Nitrogen (N) loss from rice production systems in the form of ammonia (NH₃) can be a significant N loss pathway causing significant economic and environmental costs.

Generation of reactive oxygen species (ROS) constitutes an initial defense approach in plants during pathogen infection. Here, the effects of the two micronutrients, namely, zinc (Zn) and boron (B), on enzymatic and non-enzymatic antioxidant properties, as well as malondialdehyde (MDA) contents in leaves and roots challenged with Athelia rolfsii, which cause root rot disease, were investigated. The findings revealed that Zn and B application to the potting soil alleviated the adverse effect of A. rolfsii on sugar beet plants and increased the chlorophyll content in leaves. The increased enzymatic antioxidant activities such as catalase (CAT), peroxidase (POX), and ascorbate peroxidase (APX), and non-enzymatic antioxidants such as ascorbic acid (AsA) were observed in Zn applied plants compared to both uninoculated and inoculated control plants. A significant rise in CAT activity was noted in both leaves (335.1%) and roots (264.82%) due to the Zn₂B_1.5 + Ar treatment, in comparison to the inoculated control plants. On the other hand, B did not enhance the activity of any one of them except AsA. Meanwhile, A. rolfsii infection led to the increased accumulation of MDA content both in the leaves and roots of sugar beet plants. Interestingly, reduced MDA content was recorded in leaves and roots treated with both Zn and B. The results of this study demonstrate that both Zn and B played a vital role in A. rofsii tolerance in sugar beet, while Zn enhances antioxidant enzyme activities, B appeared to have a less pronounced effect on modulating the antioxidant system to alleviate the adverse effect of A. rolfsii.

The critical limit for zinc (Zn) varies from 0.38 to 2 µg/g soil depending on the crop and soil type. However, the critical limit for Zn was not explored recently for rice and potato cultivation in the floodplain soils of Bangladesh. A pot experiment was conducted to determine the critical limits of Zn in soil and plants for rice and potato cultivation in two agro-ecological zones (AEZs) of Bangladesh. The soil samples were collected from 20 different locations of Old Brahmaputra and Active Ganges Floodplains with low (1.80 µg/g) Zn status. The experiment was laid out in a factorial and completely randomized design with two levels of Zn (Zn₀ and Zn₁ (0 and 4.87 kg/ha as Zn sulphate)) applied to 20 different soil samples for rice and potato cultivation using three replications. The critical limit of Zn was determined through a graphical and statistical approach and crops were harvested at the stem elongation (for rice) and tuber filling (for potato) stage. The critical limit of Zn in soil for rice was found to be 0.8 and 0.85 µg/g by graphical and statistical methods, respectively, and both methods revealed the same value (0.73 µg/g) for potato. The critical limit of Zn in rice plants was 23.9 and 24.32 µg/g, whereas in potato plants it was 27.1 and 26.61 µg/g, determined by graphical and statistical methods, respectively. The added Zn supply in soil significantly increased the dry matter accumulation in rice (by 5.6%) and potato (by 10%) compared to no Zn supply. Therefore, a significant positive response to added Zn could be observed on crop growth and yield when the Zn concentration remained below the mentioned critical level for rice and potato cultivation in floodplain soils of Bangladesh.

Microplastics (MPs) pollution of environments due to human activities is a global concern. In the present study, we examined the occurrence of MPs in coastal hill soils (burned and non-burned) collected from the Rohingya Refugee camps in Cox’s Bazar, Bangladesh. The total number of MPs per kg of burned soil (402–403 items/kg) sample was significantly higher than that in non-burned soil (210 items/kg) sample. Fibers (24–57%) dominated in all the samples, followed by fragments (18–51%), sheet (12–29%), and microbeads (12–13%). The most common color of MPs was blue (16–68%), followed by red (14–25%), transparent (14–24%) and brown (14–22%). Among the size groups, MPs of 0.5-<1.0 mm (34–44%) dominated in all the samples, followed by 1.0–5.0 mm (27–45%) and <0.5 mm (14–29%). Attenuated Total Reflectance Fourier Transform Infrared spectroscopy analysis confirmed the most abundant polymer type in burned soil was polystyrene (28%) followed by polypropylene (23%), polyethylene (21%), polyamide (15%), ethylene-vinyl acetate (8%), and polyvinyl chloride (3%). The study confirms the presence of high MPs loads in burned soil, with high potential of trophic transfer to plants and washed out to aquatic environment and will appear as base line information for further assessment of MPs effects on biota.