This article is devoted to some aspects of the fragrant substances of plant origin applied in the food industry and perfumery as well. Since antiquity many extractive techniques have been developed to obtain essential oils. Some of them are still applied, but new ones, like microwave or ultrasound-assisted extractions, are more and more popular and they save time and cost. Independently of the procedure, the resulting essential oils are the source of many so-called isolates. These can be applied as food additives, medicines, or can be used as starting materials for organic synthesis. Some substances exist in very small amounts in plant material so the extraction is not economically profitable but, after their chemical structures were established and synthetic procedures were developed, in some cases they are prepared on an industrial scale. The substances described below are only a small fraction of the 2000–3000 fragrant molecules used to make our life more enjoyable, either in food or perfumes. Additionally, a few examples of allelopathic fragrant compounds, present in their natural state, will be denoted and some of their biocidal features will be mentioned as an arising “green” knowledge in agriculture.

Solidago canadensis L. is an expansive perennial that forms persistent, species-poor plant communities. It often spreads in fallow areas, displacing native floristic ingredients. Its expansiveness is largely due to morphological features, but it can also be the effect of allelopathic interaction. The aim of the experiment was to investigate the effect of aqueous extracts (decoction, infusion, and maceration) from dry S. canadensis leaves on germination and early growth stages of Raphanus sativus L. var. radicula Pers., in three cultivars: ‘Rowa’, ‘Półdługa’, and ‘Krakowianka’. In comparison to the control, the percentage of germinated radish seeds of ‘Rowa’ cultivar was statistically lower on the infusion and macerate. Regardless of the cultivar, the smallest changes in germination were found in seeds watered with decoction, and the largest with macerate. Seedlings length was most inhibited on macerate substrates, and least with infusion. Regardless of the form of the extract, each of them negatively affected the initial growth of radish seedlings. A fresh mass of ‘Rowa’ seedlings was inhibited by all Canadian goldenrod extracts. In relation to the control, the ‘Krakowianka’ cultivar was the least sensitive to S. canadensis extracts. The total chlorophyll content was the lowest in the seedlings of the ‘Rowa’ and ‘Półdługa’ cultivars germinated on macerate, compared to the control and two others extracts. The percentage of electrolyte leakage depended on the type of extract used and the radish cultivar. The study showed that depending on the cultivar, the aqueous extracts from S. canadensis leaves decreasing of germination and early growth of R. sativus.

Agricultural production is a crucial part of policy issue in preventing depopulation of mountainous areas across Europe. However, soil and climate conditions are limiting yields and profitability of crop production in these regions. The European Union (EU) subsidizes agriculture in mountains by special payments (Less Favoured Area (LFA) subsidy) when areas match law-specified natural handicaps. This study aims to assess whether LFA subsidy in Poland is sufficient to cover losses caused by lower yields of crops cultivated in a mountainous region of Poland (Low Beskid Mountains in Carpathians) compared to lowland regions (non-LFA areas). The results indicated that LFA subsidy was adequate for crops (facultative wheat, winter wheat, field bean and spring barley) grown in the years 2015–2018.

Cultivation of spring cereal mixtures (SCMs) is one of the ways to increase the yield of crops in mountainous areas of Poland. There are only a few current long-term studies on this topic. Our study aimed at analyzing yield and competitiveness as well as the economic indicators of spring cereals in pure or mixed sowings in integrated or organic crop rotations over nine years. A field experiment including pure sowings of oats, spring barley, or spring triticale and their two-component SCMs, each in two systems, organic and integrated crop rotation, was carried out in the Mountainous Experimental Station in Czyrna, Poland, in the years 2011–2019. On average, cereals in the pure sowings and mixtures yielded 18% lower in the organic rotations compared with the integrated ones. However, SCMs yielded higher than the pure sowings, and displayed a higher leaf area index and land equivalent ratio. The average gross margin without subsidies was almost two times higher in the organic crop rotations than in the integrated ones, which was influenced mainly by the cultivation of barley in pure sowing. Summing up, the cultivation of SCMs in the mountainous areas of southern Poland is advised because of both productive and economic factors.

Phacelia tanacetifolia Benth. is a melliferous, phytosanitary fodder plant. An important factor in understanding the biology of this plant is to investigate its allelopathic potential. In the experiment conducted here, ×Triticosecale Wittm. cv. Mamut was treated with water extracts from the roots, stems, leaves, and flowers of phacelia at concentrations of 10%, 12.5%, 15%, and control with 0% of extract. After 7 days of exposure, the germination of grains was assessed by analysing, seedling growth, mass parameters, water content, and electrolytes leakage. Aqueous extracts from the stalks, leaves, and flowers of phacelia significantly inhibited kernel germination at a 10% concentration, and from roots at a 12.5% concentration. The elongation growth of triticale seedlings was significantly inhibited by each of the extracts. Extracts from the leaves and flowers caused a significant reduction in fresh mass at a 10% concentration and extracts from the stalks at a 12.5% concentration. A significant reduction in water content was also found in seedlings watered with extracts of 10% from roots, stalks, and leaves and 12.5% from flowers. Extracts from phacelia roots at a 12.5% concentration and extracts from stalks, leaves, and flowers at a 10% concentration significantly increased the leakage of electrolytes. In general, phacelia exhibits allelopathic potential at higher concentrations of extracts.

The changes of pH value followed by various agricultural practices are crucial for biotic components of soil, along with other environmental factors, like temperature and moisture content. In this paper, the earthworms population in triticale continuous cultivation was monitored. Their presence associated with various agrotechnical methods (e.g., stubble crops maintained as mulch, mineral fertilization without pesticides) were assessed twice by the handsorting method, and their presence during the triticale vegetation season (occurrence of coprolites) were monitored too. The aim of the study was to analyse the distribution of earthworm populations in cereal continuous cultivation fields, and whether they prefer any of the stubble crop species (Sinapis alba L., Phacelia tanacetifolia Benth., Fagopyrum esculentum Moench.), which were sown after triticale harvest. The results reveal the most abundant earthworms occurence in the F. esculentum objects (43.1% of all sampled earthworms, which consists of 42% and 47.2% of all sampled matured and juveniles individuals, respectively), and species homogeneity (dominate Octolasion cyaneum Savigny, 1826). The changes of pH varied through the triticale vegetation season, but didn’t exhibit severe variation between sampling sites. Using earthworm services in cropping systems after having enticed them to the field through stubble crop has the potential to boost agricultural sustainability. Their ecological preferences, along with their trophic behaviour, have already been put in place to complete a case study of the autecology of the O. cyaneum Savigny 1826 species.