Biochar effects are strongly dependent on its properties. Biochar improves physical soil properties by decreasing bulk density and increasing medium and large aggregates, leading to faster and deeper water infiltration and root growth. Improvement of the chemical properties of soil is connected with pH neutralization of acidic soils, increase of cation exchange capacity and base saturation, providing a larger surface for sorption of toxicants and exchange of cations. Biochar increases the stocks of macro- and micronutrients in soil and remains sufficient for decades. Biochar effects on (micro)biological properties are mainly indirect, based on the improvements of habitat conditions for organisms, deeper root growth providing available C for larger soil volume, higher crop yield leading to more residues on and in the topsoil, better and deeper soil moisture, supply of all nutrients, and better aeration. Along with positive, negative effects of biochar while used as a soil conditioner are discussed in the review: presence of PAH, excessive amounts of K, Ca and Mg, declination of soil pH. In conclusion, despite the removal of C from the biological cycle by feedstock pyrolysis, the subsequent application of biochar into soil increases fertility and improves physical and chemical properties for root and microbial growth is a good amendment for low fertility soils. Proper use of biochar leads not only to an increase in crop yield but also to effective sequestration of carbon in the soil, which is important to consider when economically assessing its production. Further research should be aimed at assessing and developing methods for increasing the sequestration potential of biochar as fertilizer.

Ethylenediaminetetraacetic acid (EDTA), when used as a main chelator for complex plant microfertilizers, causes many negative environmental effects; therefore, new compounds or new use of the known compounds to replace EDTA have been widely studied. In the present study, biodegradation rate, plant (Raphanus sativus) growth stimulation and ecotoxicity towards Daphnia magna and Chlorella vulgaris of iminodisuccinic acid (IDS), considered as an alternative for EDTA in agriculture, has been investigated. It was demonstrated that IDS’ biodegradation rate over 28 days was 28.1%, which is 4.5 times higher than that of EDTA. Similar to EDTA, complexation with metals led to an increase in the degradation rate by 1.8-fold. The majority of compounds were degraded within first 7 days. The GI values for IDS implemented at concentrations of 100 mg/L (both in pure form and in combination with microelements) were 2.4–2.6 times higher than those of EDTA. The ecotoxicity index EC10 of IDS was estimated to be 2.0 g/L and 5.8 g/L towards D. magna and Ch. vulgaris which are 4.1- and 10-fold higher than those for EDTA, respectively. It can be concluded that IDS is a promising agent to chelate microelements used in plant nutrition.

Antibiotics enter the soil with compost prepared from livestock manures and other sources. There is concern that they may influence plant growth and cause antibiotic resistance in soil and plant endospheric microbiomes. In the present work, lettuce plants were cultivated in soil and hydroponics spiked with oxytetracycline (0, 15, and 300 mg × kg⁻¹ and 0, 15, and 50 mg × L^–1, respectively) during a 28-day greenhouse experiment. It was revealed that the antibiotic reduced the chlorophyll content, the biomass, and the length of the roots and stems by 1.4–4.7, 1.8–39, 2.5–3.2, and 1.8–6.3 times in soil and in hydroponics. The copy numbers of the tet(A) and tet(X) genes were revealed to be 4.51 × 10³–1.58 × 10⁵ and 8.36 × 10⁶–1.07 × 10⁸ copies × g^–1, respectively, suggesting the potential migration of these genes from soil/hydroponics to plant roots and leaves. According to a non-metric multidimensional scaling (NMDS) analysis of the 16S rRNA amplicon sequencing data, endospheric bacterial communities were similar in leaves and roots independent of the growing substrate and antibiotic concentration. While soil bacterial communities were unaffected by the presence of antibiotics, hydroponic communities exhibited dependency, likely attributable to the absence of the mitigating effect of soil particle absorption.

The production of biosurfactants from organic wastes has received significant attention due to its potential cost savings. This study involved the isolation of biosurfactant-producing microorganisms from waste sources. The surfactant properties of the 37 studied isolates were assessed by reducing surface tension and their emulsifying properties, determined by the emulsification index E24. We assessed the ability of these isolated strains to produce biosurfactants using various waste substrates, namely potato peelings, waste cooking oil and sunflower cake. Our results showed that sunflower cake exhibited better growth and biosurfactant production for most of the strains studied. This highlights that sunflower cake is a potentially effective and economical substrate for the production of biosurfactants. The most effective strains allowing to achieve an emulsification index above 50% and reduce surface tension below 40 mN m⁻¹ were Enterobacter sp. 2pp, strain 2wfo, Peribacillus sp. 1mo, Sphingomonas sp. 2mo, Ochrobactrum sp. 5mo, Shouchella sp. 6mo, Bacillus sp. 1os, Bacillus sp. 2os. Among these strains, both previously known strains as biosurfactant producers and previously unknown strains were found. Thus, we found that among representatives of the genus Sphingomonas there are effective producers of biosurfactants. The highest yield of biosurfactant on a medium with glycerol and glucose was shown by the Bacillus sp. 2os strain of 0.501 and 0.636 g L⁻¹, respectively.

Plant-associated microbiomes play a critical role in plant health, nutrition, growth, and adaptation. This study aimed to investigate the formation pathways of the endospheric microbiome in lettuce (Lactuca sativa) through vertical (seed) and horizontal (substrate) transmission in hydroponic and soil environments. The bacterial microbiomes from the seeds, roots, leaves, and substrates were analyzed via 16S rRNA gene sequencing. The seed microbiome contained 236 OTUs dominated by Verrucomicrobia (31%) and Firmicutes (29%). Rhizospheric soil contained 1594 OTUs, while the hydroponic solution had 448 OTUs. The root endosphere from soil-grown lettuce contained 295 OTUs, compared with 177 in hydroponic conditions, and the leaf microbiome contained 43 OTUs in soil and 115 OTUs in hydroponics. In total, 30–51% of the leaf and root microbiomes originated from the seed microbiota, while 53–65% of the root microbiome originated from the substrate. Microbiome overlap was observed between the rhizospheric soil and the root microbiome. This study provides new insights into the microbiome of lettuce seeds and the pathways of formation of the endospheric microbiome in adult plants. These findings lay the groundwork for future research aimed at better understanding microbiome dynamics in leafy crops and plant protection.