In the mitigation strategies of climate change, improving soil carbon storage is considered as one of the main tasks to enhance agricultural sustainability and sequester atmospheric carbon dioxide. Agricultural patterns have been changing significantly and causing many impacts on soil organic carbon (SOC) storage in the upper Vietnamese Mekong Delta (VMD). Therefore, this study aims to evaluate how typical agricultural pattern changes are affecting SOC by estimating the SOC stock and identifying the correlation with soil physic-chemical properties. Soil samples were collected in both depths of 0-20 cm and 20-50 cm and analyzed physic-chemical properties such as soil texture, bulk density, pHKCl, EC and SOC. In topsoil layers, the SOC stock of the wetland forest was the highest in the opened depression of floodplain (24.42±1.38 kg C m-2; p<0.05) while that of paddy rice was the richest at depth of 20-50 cm (27.69±2.97 kg C m-2; p<0.05). In other agro-ecological areas, SOC stock in croplands was lower than forest and grassland in topsoil layer, especially in mountainous areas. SOC stock correlated positively with SOC content, clay, bulk density, and EC (p<0.05) but had a negative correlation with sand and pHKCl (p<0.05). The decrease in SOC stock in dry cultivating patterns indicated the impact of agricultural management practices and soil fertility on SOC storage. Thus, improving SOC stock is needed to maintain sustainable soil management. That can be done by increasing C input and decreasing C loss in the atmosphere.

This study investigated the impact of tree age on soil properties in citrus orchards in the upper Vietnamese Mekong Delta province, examining orchards of four age groups (<10, 10–20, 21–30, and over 30 years) at two soil depths (0–20 cm and 20–50 cm). Findings indicate notable variations in soil physicochemical properties with age and depth. In older orchards (over 20 years), bulk density increased and soil pH decreased, with overall low pH values (3.5–5.0) observed. Electrical conductivity remained consistent across all ages. Key nutrients such as nitrogen (N), phosphorus (P), potassium (K), soil organic carbon (SOC), and cation exchange capacity (CEC) generally decreased with the age of the orchards. These trends were consistent across both soil layers. The study highlights the influence of prolonged cultivation on soil health and provides insights for developing strategies to enhance productivity and sustain agricultural practices in citrus orchards.

Arsenic pollution is one of the global issues which affect the drinking water supply in Burkina Faso, mainly in rural areas. To mitigate this water pollution, ferromagnetic activated carbon (FAC) has been prepared by chemical activation using rice husk and iron chloride solution to be used as an adsorbent of arsenic. Characterization with some analytical techniques revealed this carbon is microporous with a specific surface area of 150 m²∙g^-1 and ferromagnetic properties. This work aims to evaluate the equilibrium conditions of As(V) removal and the adsorption capacity of FAC. Batch experiments were undertaken to evaluate the performance of FAC for arsenic removal under various operating conditions and the mechanism of the removal process. Results showed an increase of the removal percentage with the increase of the contact time, indicating a saturation during 60 min. The removal of As(V) is influenced by the increase of the initial arsenic concentration causing an increase of the adsorption capacity of FAC. The increase of pH showed a variation of the removal percentage indicating a maximum removal at pH 7 which corresponds to an adsorption capacity of 153 µg∙g^-1. Both monolayer adsorption and ion exchange constitute the mechanism of removal of As(V) using FAC. The kinetics of the process is described by a pseudo-second order model.

Hydrothermally synthesized carbon nanodots (CDs) were impregnated on TiO2. The product (CDs/TiO2) was mechanically mixed with zeolite Y for application in toluene photocatalytic oxidation reaction under UV radiation. Material properties of the samples were investigated by different methods. Toluene vapor was chosen as a typical volatile organic compound to investigate the performance of CDs/TiO2 – zeolite Y photocatalyst when these technological parameters were changed: toluene concentration, gas flow rate, humidity and UV light intensity. In each reaction, only one parameter was changed and the remaining conditions were fixed. The toluene concentrations at the beginning and the end of each reaction were analyzed with the use of gas chromatography (GC). The results of different reaction conditions show the trends for toluene treatment of the CDs/TiO2 – zeolite Y catalyst, thereby providing specific explanations for these trends. The experiments also show that toluene removal is highest when the toluene concentration in the inlet gas is 314 ppmv, the flow rate is 3 L/h, the humidity is 60%, and the catalyst (CDs/TiO2 – zeolite Y composite with 70% zeolite in weight) is illuminated by 4 UV lamps. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Wetlands are critical ecosystems that play a vital role in biodiversity conservation, carbon sequestration, and climate regulation. This study investigates soil physicochemical properties and soil organic carbon (SOC) stocks across four wetland types in the Vietnamese Mekong Delta (VMD): mangrove...

Rice farming is a major contributor to greenhouse gas (GHG) emissions in the agricultural sector, especially in the Vietnamese Mekong Delta (VMD). We surveyed 202 rice-farming households (382.9 ha) in Dong Thap Province (Upper VMD) and estimated CO2, CH4, and N2O emissions from post-harvest rice-straw burning using IPCC (2006) Tier-2 methods. In 2024, straw was burned on 333.9 ha (87% of the surveyed area) and removed off-field on 49.0 ha. Total emissions were 415.14 t CO2e, dominated by CH4. Emission intensity was higher in triple-crop systems (1.26–1.55 t CO2e·ha-1·yr-1) than in the double-crop system (1.03 t CO2e·ha-1·yr-1). Reducing in-field burning through straw utilization (incorporation/composting, mushroom cultivation, livestock feed) and, where feasible, moderating cropping intensity can lower emissions while maintaining soil fertility. The study provides important data to support policy development and encourages farmers to adopt low-emission alternatives for post-harvest residue management.