Antibiotics in agriculture – application, threats and legal regulations

The discovery of the first antibiotic has become one of the most important medical advances. Since this time, a pe- riod of intensive research into antimicrobial substances has be- gun, which are also used in veterinary medicine and agricultural production. In animal production, antibiotics have therapeutic, as well as prophylactic and metaphylactic applications aimed at preventing bacterial diseases. They were also used as growth stimulants, which positively influenced, among others, for weight gain and more efficient use of feed. This form of antibiotic use in animal production was legally banned in 2006 in all European Union countries. In the cultivation of plants, antibiotics are also used to combat plant pathogens. The use of antibiotic agents has many consequences, both positive and negative. The most impor- tant risk of antibiotics overusing is the spread of antibiotic resist- ant bacteria. Another effect is environmental pollution and the contamination of agricultural products. Due to these factors, the use of antibiotics in agriculture is regulated by appropriate legal regulations

The Response of Red Clover (Trifolium pratense L.) to Separate and Mixed Inoculations with Rhizobium leguminosarum and Azospirillum brasilense in Presence of Polycyclic Aromatic Hydrocarbons

This study aimed to evaluate the impact of co-inoculation Rhizobium sp. and Azospirillum sp. on plant (Trifolium pratense L.) growth in the presence of polycyclic aromatic hydrocarbon (PAH) contamination (anthracene, phenanthrene, and pyrene). Eight strains from the genus Rhizobium leguminosarum bv. trifolii were selected for biotest analysis. Two methods of inoculation were used in the chamber experiment: (1) R. leguminosarum alone and (2) a combined inoculant (R. leguminosarum and Azospirillum brasilense). For comparison, non-contaminated controls were also used. The results demonstrated that co-inoculation of plants with Rhizobium and Azospirillum resulted in more root and shoot biomass than in plants inoculated with R. leguminosarum alone. The results indicated that application of a co-inoculation of bacteria from Rhizobium and Azospirillum species had a positive effect on clover nodulation and growth under the condition of PAH contamination

The Influence of Human Agricultural Activities on the Quality of Selected Fluvisols from the Vistula River Valley, Poland—Preliminary Research

Studies on the impact of human agricultural activities on the soil microbiome and soil quality are extremely important, but such studies on floodplains in river valleys are lacking. The aim of this preliminary study was to determine the impact of blackcurrant cultivation on Fluvisols located in the Vistula River valley (Poland). The dehydrogenases (DHa) and phosphatases (acid-AcP, and alkaline-AlP) activities, carbon (MBC) and nitrogen (MBN) contents of the microbial biomass, the metabolic potential of the microbial community (EcoPlate™ Biolog) and taxonomic diversity of the soil microbiome were determined (next-generation sequencing (NGS) of the 16S rRNA gene). Enzymatic activity and metabolic potential and diversity (EcoPlate™) were higher in the soils from meadows, but MBC and MBN and biodiversity indices derived from NGS were higher in the cultivated soils. It can be confirmed that human activities affect the physicochemical, biological and microbiological parameters of Fluvisols. This may indicate that microorganisms are numerically more abundant and taxonomically more diverse in the cultivated soils, but are more active in the soils from meadows

Biodiversity and Metabolic Potential of Bacteria in Bulk Soil from the Peri-Root Zone of Black Alder (Alnus glutinosa), Silver Birch (Betula pendula) and Scots Pine (Pinus sylvestris)

The formation of specific features of forest habitats is determined by the physical, chemical, and biological properties of the soil. The aim of the study was to determine the structural and functional biodiversity of soil microorganisms inhabiting the bulk soil from the peri-root zone of three tree species: Alnus glutinosa, Betula pendula, and Pinus sylvestris. Soil samples were collected from a semi-deciduous forest located in an area belonging to the Agricultural Experimental Station IUNG-PIB in Osiny, Poland. The basic chemical and biological parameters of soils were determined, as well as the structural diversity of bacteria (16S ribosomal RNA (rRNA) sequencing) and the metabolic profile of microorganisms (Biolog EcoPlates). The bulk soils collected from peri-root zone of A. glutinosa were characterized by the highest enzymatic activities. Moreover, the highest metabolic activities on EcoPlates were observed in bulk soil collected in the proximity of the root system the A. glutinosa and B. pendula. In turn, the bulk soil collected from peri-root zone of P. sylvestris had much lower biological activity and a lower metabolic potential. The most metabolized compounds were L-phenylalanine, L-asparagine, D-mannitol, and gamma-hydroxy-butyric acid. The highest values of the diversity indicators were in the soils collected in the proximity of the root system of A. glutinosa and B. pendula. The bulk soil collected from P. sylvestris peri-root zone was characterized by the lowest Shannon’s diversity index. In turn, the evenness index (E) was the highest in soils collected from the P. sylvestris, which indicated significantly lower diversity in these soils. The most abundant classes of bacteria in all samples were Actinobacteria, Acidobacteria_Gp1, and Alphaproteobacteria. The classes Bacilli, Thermoleophilia, Betaproteobacteria, and Subdivision3 were dominant in the B. pendula bulk soil. Streptosporangiales was the most significantly enriched order in the B. pendula soil compared with the A. glutinosa and P. sylvestris. There was a significantly higher mean proportion of aerobic nitrite oxidation, nitrate reduction, sulphate respiration, and sulfur compound respiration in the bulk soil of peri-root zone of A. glutinosa. Our research confirms that the evaluation of soil biodiversity and metabolic potential of bacteria can be of great assistance in a quality and health control tool in the soils of forested areas and in the forest production. Identification of bacteria that promote plant growth and have a high biotechnological potential can be assume a substantial improvement in the ecosystem and use of the forest land