Search Results (3)

Considering that urban horticulture benefits from green roof technology, the effects of substrate type (compost-perlite-pumice 3:3:4, v/v and compost-perlite-pumice-soil 3:3:2:2, v/v) and depth (7.5 cm and 15 cm) were comparatively evaluated in the cultivation of Crithmum maritimum and Origanum dictamnus on an urban green roof in modules that included a green roof infrastructure layering. During the first cultivation period (December 2015–August 2016), plants of C. maritimum were taller and had greater diameter than those of O. dictamnus. Greater fresh and dry weights of all plant parts were observed in C. maritimum, as well as in the deep substrates compared to the shallow ones. During the second cultivation period (September 2016–August 2017), the growth of O. dictamnus surpassed that of C. maritimum, while plant height and foliage diameter, as well as the fresh and dry weight of all plant parts were greater in the deep substrates for both species. Conclusively, both species grew satisfactorily on an extensive urban Mediterranean green roof, while the deep substrate favored all their growth parameters. O. dictamnus responded better in the soil-containing substrate regarding survival, growth, and flowering, as opposed to C. maritimum that showed equal response in both substrate types. Full article

Plants in riparian areas are well known for their beneficial functions such as providing biodiverse habitats, maintaining water quality, and stabilizing streambanks. However, riparian plants are declining in semi-arid environments due to long-term drought, a decline in groundwater table, and an increase in soil salinity. A new technique using clinoptilolite zeolite (CZ) as a wicking material with minimum artificial irrigation to grow desert willow [Chilopsis linearis (Cav.) Sweet] under field conditions is introduced; desert willow is native to riparian regions of the southwestern United States. For this study’s experiment, desert willow seedlings were planted in boreholes filled with clinoptilolite zeolite (CZ) as a substrate and in situ riparian sandy loam soil (RS) as a control. The boreholes extended to the groundwater table at two distinctive depths, shallow (avg. depth = 1.21 m) and deep (avg. depth = 2.14 m). The plants’ viability was then assessed by measuring their midday water potential (Ψ_md) as an indicator of water stress. There was no significant difference in Ψ_md (p > 0.05) between the plants grown in CZ and RS (mean Ψ_md = −0.91 vs. −0.81 MPa) where the groundwater was shallow and a significant difference (mean Ψ_md = −0.75 vs. −2.03 MPa) where the groundwater was deep. The proposed method is promising as an alternative method for growing desert willow or other plants for riparian rehabilitation with no artificial irrigation. However, its effectiveness depends on groundwater being accessible at the base of the boreholes used for planting. Full article

Satellite remote sensing may assist in meeting the needs of lake monitoring. In this study, we aim to evaluate the potential of Sentinel-2 to assess and monitor water constituents and bottom characteristics of lakes at spatio-temporal synoptic scales. In a field campaign at Lake Starnberg, Germany, we collected validation data concurrently to a Sentinel-2A (S2-A) overpass. We compared the results of three different atmospheric corrections, i.e., Sen2Cor, ACOLITE and MIP, with in situ reflectance measurements, whereof MIP performed best (r = 0.987, RMSE = 0.002 sr⁻¹). Using the bio-optical modelling tool WASI-2D, we retrieved absorption by coloured dissolved organic matter (a_CDOM(440)), backscattering and concentration of suspended particulate matter (SPM) in optically deep water; water depths, bottom substrates and a_CDOM(440) were modelled in optically shallow water. In deep water, SPM and a_CDOM(440) showed reasonable spatial patterns. Comparisons with in situ data (mean: 0.43 m⁻¹) showed an underestimation of S2-A derived a_CDOM(440) (mean: 0.14 m⁻¹); S2-A backscattering of SPM was slightly higher than backscattering from in situ data (mean: 0.027 m⁻¹ vs. 0.019 m⁻¹). Chlorophyll-a concentrations (~1 mg·m⁻³) of the lake were too low for a retrieval. In shallow water, retrieved water depths exhibited a high correlation with echo sounding data (r = 0.95, residual standard deviation = 0.12 m) up to 2.5 m (Secchi disk depth: 4.2 m), though water depths were slightly underestimated (RMSE = 0.56 m). In deeper water, Sentinel-2A bands were incapable of allowing a WASI-2D based separation of macrophytes and sediment which led to erroneous water depths. Overall, the results encourage further research on lakes with varying optical properties and trophic states with Sentinel-2A. Full article