Articles
Effects of greenhouse covering films on yields of lettuces and herbs grown in organic pipe hydroponics under sub-tropical climate zone
Article number
1356_30
Pages
255 – 262
Language
English
Abstract
The organic hydroponics developed by Makoto Shinohara use organic fertilizers in hydroponics.
By using non-synthetic inputs, this soilless cultivation can be safer and more sustainable than conventional hydroponics.
However, it is challenging.
In an organic hydroponic system, phytotoxicity would occur if the microbial mineralization is incomplete.
Soilless growing crops are subject to environmental changes without soil acting as a buffer for plant growth.
Temperature is especially crucial to both lettuce metabolism and microbial mineralization in organic hydroponics.
It affects the degree of dissolved oxygen (DO) in the nutrient solution.
To protect hydroponic systems from environmental changes and pests, it is cost-effective in a hot and humid climate region to have a small protected facility with plastic rainproof films covering its top and insect screen nets surrounding all its sides.
However, high ultraviolet (UV) solar radiation in a subtropical zone may cause excessive heat build-up under the greenhouse films.
It results in high-temperature stress limiting the growth of cool-season crops.
Therefore, this study examined yields of lettuce and herbs under customized plant protection tents with three different top cover materials, namely PE (polyethylene) white film, PEP® clear film, and ETFE (ethylene tetrafluoroethylene) clear film.
Field experiments were conducted with closed recirculating PE pipes during the spring and summer of 2019 in Chiayi County, Taiwan.
Although no significant differences were found among the three tent materials, results from previous studies suggesting that reducing incoming UV radiation had an appreciable effect on yields of hydroponic lettuce may apply to organic hydroponics for urban amateur growers to sustainably supplement fresh vegetable needs in subtropical summer.
By using non-synthetic inputs, this soilless cultivation can be safer and more sustainable than conventional hydroponics.
However, it is challenging.
In an organic hydroponic system, phytotoxicity would occur if the microbial mineralization is incomplete.
Soilless growing crops are subject to environmental changes without soil acting as a buffer for plant growth.
Temperature is especially crucial to both lettuce metabolism and microbial mineralization in organic hydroponics.
It affects the degree of dissolved oxygen (DO) in the nutrient solution.
To protect hydroponic systems from environmental changes and pests, it is cost-effective in a hot and humid climate region to have a small protected facility with plastic rainproof films covering its top and insect screen nets surrounding all its sides.
However, high ultraviolet (UV) solar radiation in a subtropical zone may cause excessive heat build-up under the greenhouse films.
It results in high-temperature stress limiting the growth of cool-season crops.
Therefore, this study examined yields of lettuce and herbs under customized plant protection tents with three different top cover materials, namely PE (polyethylene) white film, PEP® clear film, and ETFE (ethylene tetrafluoroethylene) clear film.
Field experiments were conducted with closed recirculating PE pipes during the spring and summer of 2019 in Chiayi County, Taiwan.
Although no significant differences were found among the three tent materials, results from previous studies suggesting that reducing incoming UV radiation had an appreciable effect on yields of hydroponic lettuce may apply to organic hydroponics for urban amateur growers to sustainably supplement fresh vegetable needs in subtropical summer.
Authors
Ting-I Lee, Yi Hsuan Hsieh, Yao-Yang Hsieh, Hao-Yi Chang
Keywords
bio-hydroponics, hydroponic growing tube, protected facilities, microbial mineralization, vegetable productivity
Groups involved
- Division Landscape and Urban Horticulture
- Division Horticulture for Human Health
- Division Greenhouse and Indoor Production Horticulture
- Division Horticulture for Development
- Division Precision Horticulture and Engineering
- Division Vegetables, Roots and Tubers
- Commission Agroecology and Organic Farming Systems
- Working Group Urban Horticulture
- Working Group Landscape Horticulture
Online Articles (56)