The aim of the study was to assess the root system distribution of two Catalpa species - Catalpa bignonioides and Catalpa ovata - grown in row plantings on light soil under subsurface drip irrigation. The soil profile method by Oskamp was used to analyse the vertical and horizontal root system structure, including root diameter classes. The experiment was conducted in a split-plot design with two irrigation treatments (W1 - irrigation at -40 kPa soil water tension; W2 - at -20 kPa) and compared with a non-irrigated control (W0). For both species, most roots were located within the 0-30 cm soil layer; however, C. ovata developed a deeper root system, reaching 60 cm under intensive irrigation (W2). Irrigation increased the number of fine roots (<1 mm), which dominated the root structure and accounted for more than 60% of all roots. Both species showed a clear response to the applied irrigation variants, with a stronger effect observed in C. ovata. The results confirm that subsurface drip irrigation promotes root development in the surface layer and increases the total number of roots, which may support tree survival and stability in light soils and water-deficient conditions. ...
The aim of this study was to estimate the water demand for purple coneflower (Echinacea purpurea L.) on a green roof in Bydgoszcz urban aglomeration, depending on projected climate change. A scenario of climate changes for Poland SRES: A1B was taken into account. Water needs of purple coneflower were determined by the method of plant coefficients. Based on adopted assumptions and performed calculations, it was found that in the forecast period (2021-2050) there will be greater variability in the water needs of the Purple coneflower. In the forecast period, a clear tendency towards increasing water needs of the purple coneflower is expected ( every 8.9 mm in a decade). Total rainfall deficiencies for the entire growing season of the purple coneflower (11. May - 10. July) - in an average, moderately dry and very dry year - are expected to decrease to a minor extent, from 205,9 mm, 259,4 mm and 301,9 mm in the comparative period to 198,6 mm, 254,6 mm and 298,5 mm in the forecast period, respectively (which results from more rainfall in June and July in the scenario of climate changes, which was used.) ...
Water is a crucial natural resource, influencing plant productivity and sustaining ecosystems. Black locust, known for its drought resistance and adaptability to unfavorable conditions, is frequently used in the recovery of degraded regions. During juvenile phase, black locust requires sufficient soil moisture for proper growth. The objective of the research was to assess the water needs of black locust in the second stage of growth on reclamation plantations, specifically starting three years after planting. Water requirements were evaluated for five regions in Poland between 1 June and 31 August in 1981-2010. Water requirements, quantified as crop evapotranspiration, were determined by multiplying the plant coefficient by the reference evapotranspiration. The Blaney-Criddle equation, with the plant coefficient adapted using the Żakowicz method, was applied to estimate reference evapotranspiration. It was found that the average water requirements from June to August were 370 mm. Rainfall deficits were observed in all regions, with the highest shortfalls in central Poland. Additionally, all regions demonstrated an upward trend in water requirements for this species. The results provide valuable insights for planning and implementing irrigation strategies for black locust cultivated in reclamation plantations in Poland, supporting the sustainable management of water resources in the region. ...
