Articles
Effect of cultivation system and water source on yield and photosynthetic performance of summer spinach (Spinacia oleracea) grown under netted rooftops for urban food production
Article number
1437_49
Pages
379 – 384
Language
English
Abstract
The use of green roofs as urban food production sites is receiving increased attention due to the economic, environmental and social benefits.
However, lightweight solutions are required to implement this concept on existing rooftops of old buildings.
The present study evaluated a combination of 3 green roof cultivation systems (a hydroponic system using perlite grow bags (H), an aeroponic system (A), and a green roof with 12 cm substrate (S) which served as the control and 2 fertigation schemes (modified Hoagland nutrient solution diluted either with potable water (F) or graywater (G)). The treatments were implemented in 16 outdoor weighing lysimeters (2×1 m) planted with summer spinach (Spinacia oleracea). Additionally, two empty lysimeters were used to simulate a conventional unplanted rooftop.
To protect plants from bird attacks, lysimeters were covered with netting for the entire growing period.
Plant growth and health during the cultivation were assessed using growth index (GI), relative chlorophyll concentration (SPAD), relative chlorophyll fluorescence (Fv/Fm), leaf stomatal conductance (SC) and system weight fluctuation.
Results show that treatment S (33.7 cm for T and 38.1 cm for G) had a higher GI compared to H and A (23.7 and 20.6 cm, respectively). Also, the highest SPAD values were obtained in treatment H (64.8), followed by A and S (59.5 and 48.5, respectively). Leaf SC was higher in SG (420 mmol m‑2 s‑1), while AG treatment demonstrated the lowest value (162 mmol m‑2 s‑1). Relative chlorophyll fluorescence did not indicate significant differences across treatments.
Aeroponic was the lightest urban food production system (7.7 kg m‑2), H had 46.2 kg m‑2, while S was the heaviest system (129.7 kg m‑2).
However, lightweight solutions are required to implement this concept on existing rooftops of old buildings.
The present study evaluated a combination of 3 green roof cultivation systems (a hydroponic system using perlite grow bags (H), an aeroponic system (A), and a green roof with 12 cm substrate (S) which served as the control and 2 fertigation schemes (modified Hoagland nutrient solution diluted either with potable water (F) or graywater (G)). The treatments were implemented in 16 outdoor weighing lysimeters (2×1 m) planted with summer spinach (Spinacia oleracea). Additionally, two empty lysimeters were used to simulate a conventional unplanted rooftop.
To protect plants from bird attacks, lysimeters were covered with netting for the entire growing period.
Plant growth and health during the cultivation were assessed using growth index (GI), relative chlorophyll concentration (SPAD), relative chlorophyll fluorescence (Fv/Fm), leaf stomatal conductance (SC) and system weight fluctuation.
Results show that treatment S (33.7 cm for T and 38.1 cm for G) had a higher GI compared to H and A (23.7 and 20.6 cm, respectively). Also, the highest SPAD values were obtained in treatment H (64.8), followed by A and S (59.5 and 48.5, respectively). Leaf SC was higher in SG (420 mmol m‑2 s‑1), while AG treatment demonstrated the lowest value (162 mmol m‑2 s‑1). Relative chlorophyll fluorescence did not indicate significant differences across treatments.
Aeroponic was the lightest urban food production system (7.7 kg m‑2), H had 46.2 kg m‑2, while S was the heaviest system (129.7 kg m‑2).
Publication
Authors
P.A. Nektarios, I. Mpaira, K. Gaitanaki, D. Harkoutsis, K. Ferro, I.N. Daliakopoulos, D. Paradimitriou, T. Manios
Keywords
green roofs, urban greening, grey water, nutrient solution, lysimeters, load cells
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