The study was conducted to evaluate the influence of silicon application on the botanical composition of grass–legume mixtures as well as the nutritional value of individual species and mixtures. The two-factor field experiment was established in a split-block arrangement. The two grass–legume mixtures, consisting of Dactylis glomerata, Festulolium braunii and Trifolium pratense or Medicago x varia and grass mixture—Dactylis glomerata, Festulolium braunii and Lolium perenne, were sown on arable land. Silicon foliar and mineral NPK fertilization was applied in three variants: NPK (non-Si-fertilized), NPK+Si (Herbagreen), NPK+Si (Optysil). Changes in the botanical composition in the sward of mixtures during the study period were influenced by the competitiveness of individual plants and weather conditions, whereas the effect of foliar fertilization with silicon was only slightly marked. The nutritional value of individual species of grasses and legumes varied over the years and also depended on the application of silicon. The greatest content of crude protein (CP), irrespective of the species and variant of silicon fertilization, was noticed in years with no drought. Our research confirmed the beneficial effect of silicon fertilization, independent of weather conditions, on the CP content and on the reduction of crude fibre (CF), neutral detergent fibre (NDF) and acid detergent fibre (ADF) in plants, especially when Herbagreen was applied. The nutritional value of the mixtures under applied silicon fertilization depended on botanical composition. In the conditions of low rainfall, a large share of F. braunii and an approximately 20% contribution of T. pratense resulted in a higher content of CP. These results may be used in the fertilization practices of temporary grassland for enhancing nutritional value, especially crude protein content, and on the reduction of fibre in the sward.

The current conservation status of semi-natural grassland habitats in Poland indicates that actions for their restoration are necessary. Many of the degraded sites require the introduction of diaspores of representative species because other methods of improving their condition are not sufficiently effective. Meanwhile, little is known about the diaspores of native wild-flower species and the biology of their seeds. The aim of the present study was to find an answer to the question of which features of the seed material can guarantee the success of the introduction. The study covered 28 plant species of 4 non-forest natural habitats (codes: 6440, 6410, 6510, 6210) occurring in river valleys. Diaspores were collected in 2015–2017. Morphometric measurements of diaspores were performed, the weight of 1000 diaspores was determined and the germination capacity analysis was carried out in accordance with ISTA Rules. The analysis was made with the division into normal seedlings, abnormal seedlings, dead seeds and fresh ungerminated seeds. Species with similar parameters of seed material were selected using the method of hierarchical clustering and PCA analysis. Three groups of species were distinguished: (1) with good seed germination capacity (above 65%), which, regardless of weather conditions during the generative development, and despite the small size of diaspores, can guarantee successful introductions (Verbascum thapsus, Veronica longifolia, Daucus carota, Plantago lanceolata); (2) species of little suitability for introduction, due to the large proportion (over 50%) of dead seeds (Armeria maritima, Linaria vulgaris, Potentilla erecta, Centaurea stoebe, Sanguisorba officinalis, Cnidium dubium); (3) species with relatively large size of diaspores and low seed germination capacity, due to the high proportion of fresh ungerminated seeds which means dormant seeds (Lathyrus pratensis, Geranium pratense).

The flora of willow (Salix viminalis L.) plantations consists of various plant groups, including plants related to arable land, called segetal plants. Knowledge of this flora is important for maintaining biodiversity in agroecosystems. The aim of the study was to assess the segetal flora of the willow plantations in central Poland, depending on the land use before the establishment of the plantations (arable land or fallow) and the age of the plantations. Moreover, the aim was also to check for the presence of invasive, medicinal, poisonous and melliferous species. The vegetation accompanying willow was identified based on an analysis of 60 phytosociological relevés performed using the Braun-Blanquet method. For each species, the following parameters were determined: the phytosociological class; family; geographical and historical group; apophyte origin; biological stability; life-form; and status as an invasive, medicinal (herbs), poisonous or melliferous species. The results were statistically processed. Segetal species accounted for 38% of the flora accompanying willow. The plantations on former arable land were richer in segetal species than those on fallow. Mostly, short-lived and native species dominated. In line with the age of the plantations, the number of segetal species decreased. The share of apophytes increased, and anthropophytes decreased. Furthermore, many valuable plants were found among the flora accompanying willow.

The reintroduction and introduction of native plant species is becoming more and more important in the restoration of plant communities. The study aimed to determine the possibility of predicting the effectiveness of the introduction of dicotyledonous species into impoverished patches of meadows in the landscape nature reserve in the proglacial valley of the Vistula River (Poland). Fourteen species planted into the soil from seedlings, after growing them from seeds in pots, in pure stands were assessed. Field studies were carried out in 2015–2017 on post-bog soil. Parameters of plant development and growth that were analysed included, among others, range, condition and height of shoots (vegetative and generative). Based on the biometric parameters, a statistical analysis (PCA, analysis of variance, decision tree) was performed. It was found that the range, i.e., the spread of the population, did not determine the classification of species into groups with a different nature of development after introduction. This classification was mainly determined by the plant condition in the following years after the introduction (over 3.4 on a 5-point scale), and the occurrence of generative shoots in the second year after planting. The group with the highest potential efficiency of introduction included three species: Achillea millefolium, Hypericum perforatum, Veronica longifolia. The failure of the introduction of other species resulted from their life form (two years old) and unfavourable weather conditions in the third year of study (2017), due to the high level of groundwater.

In recent years, there has been increasing interest in the floristic diversity of agroecosystems, particularly for plant conservation. While old plantations claim to be more floristically diverse, little is known about this for Salix viminalis L. plantations. The aim of study was to analyse the vegetation accompanying S. viminalis and its dynamics as plantations age. The vegetation was identified in 20 plantations, based on 244 phytosociological relevés. For each species, the following were defined: botanical family, geographical and historical groups, origin of apophytes, biological stability, life-form, botanical class and phytosociological class. The relative coverage of major plant groups was statistically processed using the analysis of variance with a linear mixed model. The flora of S. viminalis plantations is rich and diverse; in central Poland, it consisted of 193 plant species. These species belonged to many phytosociological classes, of which two dominated: Molinio-Arrhenatheretea (46 species) and Artemisietea vulgaris (32 species). Perennial species, meadow, woodland, and shrub apophytes, as well as hemicryptophytes, were prevalent. As the plantations aged, the proportion of perennial species, meadow, woodland, and shrub apophytes increased, while therophytes and anthropophytes declined. Photophilous species dominated mainly in young crops (4–5 years old), but their coverage and frequency decreased over time. With plantations age, vascular flora diversity (total number of species) and coverage of ecologically important groups (Poaceae family, Molinio-Arrhenatheretea class) decreased. These were gradually replaced by mega- and nanophanerophytes and species from the A. vulgaris class. The stabilisation of flora occurred after eight years of willow cultivation.

Celem badań było określenie wpływu stopnia zasobności gleb w fosfor na różnorodność i dynamikę flory towarzyszącej uprawom wierzby energetycznej Salix viminalis L. w dwóch przedziałach czasowych. Badania przeprowadzono w latach 2013-2014 na plantacjach 5-7 letnich i w roku 2018 na plantacjach 10-11 letnich, w trzech miejscowościach województwa łódzkiego. Oceniono 6 plantacji założonych w latach 2006-2008 na dwóch grupach gleb: 1) o bardzo niskiej i niskiej zawartości fosforu oraz 2) o średniej i wysokiej zawartości fosforu. Przed założeniem plantacji grunty były odłogowane. W trakcie badań nie były nawożone. Wierzbę zbierano systematycznie co 2-3 lata. Roślinność towarzyszącą wierzbie oceniono na podstawie analizy 40 zdjęć fitosocjologicznych wykonanych metodą Brauna-Blanqueta. Wyniki opracowano statystycznie za pomocą analizy składowych głównych (PCA) oraz analizy skupień. W celu pogrupowania silnie powiązanych zmiennych zastosowano odległość euklidesową i metodę Warda. Flora upraw wierzby energetycznej założonych na glebach o różnej zawartości fosforu różniła się ogólną liczbą gatunków roślin naczyniowych. Na plantacjach 5-7 letnich rozwijających się na glebach o niższej zawartości fosforu stwierdzono występowanie 71 taksonów, natomiast na glebach o wyższej zawartości fosforu ich liczba wynosiła 56. W 10-11 letnich uprawach Salix viminalis L. liczba gatunków była mniejsza i wynosiła odpowiednio 35 i 42. We florze obu grup plantacji, niezależnie od okresu badań, dominowały gatunki wieloletnie, dwuliścienne (74%-83%), hemikryptofity, apofity leśno-zaroślowe i łąkowe. Najwięcej gatunków należało do klas: Artemisietea vulgaris, Molinio-Arrhenatheretea i Stellarietea mediae. Analiza dynamiki flory wykazała zmniejszanie się ogólnej liczby gatunków wraz z wiekiem plantacji. W obu grupach plantacji wzrastał udział gatunków wieloletnich, apofitów leśnych i zaroślowych. W uprawach rosnących na glebach o niższej zawartości fosforu w drugim okresie badań dominowały gatunki z klasy Artemisietea vulgaris, a na bogatszych w fosfor – gatunki z klasy Molinio-Arrhenatheretea, duży udział stanowiły także gatunki nie zaliczone do żadnej z klas fitosocjologicznych. W obu okresach badań niewielki udział miały rośliny bobowate, których występowanie i pokrycie było nieznacznie większe na plantacjach bogatszych w fosfor.