Green Infrastructure's Impact: Urban Rainwater Garden Influences on Semi-Arid Soil Health

Abstract

Climatic and anthropogenic pressures, such as extreme weather and urban heat island, are felt now and will continue to worsen in the future. Such effects exacerbate urban environments that suffer considerably from environmental degradation as well as reduce ecosystem services. On a global scale, nature based solutions, like green infrastructure (GI) are argued to reduce these societal pressures in addition to restoring ecosystem functioning and resilience. While there are many benefits derived from green infrastructure, an intended element of the feature is enhanced soil health. Although a restorative function, the relationship between green infrastructure and soil health is understudied. Historically, the study of soils is an established discipline, yet soil assessments and indicators remain unclear, uninterpretable, and uncreative. We clarify these gaps by analyzing soil health correlations as well as the influence of seasonal precipitation regimes, GI treatments, and site on important and innovative indicators of physical, biological, and chemical soil health properties. At three locations, we sampled rain garden basins soils across semi-arid Tucson during the pre and post monsoon seasons. We hypothesized that variations in physical, biological and chemical indicators would be discernible across various seasonal regime inputs, treatment, and site. Results showed that biological and chemical indicators drove significant variation in overall soil health. Seasonal precipitation regimes significantly influenced biological indicators, while GI treatments only influenced change in carbon stabilization and decomposition, suggesting that rain gardens are regulators of soil nutrient cycling and respiration. Site effects strongly influenced differences in all three component soil health properties, highlighting the importance of site land management impacts. Though newly introduced indicators of soil health proved feasible, more research should be granted to better interpret their role and solidify their induction.