Extreme precipitation enhances phenolic concentrations of spinach (Spinacia oleracea)

Understanding environmental impacts on crop growth and quality is essential in developing sustainable agricultural practices with climate change. Shifts are expected in precipitation, an essential component of agriculture, including increased intensity of rainfall. We examined the effect of extreme precipitation intensity on spinach (Spinacia oleraceaL.) growth and quality through a manipulative greenhouse study. Water treatments produced by a rainfall simulator modeled precipitation intensity of predicted storms in a spinach-growing area in northeastern USA and were compared to a flooding only treatment. Crop growth and quality were measured using biomass and total phenolic concentration (TPC), a general indicator of quality, which impacts the appearance, flavor, and health attributes of crops. Leaves from plants receiving high-intensity precipitation had smaller biomass than leaves from a flooding treatment. Root biomass exhibited a negative relationship with TPC. Excess water increased TPC of leaves in all treatments. Higher TPC only occurred in roots of the low-intensity precipitation treatment. Findings highlight that water treatments and extreme precipitation may enhance crop quality of spinach leaves in the context of climate change, though too much water could have negative impacts on yield and require climate-adaptation strategies.