Response of Eggplant to Integrated Approaches for Sustainable Reclamation and Improvement of a Cheringa Hot Spot of Acid Sulfate Soil

The application of basic slag (BS20 and BS30: basic slag 20 and 30 t ha-1) and aggregate size (A20 and A30: aggregate sizes of soil less than 20 and 20-30 mm) and different techniques (Tech 1: pyrite at top, jarosite at middle, and top soil at the bottom of ridge; Tech 2: top soil at top, pyrite at middle, and jarosite layer at the bottom of ridge) exerted significant (p≤0.05) positive effects on the growth and yield of eggplants cultivated under field condition and the effects varied not only with the kinds and amounts of amending materials but also with the techniques applied. The soil showed a silty clay loam texture, initial pH value of 4.1, pyrite content of 55 g kg-1, base saturation of 47%, ECe value of 3.6 dS m-1, high exchangeable Fe3+ and Al3+ contents of 1.47 and 5.29 cmolc kg-1, respectively. The pH value of the average soil data obtained from all the treatments during fruit set (95 days after transplantation) of eggplants was found to be increased in pH by 1.2 units higher compared with the control (i.e. initial pH value). The contents of P, K, Ca and Mg in the average soil data during fruit set were found to be increased (IOC = increased over control) by 41 to 127% IOC, while the contents of Al3+, Fe3+, Na+, Cl- and SO4 2- in the soil were found to be decreased by 28 to 92% IOC. The different treatments on eggplants grown under the modified-plain-ridge-ditch techniques in the Cheringa acid sulfate soil significantly (0≤0.05) increased the fresh yield of eggplants, and the increment was more pronounced with Tech 2. The maximum yield of 17.8 t ha-1 of eggplant for Tech 1 and 20.1 t ha-1 for Tech 2 were recorded by the application of BS30 in the soils of smaller aggregates (A20) at the ridges of Tech 2, followed by the A30BS30 treatments in both the techniques. The lowest quantity of 1.7 t ha-1 yield was recorded by the control treatment. The eggplants grown in the ridges of both the techniques exhibited the best responses on N, P, K, Ca and Mg contents in eggplant tissues during fruit set. As expected, the lowest contents of these nutrients in the eggplants were recorded in the control treatment. Sulfur content of the eggplants grown in the control plots was 3.6 g kg-1 and was in the range of adequate S content (4 g kg-1). However, the S contents in the eggplants grown in different treatments were significantly (p≤0.01) lower compared with the adequate level. The effectiveness of the treatments for the reclamation of the soil in relation to the growth of eggplants was: Tech 2 > Tech 1, BS30 > BS20, and A20 > A30. The results suggest that the physicochemical properties of the soil, and the growth, yield and nutrition of eggplants were strikingly improved by the application of flash leaching followed by BS30 and A20 treatments in the ridges of Tech 2, and are regarded as the best reclamation measures for this acid sulfate soil

Enumeration, Isolation and Identification of Nitrogen-Fixing Bacterial Strains at Seedling Stage in Rhizosphere of Rice Grown in Non-Calcareous Grey Flood Plain Soil of Bangladesh

Non-symbiotic diazotrophic systems for biological nitrogen fixation (BNF) in agriculture are most promising but the possibility for the extension of nitrogen fixation by rice is still speculative. Accordingly, the present study was conducted for the Enumeration, isolation and identification of nitrogen fixing bacterial strains at seedling stage (30 days after seed sowing) in rhizosphere of rice (BR 10, Oryza sativa L.) grown in Non-Calcareous Grey Flood Plain soil of Bangladesh. The soil is classified as ‘Inceptisol’ order and ‘Aquept’ suborder. It was identified as ‘Dhamrai series’, had ‘silt’ texture, pH 7.1 and 5.5 C/N ratio. The present results of the microbial tests on the rice rhizosphere soil evinced that out of 263 isolates, only 91 were branded as nitrogen fixing organisms per gram of soil, which was about 34.6 % of the total isolates. As per selection criteria, four individual strains were considered for identification. Biochemical tests were conducted for proper identification and the selected strains were identified as Enterobacter spp., Klebsiella spp., Bacillus spp. and Azospirllum spp

Neutralizing Capacity of Basic Slag in Acid Sulfate Soils and Its Impacts on the Solubility of Basic Cations under Various Moisture Regimes

An incubation study was conducted with the topsoils (depth: 0-20 cm) of two different series namely Cheringa (silty clay loam, pHwater 3.6, electrical conductivity = EC 18.5 dS m-1, CEC 17.2 c mol kg-1, organic matter = OM 39.1 g kg-1, and Badarkhali (silty clay loam, pHwater 3.9, EC 19.0 dS m-1, CEC 18.40 c mol kg-1, OM 30.7 g kg-1) acid sulfate soils to evaluate the effectiveness of basic slag (BS) for the neutralization of acidity and solubility of basic cations. These soils received BS at the rate of 0, 11, 22 and 33 t ha-1 under various moisture regimes (moisture at saturated condition, i.e. 100 % moisture, moisture at field condition, i.e. 50 % and wetting-drying cycles of those 50 and 100 % moisture levels). The impacts of these treatments on some selected properties and changes in water soluble bases in these soils were studied at different periods of 180 days of incubation. The application of BS was found to be increased the pH of soils from 3.6 to 5.1 for Cheringa; 3.9 to 5.2 for Badarkhali soils during the 180 days of incubation. These increments were more striking with the highest doses of BS at 33 t ha-1 under saturated moisture conditions in both the soils. The EC of the soils had not much influenced by the application of BS, regardless of time. The treatments were exerted significant (p≤0.05) effects on the solubility of basic cations in different periods of incubation. The maximum release of the bases were recorded during 180 days of incubation under saturated moisture condition and the findings will be supportive for planning of crop production on these soils

Effects of Basic Slag, Aggregate Size and Groundwater Treatments on the Production of Chilli in Acid Sulfate Soils in a Simulation Study

A simulation study was conducted to evaluate the effects of basic slag (BS10 and BS20: basic slag 10 and 20 t ha-1), aggregate size (A20 and A30: aggregate sizes of soil, less than 20 and 20-30 mm) and groundwater depth (Gw0: no influence of groundwater and Gw50: groundwater beneath 50 cm of the soil surface) as physico-chemical amendments in two pre-leached (leached for a week through tap water to remove excessive acidity and salinity from the soil before transplantation) acid sulfate soils of Badarkhali (Salidic Sulfaquept) and Cheringa (Typic Sulfic Halaquept) series in relation to the production of Chilli (Capsicum annum L.). Maximum growth and yield of chilli were recorded by the treatment combining A30Gw50BS20 in both the Cheringa (green chilli weight: 4.82 t ha-1) and Badarkhali (4.51 t ha-1) soils. The application of basic slag (BS20) was found to be the most effective among the individual treatments, followed by the BS10 > A30 > Gw50 treatments. The application of BS20 increased the yield in combination with the Gw0 treatment by 40% for A20, while by 107% for A30 in the Badarkhali soil. On the other hand, in the case of Gw50, these increments were 49 and 141% for A20 and A30, respectively. The application of BS at the highest rate (BS20) to the Cheringa soil was more effective compared with the A20 and A30 treatments in the Badarkhali soil. The same rate of BS20 in combination with the Gw50 treatment increased the yield by 59 to 147% in the Cheringa soil compared with 49 to 141% in the Badarkhali soil. Almost similar and significant (p≤0.05) effects were observed for the other growth parameters of chilli cultivated in both soil series

Source and Sink Strength of Carbon Dioxide, Methane and Distribution of Sulfate in Salt-marsh Soils at the Wadden Sea Coast of Northern Germany

A field study was conducted at Schleswig-Holstein of Kiel in Germany to evaluate the factors controlling carbon and sulfate dynamics along a toposequence of coastal salt marsh soils. The soil at the top end of the salt marsh was salic silty to clayic Typic Sulfaquent (Salzrohmarsh) and the bottom end was sandy to silty Haplic Sulfaquent ( cbergangsmischwatt). The mean (depth: 0-100 cm) values of pH and rH were 6.8-6.9; 6.8-7.0 and 17.3-8.1; 15-8.6 for the Typic Sulfaquent (TS) and Haplic Sulfaquent (HS) throughout the year, respectively. The net-emission of CO2 was negative (-14.0 g m-2 yr-1) for the HS but highly positive (857 g m-2 yr-1) for the TS throughout the year. The annual emissions of CH4 were almost 10 fold higher in HS (0.3 g m-2 yr-1) than that of the TS (0.03 g m-2 yr-1). The concentrations of CH4 at different seasons showed almost inverse relationships with the concentrations of CO2, varied significantly (p 640.05) with the seasons and depth function, and showed no dependence to temperature. The SO4 contents were observed maximum in the TS than that of HS during all the seasons. There was no noticeable correlation (r=- 0.09) between SO4 and CH4 concentrations. Moreover, even CH4 was determined at depths where the SO4 concentration was about 1200 mg SO4 L-1

Assessment of radiation level and potential risk to public living around major hospitals in central and western Bangladesh

Human beings are continuously bathed in radiation coming from natural and artificial sources. Although the use of radiation in medical applications is beneficial to patients, it also contributes significantly to the health hazard for radiation workers and the public if radiation-generating equipment and radioactive sources are not handled properly. 96% dose contributed from medical uses of ionizing radiation in the US population among man-made sources as per NCRP Report No. 160. There is no extensive study conducted on the large hospitals in Bangladesh following the In-Situ method. We used a real-time digital portable radiation monitor with Garmin eTrex Global Positioning System at 320 monitoring points for radiation monitoring and positioning around the ten largest hospitals in central & western Bangladesh from September to November 2021. The mean radiation dose rates around Bangabandhu Sheikh Mujib Medical University, Dhaka Medical College Hospital, Evercare Hospital, Khulna Medical College Hospital, Mitford Hospital, National Institute of Cancer Research Hospital, Popular Hospital, Rajshahi Medical College Hospital, Shaheed Suhrawardy Medical College Hospital, and Square Hospitals were measured as 0.145 ± 0.012 μSv/h, 0.135 ± 0.009 μSv/h, 0.148 ± 0.008 μSv/h, 0.139 ± 0.01 μSv/h, 0.133 ± 0.007 μSv/h, 0.153 ± 0.011 μSv/h, 0.144 ± 0.012 μSv/h, 0.137 ± 0.008 μSv/h, 0.145 ± 0.01 μSv/h, and 0.153 ± 0.009 μSv/h, respectively. The mean excess lifetime cancer risk (ELCR) of the public who lives nearby the hospital's boundary was estimated at 1.05 × 10−3, 0.983 × 10−3, 1.071 × 10−3, 1.004 × 10−3, 0.964 × 10−3, 1.084 × 10−3, 1.043 × 10−3,0.996 × 10−3, 1.051 × 10−3 & 1.112 × 10−3 respectively. ELCR in most of the locations around the ten largest hospitals in central & western Bangladesh is higher than the global average value. Radiation monitoring is significant for minimizing the public's radiation risk and keeping hospital environments as radiation-free as possible