Substituting peat moss with compost derived from organic waste in plant nurseries presents a promising solution for reducing environmental impact, improving waste management, and enhancing soil health while promoting sustainable agricultural practices. However, selecting the appropriate proportions of both materials is crucial for each plant species. This study investigates the effects of different ratios of compost and peat mixtures on the growth and development of pepper seedlings. The compost mixtures used in the study included the following combinations: sewage sludge with sawdust (A), sewage sludge with sawdust and biodegradable garden/park waste (B), and biodegradable garden/park waste with sawdust (C). The final substrates used for seedling production were composed of composts (A, B, C) and peat (O) as a structural additive, mixed in different proportions by mass: I-O 25%, II-O 50%, and III-O 75%. Seedlings grown in these substrates were assessed using biometric and physiological measurements. Nematode species present in substrates were identified by metabarcoding analysis. The results revealed that substrate productivity depended not only on nutrient content but also on structural properties, which were significantly influenced by the peat proportion. Among the tested compost mixtures, variant A I emerged as the most effective substrate, promoting optimal seedling growth. Molecular nematode analysis revealed significant nematode contamination in substrates with higher peat proportions (C II and C III), including Meloidogyne sp. Lichtenburg (26%), Meloidogyne hispanica (5%), Meloidogyne sp. Mi_c1 (3%), Meloidogyne ethiopica (2%), and Meloidogyne thailandica (1%). The findings underscore the critical importance of achieving an optimal balance between nutrient content and structural properties in substrates to support the healthy growth and development of pepper seedlings. To further enhance crop performance and reduce the risk of pest-related damage, it is essential to prioritize the improvement of substrate selection strategies. Monitoring for nematode contamination is crucial to prevent potential compromises in seedling quality and overall productivity.

Environmental context Mitigating the environmental fallout of industrial accidents is crucial. In a recent study, researchers conducted tests on model substrates to explore the effectiveness of bioremediation in treating complex refinery contaminants resulting from both accidental and deliberate facility damage. The research reveals that bioremediation can be a promising, eco-friendly solution for cleaning up such pollutants, aligning with broader efforts to combat environmental harm resulting from industrial incidents.Rationale Bioremediation harnesses microorganisms' diverse metabolic abilities to detoxify and eliminate pollutants, particularly hydrocarbon-based ones such as oil. This natural biodegradation process performed by microorganisms is a cost-effective method for environmental cleanup compared to other remediation technologies.Methodology In this study, we examined the fate of heavy metals, cobalt and molybdenum, by the analysis of the basic chemical parameters of other sample components, such as n-hexane extractable substances and total petroleum hydrocarbons. The metal content was determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). Exchangeable (loosely bound to the surface of particles and due to its high mobility and availability is crucial for understanding the potential immediate impact of metal contamination) and more stable fractions of the metal and the metal forms were determined using a sequential extraction method. The phase composition of the samples was determined by X-ray diffraction.Results In our microbiological analysis, we isolated various cultures from a consortium of microorganisms. Basic chemical analysis indicators, such as n-hexane extractable substances, total petroleum hydrocarbons and humic acids, reflected robust microbiological activity. During the study, metals in exchangeable form decreased and those in more stable forms increased.Discussion The sequential extraction of cobalt and molybdenum revealed shifts in various metal fractions within the bioaugmented substrate post-bioremediation, differing from the initial substrate. These alterations in metal fractions are likely attributable to microbial actions, leading to the formation of more stable metal fractions throughout the bioremediation process.

Soil nitrogen is crucial for agriculture, but it is often limited, affecting crop yields. Deficiency requires synthetic fertilizers, but their improper use results in environmental damage and high costs. Bacteria of the genus Rhizobium , symbionts of legumes, offer a sustainable solution by fixing nitrogen, thus reducing dependence on fertilizers. This research determined the most probable number (MPN) of cells of Rhizobium spp. from two commercial biofertilizers of Ecuadorian and Mexican origin under greenhouse conditions. For this, direct inoculation with serial dilutions (10(-1) to 10(-10) ) was performed in pots with steam -sterilized pumice where Blue Lake variety snap bean ( Phaseolus vulgaris L.) plants were germinated. The following morphological indicators were evaluated at 45 days after sowing (DAS): leaf area, plant wet weight, plant height, and number of flowers, determining statistical differences between the type of biofertilizer and the concentration of each dilution. The experiment followed a randomized complete block design with a split -plot arrangement, with three replicates per dilution, considering temperature fluctuations in the study area. The MPN at 95% confidence was 4.45x10(7) rhizobia g -1 of pumice at a 10(-5) dilution for the Mexican biofertilizer, and 1.48x10(5) rhizobia g(-1) of pumice at a 10(-4) dilution for the Ecuadorian biofertilizer. The estimated optimal dilution for both products was 10(-8).