Paspalum vaginatum NDVI When Grown on Shallow Green Roof Systems and Under Moisture Deficit Conditions

Management of conventional crops must adapt to the particularities of urban greening techniques, such as green roofing. The aim of the study was to determine seashore paspalum (Paspalum vaginatum Swartz ‘Platinum TE’) response when grown in shallow green roof substrates and under moisture deficit conditions during two summer periods. Treatments included: (i) six different green roof substrates formulated from locally available materials by mixing combinations of sandy loam soil, pumice, perlite, clinoptilolite zeolite, peat, and compost; (ii) two substrate depths (7.5 or 15 cm); and (iii) two irrigation regimes (60 or 100% crop evapotranspiration). Measurements included the determination of substrate moisture content (SMC) and turfgrass normalized difference vegetation index (NDVI). It was found that, during moisture deficit periods, NDVI was mostly affected by irrigation regime and substrate depth but not by substrate type. Turfgrass retained higher NDVI values for longer time intervals when the high irrigation regime of 100% crop evapotranspiration was combined with the deeper substrates of 15 cm. Regression between SMC and NDVI revealed that SMC should be retained from 23.7 to 28.5% (v/v) to keep seashore paspalum within acceptable NDVI values when grown under shallow green roof conditions.