The aim of the research was to determine the effect of fertilising with various doses of ash from biomass combustion (D2–D6) compared to control plots and classic NPK (D1) fertiliser on the morphological and mechanical properties of potato tubers (Solanum tuberosum L.). The field experiment was carried out in the years 2019–2021 (south-eastern Poland, 49°59′ N, 21°57′ E) on two types of soil: Gleyic Chernozem (silty loam) and Haplic Luvisol (silt). The values of mechanical parameters, such as the peel and flesh punching force (FD), deformation (DR) and energy (ED) needed to destroy the test sample, were assessed. The biometric features of the tubers were also assessed. It was found that tubers obtained from the experimental fields where D3 and D4 ash fertiliser doses were applied (corresponding to doses of 188 and 282 kg∙ha−1 K) had the highest tuber yields and the highest resistance to mechanical damage under quasi-static loads. Ash from biomass combustion can be an alternative to conventional mineral fertilizers and can be used in the development of mineral fertilization plans for sustainable agriculture, which will help to solve the problem of storage of this waste.
Corynebacteria exist as part of human skin microbiota. However, under some circumstances, they can cause opportunistic infections. The subject of the study was to examine the macrolide-lincosamide-streptogramin B (MLSB) antibiotic resistance in 99 lipophilic strains of Corynebacterium genus isolated from the skin of healthy men. Over 70% of the tested strains were resistant to erythromycin and clindamycin. All of which demonstrated a constitutive type of MLSB resistance mechanism. In all strains, there were being investigated the erm(A), erm(B), erm(C), erm(X), lin(A), msr(A), and mph(C) genes that could be responsible for the different types of resistance to marcolides, lincosamides, and streptogramin B. In all strains with the MLSB resistance phenotype, the erm(X) gene was detected. None of the other tested genes were discovered. Strains harboring the erm(X) gene were identified using a phenotypic method based on numerous biological and biochemical tests. Identification of the chosen strains was compared with the results of API Coryne, MALDI-TOF MS, and 16S rDNA sequencing methods. Only 7 out of the 23 investigated resistant strains provided successful results in all the used methods, showing that identification of this group of bacteria is still a great challenge. The MLSB resistance mechanism was common in most frequently isolated from healthy human skin Corynebacterium tuberculostearicum and Corynebacterium jeikeium strains. This represents a threat as these species are also commonly described as etiological factors of opportunistic infections.
The aim of the study was to compare the effect of conventional, simplified, and organic farming systems on changes in the content of soil organic carbon, organic matter fractions, total nitrogen, and the enzymatic activity. The research was conducted from 2016–2018 on arable land in the south-eastern part of Poland. The selected soils were cultivated in conventional tillage (C_Ts), simplified tillage (S_Ts), and organic farming (O_Fs) systems. The analyses were performed in soil from the soil surface layers (up to 25 cm depth) of the experimental plots. The highest mean contents of soil organic carbon, total nitrogen, and organic matter fractions were determined in soils subjected to the simplified tillage system throughout the experimental period. During the study period, organic carbon concentration on surface soil layers under simplified tillage systems was 31 and 127% higher than the soil under conventional tillage systems and organic farming systems, respectively. Also, the total nitrogen concentration in those soils was more than 40% and 120% higher than conventional tillage systems and organic farming systems, respectively. Moreover, these soils were characterised by a progressive decline in SOC and Nt resources over the study years. There was no significant effect of the analysed tillage systems on the C:N ratio. The tillage systems induced significant differences in the activity of the analysed soil enzymes, i.e., dehydrogenase (DH) and catalase (CAT). The highest DH activity throughout the experiment was recorded in the O_Fs soils, and the mean value of this parameter was in the range of 6.01–6.11 μmol TPF·kg−1·h−1. There were no significant differences in the CAT values between the variants of the experiment. The results confirm that, regardless of other treatments, such as the use of organic fertilisers, tillage has a negative impact on the content of SOC and organic matter fractions in the O_Fs system. All simplifications in tillage reducing the interference with the soil surface layer and the use of organic fertilisers contribute to improvement of soil properties and enhancement of biological activity, which helps to maintain its productivity and fertility.
The aim of the study was to assess the effect of soil type and the application of fertilizer composed of ashes from biomass combustion to potatoes on selected physicochemical, rheological, and thermal properties of potato starches isolated by using the laboratory method. Potatoes were grown in Haplic Luvisol (HL) and Gleyic Chernozem (GC) soil and fertilized with different doses of biomass combustion ash (D1–D6) with different mineral contents. The thermodynamic characteristics of gelatinization and retrogradation were identified by DSC. The analyses of rheological properties included the determination of the gelatinization characteristics by using the RVA method, flow curves, and assessment of the viscoelastic properties of starch gels. It was found that the starches tested contained from 24.7 to 29.7 g/100 g d.m. amylose, and the clarity of 1% starch pastes ranged from 59% to 68%. The gelatinization characteristics that were determined showed statistically significant differences between the starches analyzed in terms of the tested factors. The value of maximum viscosity and final viscosity varied, respectively, in the range of 2017–2404 mPa·s and 2811–3112 mPa·s, respectively. The samples of the potato starches studied showed a non-Newtonian flow, shear thinning, and the phenomenon of thixotropy. After cooling, the starch gels showed different viscoelastic properties, all of which were weak gels (tan δ = G″/G′ > 0.1).
We investigated the changes in the physiological and biochemical properties of potato plants exposed to differing ozone (O3) concentrations (5 ppm, 10 ppm) and exposure times (2, 4, 8, 12, 16 min) to determine the safe dose that could be used in crop protection programs. We measured the gas exchange, relative chlorophyll content, chlorophyll fluorescence and total antioxidant capacity in potato leaves exposed to O3 fumigation. The fresh weight (FW) of the aboveground part of the plants and a visual assessment of plant condition were determined after the end of the experiment. The plants were given two O3 treatments and measurements were carried out four times: on the 1st and 7th day after treatment. We conclude that O3 exposure time had a greater impact on the reduction in the efficiency of the potato photosynthetic apparatus than O3 concentration. Research has showed that O3 in 5 ppm concentration for 2 and 4 min and 10 ppm for 2 min increased the efficiency of the photosynthesis and antioxidant activity in leaf processes, and these doses could be taken into account in further research on the potential for using O3 in potato protection.
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