The article presents the research into hygienizing process of chicken manure using calcium peroxide (CaO₂) as an environmentally friendly biological deactivation agent. The influence of the addition of CaO₂ to chicken manure on the bioavailability of phosphorus was also analyzed. The process of biological deactivation using CaO₂, CaO and Ca(OH)₂ agents was analyzed applying the disk diffusion method. To optimize the effect of the hygienizing parameters, (CaO₂ concentration, pH, temperature and time) on the reduction of Enterobacteriaceae count the Taguchi method was applied. The content of bioavailable phosphorus was measured with the Egner-Riehm method and determined with spectrophotometry. The reduction in bacterial count followed an increase in the concentration of CaO₂ in a sample. The optimal experimental conditions (CaO₂=10.5 wt.%, pH=9.5, T=40°C, t=180 h) enabled a significant decrease in the Enterobacteriaceae count, from 10⁷ cfu/g to 10² cfu/g. Analysis of the samples with Egner-Riehm method showed that the phosphorus content decreased with the addition of biocide CaO₂: from 26.6 mg/l (for 3.5 wt.%) to 3.5 mg/l (for 10.5 wt.%). These values were slightly higher than the content of phosphorus deactivated with Ca(OH)₂ i.e., from 11.25 mg/l (for 3.5 wt.%) to 4.49 mg/l (for 10.5 wt.%). The application of CaO₂ for hygienizing chicken manure enables effective reduction of Enterobacteriaceae count to an acceptable level (below 1000 cfu/g). In comparison with the traditional techniques of hygienization, the application of CaO₂ has a positive effect on the recovery of bioavailable phosphorus.

The objective of this work was investigation of the growth dynamics of proteolytic bacteria and the enzymatic activity in soil for the cultivation of maize (Zea mays L.), as well as the maize yield under application of some selected organic fertilizers. Intensity and the direction of the developed changes in the soil depended on the type of applied organic fertilizer, the size of its dose introduced into the soil and on the developmental phase of the grown plant (maize). On the basis of obtained results it was found that all tested organic substances stimulated the activity of proteases. Yields ofmaize as raw material for silages obtained from soil fertilized with sewage sludge were similar to those obtained after the application of pig slurry and they exceeded maize yields harvested from other ferti I ization objects.

The perspective direction in the biological regulation of insect pest populations is the combined use of different products of organic origin including fungal biological control agents. Therefore, the present study was aimed to evaluate the efficacy of products of natural origin (Aminogreen 24, Nitrogreen, Foliamin and Naturalis − strain ATCC 74040 of entomopathogenic fungus Beauveria bassiana) and one synthetic insecticide − standard (deltamethrin + thiacloprid), applied alone and in a mixture in the control of Acyrthosiphon pisum in forage pea. The study was conducted in a field experiment during the period 2017 − 2020. Infestation by leaf aphids was estimated by calculating the cumulative insect- -days ( CID). It was found that the combination of Aminogreen 24 + Naturalis had the most pronounced decrease in CID among products over the years from 2017 to 2020 and the average for the period. The greatest, significant reduction in the number of aphids occurred on day 5 (F8.5 = 15.244; p < 0.033) and day 7 (F8.5 = 33.087; p < 0.037) after treatment. On the 14th day, the decrease in CID (57.4% decrease) statistically exceeded the Proteus 110 OD standard (55.3% decrease) (F8.5 = 49.841; p < 0.049). Good protection against A. pisum was also found with Naturalis and Nitrogreen + Naturalis. There was an additive effect between Naturalis and Aminogreen 24 throughout the entire study period. The ratio of chlorophyll a (Chl a) to chlorophyll b (Chl b) and the ratio of green pigments (Chl a + + Chl b) to carotenoids determined that plants treated with Aminogreen 24 + Naturalis and Naturalis had the best physiological state. The combination of Aminogreen 24 and Naturalis gave the largest, significant, increase in stem height, followed by Nitrogreen + Naturalis. The use of Naturalis, alone and in a combination with Aminogreen 24 and Nitrogreen can be a successful alternative to conventional chemical control.