Changes of carbon amount, soil microbial activities and nitrogen amount in rooftop lawns over the years.

Abstract

We examined changes of carbon amount, soil microbial activities and nitrogen amount in several rooftop lawns of different age. Consequently, we suggested that rooftop lawns serve as carbon sinks because plant dry weight in rooftop lawns increased with age and thatch seemed to be accumulated in organic layer although respiration rate significantly increased after completion. Regarding nitrogen leaching, it was suggested that reduction in nitrification rates after completion results in low leaching losses. In addition, amount of microbial biomass carbon in rooftop lawns significantly increased after completion. Thus, it is suggested that microbial biomass in a roof top lawn increases after construction. Therefore, we hope that the findings of this study will serve for increase of CO₂ sequestration and reduction in nitrogen leaching loads in rooftop lawns.