Higher accumulation of heavy metals in food grains is one of the leading problems for carcinogenic effects in the body. That’s why; scientists have taken this problem as a potential indicator for ensuring safe food. The present study was carried out to assess the ecological risk of heavy metals such as nickel, copper, arsenic, lead, and manganese in agricultural soil and transfer status to rice grain. Soil samples were collected from four agricultural fields at different times in the Dumuria Upazila under Khulna district in Bangladesh. Heavy metal concentration in soil extracts, irrigation water samples, and grain samples was determined by Atomic Absorption Spectrometer. Average metal concentrations in soil were calculated and compared with the reference value in soil. In most cases, heavy metals in agricultural soil (Ni: 61.73–94.52 mg/kg; Cu: 23.33–37.5 mg/kg; As: 7.53–19.63 mg/kg; Pb: 15.17–29.19 mg/kg; Mn: 322.98–478.45 mg/kg) were greater than the reference soil (Ni: 13.08–24.55 mg/kg; Cu: 10.35–13.28 mg/kg; As: 1.87–4.61 mg/kg; Pb: 4.88–8.27 mg/kg; Mn: 52.17–74.3 mg/kg). Overall risk index stated that the examined soils were at moderate risk of contamination. Transfer Factor of arsenic (0.018–0.032 mg/kg) and manganese (0.059–0.155 mg/kg) was higher from soil to rice grain. On the other hand, transfer factor of lead was found negligible that is a good sign of improvement. The findings of the study will be good documentation for planning, risk assessment, and decision-making by environmental managers in this region.
Soil salinity is a major concern in southwestern part of Bangladesh because almost 30% cultivable lands are currently lying under risk of salinity where 30-50% yields loss is happening. Organic amendments have found to be effective in the amelioration of saline soil by improving soil physical and chemical properties as well as crop selection is another criteria for sustaining viability of crops in saline soil. For ensuring sustainable saline soil management, a comparative pot study was carried out during kharif 1 season in 2015 to observe the effect of organic amendments (solid waste, vermicompost and cow dung) on soil salinity and its influence on the growth of maize. Composite soil was collected at a depth of 0-15 cm from Gozalmari village of Jalma Union in Batiaghata Upazila under Khulna district, Bangladesh that was saline (10.6 dS/m) in nature and the irrigation water sample was collected from beside Kazibacha river (4.28 dS/m) that was also moderately saline. The maize cultivar “Shuvra” was used for cultivation in the study. The experiment comprised of four treatments viz. T0: Control (No organic manure); T1: Solid waste (36g); T2: Vemicompost (72g); T3: Cow dung (33g). Five seeds were sown in each pot. Seeds were treated with Agrosan GN to protect them from seed and soil borne pathogens. Chemical fertilizers were not used in the experiment. Irrigation was done two times before harvesting: at 20 days after sowing (DAS) and at 40 DAS with river water and rain water was irrigated naturally during the season. Findings were that the organic amendments significantly influence the physico-chemical properties of the saline soil. All organic treated soils significantly reduce the soil EC (from 10.6 dS/m to 3.4 dS/m) and pH (from 7.63 to 7.38) compared to control soil (p?0.05). In case of survival parameters (e.g %gemination, rate of survival at 50 DAS) of maize, the treatments were found insignificant (p?0.05). But in terms of growth parameter (plant height and root length), significant differences were found between control and organic amendments treated soil (p?0.05). It may be concluded that organic amendments treated soils showed better results than that of control soil. If proper management can be implemented, this positive results will bring hope to the local poor farmers at least can introduce a new crop in fallow agricultural land during the kharif 1 season.
Globally, pest-induced crop losses ranging from 20% to 40% have spurred the extensive use of pesticides, presenting a double-edged sword that threatens not only human health but also our environment. Amidst various remediation techniques, bioremediation stands out as a compelling and eco-friendly solution. Recently, the phytomicrobiome has garnered increasing attention as endophytic microbes, colonizing plants from their roots, not only foster plant growth but also enhance the host plant’s resilience to adverse conditions. Given the persistent demand for high crop yields, agricultural soils often bear the burden of pesticide applications. Biodegradation, the transformation of complex pesticide compounds into simpler forms through the activation of microbial processes and plant-based enzymatic systems, emerges as a pivotal strategy for restoring soil health. Manipulating the phytomicrobiome may emerge as a viable solution for this purpose, offering a native metabolic pathway that catalyzes pollutant degradation through enzymatic reactions. This review delves into the pivotal role of phytomicrobiomes in the degradation of diverse pesticides in soil. It explores contemporary innovations and paves the way for discussions on future research directions in this promising field.
18 March 2021 in Caraka Tani: Journal of Sustainable Agriculture
People in southwestern Bangladesh have been facing the waterlogging problem and protesting on the impacts for the nature for a long time. In the 1960s, the government introduced polders, embankments and cross dams to overcome the destructive scenario. Due to the failure of government initiatives, the local people of the coastal area cut into the polder so that the sediment deposited within the beel known as Tidal River Management (TRM). Then, TRM was applied several times in different catchments. The study was carried out from December 2018 to November 2019 to assess the positive and negative environmental and institutional impacts of TRM on Pakhimara beel in Tala Upazila (Sub-district), Satkhira District, by using the Sustainability Index of Tidal River Management (SITRM) framework. Sustainability Indices of TRM were designed to provide information on social, environmental and institutional gains. The environmental and institutional impacts were assessed by conducting household survey and Key Informant Interviews (KIIs). Agricultural impacts on crop, poultry, fisheries and vegetation, were also analyzed by comparing GIS map and agricultural production data (before and after TRM). This study investigated that Pakhimara beel was freed from waterlogging during the with-TRM event by 3,200 ha and the reduction of waterlogging increased agricultural land by 1,500 ha in 2018, compared to 2014. This study argued that only 54% of marginal farmers received crop compensation whereas 85% of crop production decreased due to TRM. For promoting sustainable TRM in the studied area, compensation should be guaranteed for all impacted parties, especially marginal farmers and the creation of employment opportunities, and settlement should be ensured.
Insecticides not only control target pests but also adversely affect non-target communities including humans, animals, and microbial communities in host plants and soils. The effect of insecticides on non-target communities, especially endophytic bacterial communities, remains poorly understood. Two phases of treatments were conducted to compare the trends in endophytic bacterial response after insecticide application. Endophytic bacteria were isolated at 2 and 4 weeks after germination. Most insecticide treatments showed a declining trend in bacterial diversity and abundance, whereas an increasing trend was observed in the control. Therefore, insecticide use negatively affected non-target endophytic bacterial communities. Bacillus spp. was mostly dominant in the early stage in both insecticide treatment and control groups. Nevertheless, in the matured stage, mostly bacteria including Pseudomonas spp., Priestia spp. were dominant in groups treated with high insecticide concentrations. Therefore, plants can regulate and moderate their microbiome during their lifecycle depending on surrounding environmental conditions.
A successive 2-year (2019 and 2020) field experiment was conducted in northern Bangladesh (Rangpur district) to observe the status of soil quality and heavy metal risk due to tobacco cultivation in this area. Soil samples were collected randomly from four major sub-districts (Rangpur Sadar, Badargonj, Gangachara, and Mithapukur Upazila) where Mithapukur was a non-cultivating tobacco field and the rests were tobacco-growing fields. Along with heavy metal concentrations, physicochemical parameters were analyzed to observe the progressive change in the soil. Results depicted that values of bulk density, particle density, porosity, soil organic matter (SOM), and major nutrients (N, P, K, S) were decreased in the tobacco-growing field from 2019 to 2020, whereas significant improvement was observed in non-tobacco-growing field at successive year analysis. However, exchangeable bases were raised in the tobacco cultivated field from 40.86 to 52.98% compared to the non-tobacco cultivated field which was in a declining trend (43.66–34.33%). Overall, the soil pollution index depicted that Pb was shown a moderate risk of contamination in 2020. The ecological risk analysis also stated that the tobacco field in Rangpur Sadar was at a moderate risk of soil pollution (RI = 126.16), although the non-tobacco field in Mithapukur was at no risk of pollution (RI = 45.23). So, it can be recommended that tobacco cultivation harms the soil health, and thus, it should be prohibited from the agricultural field.