This paper presents the results of the authors’ own research and literature research on the impact of selected environmental and agronomical factors on the yield of potato grown under the organic system and the possibility of increasing the yield. The results are based on research conducted for several years at the Institute of Plant Breeding and Acclimatization in Jadwisin, Poland. The influence of factors such as soil quality and climatic conditions, selection of varieties, seed potato preparation, irrigation of plantations, complementary fertilization, and protection against the late blight was described. The aim of this work was to indicate which of these factors affect the yield increase and to what extent. It was stated that it is possible to increase the yield of potato tubers grown under the organic system through all of the proposed treatments. In our studies, using drip irrigation and complementary fertilization had the greatest effect (25.5% and 19%, respectively). Seed potato presprouting had a smaller influence (4.3%) on the final tuber yield. In the years with high pressure of the pathogen Phytophthora infestans, the selection of cultivars with high resistance was very important. Most of the agronomical treatments not only improved the total yield of tubers, but also increased the share of tubers with a larger diameter. A very high variability of potato yielding depending on weather conditions and a selection of cultivars was emphasized. We can say that a proper agronomical practice carried out on an organic potato plantation can largely eliminate the yielding gap between a conventional and an organic system.

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 research was to evaluate an effect of weather conditions in the years of study considering the air temperature and precipitation as well as granulometric distribution of soil, taking into account the temperature and moisture content, on asymptomatic infection caused by Clavibacter michiganensis subsp. sepedonicus (Cms) in leaves and tubers. The level of infection of leaves and tubers with Cms was differentiated by the thermal and humidity conditions occurring in the years of research. The granulometric distribution of soil (soil profile) had a significant effect on the level of leaf infection. In the year 2014, with moderate temperature and humidity, the highest intensity of leaves and tubers infection was observed on soil of the highest moisture content – sandy loam. In the years with extreme weather conditions, i.e. the drought in 2015 or the abundant rainfall in 2016, the most intensive infection was observed in leaves and tubers grown on soil of low humidity – slightly loamy sand and loamy sand. The degree of infection was found to decrease with increasing air temperature and precipitation level as well as with the increase of soil moisture. On the other hand, increasing soil temperature favoured infection in tubers. El objetivo de esta investigación fue evaluar el efecto de las condiciones meteorológicas en los años de estudio, considerando la temperatura del aire y la precipitación, así como la distribución granulométrica del suelo, tomando en cuenta la temperatura y el contenido de humedad, en la infección asintomática causada por Clavivacter michiganensis subesp. Sepedonicus (Cms) en hojas y tubérculos. El nivel de infección de las hojas y los tubérculos con Cms se diferenció por las condiciones térmicas y de humedad que se presentaron en los años de la investigación. La distribución granulométrica del suelo (perfil del suelo) tuvo un efecto significativo en el nivel de infección foliar. En el año 2014, con moderada temperatura y humedad, la más alta intensidad de infección de hojas y tubérculo se observó en suelo con el contenido de humedad más alto, franco arenoso. En los años con las condiciones meteorológicas extremas, i. e., la sequía en 2015, o la lluvia abundante en 2016, la infección más intensiva se observó en hojas y tubérculos cultivados en suelo de baja humedad, ligeramente areno-arcilloso y areno-arcilloso. El grado de infección se encontró que disminuía con el aumento de la temperatura del aire y el nivel de precipitación, así como con el incremento de humedad del suelo. Por otro lado, al aumentar la temperatura del suelo se favorecía la infección en los tubérculos.

The results of the studies carried out over the last 50 years have not provided a clear answer to questions concerning the interaction betweenClavibacter sepedonicus(Cs), potato and the environment. The reason is insufficient knowledge of the biology of the causal agent of ring rot, problems of research methodology and the influence of many environmental and biotic factors on the degree of plant infestation. The research conducted in the years 2013–2016 in the Plant Breeding and Acclimatization Institute – National Research Institute concerned the determination of the influence of weather conditions, involved the influence of temperature and Sielianinov hydrothermal coefficient on the development of Cs bacteria in stems and progeny tubers, as well as the occurrence of disease symptoms on plants and in tubers of eight potato varieties. It was found that genotype had the greatest impact on leaf and tuber infestation, while weather conditions were less significant. The results of correlation analysis indicate that the weight of tubers of plants infected by Cs increased statistically significantly with increases in air and soil temperature. On the other hand, air and soil temperature in the initial vegetation period did not significantly affect the number of potato plant tubers infested by Cs. In a 4-year experiment, it was not shown how air and soil temperature and the Sielianinov hydrothermal coefficient affected the degree of potato leaf and tuber infestation. In most cases, potato infestation by Cs caused a decrease in yield.

In a 2-year field study, the impact of mineral nitrogen fertilization on the productivity of a new potato cultivar, promising due to the highest resistance to potato late blight among the registered ones, was compared to the proven, widely cultivated Denar cultivar. The study determined morphological features (size and weight of organs), physiological indicators (cover of soil by leaves – LAI. leaf greenness – SPAD) of potato plants during the growing season, yield and quality characteristics of tubers and optimal level of nitrogen fertilization. Tuber quality was assessed based on the share of tuber size and external defects in the yield structure. Optimal mineral nitrogen fertilization was determined based on the relationship between the increase in tuber yield and the increasing dose of this ingredient. The research took into account two factors: nitrogen dose (0, 50 kg‧ha–1, 100 kg‧ha–1, 150 kg‧ha–1) and cultivar (Gardena and Denar). The increase in the dose of mineral nitrogen fertilization to 150 kg‧ha–1 resulted in a significant increase in plant height, the weight of the root system, stems, leaves and the share of large tubers in the yield. It was shown that the Gardena cultivar was characterized by greater requirements for mineral nitrogen fertilization, low effectiveness of its use, a higher share of large tubers (diameter above 60 mm) and lower tuber yield than the Denar cultivar. In a year characterized by excess rainfall, plants produced a greater mass of the root system and the mass of the above-ground part, and in a year with an amount of rainfall close to optimal the final yield of tubers and the share of large tubers in the yield were higher.