Stratified Soilless Substrates Decrease the Vertical Gravitational Water Gradient Altering Helianthus Root Morphology

Containerized soilless substrates are highly porous to ensure adequate air storage to overcome the “container” effect- the lower part of the container nears saturation which can decrease root health and growth. Substrate porosity is dynamic, evolving over time. As roots fill pores, substrate decomposition and in-situ particle movement change the physical structure, shifting its storage properties and performance. Research is sparse in understanding how developing roots change their morphology throughout production (temporally) and while growing throughout the three-dimensional substrate matrix (spatially). Thus, it would be beneficial to understand how root development impacts container moisture characteristics. This study aimed to quantify root morphological development and water storage (θ) spatiotemporally in conventional or engineered soilless substrate systems. Helianthus annus ‘Rio Carnival’ was grown in 30.5 cm tall PVC columns in a conventional (non-stratified; 100