Epsilon Archive for Student Projects

Abstract

Urban Rooftop Agriculture (URTA) is a novel field within urban vegetable
production, which can help create access to local food in a rapidly urbanizing world.
For these systems to succeed, it is vital to implement a proper choice of
substrate/growing medium (SGM). This study uses a literary synthesis, to analyze
URTA SGM by investigating three of its key features, namely components, depth,
and organic matter (OM) type and amount, with the intention of facilitating
thoughts for future research and providing URTA-stakeholders with guidelines for
choice of SGM. Results indicate that leafy vegetables and tomatoes can be
cultivated in URTA-systems, potentially delivering yields comparable to
conventional in-ground farming, using a wide range of SGM-substances, depths,
and OM sources. It is not advisable to advocate for one specific SGM-substance.
Instead URTA-farmers should strive to integrate locally produced light-weight
material with numerous internal pores into their SGM. Shallow depths,
corresponding to those found in extensive green roof systems (<15 cm) suffice for
satisfactory URTA-yields. Continuous OM-/compost addition is a necessity for
URTA-systems and consequently the proportion of OM/compost exceeds
guidelines for more conventional green roof systems. More research is needed to
understand the behavior of specific compost components in relation to density and
URTA-crop production. An advanced knowledge of soil science is vital for
engineering an URTA SGM that is light-weight simultaneously providing for
sufficient cation exchange capacity (CEC), aeration, plant available water (PAW)
and permeability. Therefore professionals, such as landscape engineers play a
central role in URTA-SGM implementation.