The determination of the maturity of compost and other organic fertilizers is very important because of possible phytotoxic or phytostimulating effects. The maturity of compost can be assessed on the basis of chemical analyses, and a germination test with different test plants is most often used to determine phytotoxicity. In this research, the maturity of compost produced from the plant residues subsequent to the maintenance of green public areas was assessed using the results of chemical analyses. Simultaneously, a germination test was carried out with the four test plant species (cucumber, garden cress, triticale, and barley) to determine the phytotoxicity of compost extract in a ratio of 1:2.5 v/v (1:3.3 w/v) and 1:10 v/v (1:13.3 w/v) and the three ammonium N solutions (in the concentrations of 200, 400, and 600 mg/L NH₄-N). According to the chemical properties of compost (primarily the C/N, NH₄-N/NO₃-N ratios, and the NH₄-N concentration) and the germination test with cucumber and garden cress, we may conclude that the tested compost was mature and that we did not expect a phytotoxic effect. The choice of a plant is very significant because the germination test with a compost extract demonstrated an undoubted phytostimulating effect on the garden cress and cucumber, with a more pronounced phytostimulating effect of the 1:10 than that of the 1:2.5 v/v compost extract. No such effect was detected on the monocotyledonous test plants triticale and barley since the 1:10 v/v extract had no significant effect, and the 1:2.5 v/v extract had a phytotoxic effect, moderate on the triticale and high on barley. The conclusion is that garden cress and cucumber are suitable test plants for the determination of compost’s phytostimulative effect, but they are not suitable for the determination of phytotoxicity for monocotyledonous plants, especially if the cause of phytotoxicity is a non-ammonium component. Barley is the most suitable species for the determination of compost’s non-ammonium phytotoxicity and nitrogen’s ammonium-form phytostimulative or phytotoxic effect. It would be very useful to conduct a comparative germination test with the compost extracts in the ratios 1:2.5 and 1:10, whereby the 1:2.5 extract would be used as a test of phytotoxicity, and the 1:10 extract for the test of a phytostimulating effect.

Possible agricultural utilization of four different processed slaughterhouse waste composts and meat powder was examined in a field experiment in 2002–2008. The trial was set up with different crops on a calcareous sandy soil. The site was prone to drought. The soil was weakly supplied with N, P and K. Composts were applied once at five levels (0, 25, 50, 100, 200 t ha⁻¹ fresh compost and 0, 2.5, 5.0, 10, 20 t ha⁻¹ meat powder) in four replications. The fertilizing effect of these by-products was pronounced. Their N, P, Ca, Zn and Cu content might be many fold compared to manure. In the year of application, the 25 and 50 t ha⁻¹ doses showed only slight positive effects on yield, partly due to drought. Extreme doses (100–200 t ha⁻¹) of immature compost and semi-mature compost combined with dry weather in 2002 and 2003 (483 and 337 mm year⁻¹ precipitation) caused depressions. Residual effects of composts were pronounced in 2004 when the triticale yield increased threefold compared to control. In the following years, the residual effects decreased, so the meat powder lost its effect after 2007, but immature and semi-mature composts significantly raised the yield even in 2008.

Green energy is expected to play an increasingly important role in the energy sector, so the volume of biogas production and the formation of anaerobic digestates is likely to increase in the future. A wide range of biodegradable organic materials are used in anaerobic digesters to produce biogas. This review focuses on the properties of anaerobic digestates and their effects on physical, chemical and biological soil parameters discussing the benefits, limitations and potential risks. Due to the variety of technologies and raw materials used, anaerobic digestates have diverse properties. Therefore, their impact on specific soil parameters, such as bulk density, aggregate stability, pH, electrical conductivity (EC), soil organic matter (SOM) or microbial activity can vary in magnitude and direction. These effects are also influenced by the variety of soils. Although digestates usually have a significant macro- and micronutrient content, their potentially toxic components or high salt content may limit their use. Despite the limitations, the application of anaerobic digestates generally has more advantages than disadvantages. The use of good-quality anaerobic digestates can improve the physical and chemical properties of the soil, increase soil nutrient and SOM content, as well as soil microbial activity.

The most important environmental source of boron (B) contamination is irrigation water. The data on the effect of B on the elemental composition in the edible parts of vegetables are scarce. A greenhouse pot experiment investigated the effect of irrigation water containing 0.1 and 0.5 mg/L B on the biomass, elemental (e.g., B, Mg, K, Fe, Cu, and Zn) composition, and photosynthetic parameters of tomato (Solanum lycopersicum), green bean (Phaseolus vulgaris), potato (Solanum tuberosum), and cabbage (Brassica oleracea) plants grown on 10 kg of sand, silty sand, or silty soil. The biomass of the edible part was unaffected by B treatment. The soil type determined the effect of B irrigation on the elemental composition of vegetables. The B content increased by 19% in tomatoes grown on silty soil. The 0.1 mg/L B treatment facilitated tomato fruit ripening on all soils, and the 0.5 mg/L B treatment doubled its chlorophyll content index (CCI) on silty soil. The 0.5 mg/L B treatment negatively affected the nutritional value of green beans on all soils, decreasing the Fe and K contents by an average of 83 and 34%, respectively. The elemental composition of potato was unaffected by the treatments, but the CCI of potato leaves increased in the 0.5 mg/L B treatment by 26%. The B content was increased by 39% in cabbages grown on light-textured soils. In conclusion, B concentration of up to 0.5 mg/L in irrigation water had no significant beneficial or adverse effect on the investigated vegetables, but 0.1 mg/L B treatment could shorten tomato fruit maturation time on B-poor soils. The B levels in vegetables remained suitable for human consumption.

Determining the maturity of compost and other organic fertilizers is very important because of possible phytotoxic or phytostimulative effects. The maturity of the compost can be assessed on the basis of chemical analyses, and the germination test with different test plants is most often used to determine phytotoxicity. In this research, using the results of chemical analyses, the maturity of compost produced from plant residues after maintenance of green public areas was assessed. At the same time, a germination test was carried out with 4 test plant species (cucumber, garden cress, triticale, barley) to determine the phytotoxicity of compost (i.e. compost extract in a ratio of 1:2.5 and 1:10) and 3 ammonium N solutions (in concentrations of 200, 400 and 600 mg/L NH4-N). According to the chemical properties of compost, primarily the C/N and NH4-N/NO3-N ratios, as well as the NH4-N concentration, and the germination test with cu-cumber and garden cress, we can conclude that the tested compost was mature and that we do not expect a phytotoxic effect. The choice of the plant is very significant because the germination test with compost extract shows an undoubted phytostimulative effect on garden cress and cu-cumber with more pronounced phytostimulative effect of compost 1:10 than 1:2.5 extract. No such effect was found on the monocotyledonous test plants triticale and barley since the 1:10 ex-tract had no significant effect, and the 1:2.5 extract had a phytotoxic effect, moderate on triticale and high on barley. The conclusion is that garden cress and cucumber are suitable test plants for determining phytostimulative effect of compost, but they are not suitable for determining phytotoxicity for monocotyledonous plants, especially if the cause of phytotoxicity is some non-ammonium component. Barley is the most suitable species for determining non-ammonium phytotoxicity of compost and phytostimulative or phytotoxic effect of ammonium form of nitrogen. It would be very useful to conduct a comparative germination test with compost extracts in the ratio 1:2.5 and 1:10, whereby the 1:2.5 extract is used as a test for phytotoxicity, and the 1:10 extract for testing phytostimulative effect.

Phytoremediation is an approach designed to extract excessive heavy metals from contaminated soils through plant uptake. Cadmium (Cd) is among the elements most toxic to living organisms. Health hazards associated with the lethal intake of Cd include renal (kidney) damage, anaemia, hypertension and liver damage. A greenhouse experiment was carried out with Indian mustard (Brassica juncea) grown on artificially spiked soil (100 μg Cd g⁻¹) with EDTA (2 mmol kg⁻¹ in 5 split doses), FYM, vermicompost (VC) and microbial inoculants (MI) such as Azotobacter sp. and Pseudomonas sp. The growth of Brassica juncea L. was better in soil amended with FYM or VC as compared to unamended Cd-polluted soil. Growth was slightly suppressed in EDTA-treated soil, whereas it was better after treatment with MI. The application of FYM and VC increased the dry matter yield of Indian mustard either alone or in combination with microbial inoculants, while that of EDTA caused a significant decrease in the biomass of Indian mustard. The application of microbial inoculants increased the dry matter yield of both the roots and shoots, but not significantly, because MI shows greater sensitivity towards cadmium. The maximum cadmium concentration was observed in the EDTA +MI treatment, but Cd uptake was maximum in the VC + MI treatment. The Cd concentration in the shoots increased by 120% in Cd_EDTA over the Cd₁₀₀ treatment, followed by Cd_VC (65%) and Cd_FYM (42%) in the absence of microbial inoculants. The corresponding values in the presence of MI were 107, 51 and 37%, respectively. A similar trend was also observed in the roots in the order Cd_EDTA+M > Cd_VC+M > Cd_FYM+M>Cd_100+M.MI caused an increase in Cd content of 5.5% in the roots and 4.1% in the shoots in the Cd_EDTA+M treatment compared with the Cd_EDTA treatment. FYM, VC and EDTA also increased Cd uptake significantly both in the shoots and roots with and without microbial inoculants.The results indicated that Vermicompost in combination with microbial inoculants is the best treatment for the phytoremediation of Cd-contaminated soil by Indian mustard, as revealed by the Cd uptake values in the shoots: Cd_VC+M (2265.7 μg/pot) followed by Cd_EDTA+M (2251.2 μg/pot), Cd_FYM+M (1485.7 μg/pot) and Cd_100+M (993.1 μg/pot).