The experiment was conducted between 2015–2017 in the Research Station for Cultivar Testing in Uhnin (51°34′ N, 23°02′ E), in Luvisols developed from sandy loam soils. Soil samples for the tests of enzymatic activity were collected after the crop was harvested. The measurements included: the content of dehydrogenases, phosphatases, urease and protease, as well as total organic carbon, total nitrogen and mineral nitrogen in soil, based on standard methods. The research results point to changes in the enzymatic activity of light soil under the influence of varied nitrogen fertilization. In objects fertilized with this ingredient, the activity of the analysed enzymes was significantly higher than in the control soil, except for combinations fertilised with 150 kg ha⁻¹ N characterised by the highest accumulation of N-NO₃⁻ in soil. The activity of dehydrogenases, phosphatases and urease changed as the nitrogen dose increased. The polynomial regression analysis enabled a better understanding of those dependences. In the case of dehydrogenases, phosphatases and urease, a third-degree curvilinear relation of enzymatic activity to nitrogen fertilisation was observed (a fourth-degree relation was found, with a coefficient R² in those equations amounting to =0.958, 0.977, 0.979, respectively) and in the case of protease activity, a fourth-degree relation, with coefficient R² = 0.989. However, soil acidity did not have a significant influence on either the enzymatic activity or physico-chemical characteristics of soil under the cultivation of sweet potatoes. The C:N ratio turned out to be significantly negatively related to the content of the enzymes dehydrogenase (Adh), phosphatase (AF), urease (AU) and protease (AP) as well as the content of total nitrogen, especially its ammonium form (N-NH₄). The obtained results indicate the usefulness of research on enzymatic activity as an indicator of soil reaction to nitrogen fertilization and will enable maintenance of the optimal biological balance of cultivated soils.

The aim of the study was to assess the nutritional value of H. tuberosus tubers grown in the organic farming system in Poland and Lithuania. The work was based on field experiments carried out in 2015–2017 in Parczew (Poland) and Akademija (Lithuania). The experiments were carried out using the randomized block method in four replications. Two cultivars of Jerusalem artichoke (JA) ‘Albik’ and ‘Rubik’ were tested. After the harvest of tubers, an assessment of their quality was carried out by standard methods. Due to the relocation of JA cultivation from Central and Eastern Europe to Northeast Europe, there were changes in the chemical composition of H. tuberosus tubers. The tubers from crops in Lithuania were characterized by a lower content of inulin, crude fiber and protein, ascorbic acid, total and endogenous amino acids than in Poland, but a higher content of true protein and macroelements. Edaphic factors determined, to a greater extent than genetic factors, the nutritional value of tubers. Assessment of the influence of varietal characteristics, meteorological conditions, and geographic location on the amount of biologically active compounds in JA will allow growers and consumers to choose the most suitable cultivars.

Background: Currently, in the face of constant climate change and the development of the mining industry, recovering soils degraded by industry for agricultural production and ensuring more food security for the world has become more difficult. Soil contamination is of particular concern as it affects not only human health but also vegetation growth and the biological environment. The aim: The aim of our research is to develop an appropriate cultivation technology in the area of former and present oil extraction areas and monitor their recovery for agricultural purposes and, thus, for food production. Methods: Experimental, descriptive, laboratory, and comparative methods were used. Results: A significantly decreased content of PAHs in the tested soil under the influence of the “Green technology” was observed just in the third year of the research. Eight years after the introduction of “green technology”, the sum of PAHs in the soil degraded by the oil extraction industry was more than 2-fold reduced. Therefore, there is a need to develop a nature-friendly and cost-effective method of removing and minimizing the effects of soil contamination by oil and its products. Conclusions: T. repens turned out to be a species that significantly prevents the degradation of the agricultural environment and restores soil for agricultural use, consequently encouraging the production of food safe for humans. The immeasurable effect of the use of “Green technology” was to ensure the biodiversity of the grasslands and to return the sources of natural nitrogen bound by bacteria of the genus Rhizobium in coexistence with plants from the Fabaceae family.

Phytotoxicity refers to the capacity of chemical substances or environmental factors to have a negative impact on plants. This is a crucial issue in both the context of crop cultivation and environmental protection. The research results were based on a 3-year field experiment conducted at an experimental station in Jadwisin (52°28′ N, 21°02′ E) on loamy soil. The experiment was set up using a randomized sub-block design in a split–split–plot arrangement with three replications. The first-order factor consisted of potato cultivars, while the second-order factors were weed control methods: (1) without protection; (2) mechanical weed control, extensive mechanical treatments to close rows; (3) Sencor 70 WG—pre-emergence (PRE) of potatoes; (4) Sencor 70 WG + Titus 25 WG + Trend 90 EC—PRE of potatoes; (5) Sencor 70 WG—post-emergence (POST) of potatoes; (6) Sencor 70 WG + Titus 25 WG + Trend 90 EC—POST of potatoes; (7) Sencor 70 WG + Fusilade Forte 150 EC—POST of potatoes; and (8) Sencor 70 WG + Apyros 75 WG + Atpolan 80 SC—POST of potatoes. The phytotoxic effects of herbicides on potato plants and weeds were assessed every 7 days, starting from the date when the first signs of damage appeared until they stabilized or disappeared. Phytotoxic damage to potato and weed plants was caused by the chemical weed control methods used. The response of potato plants to herbicides was significantly related to the genetic traits of the cultivars and meteorological conditions in the years of research. Phytotoxicity is an important aspect in both agriculture and environmental protection. Research on its mechanisms and impact will enable the development of effective plant protection strategies and the preservation of ecosystem balance.

The aim of the research was to determine the impact of potato cultivation management and weeding systems on weed infestation and to evaluate the possibility of using biomarkers to assess consumer exposure to herbicide residues in potato tubers. The experiment was carried out in 2016–2018 in Central-Eastern Poland. The subject of research was the very early variety Lord. The experiment was established using the randomized block method in a split-plot design. The first order factor was cultivation management: (A) traditional and (B) under polyethylene sheeting (PE-sheeting) put “on flat”. The second-order factors were weed control systems: (a) mechanical (b) to (d)-chemical. The study determined the degree of damage to crops and weeds, fresh and dry weight of weeds, their number and floristic composition, and herbicide residues in tubers and in the soil. The fresh and dry mass of weeds was most effectively limited by mechanical and chemical treatment with the use of a preparation containing linuron. Managing potato cultivation with PE-sheeting and soil herbicides has proven to be safe for very early potato production. Used for pre-emergence care, the preparation containing linuron did not leave even trace amounts of this active substance in the tubers. The determined amount of the active substance fluorochloridon and clomazone was lower than the Maximum Residue Level (MRL) norm in the EU (European Union). As a result, the adopted, innovative management and weeding control systems in the cultivation of early potato varieties can be considered safe for the consumer.

Weed resistance to herbicides should be minimized, as this can lead to serious limitations in the food security for people around the world. The aim of the research was to summarize the latest research on the reactions of plants to pesticides, including herbicides, in order to assess the possibility of using jasmonates and brassinosteroids to stimulate the natural, induced systemic immunity of plants, as well as outline the possibility of the interaction of oxylipins with ethylene, salicylates and other compounds. Multiple types of resistance correspond to developed mechanisms of resistance to more than one herbicide, and this resistance has been induced by selection processes. Activation of the mechanisms of systemic immunity depends on the reception of extracellular signals, and their transduction between individual cells of the plant organism. Jasmonic acid (JA), as well as its methyl ester (MeJA), ethylene (ET), salicylic acid (SA) and methyl salicylate (MeSA), are key plant growth regulators that play a fundamental role in this process. JA and ET activate the mechanisms of induced systemic immunity (ISR), while SA determines the acquired systemic immunity (SAR). JA, MeJA and OPDA belong to the family of oxylipins, which are derivatives of linolenic acid (CLA), and are a group of active signaling molecules that are involved in the regulation of many physiological processes, including those that are related to herbicide resistance. Understanding the signaling mechanism in oxylipins, and mainly brassicosteroids (BRs) and jasmonates (Jas), would allow a better understanding of how immune responses are triggered in plants.