Spectral Analysis of Radiation in Row Tunnels with Different Covering Materials
Other Title
不同被覆材質隧道式簡易栽培設施之光譜分析
Journal
中華農學會報
Journal Issue
新183
Pages
24-35
Date Issued
1998-09
Author(s)
Chwen-Ming Yang
Muh-Rong Su
楊純明
蘇慕容
Abstract
Row covers/tunnels are widely used for planting vegetables and fruits in Taiwan currently. The purposes are for temperature, radiation, and humidity modifications as well as protection against frost, insect, birds, and animals. The spectrum and irradiance in row tunnels depend mainly on spectral properties of covering materials. Three types of covers, namely, nonwoven fabric (NWF), ordinary transparent polyethylene (PE) and UV-filtered polyethylene (UV-cut), were tested for spectral analysis, in both the laboratory and the field. As results indicated, these three covers barely absorbed light, and in average more than 85% has passed through and less than 13% was reflected. NWF has the highest reflectivity and UV-cut has filtered out mostly wavelengths below 415 nm. Wavelength regions in ultraviolet, visible and near infrared can evenly transmit through or reflect from NWF and PE, respectively. Spectral property of UV-cut plastic was similar to ordinary PE film, except it absorbs more than 70% of ultraviolet. Row tunnels for field experiment were built at Tunsan, Tainan County. It showed that radiant energy transmitted through covering materials was reduced, either reflected or absorbed by covers, and was consistent with the respective spectral properties. It was 84, 78, and 75% of solar radiation received in tunnels of PE, NWF, and UV-cut coverings at the first day of measurements. Transmittance was further decreased to 75,67, and 60% at the end of measurements, may due primarily to the loading of dust particles on the covers and aging of the covers. The spectral irradiances measured in tunnels were similar, with lesser extent, to the pattern of sunlight. Using solar radiation curve as the common denominator, the fluctuation of the 3-D curves of transmittance indicated a variation of weather in the measuring days and a drop in ultraviolet portion of UV-cut plastic. In this way spectral transmittance in the tunnels can be compared to natural light and among covers.
以隧道式簡易設施栽培高經濟價值作物（如蔬菜、水果）近年來非常的盛行，其 目的兼具環境因子（如溫度、濕度、光照）的調整及寒霜害、蟲害、鳥害、及動物取食等的 保護。設施內的光譜及輻射量端視被覆材質種類而異，將影響設施內作物的生長與產量。本 文研究旨在分析與追蹤被覆材質的光學特性及設置田間之隧道式簡易設施光譜（質）隨時間 演進的實際變化，試驗選用非織性多元脂類之不織布(NWF)、一般透明聚乙烯塑膠布(PE)、 及具有濾除紫外線效果之透明聚乙烯塑膠布(UV-cut)等三種不同材質參試。根據試驗結果， 此三種被覆材質對光照平均吸收率(7%以下)，平均穿透率高於85%，平均反射率小於13%。 不織布之反射率最高，濾除紫外線之UV-cut可顯著減少415 nm波長以下光照。對不織布 及一般透明塑膠布而言，無論係紫外光、可見光、或近紅外光波段均可均勻穿透或反射，其 穿透率分別為0.86-0.87及0.89-0.90，反射率分別為0.12-0.14及0.08-0.11。UV-cut光學特性 類似一般PE，惟吸收紫外線波段達70%。田間試驗設於臺南縣東山鄉大庄村，隧道式簡易 設施內測得之光輻射低於日照光輻射，而其反射、穿透、及吸收表現如被覆材質之光特性。 試驗首日PE、NWF、及UV-cut材質被覆之設施內穿透率分別為84、78、及75%，試驗終 止日則分別為75、67、及60%，可能因吸附於被覆材質外表的空氣浮塵粒子經長期堆積及 材質老化而影響光輻射的空透。設施內測得之光譜類似於日照光譜，然輻射量較低；由3-D 立體穿透率光譜，可以清楚地呈現天氣變異對光譜的影響及紫外線在UV-cut材質的大幅吸 收，而作為被覆材質間之比較參考。
Subjects
Spectral analysis
radiation
Row cover
Tunnel
covering material
光譜分析
光輻射
條狀覆蓋
隧道式栽培設施
被覆材質
Publisher
中華農學會
Type
journal article