns, after harvesting of t.aman rice maximum land remains fallow for about 90 days until establishment of the boro rice. Presently, this rice land cannot be used to grow lentil since varieties have 110-115 days duration (AIS, 2017). Promising biofortified short duration (83-90 days) lentil varieties can play an important role to expand its cultivation through establishing lentil by relay sowing into t.aman rice and harvesting before boro rice. The relay cultivation method involves no tillage and residue retention, and establishes the lentil before t.aman rice is harvested. The selection of promising biofortified short duration lentil genotypes under relay cultivation method is therefore important to accommodate in fallow between t.aman and boro rice

Potentiality of vermicomposting in the South Pacific Island countries: A review

Incorporation of vermin culture in the composting system produces “vermicompost”, an enriched biofertilizer known to improve the physical, chemical, and biological properties of soil. It is applied in granular form and/or in liquid solution (vermiwash), and in both open fields and greenhouses. Vermicompost has been shown to contain plant growth hormones, which stimulate seed germination and improve crop yield, the ‘marketability’ of products, plant physiology, and their ability to fight against disease. In recent years, South Pacific island countries (SPICs) have placed an increasing emphasis on the importance of organic agricultural practices as a means of achieving more sustainable and environmentally friendly farming practices. However, vermiculture is not practiced in South Pacific island countries (SPICs) largely due to the lack of awareness of this type of application. We consider the inclusion of vermiculture in this region as a potential means of achieving sustainable organic agricultural practices. This study represents a systematic review in which we collect relevant information on vermicomposting and analyze the applicability of this practice in the SPICs based on these nations’ physical, socioeconomic, and climatic conditions. The tropical climate of the SPICs means that they meet the combined requirements of a large available biomass for composting and the availability of earthworms. Perionyx excavatus and Pontoscolex corethrurus have been identified as potential native earthworm species for vermicomposting under the conditions of the SPICs. Eisenia fetida, a well-known earthworm species, is also effectively adapted to this region and reported to be an efficient species for commercial vermicomposting. However, as a new input into the local production system, there may be unforeseen barriers in the initial stages, as with other advanced technologies, and the introduction of vermiculture as a practice requires a steady effort and adaptive research to achieve success. Further experimental research is required to analyze the productivity and profitability of using the identified native earthworm species for vermiculture using locally available biomass in the SPICs

Potential methane emission reduction strategies from rice cultivation systems in Bangladesh: a critical synthesis with global meta - data

Methane (CH4) is one of the dominant greenhouse gases (GHG) that is largely emitted from rice fields and thus, significantly contributes to global warming. Significant efforts have been made to find out suitable strategies to mitigate CH4 emission from rice culture. However, the effectiveness of these management practices is often diverse with negative, no, or positive impacts making it difficult to adopt under a particular condition. The diversity of rice cultivation in terms of agro-climatic conditions and cultivation practices makes it difficult for providing specific recommendations. Here, we collected data from a total of 198 studies reporting 1052 observations. The management practices are categorized into five different management practices i.e., water, organic and inorganic fertilizer management, crop establishment method, and agronomic practices while major categories were subdivided into different classes. To test statistically significant differences in the effectiveness between major management practices, an analysis of variance (ANOVA) was applied. The Gaussian and bootstrapping model were applied to find out the best estimate of the effectiveness of each practice. In addition, mechanisms controlling the CH4 emission reductions were synthesized. Next, the adoption potentials of these practices were assessed based on the existing rice cultivation systems in Bangladesh. Our results showed that water and organic matter management were the most effective methods irrespective of the growing conditions. When these technologies are customized to Bangladesh, water management and crop establishment methods seem most feasible. Among the rice-growing seasons in Bangladesh, there is a larger scope to adopt these management practices in the Boro season (December to May), while these scopes are minimal in the other two seasons due to their rain-fed nature of cultivation. Altogether, our study provides fundamental insights on CH4 reductions strategies from rice fields in Bangladesh

Soil nitrogen storage and availability to crops are increased by conservation agriculture practices in rice - based cropping systems in the Eastern Gangetic Plains

On-farm adoption of minimum soil disturbance and increased residue retention will alter nitrogen (N) dynamics in soils and N fertiliser management in the intensive rice–based triple cropping systems of the Eastern Gangetic Plains. However, the consequences of changes in N forms, N mineralisation and its availability for crops have not been determined. Field experiments were conducted at two locations (Alipur and Digram) of north–west Bangladesh (NWB) to examine N cycling under three planting practices (conventional tillage (CT), strip planting (SP) and bed planting (BP)) with increased (HR) or low residue retention (LR– the current practice) on Calcareous Brown Flood Plain and Grey Terrace soils. Total N and available N were measured on soil samples as was N uptake by crops at different growth stages in the 13–14th (Alipur) and 12–13th (Digram) crops since treatments commenced. At each location (0–10 cm soil depth), SP, including non–puddled transplanting of rice seedlings (NP), together with HR increased total N by 9 and 32 % relative to BPHR, and CTHR and by 62 % relative to the current farm practice (CTLR). In general, the cumulative available N in soils during mustard and rice cropping under CT with HR was higher than other crop establishment and residue retention practices while under wheat and jute, total availability of N did not vary among crop establishment types with increased residue retention. Nitrogen availability in the initial phase of crop growth (0–60 DAS) was generally higher with CT than SP and BP. By contrast, for all crops, the estimated potentially mineralisable N was higher and its decay rate was lower under SPHR than other crop establishment and residue retention practices. Conservation Agriculture practices (SP, and NP of rice, together with HR) have altered the N cycling by reducing the level of mineral N available to plants in the early growing season when crop demand is low, but by increasing soil total N (0−10 cm) and plant N uptake which enhanced the synchrony between crop demand and available N supply

HEAVY METAL TOXICITY IN FISHES OF POLLUTED LAKES OF DHAKA CITYAND ITS IMPACTS ON HUMAN HEALTH

The City of Dhaka is not built up plan wise from the beginning yet till date. The land uses are not following the urbanization rules correctly. Due to the laggings of proper water and air flow and basic treatment of household and industrial utilizing water, some of the major health issues are concerned. This research works is on the focus of heavy metal contamination in fishes of two major lakes in Dhaka city called Dhanmondi Lake and Gulshan Lake. The research is focusing mainly the study on Cr, Cd and Pb concentration in fishes along with other elements. Concentration of Cr is found in ranges of 3.45 μg/gm – 10.25 μg/gm, Cd is 2.17 μg/gm – 9.78 μg/gm and Pb is 1.132 – 7.102 μg/gm. The major element K and Ca with other trace elements are also projected. The data acquisition setup is calibrated using 2.2 MeV proton beam in the current ranges of 5nA to 15nA. The Van-de Graff Accelerator of Atomic Energy Centre, Dhaka has been used for sample irradiation. The IBA technique Proton Induced X-ray Emission (PIXE) has been applied using Si(Li) detector (SL30165) and other ORTEC nuclear electronics. The calibration and standardization of PIXE setup has been done using X-ray source, and IAEA standard CuSx (thin), Soil-7 (thick)

Nutrient release from Vermicompost under anaerobic conditions in two contrasting soils of Bangladesh and its effect on wetland rice crop

Although its mechanism of action, particularly under wetland condition, is not clearly understood, vermicompost, a good source of humus and plant nutrients, has been used as organic manure in many parts of the world in order to increase crop production. Here, an anaerobic incubation study and a field study were conducted to observe the nutrient release pattern from vermicompost and its influence on performance and nutrient uptake in wetland rice. Two contrasting soils, viz. highly weathered terrace soil and very young floodplain soil, were subjected to anaerobic incubation, while the field trial was conducted in the terrace soil with control (no amendments), mineral fertilizer, vermicompost (10 t ha−1) + mineral fertilizer, cow dung (10 t ha−1) + mineral fertilizer, vermicompost (20 t ha−1) + mineral fertilizer and vermicompost (local farmer’s practice) + mineral fertilizer treatments. Results showed that there were significant increases in nitrogen (N) and phosphorous (P) release in floodplain soil but not in terrace soil, suggesting that nutrient release from vermicompost is soil-dependent. The performance of Boro rice in terms of yield and yield attributes improved significantly in the case of the integrated application of vermicompost with mineral fertilizer. Specifically, combined application of mineral nutrients and vermicompost (10 t ha−1) significantly increased grain yield by 25% compared to the control treatment. We believe that this occurred due to an improvement in supply and subsequent uptake of nutrients, especially N and P. Altogether, our results suggest that vermicompost could increase crop performance under field conditions, and, although these effects may not be significant in short-term incubation studies, they may be even larger in floodplain soil