The study presents a comparison of some nutritional values of juices made from organic and conventional apple, pear, blackcurrant, carrot, beetroot and celery. Higher soluble solids content (SSC) for organic juices than for conventional ones was recorded for blackcurrant (14.9% and 12.5%, respectively) and beetroot (12.3% versus 8.3%). The highest organic acids content was noted for blackcurrant (3.7 g malic acid 100 g^− 1), whereas the lowest was for celery (0.57 g 100 g^− 1 on average). Higher organic acids content was shown in apple, pear, and especially blackcurrant grown organically. Amounts of juice NH₄-N content were lower in organic vegetable juices than in conventional ones. The conventional farming method favoured greater NO₃-N accumulation for beetroot (846 mg NO₃-N kg^− 1 f.w.) than for organic juice (229 mg NO₃-N kg^− 1 f.w.). The data showed the organic juices to have polyphenols and ascorbic acid contents similar to, and antioxidant activity slightly higher than, conventional juices.

Pyrolyzed organic residues can be incorporated as a soil additive to improve their properties, crop productivity, or to increase retention or absorption of different compounds. However, in agronomy, the practice of biochar application is still under examination. The interactions between plant, soil, and biochar can be complex, and determines the agronomic effects obtained. A three-year field experiment was conducted to determine the effects of biochar addition and nitrogen (N) fertilization on biomass productivity and nutrient uptake of Mentha piperita L. The experiment was conducted with a three-factorial design in triplicate at N fertilizer rates of 75, 100, and 125 kg N ha⁻¹ and biochar rates of 0, 5, 15, and 45 t ha⁻¹. Commercial wood-based biochar produced at 650 °C was incorporated into sandy soil in 2017. Generally, our results demonstrated potential for treating a sandy soil, since biochar improved the nutrient availability for peppermint. However, on average, during a three-year mint-yielding period, no significant effect of the applied dose of biochar on this parameter was found. Significantly more soluble Ca, K, and SO₄-S was found in the soil amended with biochar as compared with the control soil. Biochar, in doses of 15 and 45 t ha⁻¹, increased the NH₄-N concentration in the soil in the second and third year of the study, as well as NO₃-N in 2018. The greatest amount of N and P was contained in the peppermint biomass after using 15 and 45 t biochar ha⁻¹. The highest dose of biochar (45 t ha⁻¹) also increased the contents of K and S in plants. Nitrogen fertilization increased the dry matter yield of peppermint on the harvest sampling dates. The N content in the mint increased proportionally to the nitrogen dose in fertilization, regardless of the biochar dose applied. The use of biochar in doses of 15 and 45 t ha⁻¹ in coarse-textured soil contributed to increased use of nitrogen by plants after nitrogen fertilization at doses of 100 and 125 kg N ha⁻¹. These findings suggest that the time-dependent responses of soil to biochar amendment are strongly influenced by plant, microbial, and soil feedback; if so, then practical long-term biochar effectiveness requires further study.

Green roofs are becoming increasingly common practice of the urban sustainable environment. The growing substrate is the most important part of green-roof technology. The cost of engineering substrates can be reduced by using locally available components. Since green roofs are a relatively new concept in Poland, there is a need to examine substrate compositions and characteristics, including commonly used ingredients as well as alternative recycled/waste materials. The aim of our study was to assess the ability of locally sourced waste materials as roof-growing media amendments. In the greenhouse experiment we tested two grass and herb species mixtures and four waste substrate formulas. The locally disposed waste materials used as components of growing media included silica wastes (byproducts of metallic ferrosilicon alloys), cellulose, foundry sand, and organic waste material removed from the organic horizons of mucky peat. The engineered Si-waste substrates were compared with the commercially available media. The physico-chemical properties of components and substrates, their stability over time, and the influence on plant growth and mineral nutrient status were examined. Particle size distribution, bulk density, mass, water capacity, soil reaction, and total dissolved salt content of Si-waste-growing media were compatible with FLL standards. We found low amounts of available P and K, and high concentrations of Ca, Mg, S, and trace elements (with the exception of B) in Si-waste substrates in comparison with the control media. Silica waste materials have the potential to maintain pH with high buffering capacity. Engineered Si-waste substrates had a positive impact on plant growth and biomass. In general, these results indicate that contaminant elements contained in alkaline Si-waste substrates were not easily available to the root system, and consequently they did not restrict plant growth. We consider Si-wastes to be a valuable and environmentally responsible green roof media amendment.

There is a great need to assess the impact of farming methods on soil fertility, especially in specific ecoregions. In Poland, relatively limited research has been conducted on soil quality and fertility in organic, dynamically developing agricultural systems. A comparative study on soil parameters under organic and conventional cultivation was performed in 2009. Twenty-two pairs (organic-conventional) of fields located in the south and east of Poland were chosen. All organic sites were certified. The following field crops were investigated: apple, pear, blackcurrant, carrot, beetroot, and celery. The soil granulometric composition, total organic content, total nitrogen, as well as the content of available macroelements (P, K, Ca, Mg, S), microelements (Cu, Fe, Zn, Mn, B), and trace elements (Cd and Pb) were measured. The organic farm soils had a higher level of the total organic matter (2.02%) than the conventional (1.75%). The organic system increased the total soil N level in celery and beetroot fields. Low or very low concentrations of available P in organically managed orchards were observed in individual farms, whereas excessive soil P amounts were noted for organic beetroot and celery fields. Differences in soil K concentration caused by the farming system were found only for red beet. Ca concentration was higher in the conventional than in the organic soil only for celery. There was a higher soil available Cu concentration for all of the investigated conventional vegetable fields than for the organic. The reverse was true for the apple and blackcurrant farms. The highest levels of Cd and Pb were noted in soils sampled from some organic celery fields.

Apple seedlings cv. Antonovka were grown in soil taken from an orchard with a distinctive specific apple replant disease. The influence of the different available soil phosphorus (P) level (0, 20, 40 and 80 mg P dm⁻³ of soil) and arbuscular mycorrhizae fungi (AMF) inoculation on the vegetative growth, chlorophyll fluorescence, and the frequency of mycorrhizae were assessed. Moreover, leaf and root mineral composition was ascertained by means of the inductively coupled plasma mass spectrometry (ICP-MS) method. The inoculation with AMF influenced seedlings growth as well as the biomass production and partitioning. The method of inoculation (granular, quick root dip or irrigation) had a great impact on the frequency of mycorrhizae (83.3, 98.8 and 100%, respectively) as well as on the abundance of arbuscules (36.4, 62.9 and 67.3%) as compared to the control (11.7%). The beneficial effect of AMF on leaf PSII efficiency was established. AMF inoculated plants had a significantly higher content of nitrogen, potassium, phosphorus and boron (N, K, P and B) in the shoots and a higher content of nitrogen, sulfur, copper, iron, manganese, molybdenum and titanium (N, S, Cu, Fe, Mn, Mo and Ti) in the roots. Although roots showed a higher concentration of aluminium, barium, lithium, cadmium, lead and vanadium (Al, Ba, Li, Cd, Pb, and V) but upon AMF inoculation, the concentration of these cations was much lower.

Cover crops (CCs) are regarded as beneficial to agricultural practice as an option for soil quality improvement in field production systems. The main goal of this study was to assess the impact of spring phacelia (Phacelia tanacetifolia Benth.) and buckwheat (Fagopyrum Mill.) in a crop rotation (CC–leek–parsley, 2020–2021) on the physicochemical and biological properties of the soil in an organic high tunnel system. Soil analyses involved measurements of bulk density, water capacity, soil aggregation, soil organic carbon (SOC), available soil nutrients, as well as microbial abundance and diversity. Phacelia generated more aboveground biomass (58.2 t fresh matter ha⁻¹) than buckwheat (33.0 t ha⁻¹), and their biomass contained 161 kg N ha⁻¹ and 67 kg N ha⁻¹, respectively. A large quantity of elements, such as N, Ca, P, S, B, and Cu, were found in phacelia biomass. More Mg and Na were found in buckwheat plants. The results showed that CC biomass significantly improved some of the soil physical and chemical properties, such as soil organic carbon stock and wet aggregate stability, and decreased soil bulk density. Cover crop treatments changed the dynamics of soil bacterial and fungus populations in a high tunnel system. Phacelia increased the quantity of ammonifiers and nitrifiers in the soil substantially. Further research with a long-term focus is needed to assess the impact of cover crops on soil properties, soil quality, and subsequent crop yields in high tunnel crop rotation and management systems.