The emergence of plants is especially important for the winter crops that are grown in the challenging environmental conditions of many countries in Central and Eastern Europe. The emergence and initial growth of winter rapeseed were compared in field trials in a randomized block design with three replicates for plants sown in conventional tillage systems (CT) and strip-till (ST), which had different weather conditions and on soil with a non-uniform texture over a period of two years. Sowing in the CT was carried out using Horsch Pronto 4DC (Germany) at a row distance of 0.29 m. The ST operations were performed using a Pro-Til 4T drill manufactured by Mzuri Limited (Great Britain) - row spacing of 0.36 m. In favourable rainfall and thermal conditions, the density of winter rapeseed plants two weeks after sowing was found to be higher if it was sown after the CT than in the ST system. In the year that had a serious shortage of rainfall during the sowing period, a considerably higher density of plants was achieved using the ST system. The uniformity of plant growth using the ST technology in soil with a varied texture, especially in a year with an unfavourable distribution of rainfall, was proven by less variability in the number of leaves in the rosette, in the dry mass of the leaf rosette and in the root neck thickness of the winter rapeseed than in the CT system. The ST system can create good conditions for the initial development and preparation of rapeseed plants for wintering.

The aim of the research was to evaluate the chemical properties and enzymatic activity of arable soils which, for the period of 10 years, were fertilized with poultry manure (PM). Fertilization with PM resulted in a significant increase in the content of organic carbon and total exchangeable bases in soil. The application of that fertilizer increased the pH value. Fertilization with PM also slightly increased the total content of copper, manganese and iron. There was found, however, a significant increase in the total content of Zn. The annual application of 10 tonnes of PM significantly increased the content of phosphorus and potassium available to plants. That fertilizer inhibited the activity of both alkaline and acid phosphatase, which must be related to a very high content of phosphorus available to plants. Poultry manure resulted in higher values of the biological index of fertility of soil, whereas the activity of phosphomonoesterases was significantly lower.

Herbicide resistance in weeds, including corn poppy (Papaver rhoeas L.), is an increasing problem compromising global crop production. The aims of this study were to evaluate the susceptibility of P. rhoeas populations in Poland to acetolactate synthase (ALS) inhibitors and elucidate their mechanisms of resistance. Between 2017 and 2020, 157 seed samples were collected nationwide and a dose-response study with various ALS-inhibiting herbicides was performed in glasshouses. This revealed 14 resistant populations with R/S ranges of 2.3–1450.2, 9.5–398.5 and 2–2.5 for tribenuron, iodosulfuron and florasulam, respectively. Eight of them were cross-resistant to both tribenuron and iodosulfuron, three and one populations were singly resistant to tribenuron and iodosulfuron, respectively, and one population had reduced susceptibility to florasulam only. In one population, cross-resistance to tribenuron, iodosulfuron and florasulam was identified. The ED50 of many populations susceptible to ALS inhibitors was close to half the recommended dose of the herbicides tested. In seven out of eight resistant P. rhoeas populations analysed, target-site resistance was identified. Six amino acid replacements were found (Ala197, Arg197, His197, Leu197, Ser197 and Thr197). In one population resistant to ALS inhibitors, no mutations in the ALS gene were detected. An efficient anti-resistance strategy is needed to reduce the development of herbicide resistance in P. rhoeas in Poland.

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Competitive ability of cereals against segetal weeds depends among other things, on soil properties and the weather. Concerning cornflower (Centaurea cyanus L.), this issue is poorly recognized, as there are no reports on the impact of environmental conditions on the competitiveness of wheat against susceptible and resistant biotypes. Our study aimed to evaluate the effects of site and weather conditions on the competitive effects between winter wheat (WW) and two cornflower biotypes, either florasulam and tribenuron-methyl resistant (R) or sensitive (S). The experiment was conducted in a replacement series model at six sites across Poland in three growing seasons. The competitive relations were determined on the basis of two indices, i.e., the relative biomass and the number of seeds produced by the tested plants. The relative yield of wheat and weed were plotted on graphs and fitted to one of five competition models. In addition, a competitive ratio (CR) was calculated on the basis of fresh plant biomass and the number of seeds. Correlation coefficients were determined between the length of the plant, yield, biomass, the number of seeds per plant, hydrothermal coefficient K, and soil texture. Biometric parameters of wheat for its competition with two cornflower biotypes were analyzed using canonical variate analysis (CVA). The number of days to WW emergence and the day-difference between WW and cornflower (B) emergence were also calculated. The environmental characteristics of the sites, i.e., hydrothermal coefficient K and soil texture, were used as categorizing variables. Drought generally favored the greater competitive ability of WW against B for both biomass accumulation and seed production. During the first season of the research (relatively dry), only in one case out of 12 cases cornflower was more competitive than wheat. In the second year of the experiment (dry season), the competition of WW against B for resources was lower. It depended more on the site than on the cornflower biotype or the proportion of plants in the mixture. Under high or optimal rainfalls (the third year of the experiment), the competitiveness of WW toward B was significantly lower than in years with rainfall deficiency. In addition, the ability of wheat competition against the weed may have been influenced by the earlier emergence of wheat than cornflower. Even though it was sown together with wheat, cornflower emerged 0–12 days later than the tested cereal. It was also noticed that wheat was more competitive on light soils against the herbicide-susceptible (S) biotype. In contrast, greater WW competitiveness was observed against herbicide-resistant (R) cornflower on heavy soils. In conclusion, winter wheat competitiveness against herbicide-resistant or herbicide-sensitive cornflower biotypes is significantly dependent on weather and soil conditions. It is therefore reasonable to study this phenomenon in more detail. It would also be interesting to learn more about the underground competition on varying soil types under different water availability.

W doświadczeniu polowym, przeprowadzonym w latach 2003–2007 w Mochełku koło Bydgoszczy, na glebie kompleksu żytniego dobrego, oceniano wpływ nawożenia (147 kg NPK·ha-1, 221 NPK·ha-1), ochrony roślin (bez ochrony roślin, herbicyd, herbicyd + fungicyd) i gęstości siewu (400 ziaren·m-2, 600 ziaren·m-2) na zachwaszczenie pszenicy ozimej odmiany Tonacja uprawianej w krótkotrwałej monokulturze. W badaniach wykazano znaczny wzrost liczby i masy chwastów w pszenicy uprawianej po sobie bez stosowania herbicydów. Zastosowanie herbicydu Huzar 05 WG (jodosulfuron metylosodowy + mefenpyr dietylu) ograniczało zachwaszczenie. Zwiększenie gęstości siewu pszenicy z 400 do 600 ziaren·m-2 spowodowało niewielkie zmniejszenie liczby i masy chwastów. W doświadczeniu nie stwierdzono istotnych zmian zachwaszczenia w zależności od poziomu nawożenia mineralnego