ISSN: 1659-2751



Evaluation of Substrates for Roof Gardening in Humid Tropic Conditions


An evaluation was conducted with local substrates to determine their production potential under humid tropical conditions in roof gardening system. Eight treatments were prepared with different percentages of coconut fiber, rice husks and vegetable charcoal, with two levels of organic matter, 25 % and 50 %. Physicochemical variables and yield of fresh and dry weight of pak choy (Brassica chinensis) were analyzed during two production cycles. A randomized complete block design with three replications of each treatment was implemented. Pak choy was shown to be adaptable to the system and the highest yield was with the treatment of 50 % organic matter, 25 % vegetable charcoal, 12.5 % rice husks, and 12.5 % coconut fiber). The lowest yield was observed with the treatment of 25 % organic matter, 18.7 % vegetable charcoal, 37.5 % rice husks, and 18.7 % coconut fiber). Among the physical variables, cation exchange capacity and humidity retention were the determining factors in the development of the crop roots and leaves, and the relationship with substrates that increase those properties was identified. A high content of organic matter is not recommended due to microbial activity, degradation, and potential saturation of pore space creating unfavorable conditions.

Key words: roof gardening, vegetable charcoal, coconut fiber, rice husks, organic matter, pak choy.

Artículo en español (pdf) (674)