The aim of this study was the effect of the subsurface drip irrigation with nitrogen fertilization chosen asparagus cultivars on the occurrence of asparagus beetles.The field experiment was carried out in two consecutive years (2009-2010) at Kruszyn Krajeński near Bydgoszcz. The experiment was conducted in a rando-mized block design of a two-factorial system with four replications. The first tested factor was irrigation in two following variants: non-irrigated plots (control) with hand sowing nitrogen fertilizer and subsurface drip irrigated plots with nitrogen fertigation. The second factor was associated with asparagus cultivars: 5 from USA: Apollo, Atlas, UC-157, Grande and Purple Passion, and 3 from Germany: Ramada, Rapsody and Ravel. The number of adults and larvae of both asparagus beetles was observed on every single plot area; three times during the vegetation period from July to August (beginning from the first decade of July and continuing every third week). The harvest plot area was 14,7 m2 (20 plants x 0,35m x 2,1m).The adults and larvae of twelve-spotted asparagus beetles were more nu-merous than common asparagus beetles on tested asparagus cultivars. The adults of twelve-spotted asparagus beetles prefered subsurface drip irrigation asparagus plants: Atlas, UC-157, Grande and Rapsody, than non-irrigated plants of these ...
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. ...
