A total of 939 isolates of 11 genera representing 15 species of keratinophilic fungi were isolated and identified from the soils of three long-term fold-grazed pastures in national parks of Slovakia (Pod Ploskou, Strungový príslop, and Pod Kečkou) and one non-fold-grazed pasture in sierra Stolicke vrchy (Diel) using the hair-baiting technique. Keratinophilic fungi were present in all soil samples with a prevalence of Trichophyton ajelloi and Paecilomyces lilacinus. These fungi were more abundant in soil from fold-grazed pasture (Strungový príslop) compared to non-fold-grazed pasture (Diel). The occurrence of the other keratinophilic fungi was substantially lower, likely because of low pH in some soils.

The aim of our work was to survey and state the representative values and range of the microbial biomass carbon (C mic ) and microbial respiration activities in arable soils of three types (Chernozem, Luvisol, Planosol) and in pasture grassland soil (Cambisol). In arable soils no significant differences between the soil types were found concerning the content of C mic . Way of soil use significantly influenced C mic with higher values on pasture grassland soil. In Cambisol, a relatively strong relationships between C mic and C org (r = 0.919) as well as between C mic and N tot (r = 0.922) were determined. The basal respiration (BR) was no affected neither by a soil type nor by a way of soil use. On all monitored sites microbes responded positively to the addition of glucose (potential respiration -PR), but the strongest response was observed on the soil types with good mineralisation ability, such as Chernozems and Luvisols. On pasture grassland soil, the substrate availability index (PR/BR) with values of 2.32 was observed, which is lower compared to 7.60 of arable soil. This fact to indicate that pasture grassland soil had more easy decomposable organic compounds than arable soils.Keywords: arable soil; pasture grassland soil; microbial biomass carbon; respiration. AbstraktCieľom našej práce bolo preskúmať a stanoviť reprezentatívne hodnoty a rozsah hodnôt uhlíka mikrobiálnej biomasy (C mic ) a respiračnej aktivity ornej pôdy troch pôdnych typov (černozem, hnedozem, pseudoglej) a pôdy pasienka (kambizem). V ornej pôde neboli zistené preukazné rozdiely v obsahu C mic medzi pôdnymi typmi. Spôsob využívania pôdy preukazne ovplyvnil C mic , s vyššími hodnotami pri pasienku. V kambizemi boli zistené relatívne silné vzťahy medzi C mic a C org (r = 0,919) a C mic a N tot (r = 0,922). Bazálna respirácia (BR) nebola ovplyvnená pôdnym typom ani spôsobom využívania pôdy. Na všetkých sledovaných stanovištiach mikroorganizmy pozitívne reagovali na prídavok glukózy (potenciálna respirácia -PR), ale najsilnejšia odpoveď bola pri pôdnych typoch s dobrou mineralizačnou aktivitou ako černozem DETAILNÝ ABSTRAKTUvedenou štúdiou sme zmonitorovali veľkosť uhlíka mikrobiálnej biomasy a respiračnú aktivitu v štyroch najrozšírenejších pôdnych typoch Slovenska využívaných ako orná pôda a pasienok. Medzi pôdnymi typmi hnedozem (8 lokalít), černozem (7 lokalít) a pseudoglej (6 lokalít) na ornej pôde sme v množstve uhlíka biomasy mikroorganizmov nezistili preukazné rozdiely (pseudoglej od 107 do 777, s priemernou hodnotou 456 µg C g -1 ; černozem od 146 do 802 s priemernou hodnotou 362 µg C g -1 ; hnedozem od 108 do 714 s priemernou hodnotou 257 µg C g -1 ). Avšak pri tomto type využívania pôdy bolo štatisticky preukazne nižšie zastúpenie uhlíka biomasy mikroorganizmov ako v pôde pasienka (kambizem od 1024 do 1592 s priemernou hodnotou 1294 µg C g -1 ). Bazálna respirácia (BR) nebola ovplyvnená pôdnym typom ani spôsobom využívania pôdy. Na prídavok glukózy (potenciálna respirácia PR) pozitívne reagovali mikroorganizmy zo všetkýc...

No abstract

In laboratory assay, the diversity of bacteria and microscopic fungi and the community-level physiological profiling (CLPP) of microorganisms were observed after the addition of bio-sludge (40 t.ha-1) from a biogas station and addition of bio-fertlizers-AZOTER (10 dm-3 .ha-1) to the arable soil with PCR-DGGE and BIOLOG ® method (Eco Plates). The differences were recorded in the microbial diversity (bacteria and microscopic fungi) among variants according to the Shannon index. The differences in community of microscopic fungi were markedly higher among the soil samples with the additions of both bio-fertilizers compared to control soil samples. The occurrence of individual OTUs (operational taxonomic units) bacteria and microscopic fungi were different after 105 days of incubation from the status after the 1 st day of incubation. The community metabolic diversity (CMD) was influenced by the incubation time (105 days) as well, but not by application of bio-fertilizers. We observed a significant decrease (LSD test, P <0.05) in community metabolic diversity (CMD) and average metabolic response (AMR) of microorganisms in samples collected on the 105 th day of the experiment compared to samples collected on the 1 st day of the experiment in all tested samples.

The presented paper deals with the analysis of potential differences between organic waste compost (CBD), vermicompost (CVER) and mineral fertilizer (MF; 27% of N) applications affecting the quality of arable soil by influencing microbial activity therein. The selected types of compost represent alternatives to conventional organic fertilizers, which are, however, not available to Czech and Slovak farmers in sufficient amounts. Their mutual comparison and the comparison with organic fertilizers aim to provide farmers further information about their influence on arable land and thus to give them the possibility of deciding on the most suitable amendments. To demonstrate the effect of these amendments, six variants were prepared: one without the addition of fertilizers; two variants with the addition of 40 Mg/ha of CVER and CBD; one variant with the addition of double dosed CVER (80 Mg/ha), and the remaining two variants were fertilized only with MF (0.22 Mg/ha) and with the combination of CVER (0.20 Mg/ha) and MF (0.11 Mg/ha). Substrate induced respiration (SIR), basal respiration (BS), microbial carbon (Cmic) and enzymatic activities (hydrolysis of fluorescein diacetate—FDA, dehydrogenase activity—DHA, and phosphatase activity—PA) were used to evaluate the effect of CBD, CVER and MF application on the soil quality. Both organic and mineral amendments affected BS and SIR. The highest BS and SIR rates were found in variants with compost application (CVER and CBD). All variants treated with the mineral fertilizer showed the lowest level of enzyme activities; lower by about 30% in comparison with variants where CVER, CBD and the combination of MF and CVER were applied. We found insignificant differences between the individual types of compost. More importantly, we compared the situation at the beginning of the experiment and after its end. It was found that the application of mineral fertilizers automatically led to the deterioration of all enzymatic parameters, on average by more than 25%, as compared with the situation at the beginning of the experiment. However, when the mineral fertilizer dose was supplemented with organic amendments (CVER), this negative effect was eliminated or significantly reduced. Furthermore, both composts (CVER and CBD) positively affected plant biomass production, which reached a level of production enhanced by the MF. Results clearly showed that the application of both compost types could be used to improve soil quality in agriculture.

MATERIAL AND METHODS Sample collection Actinomycetes were isolated from soil (Haplic Fluvisol) located near Nitra (Slovakia-latitude 48° 31' 35.97'' N, longitude 18° 11' 46.82'' E), one compost, one vermicompost and soil amended with compost or vermicompost. Vermicompost and compost were applied to the soil at a total dose of 20 Mg.ha −1. The applied compost was prepared by mixing straw (11% by dry weightdw), hay (3% by dw), silage (32% by dw), sheep manure (9% by dw), cow manure (34% by dw) and soil from the subsoil (11% by dw). Vermicompost was prepared by mixing the compost (41% by dw), cow manure (20% by dw), peat and forest litter (21% by dw), soil (10% by dw), a compound of grass, straw and hay (6% by dw) and the fill vermin (2% by dw). The fill vermin (older vermicompost) containing earthworms and cocoons of earthworms (70 earthworms dm −3) was added to the compost. The basic chemical and microbial characteristics of soil samples and both composts (Table 1) were determined according to the defined values: oxidizable carbon (Cox) by the Tiurin method, total nitrogen (Nt) by the Kjeldahl distillation method, pH (H2O) and microbial biomass carbon (Cmic), which was determined by the fumigation-extraction method of Vance et al. (1987). Plant diseases caused by pathogenic fungi are a severe problem for agriculture, and some organic fertilizers have shown a suppressive capacity due to the antagonistic action of microbial communities inhabiting those substrates. The purpose of this work was to isolate and identify actinomycetes from soil, compost and vermicompost able to antagonize phytopathogens. In total, out of 352 actinomycetes successfully recovered on Pochon medium and of which were selected representative 22 mycelium forming isolates, which were subjected to morphological and genotypic characterization. Genetic characterization based on 16S rDNA fragment sequencing revealed that, all the actinomycete isolates belong to the genus Streptomyces. The antifungal activity of isolates was tested against eight phytopathogenic fungi, and they were most activated against Rhizoctonia solani, Alternaria tenuissima, Aspergillus niger and Penicillium expansum. Isolates 51VK13 (Streptomyces sampsonii) and 12VK13 (Streptomyces flavovariabilis) isolated from soil amended with vermicompost showed the greatest antagonistic activity. Their bioactive potential was also confirmed by presence of genes for nonribosomal peptide synthetase (NRPS) and polyketide synthase types I and II (PKS-I and PKS-II). It can, therefore, be concluded that soil amended with organic fertilizers such as compost, and in particular vermicompost, provides a lower incidence of phytopathogens, especially fungi. Isolated actinomycetes have also shown high potential for the production of bioactive compounds useful in the control of plant diseases. ARTICLE INFO

Rapeseed is an important oil crop strongly dependent on high agrochemical inputs. Some pathogens, including Leptosphaeria maculans, cause blackleg disease and can drastically decrease yields. Microbial inoculants seem to be a promising solution to these problems. However, a selection of potent bacterial strains able to improve growth and/or suppress disease is needed. Endophytic bacteria (n = 38) isolated from rapeseed plants with exceptionally good growth were screened for plant growth promoting (PGP) traits and L. maculans antifungal activity. A majority of isolates (35) showed the ability to produce siderophores, 17 isolates solubilized phosphate, and 28 isolates inhibited the growth of L. maculans. The six most promising isolates belonging to Bacillus genera were characterized in detail and compared to two previously published PGP strains. Plant growth measured as total weight and root length of rapeseed seedlings was stimulated by all isolates in comparison to control. The best isolate, 1L6, preliminary identified as Bacillus pumilus showed the highest phosphate solubilization, IAA and HCN production, and growth promotion of plants. Isolates with high antifungal activity in screening showed good potential to suppress disease on plants, with 87% reduction of lesions caused by L. maculans. These strains are good candidates to be explored under field use either solely or in combination.

Soil microorganisms and their activities are essential for maintaining soil health and fertility. Microorganisms can be negatively affected by application of herbicides. Although effects of herbicides on microorganisms are widely studied, there is a lack of information for chloroacetamide herbicide dimethachlor. Thus, dimethachlor and well known linuron were applied to silty-loam luvisol and their effects on microorganisms were evaluated during112 days long laboratory assay. Dimethachlor and linuron were applied in doses 1.0 kg ha−1 and 0.8 kg ha−1 corresponding to 3.33 mg kg−1 and 2.66 mg kg−1 respectively. Also 100-fold doses were used for magnification of impacts. Linuron in 100-fold dose caused minor increase of respiration, temporal increase of soil microbial biomass, decrease of soil dehydrogenase activity, and altered microbial community. Dimethachlor in 100-fold dose significantly increased respiration; microbial biomass and decreased soil enzymatic activities. Microbial composition changed significantly, Proteobacteria abundance, particularly Pseudomonas and Achromobacter genera increased from 7 to 28th day. In-silico prediction of microbial gene expression by PICRUSt2 software revealed increased expression of genes related to xenobiotic degradation pathways. Evaluated characteristics of microbial community and activity were not affected by herbicides in recommended doses and the responsible use of both herbicides will not harm soil microbial community.