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A field experiment was conducted at Bangladesh Agricultural University farm, Mymensingh, Bangladesh, during the Boro season, 2017 with six different K fertilizer rates: 0, 10, 20, 30, 40 and 50 kg ha-1 to determine the optimum rate of potassium (K) fertilization for the improved yield of a specific rice variety in the irrigated ecosystem under floodplain area. Compared with no K fertilizer, adding K increased the rice grain and straw yields significantly, with all other yield contributing components, except 1000-grain weight. The highest yield of grain (7.07 ton ha-1) and straw (8.48 ton ha-1) were recorded in recommended fertilizer dose (RFD) of NPS + 50kg K treatment, which were statistically identical with RFD of NPS + 40 kg K. Rice grain and straw yields due to the different treatments increased by 18.65% to 53.74% and 18.67% to 53.78%, respectively over control. K content and uptake through grain and straw were significantly influenced by applying different levels of K. These results specified that the use of 40 kg K ha-1 had better performance on the grain and straw yields. Therefore, we conclude that the application of 40 kg K ha-1 along with the RFD of NPS for BRRI dhan29 cultivation is the best option for higher yield in Old Brahmaputra Floodplain soil. [ABSTRACT FROM AUTHOR]

On low-lying land in the Ganges Delta, waterlogging, salinity, and poor soil structure are constraints to intensifying cropping systems. Early sowing of dry season (rabi) crops in this area is hypothesized to increase yield potential because the current late sowing exposes the crop to less favourable temperature conditions, soil dryness, and salinity stresses. Field experiments were conducted over 2 years to identify the opportunities and challenges of early sowing between mid-November and mid-December for maximizing sunflower yield in Southern Bangladesh. Sunflower was dibbled into untilled wet soil on five occasions (23 and 30 November and 10, 20, and 30 December in 2016–2017 and 25 November, 14 and 25 December, and 10 and 25 January in 2017–2018), with two mulching treatments (rice straw at ~ 5 t ha−1 and 15–20% rice residue retention). Sowing before 15 December was associated with larger heads, more seeds per head, greater seed weight, and higher grain yield (3.5–4 t ha−1) in the first year, but early sowing was also risky since, in the second year, the sunflower sown on 25 November was hampered by heavy rainfall, which depressed yield compared to crops sown on 15 December. Increased yield from early sowing before 15 December was associated with higher soil water, lower soil salinity, and higher solute potential compared to sowing after 15 December. Lower yield in late sown crops was also associated with increased temperature at grain-filling stage. The rice straw mulch significantly improved soil water availability, reduced soil salinity, increased soil solute potential, and increased yield in the second year. In this paper, we show for the first time that sunflower sown before 15 December in the Ganges Delta has higher yield potential, but to gain the benefits of the earliest sowing, growers will need to manage the increased risk of yield loss due to waterlogging. [ABSTRACT FROM AUTHOR]

The study was conducted at the experimental field of the Department of Soil Science of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur, Bangladesh during July to November 2015 in transplanted aman (T. aman) season to evaluate the influence of rice straw application on growth and yield of rice (BINA dhan7) and soil fertility. The experimentation was established following a randomized complete block design (RCBD) using 3 treatments (T1= Inorganic fertilizer dose as per STB, T2= rice straw + inorganic fertilizer as IPNS basis and T3= Farmer's practice). Results of the experiment showed that application of rice straw along with inorganic fertilizers as IPNS basis did not produce any significant (p<0.05) variation in yield and yield regulating parameters of T. aman rice but ensured higher filled grains panicle-1 (96.68), 1000- grain weight (23.23g), straw (6.97 t/ha) and grain yield (6.32 t/ha) as compared to other treatments. Short term addition of rice straw in soil did not create any significant influence on post harvest soil nutrient status except K which was found high. Significantly highest N contents in grain and straw were observed in straw added plots, which further contributed to higher nutrient uptake by grain and straw. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to identify the effect of complete pellet feed on animal performances in both on-station and on-farm trials conducted on growing goats. Materials and Methods: A complete pellet feed was developed with 40% roughage (rice straw) and 60% concentrate [rice polish (50%), maize crush (16%), soybean meal (20%), molasses (10%), salt (2%), Dicalcium Phosphate (1%), vitamin–mineral premix (0.5%), and pellet binder (0.5%)] for commercial goat production and the research trial was carried out on the research station and on the farmers’ validation level. Results: The results of the experiment on the effect of the developed complete pellet feed on goat production under stall feeding condition demonstrated that feeding complete pellet feeds helped in increasing the daily body weight gain of goats (36.96 and 52.46 gm, respectively) compared to traditional semi-intensive feeding (17.76 gm) with significantly (p < 0.05) better body condition score of goats. Feed Conversion Ratio was considerably lower (5.7) in the pellet feeding group than in the other groups where no pellet feed was used (8.32 and 8.03). Significantly (p < 0.05) lower feed price per kg weight gain was also observed in the pellet feeding group (BDT 124.22) compared to other groups (BDT 203.85 and BDT 214.74, respectively). Conclusion: The results suggest that complete pellet feed can be more economical for commercial goat production under the stall feeding condition, and farmers can be benefited by about 40% more compared to conventional grass, urea molasses straw, and concentrate-based feeding system. [ABSTRACT FROM AUTHOR]

Two sets of experiments were conducted in Bangladesh for 10 successive growing seasons of transplanted aman and boro rice during 2010–2015 to assess the effects of tillage and organic amendments on properties and carbon sequestration index (CSI) of terrace soil. The experiment 1 comprised of two tillage practices (minimum and traditional) and three rice straw management (zero, incorporation, and mulch). The experiment 2 consisted of five treatments viz. control, poultry manure (PM), cowdung (CD), rice straw (RS), and soil test-based fertilizers. A fixed carbon (C) rate of 2 t ha−1 was ensured from organic amendments in each crop season. Data were collected after harvesting of the 10th crop in 2015. Traditional tillage and RS mulch were found immensely positive for microbial population and biomass C and nitrogen (N) in soils. Minimum tillage tied with RS incorporation was appeared positive in holding C and nutrients and increasing CSI. Poultry manure contributed to higher quantities of bacteria, fungi, and actinomycetes and attributed to maximum biomass C and N compared to other organic treatments. Organic amendments increased soil aggregate stability, nutrients, and moisture contents. The CSI of RS (0.21–0.29), PM (0.25), and CD (0.22) can be used to predict soil C sequestration. [ABSTRACT FROM AUTHOR]

Abstract: This work scopes the potential for existing common feedstocks to be used in existing types of anaerobic digester units to produce biogas in Bangladesh. A preliminary study identified three commonly occurring scenarios of smallholdings with cattle, poultry farms and daily cattle markets, which produce dung, poultry litter, and dung mixed with rice straw, respectively. This third feedstock is proposed as a novel and significant newly recognised prevalent source. The main study involved carrying out surveys of representative samples of each of these (N=125, 125, and 30) for the district of Gazipur in order to determine the distribution of herd and flock sizes, and thus the relevant biogas plant types and potential yields. The results were scaled up for nationwide figures, which approximated the total potential biogas energy from these feedstock types at 240×106 MJ (240TJ) per day, or 66.7×106 kWh, which in principle could meet the current cooking energy requirements of 30 million people in Bangladesh. Of this, 70% of the potential energy from AD could come from cattle feedstock (with 87% of this from domestic-sized plant); 16% from poultry feedstock (with 63% of this from medium-sized plant); and 14% from rice straw bedding from cattle markets (all requiring very large or extremely large plant). There is potential for around 2 million domestic units, 340,000 medium units and 19,000 large units, as well as 500 very large units that might be more suited for larger users such as businesses, schools or hospitals. [Copyright &y& Elsevier]

Lead (Pb) pollution in the environment predominantly occurs through anthropogenic activities, which pose significant threats to human health and that of biota. In this study, Pb and other elements were investigated in different soils (n = 52), crops (n = 24) and water (n = 13) around a lead-acid battery (LAB) recycling workshop in southwestern Bangladesh. Most of the elements' concentrations (except Se and Ag) in soil were lower than the background concentrations. However, excessive concentrations of Pb were found in both surface (966 ± 2414 mg kg−1 at 0–15 cm) and subsurface (230 ± 490 mg kg−1 at 15–30 cm) soil. Although no definitive pattern or direction in elemental concentration in soil was observed, relatively higher concentrations of most elements were detected at the southeast part of the factory. The LAB factory, brick kiln, agricultural and geogenic activities might be the sources of these elements in soil. Extremely high amounts of Cr, As, Cd, and Pb were found in the food crops around the area. In particular, the Pb concentrations were 114 ± 155 and 665 ± 588 mg kg −1 dry weight in rice grain and straw, respectively, which reflected the emissions of Pb from the LAB recycling workshop. Moreover, 40% and 100% of the groundwater samples exceeded, respectively, the WHO provisional guideline values for As (0.01 mg L−1) and Pb (0.05 mg L−1). Consequently, a high level of Pb contamination in the soil was observed while assessing different soil pollution indices. Human health risk assessment indicated severe carcinogenic (from Pb, As, and Cr intake) and non-carcinogenic (from Pb, As, Co, Cr, Ni and Sb intake) health risks are associated with rice and groundwater consumption. It is concluded that all LAB recycling workshops should be better managed to prevent Pb pollution from seeping into the environment. [Display omitted] • This study reports severe lead (Pb) pollution at the LAB factory, Magura, Bangladesh. •Pb acid battery recycling was responsible for elevated Pb emissions into the environment. •Rice grain and straw including other vegetables accumulated large amounts of Pb. •Lead in groundwater was17-fold higher than the WHO guideline value. [ABSTRACT FROM AUTHOR]

Puddling of clay soils for rice transplanting causes a loss of soil structure and vertical shrinkage cracks that are hypothesized to hamper sunflower root growth in the following dry season. To alleviate soil constraints for sunflower root growth and yield, we examined the effects of three levels of mulch and two irrigation regimes in the dry season on a clay-textured soil in the coastal zone of Bangladesh. These treatments were no-mulch, rice straw mulch at 5 t ha−1 and 10 t ha−1, irrigation applied to the field capacity (I1) and a water supply double that of the I1 treatment (I2). The rice straw mulch significantly increased soil water content by 3–9% and decreased soil penetration resistance by 28–77% and crack volume by 84–91% at A 0–30 cm soil depth relative to the no-mulch treatment. The better root development with the rice straw mulch increased sunflower yield by 23%. No benefit or further reduction in soil penetration resistance or yield improvement was obtained from increasing the level of mulch from 5 to 10 t ha−1 or the volume of irrigation water. It is concluded that ameliorating soil constraints by mulch application led to better root growth in the upper root zone and the increased yield in the clay soil. [ABSTRACT FROM AUTHOR]

Fertilization with organic matter (farm yard manure and/or rice straw) is thought to enhance arsenic (As) mobilization into soil porewaters, with subsequent As assimilation by rice roots leading to enhanced translocation to the grain. Here, interlinked experiments (field manuring and soil batch culture) were conducted to find the effect of organic matter at a field application rate practiced in Bangladesh (5 t/ha) on As mobilization in soil for paddies impacted by As contaminated groundwater irrigation, a widespread phenomenon in Bangladesh where the experiments were conducted. Total As concentration in a paddy soil (Sonargaon) ranged from 21.9 to 8.1 mg/kg down the soil profile and strongly correlated with TOC content. Arsenic, Fe, Mn, and DOC release into soil solution, and As speciation, are intimately linked to OM amendment, soil depth and temporal variation. Organic matter amendments lead to increased mobilization of As into both soil porewaters and standing surface waters. The As speciation in the porewater was dominated by inorganic As (As i) (arsenite and arsenate), with traces amounts of methylated species (DMAV and MMAV) only being found with OM amendment. It was noted in field trials that OM fertilization greatly enhanced As mobility to surface waters, which may have major implications for the fate of As in paddy agronomic ecosystems. Image 1 • We investigated the effects of paddy soil manuring on the mobilization of As in porewater. • Arsenic concentrations down the soil profile is strongly correlated with total organic carbon. • Paddy pore and surface water As concentrations were associated with iron, manganese and dissolved organic carbon. • The arsenic speciation in paddy soil porewater was dependent on the organic amendments. Organic matter fertilization greatly enhances As mobility to surface waters: major implications for fate of As in paddy agronomic ecosystems. [ABSTRACT FROM AUTHOR]