Plastic pollution has become a major environmental problem, while the products of its degradation, microplastics (MPs), appear everywhere on Earth. Data on MPs in agricultural soils have appeared lately, but a significant knowledge gap exists regarding forest soils. In Serbia, municipal waste is often dumped in forests, creating environmental problems that have not been documented. To explore the impact of waste dumping and MPs on forest fluvisols, we evaluated MPs from topsoils of three waste dumps and adequate visibly plastic non-contaminated forest sites located in alluviums of the largest rivers in Serbia. For assessing the influence of environmental factors on soil MPs, samples were taken in three forest vegetational seasons, in two years. The impact of MPs on soil structure, chemistry, and microbial respiration (MR) was examined. Undisturbed soil columns from uncontaminated sites with added known MP particles were used to estimate the dynamic of MP transfer through the topsoil. Large aggregate formation, soil coarse sand content, specific mass, porosity, and available P, but not MR were affected by contamination. Seasonal and annual environmental changes significantly influenced the behavior of MPs in forest luvisols. MPs effectively penetrated the deeper layers of soil columns within 3 months, with strong accumulation in the 0–10 cm layer.

The principles of sustainable agriculture in the 21st century are based on the preservation of basic natural resources and environmental protection, which is achieved through a multidisciplinary approach in obtaining solutions and applying information technologies. Prediction models of bioavailability of trace elements (TEs) represent the basis for the development of machine learning and artificial intelligence in digital agriculture. Since the bioavailability of TEs is influenced by the physicochemical properties of the soil, which are characteristic of the soil type, in order to obtain more reliable prediction models in this study, the testing set from the previous study was grouped based on the soil type. The aim of this study was to examine the possibility of improvement in the prediction of bioavailability of TEs by using a different strategy of model development. After the training set was grouped based on the criteria for the new model development, the developed basic models were compared to the basic models from the previous study. The second step was to develop models based on the soil type (for the eight most common soil types in the Republic of Serbia—RS) and to compare their reliability to the basic models. From the total number of developed models by soil type (80), 75% were accepted as statistically reliable for predicting the bioavailability of TEs by soil type and 70% of prediction models had a higher determination coefficient (R²), compared to the basic models. For the Fluvisol soil type, all prediction models were accepted, while the least reliable prediction was for the Planosol type. As in the previous study of bioavailability prediction for TEs, the prediction models for Cu stood out, with more than half of the models with R² greater than 0.90. Results of this study indicated that the formation of a testing set by soil type derives models whose predictions are more reliable than the basic ones. To improve the performance of prediction models, it is necessary to include additional physicochemical parameters and to conduct an adequate analysis of extensive testing sets with more comprehensive statistical techniques.

(1) Background: Oat (Avena sativa L.) is a crop that is widely used in human nutrition, while it also plays an important role in animal husbandry as a high-quality forage crop. However, this crop is particularly susceptible to combined biotic stressors, including insect pests (Agriotes lineatus) and fungal infections (Fusarium spp.). These stresses act synergistically: root damage caused by wireworms increases the plant’s susceptibility to fungal infection, while pathogens further limit nutrient uptake and root system development. In recent years, the reduced efficacy of chemical pesticides against both insect pests and fungal pathogens has highlighted the need for alternative strategies in oat protection, leading to an increased focus on developing bacterial bio-inoculants as sustainable and effective biocontrol agents. (2) Methods: This study aimed to identify bacterial strains capable of suppressing wireworms (Agriotes lineatus) and Fusarium spp. in oats, while simultaneously promoting plant growth. Bacterial isolates were screened for key Plant Growth Promoting (PGP) and biocontrol traits, including IAA and siderophore production, phosphate solubilization, and the presence of toxin- and antibiotic-coding genes. (3) Results: The highest insecticidal effect against wireworms was recorded for Bacillus velezensis BHC 3.1 (63.33%), while this isolate also suppressed the growth of F. proliferatum for 59%, F. oxysporum for 65%, F. poae for 71%, and F. graminearum for 15%. The most effective Bacillus strains (with insecticidal and antifungal activity) were identified and tested in two pot experiments, where their ability to enhance plant growth in the presence of insects and fungi was evaluated under semi-controlled conditions. An increase in plant biomass, grain yield, and nitrogen content was observed in oat inoculated with B. velezensis BHC 3.1 and B. thuringiensis BHC 2.4. (4) Conclusions: These results demonstrate the strong potential of both strains as multifunctional bio-inoculants for enhancing oat growth and mitigating the adverse effects of wireworm damage and Fusarium infection.

Wireworms are often referred as a hardly manageable group of pests due to their unstable lifestyle and uneven distribution in soils. The current strategy of wireworm control involves the heavy use of chemical pesticides. To find an effective and eco-friendly biological control agent against wireworms, evaluation of bacterial properties and insecticidal effects of six Bacillus thuringiensis (Bt) strains against Agriotes lineatus was performed under laboratory conditions. The presence of cry11, cyt2 and krsA gene was detected in Bt strain BHC 2.4, while the same strain had the ability to produce siderophores, protease, amylase and cellulase. Single inoculums of Bt strains (BHC 2.4; BHC 4.5; BHC 4.7; 1.5; 4.3; 6.1) showed mortality against Agriotes lineatus larvae in the range of 6.67–72.22%. However, the compatible Bt dual cultures showed significantly higher efficiency in comparison with the single inoculums, with the highest efficiency of 79.63% recorded for Bt strain BHC 2.4 + Bt strain 1.5. The efficiency of applied Bt strains might be associated with the presence of genes coding for antibiotics and toxins. Therefore, the use of selected Bt strains applied in a form of compatible mixes could offer a sustainable solution for wireworm management in wheat.

This study was conducted over a four–year period (2019–2022) in an experimental red currant (Ribes rubrum L.) orchard to examine the effect of organic fertilization on the contents of macroelements (C, N, P, K, Ca, Mg, S) and microelements (Fe, Mn, Cu, Zn, B) in the leaves and fruits. Two organic fertilizers were applied: well–decomposed cattle manure (CM) at 60 t ha⁻¹, and pelletized poultry manure (PPM, ‘Italpollina’, NPK 4:4:4) at 1.6 t ha⁻¹. The study evaluated nutrient balance using the Deviation from Optimum Percentage (DOP) index in two cultivars, ‘Rolan’ and ‘Jonkheer van Tets’. In 2021, no differences in balance of macronutrient were observed between cultivars; however, in 2022, ‘Rolan’ exhibited a higher imbalance than ‘Jonkheer van Tets’. ‘Rolan’ showed greater imbalance for micronutrients in 2021, whereas in 2022 the opposite trend was recorded, with ‘Jonkheer van Tets’ showing higher ΣDOP values. Fertilization treatment affected nutrient balance, with CM causing the highest macro- and micronutrient nutrient differences in 2022, while PPM promoted a more moderate and stable nutrient status. The greatest differences were observed in the R–CM treatment. The findings highlight the importance of selecting appropriate fertilizer to maintain nutrient balance and optimize red currant cultivation.

The objective of this research is to investigate the application of new Bacillus spp. isolates from alkaline soil as potential biocontrol agents for the management of wheat pest-wireworms (A. lineatus larvae), diseases caused by the phytopathogenic fungi Fusarium spp., and their plant growth-promoting potential. Among five new Bacillus spp. isolates, BHC 1.3 and BHC 1.5 showed ability to suppress only mycelial growth of F. proliferatum. Insecticidal activity resulting in a wireworm mortality rate of 17.24% after ten days of experimentation was observed for BHC 1.5. The final percentage of seed germination was in the range of 95% – 100% with the additional highest production of indole-3-acetic acid (IAA) by BHC 1.5. The results of this study indicate that the new Bacillus spp. isolate may have the potential for formulating microbial inoculants effective in promoting wheat plant growth and biocontrol of soil-borne diseases and pests.