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Shallow tube wells (STW) are widely operated in Bangladesh to draw groundwater for irrigating the crop field. About 65% of irrigated area is covered by more than 1.3 million STW. However, farmers are facing difficulties in starting STW due to priming problem. Therefore, this study was undertaken to design and develop a check valve (CqV)/non-return valve to overcome the priming problem as well as reduce the drudgery of farmers while starting STW. The check valve was designed based on the working principles of hand tubewell operating system. Considering the tubewell size of 100 mm, check valve having three diameters of 125 mm, 150 mm, and 175 mm for two-valve fitting lengths of 150 mm and 225 mm based on the flange or thread joint were fabricated using locally available material at Bangladesh Rice Research Institute (BRRI) research workshop. Check valves were tested at the field level in different locations of Bangladesh. The results revealed that the field performance of check valve overcame the priming problem, made easy starting and reduced the drudgery of farmers. The best performance was found when the diameter of the cheque valve was at least 50 mm over the size of tube well and the minimum length was 150 mm. The installation of check valve could not create any adverse effects on tube well discharge and engine revolution per minute (RPM). It could successfully reduce the starting time and facilitate the easy use of plastic pipe/ polythene pipe, which reduces the water conveyance loss and pumping hours. Bangladesh Rice J. 25 (2) : 77-84, 2021

Growing crops in a piece of land influence soil fertility depending on adopted management practices and intensity of cropping. Farmers in many cases do not use balanced fertilizers because of socio-economic conditions and thus nutrient mining is inevitable. We hypothesize that soil degradation is likely along with reduced crop productivity in future with researcher proposed four crops production packages. Semi-structured questionnaire, and IDRISI3.2 were used for data collection and mapping, respectively. Net quadruple cropped areas were about 7.09%. Soil fertility scores of those areas were 40–50 and above 50, covering about 4.56% and 3.66%, respectively of the net cropped areas indicating medium fertility status. Apparent nutrient balances for nitrogen, phosphorus, potassium, sulfur, calcium, magnesium and silicon were negative with researcher's introduced cropping patterns and fertilizer management compared to existing patterns. Zinc with all introduced cropping patterns and boron with Potato–Boro–T Aus–T Aman pattern are increasing but other micro nutrients are diminishing. Phosphorus and Sulfur build ups are taking place under farmer's practice in Mustard–Boro–T Aman, Potato–Boro–T Aman and Boro–Fallow–T Aman patterns. Zinc build up is taking place under farmer's managed cropping patterns; but iron, copper, boron, molybdenum and chloride are deteriorating from the soils. These indicate that growing four crops in a year with existing fertilizer recommendations are not sustainable in terms of soil fertility. Adoption of such intensive crop culture by the majority of the farmers is unlikely except in some sporadic areas having market driven economy of vegetable cultivation.

Declination of available water resources is threatening the dry season crop production in Bangladesh. Sustainable water management is crucial need to meet future food production. This study was aimed to determine futuristic water management strategy for rice cultivation. Both surface and groundwater is getting scarce in north-west region, whereas abundant of fresh surface water creating opportunities to irrigate dry season crops in south-central region. This study has outlined irrigation management for rice cultivation and groundwater utilization in water scarce area of north-west region. More than 75% of annual rainfall occurred during monsoon and crops other than monsoon often faced water shortage. Timely establishment of T. Aus rice on 01 May accounted average 183 mm supplemental irrigation for north-west and south-west region. Transplanting of T. Aman rice before 24 July found the low risk period of drought and gave about 1 t ha-1 yield advantage than late transplanting after 15 October. Supplemental irrigation in drought year gave up to 26% yield advantage than the rain-fed condition of T. Aman rice in experimental plot. Over exploitation of groundwater by famers for crop cultivation makes the groundwater status worsen. Farmers used 38% excess water than the actual requirement for Boro rice cultivation. For that annual groundwater withdrawal was higher than annual recharge causing groundwater level depletion in most of the districts. Groundwater table went below suction limit of shallow tubewell (STW) during dry season and thus it become unable to operate. Improved distribution system with plastic pipe, buried pipe could save about 25% of irrigation water. Alternate wetting and drying (AWD) irrigation method saved 20-25% water than farmer’s practice. Application of these on-farm water management technologies in Boro rice reduced water demand and made the groundwater balance positive as well as reduced the groundwater withdrawal pressure. On the contrary, irrigation with less saline surface water resources in river and canals of south central regions could expand Boro production and increased land productivity. Intervention of low lift pump with plastic pipe distribution in non-saline tidal areas could increase land productivity. Besides, trapped freshwater in to the canals inside the polders and re-excavation of these canals would make crop intensification. Thus, additional food production could help to achieve sustainable development goal and sustained food security. Bangladesh Rice J. 25 (1) : 37-50, 2021

Solid waste management (SWM) is one of the key responsibilities of city administrators and one of the effective proxies for good governance. Effective SWM mitigates adverse health and environmental impacts, conserves resources, and improves the livability of cities. However, unsustainable SWM practices, exacerbated by rapid urbanization and financial and institutional limitations, negatively impact public health and environmental sustainability. This review article assesses the human and environmental health impacts of SWM practices in the Global South cities that are the future of global urbanization. The study employs desktop research methodology based on in-depth analysis of secondary data and literature, including official documents and published articles. It finds that the commonplace SWM practices include mixing household and commercial garbage with hazardous waste during storage and handling. While waste storage is largely in old or poorly managed facilities such as storage containers, the transportation system is often deficient and informal. The disposal methods are predominantly via uncontrolled dumping, open-air incinerators, and landfills. The negative impacts of such practices include air and water pollution, land degradation, emissions of methane and hazardous leachate, and climate change. These impacts impose significant environmental and public health costs on residents with marginalized social groups mostly affected. The paper concludes with recommendations for mitigating the public and environmental health risks associated with the existing SWM practices in the Global South.

This study demonstrates a successful processing and utilization of banana rachis cellulose nanocrystals (CNCs) dispersed clay composite filter which is capable of adsorbing dye and heavy metal ions namely Pb(II) and Cr(III) from industrial wastewater. The composite of different compositions was prepared by dispersing the cellulose nanocrystals, obtained by acid hydrolysis of banana rachis fibres, within the tri-ethyl amine treated clay. The CNC and treated clay were characterized by Fourier transform infrared (FTIR), X-ray diffractometry (XRD), and scanning electron microscopy (SEM) analyses. Industrial wastewater containing a basic yellow2 dye and two heavy metal ions, Pb(II) and Cr(III), was passed through the prepared filters set in a column. The dye and metal ions adsorption capability of the filters were analyzed by determining the dye and metal ions concentration into the water before and after passing through the composite filter. The concentration of dye and metal ions in water was determined by a UV-visible spectrophotometer and an atomic absorption spectrophotometer, respectively. It was found that the dye adsorption capacity of the composite filters was about 50 mg per gram of composite as well as Pb(II) and Cr(III) ions adsorption capacities of the composite filters were ˃10.0 mg and ˃12.4 mg respectively per gram of the composite when CNC content in the composite was ˃30 wt.%. It was also found that the metal ions adsorption capability of the composite filter was improved with increasing CNC content in the composites.

The experiment was conducted at char Sadipur the char land of Pabna during the Rabi season of 2013-14 and 2014-15 to determine appropriate fertilizer dose for enhancing production and economic return from Lentil+ Mustard mixed cropping system. The experiment was laid out in a randomized complete block design with 3 dispersed replications. Eight soil test based fertilizer packages viz.,T1: N20 P24 K20 S18 Zn2 B1.5, T2: N25 P24 K20 S18 Zn2 B1.5, T3: N25 P30 K20 S18 Zn2 B1.5, T4: N25 P24 K25 S18 Zn2 B1.5, T5: N20 P30 K25 S18 Zn2 B1.5, T6: N25 P30 K25 S18 Zn2 B1.5, T7: N15 P18 K15 S14 Zn1.5 B1kg ha-1kg ha-1 and T8: native nutrient (control) were tested for lentil + mustard mixed cropping system. Soil test based N25 P30 K25 S18 Zn2 B1.5 (T6) showed better performance on crop growth and yield of lentil and mustard in lentil+ mustard mixed cropping system in both the year. The highest lentil yield 0.70 t ha-1 in 2013-14 and 0.95 t ha-1 in 2014-15 was obtained from soil test based N25 P30 K25 S18 Zn2 B1.5 (T6). Similarly, maximum lentil equivalent yield (1233 Kg ha-1in 2013-14 and 1280Kg ha-1 in 2014-15) was also obtained from the same treatment. The maximum gross margin (Tk. 31639 ha-1 in 2013-14 and Tk. 32480 ha-1 in 2014-15) was recorded from soil test based N25 P30 K25 S18 Zn2 B1.5. So, application of soil test based fertilizer increases lentil and mustard yield as mixed crop as well as income of the farmers. Bangladesh Agron. J. 2019, 22(1): 1-6

In the face of sudden migration to online teaching due to Covid-19 pandemic, education is going under trying times globally, especially in the low resource contexts of the Global South. Little is, however, known about how this forced migration to and coping with emergency remote teaching (ERT) are happening in the low resource context of developing Bangladesh, particularly in the Higher Education (HE). This paper, therefore, aims to understand how virtual classrooms look like in the Higher Education context in Bangladesh through TESOL teachers’ narratives from initial virtual classrooms imparting ERT. Employing narrative inquiry, four teachers from four different public and private universities in Bangladesh share their experiences of doing, undergoing and reflecting as they try to adopt, adapt and strive in imparting ERT and carrying out education in HE. Insights from these initial teacher narratives may inform higher education pedagogies, teacher development in distance education environments in Bangladesh and similar contexts in the Global South. As the paper addresses HE teachers’ initial orientation to ERT without exclusively dealing with TESOL education, it has multidisciplinary approach to migration to and coping with ERT in HE in general.

The study was carried out at Multi Location Testing site, Sujanagar, Pabna during two consecutive years of 2011-12 and 2012-13 growing season to assess the performance of the pattern with newly released crop varieties against the existing one usually practiced by the farmers with traditional varieties in order to increase yield and economic return. The experiment was laid out in a randomized complete block design with six dispersed replications at farmer’s field. In improved pattern (IP) BARI Gom-26, BARI Til-4 and Binadhan-7 variety were used for wheat, sesame and T. aman rice, respectively. On the contrary in existing pattern (EP) farmers usually use BARI Gom-21, local (char shira) and Sharna cultivar for wheat, sesame and T. aman rice, respectively. The mean yield was recorded 4.66, 1.34 and 4.79 t ha-1 from wheat (BARI Gom-26), sesame (BARI Til-4) and T. aman (Binadhan-7) respectively from the improved cropping pattern whereas average yield 3.81, 0.98 and 4.58 t ha-1 was obtained from wheat (BARI Gom-21), sesame (local) and T. aman (Sharna), respectively from the existing pattern. Two years mean data also showed that improved pattern provided about 18% higher REY compared to existing pattern. Sustainable yield index and production efficiency were also found maximum with improved cropping pattern. Similarly, maximum gross margin and benefit cost ratio were obtained from improved cropping pattern. Bangladesh Agron. J. 2018, 21(2): 13-18

The dissolution of ferrous ions from the protective oxide layer and/or base metal by corrosion with the assistance of turbulent flow is called flow accelerated corrosion (FAC). Flow accelerated corrosion is the most common and continuous corrosion reaction in combined cycle power plants (CCPP). Heat recovery steam generator (HRSG) drum pressure fluctuation and/or turbulent drum water greatly influences the FAC of drum and economizer. This kind of FAC was investigated in the low-pressure drum (LPD) and low-pressure economizer (LPE) of a 210 MW gas-fired combined cycle power plant (Four-unit HRSG & GT) with an air-cooled condenser (ACC). Severe FAC was observed due to the fluctuation of pressure in the LPD with respect to time. As a result, huge amounts of soluble iron (Fe2+) and insoluble (Fe3+) was found in all running HRSG’s LPD water. Due to pressure fluctuations in the LPD, a protective oxide layer (mostly magnetite), as well as the base metal, were corroded from the LPD and LPE even after carefully maintaining recently developed water cycle chemistry in this CCPP. Severe leakage was found in the LPE due to corrosion. The actual reason for the problem was found to be a malfunctioning steam-control valve in the turbine unit’s LP system. This valve was malfunctioning by suddenly opening to 100% and then closing to around 10% continuously. This malfunction creates enormous pressure drops in both the LPD and LPE units. It is understood that water turbulence is the main cause of FAC affecting the LDP and LPE. This assessment is based on chemical laboratory analysis and physical inspection. There was no non-destructive testing (NDT) performed in this study. The severe FAC happened in four days and for this reason, HRSG and steam turbines were shut down. Maintenance work on the control valve and flushing of the LPD and LPE successfully resolved the FAC problem. One week later, LPE leakage was found on the unit-3 HRSG and as reported in this study this was also found to be the result of FAC. From this case study, it is concluded that not only water quality but also water turbulence can create severe FAC problem.

Natural hazards are very common in Bangladesh that take place every year and damage crops, livestock and settlements. Data on livestock, flood, drought, cyclone, tide, thunderstorm, hailstorm, waterlogging, tornado and economic damages were collected from the existing literature for 2009–2014. Hotspots of natural hazards and damaged area coverage were determined based on total score, and IDRISI3.2 was used to prepare maps. About 10–32% areas in Bangladesh are moderate to very high natural hazard-prone. Moderate and high drought vulnerabilities were observed in about 14% areas for livestock production. Low and very low flood hazards for livestock could be found in about 22–44% areas. Hotspots for cyclones covered about 17% areas, high and very high storm/tides in about 22% areas and no safe zone against thunderstorm. Hailstorm damages more livestock in north and northwest part of the country covering about 23.8% areas. Moderate damages by tornado are distributed in 84% areas. Waterlogging hotspots are in southern part of Bangladesh that covers about 7% areas and livestock in about 52% areas suffered from low to moderate waterlogging problems. As a whole, natural hazards mentioned above are responsible for economic loss of

Determination of soil fertility with minimum data set for crop zoning and devising fertilizer recommendations as well as soil fertility evaluation method based on soil properties. The data were collected from existing literatures and scoring was done on 0–100 scale. The lowest score was assigned for the minimum value of tested attributes and then gradually higher scoring values. Arithmetic, weighted, geometric and most minimum of mean scores were calculated and their performances were compared with grain yield of dry season irrigated (Boro) rice. Soil fertility in 10-12 and 39-52% areas in Bangladesh are very low and low, respectively. Medium fertile and fertile soils are distributed in 17-41% and in about 8% areas of the country. About 55% soils scored 70–95 (medium to high SOC) and the rest belongs to inferior quality. In some areas P build up has taken place (25% areas), but widespread K mining. Sulphur and Zn status in about 40% areas are low to very low (scored

High soil temperature due to climate change may influence nutrient mineralization and soil biology. An incubation study was conducted at Bangladesh Rice Research Institute to determine the effect of temperature (28°C and 45°C) on nutrient mineralization and soil microbial population of two different soils (terrace and saline soil) having different nutrient management practices (chemical fertilizer and integrated nutrient management). Terrace soil was clay loam and saline (6 ds m-1) soil was sandy loam in texture. Total N and organic C content was significantly high in terrace soil compared to saline soil. High temperature (45°C) enhanced C mineralization by 33% in integrated nutrient management (INM) of terrace soil and 41% in chemical fertilizer treatment in saline soil. The NH4+-N mineralization was increased by 3 fold in saline soil at 45°C as compared to the same at normal temperature of 28°C. Temperature and nutrient management options also significantly influenced phosphorus (P) and potassium (K) mineralization. High temperature significantly enhanced P mineralization in INM compared to chemical fertilizer amendment. In terrace soil, at 28°C temperature K mineralization was high in chemical fertilizer amended soil as compared to INM treatment. Temperature and nutrient sources affected soil bacterial population significantly compared to fungi, and actinomycetes. Phosphate solubilizing bacteria (PSB) were more resistant to high temperature compared to free-living N2 fixing bacteria. In general, high temperature and nutrient management practices affected C, N, P, K mineralization and soil biology; although mode of action varied and depending on soil types and nutrient management practices.

Rice-based cropping systems in Bangladesh have received little consideration of changing nitrogen (N) and carbon (C) in soil. Therefore, this study was conducted at the Research Field of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh, in monsoon to determine release patterns of ammonium–N (NH4+–N) and nitrate–N (NO3−–N), C contents of different sized soil fractions and to quantify the rates of C sequestration as influenced by organic amendments and N fertilizer in wetland paddy fields. Rice straw, vermicompost, rice husk biochar, cow dung and poultry manure were applied using 2 t C ha−1 with 0, 100 and 150 N kg ha−1 in a factorial randomized complete block design. Application of different organic materials attributed maximum amount of NH4+–N and NO3−–N in soils at 45–60 days after transplanting, while N fertilizer application considering 150 kg N ha−1 provided the maximum amounts of available N. Rice grain yield was found statistically similar between 100 and 150 kg N ha−1. Carbon contents in soils of different sized fractions inconsistently varied with organic and inorganic fertilization and time elapsed. The highest amount of organic C was sequestered in cow dung-treated plots followed by rice straw, rice husk biochar, poultry manure and vermicompost. Nitrogen fertilizer enhanced decomposition of organic materials, and therefore, C sequestration was significantly lower with higher N rates. The study recommends continuous application of organic fertilizers and optimization of N in the tropical and subtropical regions which ultimately either contribute to maintain or increase C sequestration in crop fields.

Soil quality assessment methods, based on different attributes, are available but not well calibrated/validated for subsequent operational applications. We have developed a method for soil quality index assessment by considering soil texture, organic carbon, pH, available water, cation exchange capacity, bulk density, total porosity, saturated hydraulic conductivity, salinity, aggregate stability, slope and soil depth. The scoring was done on 0 - 100 scale and the lowest score was assigned to the most limiting factor of crop growth and development. Attribute-wise rating was made by using Macros developed in MS-Excel and IDRISI3.2 was used to delineate the rating maps. About 64.6% soils scored more than 60 and the best soil group (score > 70) was only about 15%. Soil health score, as determined through our method, showed good relationship with wheat yield. Multiplicative response function was more sensitive than simple regression model. The correlation analyses with one or two attributes with most severe stress and relatively with lower rating values showed better predictability of wheat yields. The soil quality index as estimated from principal component analysis having strongly loaded (>0.75) factors showed inferior correlation with grain yields of wheat than geometric mean approach. It is concluded that geometric mean approach for soil health scoring can be utilized in similar environments around the globe with or without further improvement.

The experiment was conducted at Char Sadipur in the char land of Pabna during Aus rice seasons of 2014 and 2015 to determine appropriate fertilizer dose for enhancing yield of B. Aus rice var. Hashikalmi and also to increase farmers’ income in char land under High Ganges River Floodplain (AEZ-11). The experiment was laid out in a randomized complete block design with four dispersed replications. Eight fertilizer packages T1: N40P9K16S6Zn1(STB), T2: N50P9K16S6Zn1, T3: N50P11K16S6Zn1, T4: N50P9K20S6Zn1, T5: N40P11K20S6Zn1, T6: N50P11K20S6Zn1, T7: N30P7K12S4.5Zn0.75 kg ha-1 and T8: Native nutrients (control) were tested for B. Aus rice in Lentil-B. Aus- Blackgram cropping pattern. The treatment N50P11K20S6Zn1 (T6) produced maximum grain yield 2.60 t ha-1 and 2.81 t ha-1of B. Aus rice in 2014 and 2015 cropping season, respectively. The highest gross return (Tk. 61,810 ha-1 in 2014 and Tk. 72,250 ha-1 in 2015 cropping season) and gross margin (Tk. 12,214 ha-1 in 2014 and Tk. 21,550 ha-1 in 2015 cropping season) was also recorded from N50P11K20S6Zn1 (T6) and lowest from control in both the years. Bangladesh Agron. J. 2018, 21(1): 83-88

The experiment was conducted at charland of Charsadipur in Pabna district under AEZ-11 during Khrif season of 2014 and 2015 to determine appropriate fertilizer dose for enhancing yield of blackgram as well as to increase farmers’ income. The experiment was laid out in a randomized complete block design with four dispersed replications. Eight fertilizer packages, viz.T1: N20P15K6S9Zn2 kg ha-1(STB), T2: N25P15K6S9Zn2kg ha-1, T3: N25P19K6S9Zn2 kg ha-1, T4: N25P15K8S9Zn2 kg ha-1, T5: N20P19K8S9Zn2 kg ha-1, T6: N25P19K15S9Zn2 kg ha-1, T7: N15P11K5S7Zn1.5kg ha-1and T8: Native nutrients (control) were tested on blackgram. Fertilizer package of N25P19K15S9Zn2 kg ha-1 (T6) enhanced crop growth and yield of blackgram in both the years. Maximum seed yield of blackgram (1.43t ha-1 in 2014 and 0.97 t ha-1 in 2015) was obtained with N25P19K15S9Zn2 kg ha-1 (T6), which was 80 and 147% more than the control in 2014 and 2015, respectively. The highest gross return (Tk. 82815 ha-1 in 2014 and Tk. 65200 ha-1 in 2015) and gross margin (Tk. 51125 ha-1 in 2014 and Tk. 32020 ha-1 in 2015) were also recorded from the same treatment in both the years. The results revealed that fertilizer package of N25P19K15S9Zn2kg ha-1 might be recommended for getting higher seed yield of blackgram and economic return as well under charland condition of Pabna district Bangladesh Agron. J. 2018, 21(1): 89-94

Alternate wetting and drying (AWD) for growing rice improves water productivity (WP), minimize methane emission and net ecosystem carbon balance (CO2), but might be responsible for increased nitrous oxide emissions. The combined effects of water management and different organic manure application on methane emission, carbon dioxide and nitrous oxide fluxes, emission factor (EF) and WP are not well documented, which has been evaluated during dry seasons of 2018 and 2019. AWD and continuous flooding (CF) were imposed in NPKSZn, cowdung (CD), poultry manure (PM) and vermicompost (VC) treated plots. Closed chamber techniques were used for determining emissions of greenhouse gases. In comparison with CF, the AWD significantly reduced total GWP by 15–44% depending on soil amendments and 2–29% net ecosystem carbon balance (CO2); but additional N2O contribution to GWP was about 0.61–1.18% compared to sole chemical fertilizer treatments. Depending on soil amendments, the AWD reduced EF of CH4 (22–36%) but increased WP by 25–27% compared to CF system along with 14–43% reduction in GHG intensity (GHGI). Vermicompost treatment had the lowest GHG emission, GWP, EF and GHGI than cowdung, poultry manure under both irrigation methods. Rice yield varied because of soil amendments but not with irrigation methods. Use of vermicompost improved soil organic carbon (SOC) storage significantly than cowdung and poultry manure. In conclusion, AWD practice and amendment of rice soil with vermicompost could be an effective strategy for reducing GHG emission, GWP, EF and GHGI without sacrificing rice yield.

Decomposed organic materials, in combination with plant growth-promoting bacteria (PGPB), are environmentally friendly and reduce synthetic fertilizer use in rice production. A bio-organic fertilizer (BoF) was prepared using kitchen waste (79%), chita-dhan (unfilled rice grain) biochar (15%), rock phosphate (5%), and a consortium of 10 PGPB (1%) to supplement 30% nitrogen and to replace triple superphosphate (TSP) fertilizer in rice production with an improvement of soil health. PGPB were local isolates and identified using 16S ribosomal RNA partial gene sequences as Bacillus mycoides, Proteus sp., Bacillus cereus, Bacillus subtilis, Bacillus pumilus, Paenibacillus polymyxa, and Paenibacillus spp. Isolates could fix N2 by 0.7–1.4 g kg–1, solubilize 0.1–1.2 g kg–1 phosphate, and produce 0.1–40 g kg–1 indoleacetic acid. The performance of BoF was evaluated by 16 field experiments and 18 farmers’ field demonstration trials during the year 2017–2020 in different parts of Bangladesh. Performances of BoF were evaluated based on control (T1), full synthetic fertilizer dose of N, P, and K (T2), BoF (2 t ha–1) + 70% N as urea + 100% K as muriate of potash (T3), 70% N as urea + 100% P as TSP + 100% K as muriate of potash (T4), and 2 t ha–1 BoF (T5) treatments. At the research station, average grain yield improved by 10–13% in T3 compared with T2 treatment. Depending on seasons, higher agronomic N use efficiency (19–30%), physiological N use efficiency (8–18%), partial factor productivity (PFP)N (114–150%), recovery efficiency (RE)N (3–31%), N harvest index (HIN) (14–24%), agronomic P use efficiency (22–25%), partial factor productivity of P (9–12%), AREP (15–23%), and HIP (3–6%) were obtained in T3 compared with T2 treatment. Research results were reflected in farmers’ field, and significant (P < 0.05) higher plant height, tiller, panicle, grain yield, partial factor productivity of N and P were obtained in the same treatment. Application of BoF improved soil organic carbon by 6–13%, along with an increased number of PGPB as compared with full synthetic fertilizer dose. In conclusion, tested BoF can be considered as a green technology to reduce 30% synthetic N and 100% TSP requirements in rice production with improved soil health.

Farmers generally use more nitrogen fertilizer than others for crop production in Bangladesh because of its visible growth symptoms. Such practice is responsible for extra reactive N (Nr) load to the environment, but data are not available. Nitrous oxide (N2O) data were collected from a field trial following static closed-chamber technique, which were used for calibration and validation of DeNitrification and DeComposition model along with soil clay fraction, pH, bulk density and organic carbon contents. The model was well fitted and estimated about 364 g N2O–N ha−1 emission in Rajshahi region and only 15 g N2O–N ha−1 in Barisal region. District-wise N2O–N emissions varied from −1. In 2011–2016, N2O–N emissions from wheat fields were about 103–129 t yr−1 in Bangladesh. The model estimated nitric oxide (NO), ammonia (NH3) and nitrate (NO3) fluxes varied from 0.012 to 0.447, 7 to 12.5 and 0 to 4.7 kg N ha−1, respectively, under ambient temperature condition. In about 79% yield variabilities were explainable by N2O emission. In dominant wheat growing areas, if sowing is started from 15 to 30 November, N2O emission could be reduced by 8–40% with 5–13% reduction in yields compared to 10 November sowing. In similar areas and same sowing date with 1.5 °C temperature rise, N2O emission may increase by 8–45% and wheat yield might reduce by about 4–8%. Time of seeding and other cultural management in wheat cultivation would be the main avenue for reducing Nr loads to the environment.

In the changing climatic condition, temperature is the most vulnerable parameter and is projecting a trend of increase in the future. Crop growth and development process depend largely on air temperature. This study aims to determine the role of increasing air temperature in yield, crop water requirement (CWR), and other agronomic parameters of irrigated rice. Ceres-rice model associated in the Decision Support System for Agrotechnology Transfer (DSSAT) was used in 15 different locations of Bangladesh. Grain yield, growth duration, and crop water requirement of widely cultivated irrigated rice (Boro rice) variety BRRI dhan28 were analysed in normal temperature and elevated air temperature by 1°C, 2°C, 3°C, and 4°C. The result revealed detrimental effect of elevated temperature on growth duration and grain yield. The estimated highest growth duration reduction of 30 days was found in Moulvibazar for 4°C temperature rise. The grain yield reduction was projected by 0–17%, 16–35%, 31–49%, and 39–61% from the normal condition if the seasonal mean temperature increased by 1°C, 2°C, 3°C, and 4°C, respectively. The country average crop water requirement was found to be 405 mm of which the highest 445 mm and the lowest 358 mm were recorded in Moulvibazar and Chandpur, respectively. The study revealed that the country average rice CWR reduced by 5%, 8%, 12%, and 17% over the normal condition for 1°C, 2°C, 3°C, and 4°C rising temperature, respectively. For 1°C temperature rise, BRRI dhan28 life span shortened by 6.4 days, grain yield reduced by 695 kg, and estimated CWR decreased by 14 mm. The projected declining CWR indicated that irrigated rice will require less irrigation water, but it will cause considerable yield loss under elevated temperature. Though elevated temperature will save huge irrigation water used in country-wide Boro rice cultivation, the crop developers need to introduce new heat-tolerant cultivar to minimize yield loss.

Many nutrient rich fruits are grown in Bangladesh, but consumption is less than half of the daily requirement. Such situations are worst depending on growing seasons, natural hazards and localities of the country. The climate extremes are increasing globally including Bangladesh and damaging crops severely. So, the impacts of climate extremes on fruit crop losses and socio-ecological vulnerability were investigated in the present investigation. The socio-ecological vulnerable zones were determined based on minimum of 10 attributes, arithmetic, geometric and weighted mean scores and maps were prepared using IDRISI3.2. Banana, mango, watermelon, pineapple, and jackfruit covered the highest areas in Bangladesh. Total fruit production varied from 600000 tons depending on location of gardens and its size. North-east, south and south-east coastal regions of Bangladesh are moderate to very highly socio-ecologically vulnerable for fruit production. Most safe zones for fruit cultivation are situated in major hilly, parts of north-west and a few districts in central region in Bangladesh. Fruit crop area damages were the highest in Khulna division. Hailstorms were dominating hazards responsible for 28.83% losses followed by thunderstorms (14.73%), cyclone (14.54%) and salinity (10.86%). Based on economic losses, about 67% areas of the country are moderate to highly vulnerable for fruit cultivation. Major hilly, parts of north-west and part of central regions are safe for fruit production of country. Damages from climate extremes can be minimized by changing sowing times, selection of hazard tolerant varieties, making physical barriers, early warning for disaster preparedness and community based disaster management.

Amphiphilic poly(ethylene oxide) (PEO) macromonomers such as 1-3 homopolymerize very rapidly, via micellar organization, in water to afford regular comb polymers. Poly(macromonomer)s obtained exhibit either star-like or bottlebrush conformation depending on the relative size of backbone to arm. Micellar copolymerization between PEO macromonomers apparently enhanced the incorporation of those with a more hydrophobic polymerizing end-group. Micellar copolymerization of solubilized styrene with 1 (1/1 mol/mol) afforded an apparently unimolecular, highly branched graft copolymer of ca 30 nm size with MW of ca 107. Emulsion (in water) and dispersion copolymerization (in methanol/water mixture of 9/1 v/v) of styrene with 1 afforded nearly monodisperse polymeric microspheres of submicron to micron size.

Background: Appendicitis is notorious in its ability to simulate other conditions and in the frequency, it can be mimicked by other pathologies. The purpose of this study was to evaluate the accuracy of the diagnostic approach incorporating modified Alvarado score system (MASS) and ultrasonography with clinical findings. The aim of the study was to observe and evaluate different modalities of determining appendicitis among the non-pregnant female population of reproductive ageMethods: This prospective descriptive study was conducted at the department of surgery, Rajshahi College and Hospital, Rajshahi, Bangladesh. The study duration was 6 months, from February 2013 to July 2013. The study was conducted with a total of 101 women who were of reproductive age, presenting with right lower quadrant pain, who went through appendicectomy during the study period.Results: The incidence of negative appendicectomy was 4.95% in this study. Most of the patients having appendicitis were in second and third decades with a mean age of 24.79±10.11 years. The rate of perforation in our study was 5.94%. The overall post-operative complication rate was 13.86% with minor wound infection being the most common complication. The accuracy, sensitivity, specificity, PPV and NPV of the diagnostic approach in this study were 95.05%, 98.96%, 20.00%, 95.96% and 50.00% respectively. The accuracy, sensitivity and specificity of ultrasound were found to be 29.47%, 25.56% and 100% respectively.Conclusions: Combined use of clinical diagnosis incorporating modified Alvarado score and ultrasonography led to a significant reduction in the negative appendicectomy rate.

Mungbean (Vigna radiate L. Wilczek) is an important pulse crop for South Asian region. Its productivity is low and usually grown under water limited environments. Generally, irrigation at around flowering stage is provided if soil moisture is limiting. Its growth and yield is highly sensitive to fluctuations in climatic conditions, especially water-logging at any growth stage. Present study aimed at developing simple mungbean growth (MungGro) model, following the principles of SUCROS2 and the programme is written in Fortran Simulation Translator (FST). Water balance sub-routine has been undertaken along with G × E interaction, and the model was successfully calibrated and validated for growing environments of Bangladesh. Subsequently the model was utilized to evaluate the interaction effects of increased temperatures and carbon dioxide (CO2) levels. Yield, in general, decreased with the rise in temperature, primarily due to reduction in growth duration and seed weight growth rate of the crop. Increased CO2 levels compensated to some extent the deleterious effects of increased temperatures. Water-logging, especially at the beginning of the crop growth stage, had pronounced effect in reducing the grain yield drastically that was also reflected from the model. At present, we have calculated nitrogen (N) uptake and N fixation at the terminal stage of the crop. The model further needs to be improved by including N balance and insect-pest sub-routines.

Agricultural productivity is affected by air temperature and CO2 concentration. The relationships among grain yields of dry season irrigated rice (Boro) varieties (BRRI dhan28, BRRI dhan29 and BRRI dhan58) with increased temperatures and CO2 concentrations were investigated for futuristic crop management in six regions of Bangladesh using CERES-Rice model (DSSATv4.6). Maximum and minimum temperature increase rates considered were 0°C, +1°C, +2°C, +3°C and +4°C and CO2 concentrations were ambient (380), 421, 538, 670 and 936 ppm. At ambient temperature and CO2 concentration, attainable grain yields varied from 6506 to 8076 kg·ha-1 depending on rice varieties. In general, grain yield reduction would be the highest (13% - 23%) if temperature rises by 4°C and growth duration reduction would be 23 - 33 days. Grain yield reductions with 1°C, 2°C and 3°C rise in temperature are likely to be compensated by increased CO2 levels of 421, 538 and 670 ppm, respectively. In future, the highest reduction in grain yield and growth duration would be in cooler region and the least in warmer saline region of the country. Appropriate adaptive techniques like shifting in planting dates, water and nitrogen fertilizer management would be needed to overcome climate change impacts on rice production.

Understanding of crop water requirement is essential for irrigation scheduling and selection of cropping pattern in any particular area. A study was conducted to estimate irrigation requirement and made irrigation scheduling of T. Aman (wet season) and Boro (dry season irrigated) rice in the western region of Bangladesh using CROPWAT model. Historical climate data from three weather stations in the region along with soil and crop data were used as input to FAO Penman-Monteith method to estimate reference evapotranspiration (ETo). Effective rainfall was calculated using USDA soil conservation method. The model estimated1408 mm annual ETo in the study area, of which the highest amounts of 175 mm was in April and the lowest (70 mm) in December. The average annual rainfall was 1592 mm of which 986 mm was effective for plant growth and development. The model estimated ETc of BRRI dhan49, which was 473 to 458 mm, depending on its transplanting dates from 15 July to 15 August. Rice transplanted on 15 July required no irrigation, whereas three supplemental irrigations amounting 279 mm were required for transplanting on 15 August. The CROPWAT model estimated seasonal irrigation water requirement of 1212 mm (12 spilt applications) for BRRIdhan28 transplanted on 15 January. This model has also a potentiality to make irrigation scheduling of other crops. The Agriculturists 2017; 15(1) 19-27

Carbon (C) inputs and tillage intensity impinge on C degradation and thus CO 2 emission and soil properties get influenced. Information on CO 2 emission and soil properties under different tillage practices and straw application in rice based cropping system in Bangladesh is lacking. The effects of rice straw and tillage operations on CO 2 emission and soil properties were quantified in four consecutive seasons of transplanted Aman and Boro rice grown under two tillage operations (minimum and traditional) and three levels of rice straw (control, incorporation and mulch) during 2010 to 2012. Irrespective of tillage practices, CO 2 emission peak reached after 3-4 weeks of straw application. Carbon dioxide emission ranged from 26 to 59 kg ha -1 day -1 under minimum tillage and 25 to 96 kg ha -1 day -1 under traditional tillage. Minimum tillage accumulated more C in soil, which could be attributed to lower rates of emission and straw degradation. Carbon degradation rate constants, k were 0.000300 and 0.000394 (day -1 ) under minimum and traditional tillage, respectively. Small increment in soil C might help reducing CO 2 in the atmosphere. Mineralization of straw increased nutrient contents and thereby improved the soil fertility and availability to the crops for nutrients’ uptake. Traditional tillage significantly reduced soil bulk density and increased field capacity of the soil, whereas in addition, rice straw application furthermore increased permanent wilting point and available water content in the soil. The present study may help in identifying suitable tillage and residue management options in reducing CO 2 emission from rice fields. The Agriculturists 2017; 15(1) 127-142

Climate change is influencing rice ( Oryza sativa L.) production in some agro-ecological regions of Bangladesh. The impact of seasonal climatic variability on rainfed lowland rice (transplanted aman or T. Aman ) yield in north-west Bangladesh was analyzed based on historic weather data from 1971 to 2010. Wet season maximum and minimum temperatures were increasing by 0.0174 and 0.0083°C year -1 , respectively. Sunshine hours for the same period have decreased by 0.0259-0.027 hr year -1 . The representative concentration pathway (RCP) based projection showed increased maximum and minimum temperatures by 0.42-1.51 and 0.79-1.34°C, respectively in 2050. T. Aman rice yield could be reduced by 0.17-0.37 t ha -1 if temperature rises by 1°C. If sunshine hour decreases by 1 hr, yield reduction could be 0.20 t ha -1 . Combined effect of increased minimum temperature and decreased sunshine hours will govern T. Aman rice yield in future. The Agriculturists 2017; 15(1) 68-80

Maize is an emerging important crop in Bangladesh because of its high yield potential and economic profitability compared to rice and wheat crops. There is a need to understand the growth and yield behavior of this crop in varying production environments of Bangladesh. Crop model such as Decision Support System For Agro-technology Transfer (DSSAT) version 4.6 (DSSAT hereafter) can be utilized cost effectively to study the performances of maize under different production environments. It needs to calibrate and validate DSSAT model for commonly cultivated maize cultivars in Bangladesh and subsequently take the model to various applications, including inputs and agronomic management options and climate change that impacts analyses. So, the present study was undertaken to firstly calibrate DSSAT model for popular four hybrid maize cultivars (BARI Hybrid Maize-7, BARI Hybrid Maize-9, Pioneer 30B07 and NK-40). Subsequently, it proceeded with the validation with independent field data sets for evaluating their growth performances. The genetic coefficients for these cultivars were evaluated by using Genotype coefficient calculator (GENCALC) and Generalized likelihood uncertainty estimation (GLUE) module of DSSAT on the basis of first season experiment. The performance of the model was satisfactory and within the significant limits. After calibration, the model was tested for its performance through validation procedure by using second season data. The model performed satisfactorily through phenology, biomass, leaf area index (LAI) and grain yield. Phenology, as estimated through days to flower initiation and maturity, was in good agreement, although simulated results were slightly over predicted compared to observed values but within the statistical significance limit...when compared with observed values at specific growth stages of the crop. The final yield values (10.12 to 10.59 t·ha-1) were in close agreement with the observed values (10.16 to 10.94 t·ha-1), as the percentage error was within tolerable limit (0.39% to 6.81%). The model has been successfully calibrated and validated for Gazipur environment and now can be used for climate change impact studies for similar environments in Bangladesh.

Climate change impacts are visible in Bangladesh which requires adoption of judicious crop management practices for sustainable agriculture. Crop simulation models are effective in this regard and can be used for optimizing water and nitrogen inputs for maximization of wheat yields. Two field studies were conducted at Bangladesh Agricultural Research Institute (BARI) for evaluating the effect of increased temperature on wheat production under variable water and N rates, through the use of DSSAT v4.6 model. Thirty years historic weather data and BARI Gom-26 wheat-cultivar coefficients, as generated through use of GLUE of DSSAT model, were used for evaluating the impact of temperature rise with variable rates of irrigation water and nitrogen. The effects of four levels of nitrogen (0, 40, 80 and 120 kg ha-1) and four irrigation levels [0 (no irrigation), 1, 2 and 3] on wheat yield were evaluated under 0°C, 1°C, 2°C and 3°C rise in temperature. Simulation results indicated that wheat yield increased with increase in nitrogen application rate, but decreased with the temperature rise. Crop growing duration was reduced by about five days for each degree rise in temperature, irrespective of levels of irrigation water and nitrogen-rates. In general, there was yield reduction of 8.13, 16.77 and 24.97 % with increased temperature of 1°C, 2°C and 3°C, respectively, when compared with no temperature rise treatment. For interaction of temperature rise-N dose, the magnitude of yield decline under temperature rise was higher with increased dose of N. Agronomic N use efficiency at different N rates and temperature rise level were calculated. N use efficiency decreases with the increase in temperature rise and the highest (29.95 kg grain kg-1 N) was obtained from 40 kg N ha-1 treated plot with 0°C temperature rise i.e. existing atmospheric temperature. Simulation results indicated increase in wheat yield with higher levels of irrigation water, and interaction of irrigation level with temperature rise was significant. Irrigation use efficiency decreases with the increase in temperature rise. From the present study, it was seen that the interaction of temperature rise with varying levels of N and irrigation water was significant, and there is a need to design the appropriate inputs’ management, as the adaptation strategy, to sustain the wheat yield under climate change situation.

Public policy is an important issue in the context of international arbitration and, for that matter, domestic arbitration. However, in respect of the former there appears to be progressively a more restrictive approach applied globally than in the latter. Since the public policy issues could prove to be a stumbling block to the recognition or enforcement of a foreign arbitral award in the concerned country’s courts, an international arbitral tribunal should be mindful of the matter, though challenging, while rendering the award. The best guide for an international arbitral tribunal would be to look into the recognising or enforcing country’s law and practice in the context. The article is concerned with the public policy issues for the recognition or enforcement of foreign arbitral awards in the three major countries of the Indian subcontinent such as India, Pakistan and Bangladesh. These countries have historically had the common heritage of the English common law system which influences their respective laws, court decisions and jurisprudence. Thus, the article examines the public policy issues in the context of international arbitration in these countries in light of the English common law and international arbitration law and practice so that international arbitrators could draw upon the findings of the study while rendering arbitral awards, and when it is so relevant.

The North-West (NW) region of Bangladesh is pivotal for the country’s agricultural development, mainly in producing irrigated Boro rice. However, increasing cost of irrigation water, fertilizers, labour and other inputs, and the spatio-temporal variation in actual yield, market price and profitability of rice, have added uncertainty to the sustainability of Boro rice cultivation. In this study, we evaluated the productivity, profitability, and prospect of Boro rice production using comprehensive field data collected directly from 420 farmers’ fields over two consecutive seasons (2015–16 and 2016–17), across seven geographically distributed locations in the NW region. We also analyzed the risk and return trade of popular Boro rice cultivars using Monte-Carlo simulation. The results show that there were significant (p≤0.05) variations in rice yield between sites, irrigation pump-types, and rice varieties, with Hybrid rice and BRRI dhan29 producing highest yields (6.0–7.5 t/ha). Due to different pricing systems, the cost of irrigation water varied from site to site and from year to year, but always comprised the highest input cost (20–25% of total production). The total paid-out cost, gross benefit, and gross income of rice significantly (p≤0.05) differed between sites, type of irrigation pumps, rice varieties, transplanting dates, and two cropping years. The variations in observed yield and profitability reveal considerable scope to improve rice production systems. Market variation in the price of rice affected overall profitability significantly. Probability and risk analysis results show that Minikit and BRRI dhan29 are the most stable varieties for yield and profitability. Hybrid rice, which has the maximum attainable yield among the cultivated rice varieties, also has the risk of negative net income. Based on the analysis, we discussed ways to improve yield and profitability and the prospect of Boro rice cultivation in the region. The study provides valuable information for policy-makers to sustain irrigated rice cultivation in both the NW region and nationally.

In the present study, pulque (Agave cantala) fibers treated with acetic anhydride were grafted with styrene monomer by free radical graft copolymerization techniques. The grafted fibers were then characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), thermogravimetric analysis (TGA), and tensile mechanical tests. Untreated raw pulque fibers were also taken as control for comparison. FTIR analysis confirmed the grafting of styrene monomer onto pulque fibers. It was also found that polystyrene graft acetic anhydride-treated pulque fibers displayed higher thermal resistance, improved tensile properties, and lower moisture content as compared to untreated raw pulque fibers.

Groundwater-irrigated Boro rice is produced on 83 % of the net cultivable area (NCA) in North-West (NW) region of Bangladesh. Falling groundwater levels in many parts of the region raised concerns about the sustainability of groundwater irrigation. It is generally accepted that, in the absence of a comprehensive scientific study, uncontrolled groundwater use for Boro rice cultivation leads to water wastage and low water productivity. Therefore, it is crucial to know the actual field-level water usage and, irrigation water productivity, which will help identifying options to sustain groundwater irrigation. This study provides a comprehensive account of these aspects of Boro rice cultivation based on field observations at 420 farmers’ plots in 2015–16 and 2016–17 seasons across seven sites in the NW region. Necessary data, including land type, soil type, rice varieties, seeding and transplanting times, grain and biomass yields pump discharge, and irrigation amount were recorded. Average water productivity was 0.67 kg m−3 and 0.64 kg m−3 based on total available water (rainfall plus irrigation) in the fields, 0.80 kg m−3 and 0.95 kg m−3 based on supplied irrigation, and 1.60 kg m−3 and 1.78 kg m−3 based on estimated actual crop evapotranspiration (ETc) during 2015–16 and 2016–17, respectively. These water productivities are the highest among the major rice-growing Asian countries indicating limited scope for improving farmers’ water management practices. Comparison of the actual water supplied to the field and the estimated requirements shows that farmers are, in general, very efficient in supplying water to rice. In shallow tube well (STW) sites, water supplied by the farmers was very close to actual requirements, but rice plots in DTW sites had some over application. The average total amount of water available in the field to grow one kilogram of rice was 1,606 L (L) in 2015−16 and 1605 L in 2016−17. The Average irrigation water supplied to the field was 1402 L kg−1 in 2015−16 and 1086 L kg−1 in 2016−17. However, not all water supplied to the rice plots are consumed by the plants. Actual crop evapotranspiration is the real water use and based on that only 661 L in 2015−16 and 584 L in 2016−17 were required to grow one kilogram of rice. Percolation and seepage water return to the underlying aquifer as return flow. So, the current government policy of so called ‘water savings’ by reducing pumping of groundwater is unlikely to have any major impacts on the sustainable groundwater irrigation in the NW region.

Cropping in the polders and islands of the Ganges delta is difficult, particularly in the dry season when water is limited and salinity can damage plant growth. Cropping is generally restricted to the wet season. The limited cropping contributes to the high incidence of poverty and limited livelihood prospects in the region. Increasing crop production is desirable, and will depend upon management of the water and salt in a polder. We have developed a novel time-series model of water and salt stores and flows in an idealised polder to investigate water and salt management strategies for crop production, including strategies to cope with climate change and sea level rise. We know of no other model that simulates the overall water and salt balance of a polder, and that can assess a wide range of polder water and salt management strategies. The model adequately reproduces the dynamic water and salt behaviour observed in field data, and also agrees with results produced by a more detailed crop model. A sensitivity analysis of the model shows the results are sensitive to the key model parameters. In general, the results are more sensitive to parameters governing the transfers of salt, and less sensitive to those governing the availability of water. The crop evapotranspiration is particularly sensitive to the model parameters. The main practical consideration resulting from this simplified but robust representation of the polder salt and water balance processes is the importance of management (including drainage) to remove salt. Strategies to improve water availability, while useful, are secondary to the management of salt.

A study was conducted on long-term (for 31 years) rice–rice–fallow cropping sequence to determine the effect of balanced chemical fertilizer and integrated nutrient management (INM; chemical fertilizer + poultry manure 2 tonne ha –1 ) on soil organic carbon (SOC) sequestration. C mineralization rate (k), microbial population, SOC and C content in the mean water stable soil aggregate (MWDw) were measured from field soil. The C dynamics was described using DSSAT crop and DNDC models. INM increased soil bacteria and improved SOC stock by 27.98%, although C loss was higher with this treatment. A decreasing trend of bacterial population and SOC was observed in the balanced chemical fertilizer (15%) and fertilizer control (46%) treatments compared to initial soil. A positive correlation (r = 0.94) was found between C content of MWDw and soil bacteria population, which provided evidence of vital contribution of soil bacteria for SOC sequestration. In INM treatment, k (incubation study) was 0.011 tonne year –1 , and it was less than DNDC- and DSSAT-generated data. However, k value (0.010 tonne year –1 ) obtained in the incubation study of the balanced chemical fertilizer was similar to DNDC model data. An increasing trend of paddy yield (10 years) was observed in INM compared to balanced chemical fertilizer. In conclusion, microbial population, SOC sequestration and crop yield were high with INM. For sustainable rice production and C sequestration, INM is superior to balanced chemical fertilizer. Between two models used, DNDC is better for prediction of SOC balance.