動態浮根式水耕系統之開發與利用

《臺中區農業改良場特刊》 27號 (1991/09) Pp. 1-275

摘要

臺灣位於北半球亞熱帶之海島，北迴歸線橫越本省南部之嘉義地區；而中央山脈縱跨南北，將臺灣分割成東西兩區域，並造成全島有三分之二為丘陵及高山。由於海島氣候之影響，本省之氣溫變化極大，一月時最低平均氣溫為攝氏9.4度，七月時最高平均氣溫為攝氏34.2度；而一月時最大降雨量為25.6毫米，六月時為362.1毫米。不幸地，每年長夏時一旦颱風，豪雨及水災來襲時均嚴重地摧毀各種農業設施及農作物。因之，颱風、豪雨、水災及高氣溫乃被歸納為造成本省夏季蔬菜產銷不平穩及菜金菜土之四大主因。近年來由於國民經濟水準激增，消費者對於無農藥殘毒之高品質蔬果的需求日益迫切，然則本省夏季之高溫多濕病蟲害頻繁的困擾卻也係過去三十年來菜農過量使用農藥之癥結。為了徹底解決此困擾，筆者所服務之臺中區農業改良場在行政院農業委員會、臺灣省政府農林廳之計畫經費補助下，于民國73年9日開始從事利用水耕栽培技術來生產夏季蔬菜之研究。試驗初期中發現若沿用日本慣用之隧道型塑膠布溫室，盛夏時溫室內氣溫太高，蔬菜生長緩慢；一旦颱風來襲時則不但溫室受損，且溫室作物無一倖存，如此將導致經營者血本無歸。再者，盛夏時養液溫度會隨氣溫昇高而昇高，導致一般溫帶地區慣用水耕設施之溶氧低下，進而影響水耕蔬菜之低產。經筆者數年之努力終於成功地開發一套訂名為「動態浮根式水耕系統」，並于民國七十九年四月獲經濟部中央標準局二項十年之專利權。進一步地經農家證實不但可在盛夏栽培各種葉菜類蔬菜，且在其他季節亦有相同增產效果。本水耕系統，係由氣根式栽培床，空氣混入器，水位昇降排液器，交換槽及矮架組合式塑膠布網溫室所組成。藉由諸設計使水位由原先之8公分可降至4公分，致使充足地氧氣自由流通於水位與承板之4公分空氣層中。如此不但可誘引較多之氣根，並因之不再懼怕夏季高溫而獲致週年性一致性之豐產特性。茲將7年來之試驗研究成果及其推廣利用之潛力摘錄如下：（一）動態浮根式水耕系統之評估 1.本水耕系統之栽培床採保利龍成型之平底式，最具保溫隔熱效果。在夏季氣溫為27.1℃~35.2℃時，液溫可維持在21.2℃~27.2℃。栽培床內加舖之黑色PE布除具防漏效果外，可比其他顏色較能防止著生藻類。

並列摘要

Taiwan is an island located in the subtropical regions, with the Tropic of Cancer running across the center of the island. The Central Mountain Range, running from north to south, divides the island into the eastern and western regions, and two-thirds of the island is thus sloping or hilly land. There are marked seasonal changes in temperature, with an average minimum of 9.4℃ In January and a maximum of 34.2℃ in July. The minimum precipitation is 25.6 mm (January) and the maximum 362.1 mm (June). Typhoons and heavy rainfall followed by flooding often affect Taiwan, destroying protected agricultural facilities. Thus, typhoon, heavy rainfall and high temperature are major constraints to growing vegetables during the summer. In consequence, the supply of vegetables during this season is unpredicable, and market prices are high in summer and fluctuate throughout the year. Furthermore, with growing prosperity in Taiwan, consumers are demanding hygienic, high quality vegetables free of pesticides, while growers faced with frequent pest outbreaks in the hot, humid climate, have been tending to use too much pesticide for the past thirty years. In order to solve these problems, the Taichung District Agricultural Improvement Station (DAIS) initiated a research program in 1984 on hydroponic vegetable cultivation, to develop techniques for promoting and stabilizing the production of summer vegetables. However, the weather is too hot to grow vegetables in conventional tunnel type plastic film house. In addition, the frequent destruction of greenhouse frameworks and crops by typhoons and storms meant that farmers could not rely on getting any return for their investment. In a series of experiments on hydroponic techniques carried out at the Taichung DAIS, the results showed that the high temperatures inside the greenhouse, together with the low level of dissolved oxygen in the nutrient solution,