Corn poppy (Papaver rhoeas L.) and cornflower (Centaurea cyanus L.) are two overwintering weed species found in crop fields in Europe. They are characterised by a similar life cycle, similar competitive efforts, and a spectrum of herbicides recommended for their control. This review summarises the biology and herbicide resistance phenomena of corn poppy and cornflower in Europe. Corn poppy is one of the most dangerous dicotyledonous weeds, having developed herbicide resistance to acetolactate synthase inhibitors and growth regulators, especially in Mediterranean countries and Great Britain. Target site resistance to acetolactate synthase inhibitors dominates among herbicide-resistant poppy biotypes. The importance of non-target site resistance to acetolactate synthase inhibitors in this species may be underestimated because non-target site resistance is very often associated with target site resistance. Cornflower, meanwhile, is increasingly rare in European agricultural landscapes, with acetolactate synthase inhibitors-resistant biotypes only listed in Poland. However, the mechanisms of cornflower herbicide resistance are not well recognised. Currently, herbicides mainly from acetolactate synthase and photosystem II inhibitors as well as from synthetic auxins groups are recommended for the control of both weeds. Integrated methods of management of both weeds, especially herbicide-resistant biotypes, continue to be underrepresented.

The aim of this study was to assess the effect of long-term catch crop application on the structural properties of humin, which is considered the most recalcitrant fraction of soil organic matter. Soil samples from a 30-year field experiment on triticale cultivated with and without catch crops were analysed to determine the total organic carbon content and fractional composition of humic substances. Meanwhile, humin isolated from bulk soil was analysed to determine its elemental composition and spectroscopic properties measured with UV-Vis, fluorescence, and ¹³C-CPMAS-NMR. It was found that catch crop farming enhanced the formation of highly reactive humus substances, like low-molecular-weight fractions and humic acids, while decreasing the humin fraction. The higher H/C and O/C atomic ratios of humin and the UV-Vis, fluorescence, and ¹³C-CPMAS-NMR results confirmed a higher share of oxygen-containing functional groups in humin isolated from the soil with catch crop rotation, also corroborating its greater aliphatic nature. Under the conditions of our field experiment, the results indicated that organic residues from catch crops quickly undergo the decay process and are transformed mainly into highly reactive humus substances, which can potentially improve soil health, while mineral fertilisation alone without catch crops favours the stabilisation and sequestration of carbon.

One of the most common annual overwintering weeds in various crops worldwide is silky bent grass (Aspera spica-venti (L.) Beauv). The aim of this study was to investigate the selected morphological characteristics and chemical composition of A. spica-venti from different cultivation fields in Poland, depending on the macronutrient content of the soil. The average pH values of the soil samples, and the average concentration of nitrogen (N) and phosphorus (P) in the samples were statistically different between study sites. In turn, the concentration of potassium (K) was at the same statistical level. The average values of N, P and K concentrations in the straw of A. spica-venti (% dry matter) in particular study sites were not statistically different. The mean values of the examined morphological features of A. spica-venti did not differ statistically between the individual test sites. Overall, there was no significant impact of the habitat on the chemical composition and morphology of the A. spica-venti occurring naturally in arable fields. However, an increase in soil abundance in some macronutrients (mainly K) may positively affect the morphology of this weed as opposed to an increase in nitrogen concentration in the soil, and an increase soil pH. The lack of significant influence of soil conditions and location of APESV sites on the morphology and chemical composition of the weed indicates that it has high plasticity and is able to thrive under varying habitat conditions.

The field research was conducted at the Agricultural Advisory Centre in Łosiów in 2011 and 2012. The aim of the study was to investigate the response of spring wheat on continuous cropping and to determine the impact of regeneration treatments (biostimulants, stubble crop) on weed infestation and the yield of wheat grown in monoculture. The use of biostimulants in monoculture proved to be ineffective in reducing weed infestation of spring wheat and stubble cropping caused a decrease only in dry matter of weeds. There was no unequivocal effect of the experimental factors on the yield of spring wheat. Badania przeprowadzono w latach 2011 i 2012 na terenie Opolskiego Ośrodka Doradztwa Rolniczego w Łosiowie. Celem doświadczeń było poznanie reakcji pszenicy jarej na uprawę w monokulturze oraz określenie wpływu zabiegów regeneracyjnych (biostymulatory, międzyplon ścierniskowy) na zachwaszczenie i wielkość plonu pszenicy uprawianej po sobie. Stosowanie biostymulatorów w monokulturze okazało się nieskuteczne w redukcji zachwaszczenia łanu pszenicy jarej, a przyorywanie międzyplonu ścierniskowego sprzyjało jedynie ograniczeniu powietrznie suchej masy chwastów. Nie stwierdzono jednoznacznego wpływu czynników doświadczenia na plonowanie roślin.

In 2019–2020, pot experiments were conducted to evaluate the dynamics of emergence of Apera spica-venti mainly from winter cereal crops of different agricultural crops, mainly winter wheat, winter rye, winter rape, and characterised by different ages (fresh and 1-, 2-, 3-, and 4-year-old diaspores). The research was conducted at the Research and Training Station Swojczyce at the University of Life Sciences in Wrocław. The number and dynamics of A. spica-venti emergence from diaspores in the year of harvest significantly depended on the harvest site. The emergence of A. spica-venti were significantly variable depending on the age of the diaspores and the harvest site. Plants from 3-year-old diaspores emerged most numerous. The emergence of seedlings from 2- and 4-year-old diaspores were similar.