Water absorbing geocomposite: a novel method improving water and fertilizer efficiency in Brunnera macrophylla cultivation. Part II. Properties of the medium and macroelement uptake efficiency

The aim of the study was to determine the effect of the geocomposite (GC) on macronutrient uptake of container-grown Brunnera macrophylla and substrate properties. The GC consists of superabsorbent polymer (SAP), internal skeleton and non-woven geotextile. It was designed to retain water in the soil in a form available for plants, by roots overgrowing the geotextile to access water. The GC was soaked in a multi-compound fertilizer (Insol® U) and compared with soluble fertilizer (SF) and controlled-release fertilizer (CRF). The fertilizer rates were calculated to cover the equal N supply: 0.36 and 0.72 g N plant−1. Nitrogen uptake of Brunnera cultivated with the geocomposite was approximately twice and three times as high as that of plants fertilized with SF and CRF, respectively. Exceptionally high N content was observed in plants cultivated with the GC-0.72 g N plant−1. The use of the GC also enhanced the accumulation of K and P, while CRF strongly reduced their content in plants. Distinct relations could be observed in the case of Ca accumulation. GC-0.72 g N plant−1 increased EC and water content in the medium without direct contact between SAP and substrate.